4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device
*dev
)
46 struct spi_device
*spi
= to_spi_device(dev
);
48 /* spi masters may cleanup for released devices */
49 if (spi
->master
->cleanup
)
50 spi
->master
->cleanup(spi
);
52 spi_master_put(spi
->master
);
57 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
59 const struct spi_device
*spi
= to_spi_device(dev
);
62 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
- 1);
66 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
68 static DEVICE_ATTR_RO(modalias
);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = container_of(dev, \
88 struct spi_device, dev); \
89 return spi_statistics_##field##_show(&spi->statistics, buf); \
91 static struct device_attribute dev_attr_spi_device_##field = { \
92 .attr = { .name = file, .mode = S_IRUGO }, \
93 .show = spi_device_##field##_show, \
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
100 unsigned long flags; \
102 spin_lock_irqsave(&stat->lock, flags); \
103 len = sprintf(buf, format_string, stat->field); \
104 spin_unlock_irqrestore(&stat->lock, flags); \
107 SPI_STATISTICS_ATTRS(name, file)
109 #define SPI_STATISTICS_SHOW(field, format_string) \
110 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
111 field, format_string)
113 SPI_STATISTICS_SHOW(messages
, "%lu");
114 SPI_STATISTICS_SHOW(transfers
, "%lu");
115 SPI_STATISTICS_SHOW(errors
, "%lu");
116 SPI_STATISTICS_SHOW(timedout
, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync
, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate
, "%lu");
120 SPI_STATISTICS_SHOW(spi_async
, "%lu");
122 SPI_STATISTICS_SHOW(bytes
, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx
, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx
, "%llu");
126 static struct attribute
*spi_dev_attrs
[] = {
127 &dev_attr_modalias
.attr
,
131 static const struct attribute_group spi_dev_group
= {
132 .attrs
= spi_dev_attrs
,
135 static struct attribute
*spi_device_statistics_attrs
[] = {
136 &dev_attr_spi_device_messages
.attr
,
137 &dev_attr_spi_device_transfers
.attr
,
138 &dev_attr_spi_device_errors
.attr
,
139 &dev_attr_spi_device_timedout
.attr
,
140 &dev_attr_spi_device_spi_sync
.attr
,
141 &dev_attr_spi_device_spi_sync_immediate
.attr
,
142 &dev_attr_spi_device_spi_async
.attr
,
143 &dev_attr_spi_device_bytes
.attr
,
144 &dev_attr_spi_device_bytes_rx
.attr
,
145 &dev_attr_spi_device_bytes_tx
.attr
,
149 static const struct attribute_group spi_device_statistics_group
= {
150 .name
= "statistics",
151 .attrs
= spi_device_statistics_attrs
,
154 static const struct attribute_group
*spi_dev_groups
[] = {
156 &spi_device_statistics_group
,
160 static struct attribute
*spi_master_statistics_attrs
[] = {
161 &dev_attr_spi_master_messages
.attr
,
162 &dev_attr_spi_master_transfers
.attr
,
163 &dev_attr_spi_master_errors
.attr
,
164 &dev_attr_spi_master_timedout
.attr
,
165 &dev_attr_spi_master_spi_sync
.attr
,
166 &dev_attr_spi_master_spi_sync_immediate
.attr
,
167 &dev_attr_spi_master_spi_async
.attr
,
168 &dev_attr_spi_master_bytes
.attr
,
169 &dev_attr_spi_master_bytes_rx
.attr
,
170 &dev_attr_spi_master_bytes_tx
.attr
,
174 static const struct attribute_group spi_master_statistics_group
= {
175 .name
= "statistics",
176 .attrs
= spi_master_statistics_attrs
,
179 static const struct attribute_group
*spi_master_groups
[] = {
180 &spi_master_statistics_group
,
184 void spi_statistics_add_transfer_stats(struct spi_statistics
*stats
,
185 struct spi_transfer
*xfer
,
186 struct spi_master
*master
)
190 spin_lock_irqsave(&stats
->lock
, flags
);
194 stats
->bytes
+= xfer
->len
;
195 if ((xfer
->tx_buf
) &&
196 (xfer
->tx_buf
!= master
->dummy_tx
))
197 stats
->bytes_tx
+= xfer
->len
;
198 if ((xfer
->rx_buf
) &&
199 (xfer
->rx_buf
!= master
->dummy_rx
))
200 stats
->bytes_rx
+= xfer
->len
;
202 spin_unlock_irqrestore(&stats
->lock
, flags
);
204 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats
);
206 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
207 * and the sysfs version makes coldplug work too.
210 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
211 const struct spi_device
*sdev
)
213 while (id
->name
[0]) {
214 if (!strcmp(sdev
->modalias
, id
->name
))
221 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
223 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
225 return spi_match_id(sdrv
->id_table
, sdev
);
227 EXPORT_SYMBOL_GPL(spi_get_device_id
);
229 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
231 const struct spi_device
*spi
= to_spi_device(dev
);
232 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
234 /* Attempt an OF style match */
235 if (of_driver_match_device(dev
, drv
))
239 if (acpi_driver_match_device(dev
, drv
))
243 return !!spi_match_id(sdrv
->id_table
, spi
);
245 return strcmp(spi
->modalias
, drv
->name
) == 0;
248 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
250 const struct spi_device
*spi
= to_spi_device(dev
);
253 rc
= acpi_device_uevent_modalias(dev
, env
);
257 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
261 struct bus_type spi_bus_type
= {
263 .dev_groups
= spi_dev_groups
,
264 .match
= spi_match_device
,
265 .uevent
= spi_uevent
,
267 EXPORT_SYMBOL_GPL(spi_bus_type
);
270 static int spi_drv_probe(struct device
*dev
)
272 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
275 ret
= of_clk_set_defaults(dev
->of_node
, false);
279 ret
= dev_pm_domain_attach(dev
, true);
280 if (ret
!= -EPROBE_DEFER
) {
281 ret
= sdrv
->probe(to_spi_device(dev
));
283 dev_pm_domain_detach(dev
, true);
289 static int spi_drv_remove(struct device
*dev
)
291 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
294 ret
= sdrv
->remove(to_spi_device(dev
));
295 dev_pm_domain_detach(dev
, true);
300 static void spi_drv_shutdown(struct device
*dev
)
302 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
304 sdrv
->shutdown(to_spi_device(dev
));
308 * spi_register_driver - register a SPI driver
309 * @sdrv: the driver to register
312 int spi_register_driver(struct spi_driver
*sdrv
)
314 sdrv
->driver
.bus
= &spi_bus_type
;
316 sdrv
->driver
.probe
= spi_drv_probe
;
318 sdrv
->driver
.remove
= spi_drv_remove
;
320 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
321 return driver_register(&sdrv
->driver
);
323 EXPORT_SYMBOL_GPL(spi_register_driver
);
325 /*-------------------------------------------------------------------------*/
327 /* SPI devices should normally not be created by SPI device drivers; that
328 * would make them board-specific. Similarly with SPI master drivers.
329 * Device registration normally goes into like arch/.../mach.../board-YYY.c
330 * with other readonly (flashable) information about mainboard devices.
334 struct list_head list
;
335 struct spi_board_info board_info
;
338 static LIST_HEAD(board_list
);
339 static LIST_HEAD(spi_master_list
);
342 * Used to protect add/del opertion for board_info list and
343 * spi_master list, and their matching process
345 static DEFINE_MUTEX(board_lock
);
348 * spi_alloc_device - Allocate a new SPI device
349 * @master: Controller to which device is connected
352 * Allows a driver to allocate and initialize a spi_device without
353 * registering it immediately. This allows a driver to directly
354 * fill the spi_device with device parameters before calling
355 * spi_add_device() on it.
357 * Caller is responsible to call spi_add_device() on the returned
358 * spi_device structure to add it to the SPI master. If the caller
359 * needs to discard the spi_device without adding it, then it should
360 * call spi_dev_put() on it.
362 * Returns a pointer to the new device, or NULL.
364 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
366 struct spi_device
*spi
;
368 if (!spi_master_get(master
))
371 spi
= kzalloc(sizeof(*spi
), GFP_KERNEL
);
373 spi_master_put(master
);
377 spi
->master
= master
;
378 spi
->dev
.parent
= &master
->dev
;
379 spi
->dev
.bus
= &spi_bus_type
;
380 spi
->dev
.release
= spidev_release
;
381 spi
->cs_gpio
= -ENOENT
;
383 spin_lock_init(&spi
->statistics
.lock
);
385 device_initialize(&spi
->dev
);
388 EXPORT_SYMBOL_GPL(spi_alloc_device
);
390 static void spi_dev_set_name(struct spi_device
*spi
)
392 struct acpi_device
*adev
= ACPI_COMPANION(&spi
->dev
);
395 dev_set_name(&spi
->dev
, "spi-%s", acpi_dev_name(adev
));
399 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
403 static int spi_dev_check(struct device
*dev
, void *data
)
405 struct spi_device
*spi
= to_spi_device(dev
);
406 struct spi_device
*new_spi
= data
;
408 if (spi
->master
== new_spi
->master
&&
409 spi
->chip_select
== new_spi
->chip_select
)
415 * spi_add_device - Add spi_device allocated with spi_alloc_device
416 * @spi: spi_device to register
418 * Companion function to spi_alloc_device. Devices allocated with
419 * spi_alloc_device can be added onto the spi bus with this function.
421 * Returns 0 on success; negative errno on failure
423 int spi_add_device(struct spi_device
*spi
)
425 static DEFINE_MUTEX(spi_add_lock
);
426 struct spi_master
*master
= spi
->master
;
427 struct device
*dev
= master
->dev
.parent
;
430 /* Chipselects are numbered 0..max; validate. */
431 if (spi
->chip_select
>= master
->num_chipselect
) {
432 dev_err(dev
, "cs%d >= max %d\n",
434 master
->num_chipselect
);
438 /* Set the bus ID string */
439 spi_dev_set_name(spi
);
441 /* We need to make sure there's no other device with this
442 * chipselect **BEFORE** we call setup(), else we'll trash
443 * its configuration. Lock against concurrent add() calls.
445 mutex_lock(&spi_add_lock
);
447 status
= bus_for_each_dev(&spi_bus_type
, NULL
, spi
, spi_dev_check
);
449 dev_err(dev
, "chipselect %d already in use\n",
454 if (master
->cs_gpios
)
455 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
457 /* Drivers may modify this initial i/o setup, but will
458 * normally rely on the device being setup. Devices
459 * using SPI_CS_HIGH can't coexist well otherwise...
461 status
= spi_setup(spi
);
463 dev_err(dev
, "can't setup %s, status %d\n",
464 dev_name(&spi
->dev
), status
);
468 /* Device may be bound to an active driver when this returns */
469 status
= device_add(&spi
->dev
);
471 dev_err(dev
, "can't add %s, status %d\n",
472 dev_name(&spi
->dev
), status
);
474 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
477 mutex_unlock(&spi_add_lock
);
480 EXPORT_SYMBOL_GPL(spi_add_device
);
483 * spi_new_device - instantiate one new SPI device
484 * @master: Controller to which device is connected
485 * @chip: Describes the SPI device
488 * On typical mainboards, this is purely internal; and it's not needed
489 * after board init creates the hard-wired devices. Some development
490 * platforms may not be able to use spi_register_board_info though, and
491 * this is exported so that for example a USB or parport based adapter
492 * driver could add devices (which it would learn about out-of-band).
494 * Returns the new device, or NULL.
496 struct spi_device
*spi_new_device(struct spi_master
*master
,
497 struct spi_board_info
*chip
)
499 struct spi_device
*proxy
;
502 /* NOTE: caller did any chip->bus_num checks necessary.
504 * Also, unless we change the return value convention to use
505 * error-or-pointer (not NULL-or-pointer), troubleshootability
506 * suggests syslogged diagnostics are best here (ugh).
509 proxy
= spi_alloc_device(master
);
513 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
515 proxy
->chip_select
= chip
->chip_select
;
516 proxy
->max_speed_hz
= chip
->max_speed_hz
;
517 proxy
->mode
= chip
->mode
;
518 proxy
->irq
= chip
->irq
;
519 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
520 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
521 proxy
->controller_data
= chip
->controller_data
;
522 proxy
->controller_state
= NULL
;
524 status
= spi_add_device(proxy
);
532 EXPORT_SYMBOL_GPL(spi_new_device
);
534 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
535 struct spi_board_info
*bi
)
537 struct spi_device
*dev
;
539 if (master
->bus_num
!= bi
->bus_num
)
542 dev
= spi_new_device(master
, bi
);
544 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
549 * spi_register_board_info - register SPI devices for a given board
550 * @info: array of chip descriptors
551 * @n: how many descriptors are provided
554 * Board-specific early init code calls this (probably during arch_initcall)
555 * with segments of the SPI device table. Any device nodes are created later,
556 * after the relevant parent SPI controller (bus_num) is defined. We keep
557 * this table of devices forever, so that reloading a controller driver will
558 * not make Linux forget about these hard-wired devices.
560 * Other code can also call this, e.g. a particular add-on board might provide
561 * SPI devices through its expansion connector, so code initializing that board
562 * would naturally declare its SPI devices.
564 * The board info passed can safely be __initdata ... but be careful of
565 * any embedded pointers (platform_data, etc), they're copied as-is.
567 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
569 struct boardinfo
*bi
;
575 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
579 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
580 struct spi_master
*master
;
582 memcpy(&bi
->board_info
, info
, sizeof(*info
));
583 mutex_lock(&board_lock
);
584 list_add_tail(&bi
->list
, &board_list
);
585 list_for_each_entry(master
, &spi_master_list
, list
)
586 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
587 mutex_unlock(&board_lock
);
593 /*-------------------------------------------------------------------------*/
595 static void spi_set_cs(struct spi_device
*spi
, bool enable
)
597 if (spi
->mode
& SPI_CS_HIGH
)
600 if (spi
->cs_gpio
>= 0)
601 gpio_set_value(spi
->cs_gpio
, !enable
);
602 else if (spi
->master
->set_cs
)
603 spi
->master
->set_cs(spi
, !enable
);
606 #ifdef CONFIG_HAS_DMA
607 static int spi_map_buf(struct spi_master
*master
, struct device
*dev
,
608 struct sg_table
*sgt
, void *buf
, size_t len
,
609 enum dma_data_direction dir
)
611 const bool vmalloced_buf
= is_vmalloc_addr(buf
);
614 struct page
*vm_page
;
620 desc_len
= PAGE_SIZE
;
621 sgs
= DIV_ROUND_UP(len
+ offset_in_page(buf
), desc_len
);
623 desc_len
= master
->max_dma_len
;
624 sgs
= DIV_ROUND_UP(len
, desc_len
);
627 ret
= sg_alloc_table(sgt
, sgs
, GFP_KERNEL
);
631 for (i
= 0; i
< sgs
; i
++) {
635 len
, desc_len
- offset_in_page(buf
));
636 vm_page
= vmalloc_to_page(buf
);
641 sg_set_page(&sgt
->sgl
[i
], vm_page
,
642 min
, offset_in_page(buf
));
644 min
= min_t(size_t, len
, desc_len
);
646 sg_set_buf(&sgt
->sgl
[i
], sg_buf
, min
);
654 ret
= dma_map_sg(dev
, sgt
->sgl
, sgt
->nents
, dir
);
667 static void spi_unmap_buf(struct spi_master
*master
, struct device
*dev
,
668 struct sg_table
*sgt
, enum dma_data_direction dir
)
670 if (sgt
->orig_nents
) {
671 dma_unmap_sg(dev
, sgt
->sgl
, sgt
->orig_nents
, dir
);
676 static int __spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
678 struct device
*tx_dev
, *rx_dev
;
679 struct spi_transfer
*xfer
;
682 if (!master
->can_dma
)
686 tx_dev
= master
->dma_tx
->device
->dev
;
688 tx_dev
= &master
->dev
;
691 rx_dev
= master
->dma_rx
->device
->dev
;
693 rx_dev
= &master
->dev
;
695 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
696 if (!master
->can_dma(master
, msg
->spi
, xfer
))
699 if (xfer
->tx_buf
!= NULL
) {
700 ret
= spi_map_buf(master
, tx_dev
, &xfer
->tx_sg
,
701 (void *)xfer
->tx_buf
, xfer
->len
,
707 if (xfer
->rx_buf
!= NULL
) {
708 ret
= spi_map_buf(master
, rx_dev
, &xfer
->rx_sg
,
709 xfer
->rx_buf
, xfer
->len
,
712 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
,
719 master
->cur_msg_mapped
= true;
724 static int __spi_unmap_msg(struct spi_master
*master
, struct spi_message
*msg
)
726 struct spi_transfer
*xfer
;
727 struct device
*tx_dev
, *rx_dev
;
729 if (!master
->cur_msg_mapped
|| !master
->can_dma
)
733 tx_dev
= master
->dma_tx
->device
->dev
;
735 tx_dev
= &master
->dev
;
738 rx_dev
= master
->dma_rx
->device
->dev
;
740 rx_dev
= &master
->dev
;
742 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
743 if (!master
->can_dma(master
, msg
->spi
, xfer
))
746 spi_unmap_buf(master
, rx_dev
, &xfer
->rx_sg
, DMA_FROM_DEVICE
);
747 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
, DMA_TO_DEVICE
);
752 #else /* !CONFIG_HAS_DMA */
753 static inline int __spi_map_msg(struct spi_master
*master
,
754 struct spi_message
*msg
)
759 static inline int __spi_unmap_msg(struct spi_master
*master
,
760 struct spi_message
*msg
)
764 #endif /* !CONFIG_HAS_DMA */
766 static inline int spi_unmap_msg(struct spi_master
*master
,
767 struct spi_message
*msg
)
769 struct spi_transfer
*xfer
;
771 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
773 * Restore the original value of tx_buf or rx_buf if they are
776 if (xfer
->tx_buf
== master
->dummy_tx
)
778 if (xfer
->rx_buf
== master
->dummy_rx
)
782 return __spi_unmap_msg(master
, msg
);
785 static int spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
787 struct spi_transfer
*xfer
;
789 unsigned int max_tx
, max_rx
;
791 if (master
->flags
& (SPI_MASTER_MUST_RX
| SPI_MASTER_MUST_TX
)) {
795 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
796 if ((master
->flags
& SPI_MASTER_MUST_TX
) &&
798 max_tx
= max(xfer
->len
, max_tx
);
799 if ((master
->flags
& SPI_MASTER_MUST_RX
) &&
801 max_rx
= max(xfer
->len
, max_rx
);
805 tmp
= krealloc(master
->dummy_tx
, max_tx
,
806 GFP_KERNEL
| GFP_DMA
);
809 master
->dummy_tx
= tmp
;
810 memset(tmp
, 0, max_tx
);
814 tmp
= krealloc(master
->dummy_rx
, max_rx
,
815 GFP_KERNEL
| GFP_DMA
);
818 master
->dummy_rx
= tmp
;
821 if (max_tx
|| max_rx
) {
822 list_for_each_entry(xfer
, &msg
->transfers
,
825 xfer
->tx_buf
= master
->dummy_tx
;
827 xfer
->rx_buf
= master
->dummy_rx
;
832 return __spi_map_msg(master
, msg
);
836 * spi_transfer_one_message - Default implementation of transfer_one_message()
838 * This is a standard implementation of transfer_one_message() for
839 * drivers which impelment a transfer_one() operation. It provides
840 * standard handling of delays and chip select management.
842 static int spi_transfer_one_message(struct spi_master
*master
,
843 struct spi_message
*msg
)
845 struct spi_transfer
*xfer
;
846 bool keep_cs
= false;
848 unsigned long ms
= 1;
849 struct spi_statistics
*statm
= &master
->statistics
;
850 struct spi_statistics
*stats
= &msg
->spi
->statistics
;
852 spi_set_cs(msg
->spi
, true);
854 SPI_STATISTICS_INCREMENT_FIELD(statm
, messages
);
855 SPI_STATISTICS_INCREMENT_FIELD(stats
, messages
);
857 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
858 trace_spi_transfer_start(msg
, xfer
);
860 spi_statistics_add_transfer_stats(statm
, xfer
, master
);
861 spi_statistics_add_transfer_stats(stats
, xfer
, master
);
863 if (xfer
->tx_buf
|| xfer
->rx_buf
) {
864 reinit_completion(&master
->xfer_completion
);
866 ret
= master
->transfer_one(master
, msg
->spi
, xfer
);
868 SPI_STATISTICS_INCREMENT_FIELD(statm
,
870 SPI_STATISTICS_INCREMENT_FIELD(stats
,
872 dev_err(&msg
->spi
->dev
,
873 "SPI transfer failed: %d\n", ret
);
879 ms
= xfer
->len
* 8 * 1000 / xfer
->speed_hz
;
880 ms
+= ms
+ 100; /* some tolerance */
882 ms
= wait_for_completion_timeout(&master
->xfer_completion
,
883 msecs_to_jiffies(ms
));
887 SPI_STATISTICS_INCREMENT_FIELD(statm
,
889 SPI_STATISTICS_INCREMENT_FIELD(stats
,
891 dev_err(&msg
->spi
->dev
,
892 "SPI transfer timed out\n");
893 msg
->status
= -ETIMEDOUT
;
897 dev_err(&msg
->spi
->dev
,
898 "Bufferless transfer has length %u\n",
902 trace_spi_transfer_stop(msg
, xfer
);
904 if (msg
->status
!= -EINPROGRESS
)
907 if (xfer
->delay_usecs
)
908 udelay(xfer
->delay_usecs
);
910 if (xfer
->cs_change
) {
911 if (list_is_last(&xfer
->transfer_list
,
915 spi_set_cs(msg
->spi
, false);
917 spi_set_cs(msg
->spi
, true);
921 msg
->actual_length
+= xfer
->len
;
925 if (ret
!= 0 || !keep_cs
)
926 spi_set_cs(msg
->spi
, false);
928 if (msg
->status
== -EINPROGRESS
)
931 if (msg
->status
&& master
->handle_err
)
932 master
->handle_err(master
, msg
);
934 spi_finalize_current_message(master
);
940 * spi_finalize_current_transfer - report completion of a transfer
941 * @master: the master reporting completion
943 * Called by SPI drivers using the core transfer_one_message()
944 * implementation to notify it that the current interrupt driven
945 * transfer has finished and the next one may be scheduled.
947 void spi_finalize_current_transfer(struct spi_master
*master
)
949 complete(&master
->xfer_completion
);
951 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer
);
954 * __spi_pump_messages - function which processes spi message queue
955 * @master: master to process queue for
956 * @in_kthread: true if we are in the context of the message pump thread
958 * This function checks if there is any spi message in the queue that
959 * needs processing and if so call out to the driver to initialize hardware
960 * and transfer each message.
962 * Note that it is called both from the kthread itself and also from
963 * inside spi_sync(); the queue extraction handling at the top of the
964 * function should deal with this safely.
966 static void __spi_pump_messages(struct spi_master
*master
, bool in_kthread
)
969 bool was_busy
= false;
973 spin_lock_irqsave(&master
->queue_lock
, flags
);
975 /* Make sure we are not already running a message */
976 if (master
->cur_msg
) {
977 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
981 /* If another context is idling the device then defer */
982 if (master
->idling
) {
983 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
984 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
988 /* Check if the queue is idle */
989 if (list_empty(&master
->queue
) || !master
->running
) {
991 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
995 /* Only do teardown in the thread */
997 queue_kthread_work(&master
->kworker
,
998 &master
->pump_messages
);
999 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1003 master
->busy
= false;
1004 master
->idling
= true;
1005 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1007 kfree(master
->dummy_rx
);
1008 master
->dummy_rx
= NULL
;
1009 kfree(master
->dummy_tx
);
1010 master
->dummy_tx
= NULL
;
1011 if (master
->unprepare_transfer_hardware
&&
1012 master
->unprepare_transfer_hardware(master
))
1013 dev_err(&master
->dev
,
1014 "failed to unprepare transfer hardware\n");
1015 if (master
->auto_runtime_pm
) {
1016 pm_runtime_mark_last_busy(master
->dev
.parent
);
1017 pm_runtime_put_autosuspend(master
->dev
.parent
);
1019 trace_spi_master_idle(master
);
1021 spin_lock_irqsave(&master
->queue_lock
, flags
);
1022 master
->idling
= false;
1023 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1027 /* Extract head of queue */
1029 list_first_entry(&master
->queue
, struct spi_message
, queue
);
1031 list_del_init(&master
->cur_msg
->queue
);
1035 master
->busy
= true;
1036 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1038 if (!was_busy
&& master
->auto_runtime_pm
) {
1039 ret
= pm_runtime_get_sync(master
->dev
.parent
);
1041 dev_err(&master
->dev
, "Failed to power device: %d\n",
1048 trace_spi_master_busy(master
);
1050 if (!was_busy
&& master
->prepare_transfer_hardware
) {
1051 ret
= master
->prepare_transfer_hardware(master
);
1053 dev_err(&master
->dev
,
1054 "failed to prepare transfer hardware\n");
1056 if (master
->auto_runtime_pm
)
1057 pm_runtime_put(master
->dev
.parent
);
1062 trace_spi_message_start(master
->cur_msg
);
1064 if (master
->prepare_message
) {
1065 ret
= master
->prepare_message(master
, master
->cur_msg
);
1067 dev_err(&master
->dev
,
1068 "failed to prepare message: %d\n", ret
);
1069 master
->cur_msg
->status
= ret
;
1070 spi_finalize_current_message(master
);
1073 master
->cur_msg_prepared
= true;
1076 ret
= spi_map_msg(master
, master
->cur_msg
);
1078 master
->cur_msg
->status
= ret
;
1079 spi_finalize_current_message(master
);
1083 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
1085 dev_err(&master
->dev
,
1086 "failed to transfer one message from queue\n");
1092 * spi_pump_messages - kthread work function which processes spi message queue
1093 * @work: pointer to kthread work struct contained in the master struct
1095 static void spi_pump_messages(struct kthread_work
*work
)
1097 struct spi_master
*master
=
1098 container_of(work
, struct spi_master
, pump_messages
);
1100 __spi_pump_messages(master
, true);
1103 static int spi_init_queue(struct spi_master
*master
)
1105 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
1107 master
->running
= false;
1108 master
->busy
= false;
1110 init_kthread_worker(&master
->kworker
);
1111 master
->kworker_task
= kthread_run(kthread_worker_fn
,
1112 &master
->kworker
, "%s",
1113 dev_name(&master
->dev
));
1114 if (IS_ERR(master
->kworker_task
)) {
1115 dev_err(&master
->dev
, "failed to create message pump task\n");
1116 return PTR_ERR(master
->kworker_task
);
1118 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
1121 * Master config will indicate if this controller should run the
1122 * message pump with high (realtime) priority to reduce the transfer
1123 * latency on the bus by minimising the delay between a transfer
1124 * request and the scheduling of the message pump thread. Without this
1125 * setting the message pump thread will remain at default priority.
1128 dev_info(&master
->dev
,
1129 "will run message pump with realtime priority\n");
1130 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
1137 * spi_get_next_queued_message() - called by driver to check for queued
1139 * @master: the master to check for queued messages
1141 * If there are more messages in the queue, the next message is returned from
1144 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
1146 struct spi_message
*next
;
1147 unsigned long flags
;
1149 /* get a pointer to the next message, if any */
1150 spin_lock_irqsave(&master
->queue_lock
, flags
);
1151 next
= list_first_entry_or_null(&master
->queue
, struct spi_message
,
1153 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1157 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
1160 * spi_finalize_current_message() - the current message is complete
1161 * @master: the master to return the message to
1163 * Called by the driver to notify the core that the message in the front of the
1164 * queue is complete and can be removed from the queue.
1166 void spi_finalize_current_message(struct spi_master
*master
)
1168 struct spi_message
*mesg
;
1169 unsigned long flags
;
1172 spin_lock_irqsave(&master
->queue_lock
, flags
);
1173 mesg
= master
->cur_msg
;
1174 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1176 spi_unmap_msg(master
, mesg
);
1178 if (master
->cur_msg_prepared
&& master
->unprepare_message
) {
1179 ret
= master
->unprepare_message(master
, mesg
);
1181 dev_err(&master
->dev
,
1182 "failed to unprepare message: %d\n", ret
);
1186 spin_lock_irqsave(&master
->queue_lock
, flags
);
1187 master
->cur_msg
= NULL
;
1188 master
->cur_msg_prepared
= false;
1189 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1190 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1192 trace_spi_message_done(mesg
);
1196 mesg
->complete(mesg
->context
);
1198 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
1200 static int spi_start_queue(struct spi_master
*master
)
1202 unsigned long flags
;
1204 spin_lock_irqsave(&master
->queue_lock
, flags
);
1206 if (master
->running
|| master
->busy
) {
1207 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1211 master
->running
= true;
1212 master
->cur_msg
= NULL
;
1213 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1215 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1220 static int spi_stop_queue(struct spi_master
*master
)
1222 unsigned long flags
;
1223 unsigned limit
= 500;
1226 spin_lock_irqsave(&master
->queue_lock
, flags
);
1229 * This is a bit lame, but is optimized for the common execution path.
1230 * A wait_queue on the master->busy could be used, but then the common
1231 * execution path (pump_messages) would be required to call wake_up or
1232 * friends on every SPI message. Do this instead.
1234 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
1235 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1236 usleep_range(10000, 11000);
1237 spin_lock_irqsave(&master
->queue_lock
, flags
);
1240 if (!list_empty(&master
->queue
) || master
->busy
)
1243 master
->running
= false;
1245 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1248 dev_warn(&master
->dev
,
1249 "could not stop message queue\n");
1255 static int spi_destroy_queue(struct spi_master
*master
)
1259 ret
= spi_stop_queue(master
);
1262 * flush_kthread_worker will block until all work is done.
1263 * If the reason that stop_queue timed out is that the work will never
1264 * finish, then it does no good to call flush/stop thread, so
1268 dev_err(&master
->dev
, "problem destroying queue\n");
1272 flush_kthread_worker(&master
->kworker
);
1273 kthread_stop(master
->kworker_task
);
1278 static int __spi_queued_transfer(struct spi_device
*spi
,
1279 struct spi_message
*msg
,
1282 struct spi_master
*master
= spi
->master
;
1283 unsigned long flags
;
1285 spin_lock_irqsave(&master
->queue_lock
, flags
);
1287 if (!master
->running
) {
1288 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1291 msg
->actual_length
= 0;
1292 msg
->status
= -EINPROGRESS
;
1294 list_add_tail(&msg
->queue
, &master
->queue
);
1295 if (!master
->busy
&& need_pump
)
1296 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1298 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1303 * spi_queued_transfer - transfer function for queued transfers
1304 * @spi: spi device which is requesting transfer
1305 * @msg: spi message which is to handled is queued to driver queue
1307 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
1309 return __spi_queued_transfer(spi
, msg
, true);
1312 static int spi_master_initialize_queue(struct spi_master
*master
)
1316 master
->transfer
= spi_queued_transfer
;
1317 if (!master
->transfer_one_message
)
1318 master
->transfer_one_message
= spi_transfer_one_message
;
1320 /* Initialize and start queue */
1321 ret
= spi_init_queue(master
);
1323 dev_err(&master
->dev
, "problem initializing queue\n");
1324 goto err_init_queue
;
1326 master
->queued
= true;
1327 ret
= spi_start_queue(master
);
1329 dev_err(&master
->dev
, "problem starting queue\n");
1330 goto err_start_queue
;
1336 spi_destroy_queue(master
);
1341 /*-------------------------------------------------------------------------*/
1343 #if defined(CONFIG_OF)
1344 static struct spi_device
*
1345 of_register_spi_device(struct spi_master
*master
, struct device_node
*nc
)
1347 struct spi_device
*spi
;
1351 /* Alloc an spi_device */
1352 spi
= spi_alloc_device(master
);
1354 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
1360 /* Select device driver */
1361 rc
= of_modalias_node(nc
, spi
->modalias
,
1362 sizeof(spi
->modalias
));
1364 dev_err(&master
->dev
, "cannot find modalias for %s\n",
1369 /* Device address */
1370 rc
= of_property_read_u32(nc
, "reg", &value
);
1372 dev_err(&master
->dev
, "%s has no valid 'reg' property (%d)\n",
1376 spi
->chip_select
= value
;
1378 /* Mode (clock phase/polarity/etc.) */
1379 if (of_find_property(nc
, "spi-cpha", NULL
))
1380 spi
->mode
|= SPI_CPHA
;
1381 if (of_find_property(nc
, "spi-cpol", NULL
))
1382 spi
->mode
|= SPI_CPOL
;
1383 if (of_find_property(nc
, "spi-cs-high", NULL
))
1384 spi
->mode
|= SPI_CS_HIGH
;
1385 if (of_find_property(nc
, "spi-3wire", NULL
))
1386 spi
->mode
|= SPI_3WIRE
;
1387 if (of_find_property(nc
, "spi-lsb-first", NULL
))
1388 spi
->mode
|= SPI_LSB_FIRST
;
1390 /* Device DUAL/QUAD mode */
1391 if (!of_property_read_u32(nc
, "spi-tx-bus-width", &value
)) {
1396 spi
->mode
|= SPI_TX_DUAL
;
1399 spi
->mode
|= SPI_TX_QUAD
;
1402 dev_warn(&master
->dev
,
1403 "spi-tx-bus-width %d not supported\n",
1409 if (!of_property_read_u32(nc
, "spi-rx-bus-width", &value
)) {
1414 spi
->mode
|= SPI_RX_DUAL
;
1417 spi
->mode
|= SPI_RX_QUAD
;
1420 dev_warn(&master
->dev
,
1421 "spi-rx-bus-width %d not supported\n",
1428 rc
= of_property_read_u32(nc
, "spi-max-frequency", &value
);
1430 dev_err(&master
->dev
, "%s has no valid 'spi-max-frequency' property (%d)\n",
1434 spi
->max_speed_hz
= value
;
1437 spi
->irq
= irq_of_parse_and_map(nc
, 0);
1439 /* Store a pointer to the node in the device structure */
1441 spi
->dev
.of_node
= nc
;
1443 /* Register the new device */
1444 rc
= spi_add_device(spi
);
1446 dev_err(&master
->dev
, "spi_device register error %s\n",
1459 * of_register_spi_devices() - Register child devices onto the SPI bus
1460 * @master: Pointer to spi_master device
1462 * Registers an spi_device for each child node of master node which has a 'reg'
1465 static void of_register_spi_devices(struct spi_master
*master
)
1467 struct spi_device
*spi
;
1468 struct device_node
*nc
;
1470 if (!master
->dev
.of_node
)
1473 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
1474 spi
= of_register_spi_device(master
, nc
);
1476 dev_warn(&master
->dev
, "Failed to create SPI device for %s\n",
1481 static void of_register_spi_devices(struct spi_master
*master
) { }
1485 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
1487 struct spi_device
*spi
= data
;
1489 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
1490 struct acpi_resource_spi_serialbus
*sb
;
1492 sb
= &ares
->data
.spi_serial_bus
;
1493 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
1494 spi
->chip_select
= sb
->device_selection
;
1495 spi
->max_speed_hz
= sb
->connection_speed
;
1497 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
1498 spi
->mode
|= SPI_CPHA
;
1499 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
1500 spi
->mode
|= SPI_CPOL
;
1501 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
1502 spi
->mode
|= SPI_CS_HIGH
;
1504 } else if (spi
->irq
< 0) {
1507 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
1511 /* Always tell the ACPI core to skip this resource */
1515 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
1516 void *data
, void **return_value
)
1518 struct spi_master
*master
= data
;
1519 struct list_head resource_list
;
1520 struct acpi_device
*adev
;
1521 struct spi_device
*spi
;
1524 if (acpi_bus_get_device(handle
, &adev
))
1526 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1529 spi
= spi_alloc_device(master
);
1531 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1532 dev_name(&adev
->dev
));
1533 return AE_NO_MEMORY
;
1536 ACPI_COMPANION_SET(&spi
->dev
, adev
);
1539 INIT_LIST_HEAD(&resource_list
);
1540 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1541 acpi_spi_add_resource
, spi
);
1542 acpi_dev_free_resource_list(&resource_list
);
1544 if (ret
< 0 || !spi
->max_speed_hz
) {
1549 adev
->power
.flags
.ignore_parent
= true;
1550 strlcpy(spi
->modalias
, acpi_device_hid(adev
), sizeof(spi
->modalias
));
1551 if (spi_add_device(spi
)) {
1552 adev
->power
.flags
.ignore_parent
= false;
1553 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1554 dev_name(&adev
->dev
));
1561 static void acpi_register_spi_devices(struct spi_master
*master
)
1566 handle
= ACPI_HANDLE(master
->dev
.parent
);
1570 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1571 acpi_spi_add_device
, NULL
,
1573 if (ACPI_FAILURE(status
))
1574 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1577 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1578 #endif /* CONFIG_ACPI */
1580 static void spi_master_release(struct device
*dev
)
1582 struct spi_master
*master
;
1584 master
= container_of(dev
, struct spi_master
, dev
);
1588 static struct class spi_master_class
= {
1589 .name
= "spi_master",
1590 .owner
= THIS_MODULE
,
1591 .dev_release
= spi_master_release
,
1592 .dev_groups
= spi_master_groups
,
1597 * spi_alloc_master - allocate SPI master controller
1598 * @dev: the controller, possibly using the platform_bus
1599 * @size: how much zeroed driver-private data to allocate; the pointer to this
1600 * memory is in the driver_data field of the returned device,
1601 * accessible with spi_master_get_devdata().
1602 * Context: can sleep
1604 * This call is used only by SPI master controller drivers, which are the
1605 * only ones directly touching chip registers. It's how they allocate
1606 * an spi_master structure, prior to calling spi_register_master().
1608 * This must be called from context that can sleep. It returns the SPI
1609 * master structure on success, else NULL.
1611 * The caller is responsible for assigning the bus number and initializing
1612 * the master's methods before calling spi_register_master(); and (after errors
1613 * adding the device) calling spi_master_put() to prevent a memory leak.
1615 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1617 struct spi_master
*master
;
1622 master
= kzalloc(size
+ sizeof(*master
), GFP_KERNEL
);
1626 device_initialize(&master
->dev
);
1627 master
->bus_num
= -1;
1628 master
->num_chipselect
= 1;
1629 master
->dev
.class = &spi_master_class
;
1630 master
->dev
.parent
= get_device(dev
);
1631 spi_master_set_devdata(master
, &master
[1]);
1635 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1638 static int of_spi_register_master(struct spi_master
*master
)
1641 struct device_node
*np
= master
->dev
.of_node
;
1646 nb
= of_gpio_named_count(np
, "cs-gpios");
1647 master
->num_chipselect
= max_t(int, nb
, master
->num_chipselect
);
1649 /* Return error only for an incorrectly formed cs-gpios property */
1650 if (nb
== 0 || nb
== -ENOENT
)
1655 cs
= devm_kzalloc(&master
->dev
,
1656 sizeof(int) * master
->num_chipselect
,
1658 master
->cs_gpios
= cs
;
1660 if (!master
->cs_gpios
)
1663 for (i
= 0; i
< master
->num_chipselect
; i
++)
1666 for (i
= 0; i
< nb
; i
++)
1667 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1672 static int of_spi_register_master(struct spi_master
*master
)
1679 * spi_register_master - register SPI master controller
1680 * @master: initialized master, originally from spi_alloc_master()
1681 * Context: can sleep
1683 * SPI master controllers connect to their drivers using some non-SPI bus,
1684 * such as the platform bus. The final stage of probe() in that code
1685 * includes calling spi_register_master() to hook up to this SPI bus glue.
1687 * SPI controllers use board specific (often SOC specific) bus numbers,
1688 * and board-specific addressing for SPI devices combines those numbers
1689 * with chip select numbers. Since SPI does not directly support dynamic
1690 * device identification, boards need configuration tables telling which
1691 * chip is at which address.
1693 * This must be called from context that can sleep. It returns zero on
1694 * success, else a negative error code (dropping the master's refcount).
1695 * After a successful return, the caller is responsible for calling
1696 * spi_unregister_master().
1698 int spi_register_master(struct spi_master
*master
)
1700 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1701 struct device
*dev
= master
->dev
.parent
;
1702 struct boardinfo
*bi
;
1703 int status
= -ENODEV
;
1709 status
= of_spi_register_master(master
);
1713 /* even if it's just one always-selected device, there must
1714 * be at least one chipselect
1716 if (master
->num_chipselect
== 0)
1719 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1720 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1722 /* convention: dynamically assigned bus IDs count down from the max */
1723 if (master
->bus_num
< 0) {
1724 /* FIXME switch to an IDR based scheme, something like
1725 * I2C now uses, so we can't run out of "dynamic" IDs
1727 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1731 INIT_LIST_HEAD(&master
->queue
);
1732 spin_lock_init(&master
->queue_lock
);
1733 spin_lock_init(&master
->bus_lock_spinlock
);
1734 mutex_init(&master
->bus_lock_mutex
);
1735 master
->bus_lock_flag
= 0;
1736 init_completion(&master
->xfer_completion
);
1737 if (!master
->max_dma_len
)
1738 master
->max_dma_len
= INT_MAX
;
1740 /* register the device, then userspace will see it.
1741 * registration fails if the bus ID is in use.
1743 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1744 status
= device_add(&master
->dev
);
1747 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1748 dynamic
? " (dynamic)" : "");
1750 /* If we're using a queued driver, start the queue */
1751 if (master
->transfer
)
1752 dev_info(dev
, "master is unqueued, this is deprecated\n");
1754 status
= spi_master_initialize_queue(master
);
1756 device_del(&master
->dev
);
1760 /* add statistics */
1761 spin_lock_init(&master
->statistics
.lock
);
1763 mutex_lock(&board_lock
);
1764 list_add_tail(&master
->list
, &spi_master_list
);
1765 list_for_each_entry(bi
, &board_list
, list
)
1766 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1767 mutex_unlock(&board_lock
);
1769 /* Register devices from the device tree and ACPI */
1770 of_register_spi_devices(master
);
1771 acpi_register_spi_devices(master
);
1775 EXPORT_SYMBOL_GPL(spi_register_master
);
1777 static void devm_spi_unregister(struct device
*dev
, void *res
)
1779 spi_unregister_master(*(struct spi_master
**)res
);
1783 * dev_spi_register_master - register managed SPI master controller
1784 * @dev: device managing SPI master
1785 * @master: initialized master, originally from spi_alloc_master()
1786 * Context: can sleep
1788 * Register a SPI device as with spi_register_master() which will
1789 * automatically be unregister
1791 int devm_spi_register_master(struct device
*dev
, struct spi_master
*master
)
1793 struct spi_master
**ptr
;
1796 ptr
= devres_alloc(devm_spi_unregister
, sizeof(*ptr
), GFP_KERNEL
);
1800 ret
= spi_register_master(master
);
1803 devres_add(dev
, ptr
);
1810 EXPORT_SYMBOL_GPL(devm_spi_register_master
);
1812 static int __unregister(struct device
*dev
, void *null
)
1814 spi_unregister_device(to_spi_device(dev
));
1819 * spi_unregister_master - unregister SPI master controller
1820 * @master: the master being unregistered
1821 * Context: can sleep
1823 * This call is used only by SPI master controller drivers, which are the
1824 * only ones directly touching chip registers.
1826 * This must be called from context that can sleep.
1828 void spi_unregister_master(struct spi_master
*master
)
1832 if (master
->queued
) {
1833 if (spi_destroy_queue(master
))
1834 dev_err(&master
->dev
, "queue remove failed\n");
1837 mutex_lock(&board_lock
);
1838 list_del(&master
->list
);
1839 mutex_unlock(&board_lock
);
1841 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1842 device_unregister(&master
->dev
);
1844 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1846 int spi_master_suspend(struct spi_master
*master
)
1850 /* Basically no-ops for non-queued masters */
1851 if (!master
->queued
)
1854 ret
= spi_stop_queue(master
);
1856 dev_err(&master
->dev
, "queue stop failed\n");
1860 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1862 int spi_master_resume(struct spi_master
*master
)
1866 if (!master
->queued
)
1869 ret
= spi_start_queue(master
);
1871 dev_err(&master
->dev
, "queue restart failed\n");
1875 EXPORT_SYMBOL_GPL(spi_master_resume
);
1877 static int __spi_master_match(struct device
*dev
, const void *data
)
1879 struct spi_master
*m
;
1880 const u16
*bus_num
= data
;
1882 m
= container_of(dev
, struct spi_master
, dev
);
1883 return m
->bus_num
== *bus_num
;
1887 * spi_busnum_to_master - look up master associated with bus_num
1888 * @bus_num: the master's bus number
1889 * Context: can sleep
1891 * This call may be used with devices that are registered after
1892 * arch init time. It returns a refcounted pointer to the relevant
1893 * spi_master (which the caller must release), or NULL if there is
1894 * no such master registered.
1896 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1899 struct spi_master
*master
= NULL
;
1901 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1902 __spi_master_match
);
1904 master
= container_of(dev
, struct spi_master
, dev
);
1905 /* reference got in class_find_device */
1908 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1911 /*-------------------------------------------------------------------------*/
1913 /* Core methods for SPI master protocol drivers. Some of the
1914 * other core methods are currently defined as inline functions.
1917 static int __spi_validate_bits_per_word(struct spi_master
*master
, u8 bits_per_word
)
1919 if (master
->bits_per_word_mask
) {
1920 /* Only 32 bits fit in the mask */
1921 if (bits_per_word
> 32)
1923 if (!(master
->bits_per_word_mask
&
1924 SPI_BPW_MASK(bits_per_word
)))
1932 * spi_setup - setup SPI mode and clock rate
1933 * @spi: the device whose settings are being modified
1934 * Context: can sleep, and no requests are queued to the device
1936 * SPI protocol drivers may need to update the transfer mode if the
1937 * device doesn't work with its default. They may likewise need
1938 * to update clock rates or word sizes from initial values. This function
1939 * changes those settings, and must be called from a context that can sleep.
1940 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1941 * effect the next time the device is selected and data is transferred to
1942 * or from it. When this function returns, the spi device is deselected.
1944 * Note that this call will fail if the protocol driver specifies an option
1945 * that the underlying controller or its driver does not support. For
1946 * example, not all hardware supports wire transfers using nine bit words,
1947 * LSB-first wire encoding, or active-high chipselects.
1949 int spi_setup(struct spi_device
*spi
)
1951 unsigned bad_bits
, ugly_bits
;
1954 /* check mode to prevent that DUAL and QUAD set at the same time
1956 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1957 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1959 "setup: can not select dual and quad at the same time\n");
1962 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1964 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1965 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1967 /* help drivers fail *cleanly* when they need options
1968 * that aren't supported with their current master
1970 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1971 ugly_bits
= bad_bits
&
1972 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
);
1975 "setup: ignoring unsupported mode bits %x\n",
1977 spi
->mode
&= ~ugly_bits
;
1978 bad_bits
&= ~ugly_bits
;
1981 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1986 if (!spi
->bits_per_word
)
1987 spi
->bits_per_word
= 8;
1989 if (__spi_validate_bits_per_word(spi
->master
, spi
->bits_per_word
))
1992 if (!spi
->max_speed_hz
)
1993 spi
->max_speed_hz
= spi
->master
->max_speed_hz
;
1995 spi_set_cs(spi
, false);
1997 if (spi
->master
->setup
)
1998 status
= spi
->master
->setup(spi
);
2000 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2001 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
2002 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
2003 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
2004 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
2005 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
2006 spi
->bits_per_word
, spi
->max_speed_hz
,
2011 EXPORT_SYMBOL_GPL(spi_setup
);
2013 static int __spi_validate(struct spi_device
*spi
, struct spi_message
*message
)
2015 struct spi_master
*master
= spi
->master
;
2016 struct spi_transfer
*xfer
;
2019 if (list_empty(&message
->transfers
))
2022 /* Half-duplex links include original MicroWire, and ones with
2023 * only one data pin like SPI_3WIRE (switches direction) or where
2024 * either MOSI or MISO is missing. They can also be caused by
2025 * software limitations.
2027 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
2028 || (spi
->mode
& SPI_3WIRE
)) {
2029 unsigned flags
= master
->flags
;
2031 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
2032 if (xfer
->rx_buf
&& xfer
->tx_buf
)
2034 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
2036 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
2042 * Set transfer bits_per_word and max speed as spi device default if
2043 * it is not set for this transfer.
2044 * Set transfer tx_nbits and rx_nbits as single transfer default
2045 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2047 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
2048 message
->frame_length
+= xfer
->len
;
2049 if (!xfer
->bits_per_word
)
2050 xfer
->bits_per_word
= spi
->bits_per_word
;
2052 if (!xfer
->speed_hz
)
2053 xfer
->speed_hz
= spi
->max_speed_hz
;
2054 if (!xfer
->speed_hz
)
2055 xfer
->speed_hz
= master
->max_speed_hz
;
2057 if (master
->max_speed_hz
&&
2058 xfer
->speed_hz
> master
->max_speed_hz
)
2059 xfer
->speed_hz
= master
->max_speed_hz
;
2061 if (__spi_validate_bits_per_word(master
, xfer
->bits_per_word
))
2065 * SPI transfer length should be multiple of SPI word size
2066 * where SPI word size should be power-of-two multiple
2068 if (xfer
->bits_per_word
<= 8)
2070 else if (xfer
->bits_per_word
<= 16)
2075 /* No partial transfers accepted */
2076 if (xfer
->len
% w_size
)
2079 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
2080 xfer
->speed_hz
< master
->min_speed_hz
)
2083 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
2084 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
2085 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
2086 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
2087 /* check transfer tx/rx_nbits:
2088 * 1. check the value matches one of single, dual and quad
2089 * 2. check tx/rx_nbits match the mode in spi_device
2092 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
2093 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
2094 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
2096 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
2097 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
2099 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
2100 !(spi
->mode
& SPI_TX_QUAD
))
2103 /* check transfer rx_nbits */
2105 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
2106 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
2107 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
2109 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
2110 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
2112 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
2113 !(spi
->mode
& SPI_RX_QUAD
))
2118 message
->status
= -EINPROGRESS
;
2123 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
2125 struct spi_master
*master
= spi
->master
;
2129 SPI_STATISTICS_INCREMENT_FIELD(&master
->statistics
, spi_async
);
2130 SPI_STATISTICS_INCREMENT_FIELD(&spi
->statistics
, spi_async
);
2132 trace_spi_message_submit(message
);
2134 return master
->transfer(spi
, message
);
2138 * spi_async - asynchronous SPI transfer
2139 * @spi: device with which data will be exchanged
2140 * @message: describes the data transfers, including completion callback
2141 * Context: any (irqs may be blocked, etc)
2143 * This call may be used in_irq and other contexts which can't sleep,
2144 * as well as from task contexts which can sleep.
2146 * The completion callback is invoked in a context which can't sleep.
2147 * Before that invocation, the value of message->status is undefined.
2148 * When the callback is issued, message->status holds either zero (to
2149 * indicate complete success) or a negative error code. After that
2150 * callback returns, the driver which issued the transfer request may
2151 * deallocate the associated memory; it's no longer in use by any SPI
2152 * core or controller driver code.
2154 * Note that although all messages to a spi_device are handled in
2155 * FIFO order, messages may go to different devices in other orders.
2156 * Some device might be higher priority, or have various "hard" access
2157 * time requirements, for example.
2159 * On detection of any fault during the transfer, processing of
2160 * the entire message is aborted, and the device is deselected.
2161 * Until returning from the associated message completion callback,
2162 * no other spi_message queued to that device will be processed.
2163 * (This rule applies equally to all the synchronous transfer calls,
2164 * which are wrappers around this core asynchronous primitive.)
2166 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
2168 struct spi_master
*master
= spi
->master
;
2170 unsigned long flags
;
2172 ret
= __spi_validate(spi
, message
);
2176 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2178 if (master
->bus_lock_flag
)
2181 ret
= __spi_async(spi
, message
);
2183 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2187 EXPORT_SYMBOL_GPL(spi_async
);
2190 * spi_async_locked - version of spi_async with exclusive bus usage
2191 * @spi: device with which data will be exchanged
2192 * @message: describes the data transfers, including completion callback
2193 * Context: any (irqs may be blocked, etc)
2195 * This call may be used in_irq and other contexts which can't sleep,
2196 * as well as from task contexts which can sleep.
2198 * The completion callback is invoked in a context which can't sleep.
2199 * Before that invocation, the value of message->status is undefined.
2200 * When the callback is issued, message->status holds either zero (to
2201 * indicate complete success) or a negative error code. After that
2202 * callback returns, the driver which issued the transfer request may
2203 * deallocate the associated memory; it's no longer in use by any SPI
2204 * core or controller driver code.
2206 * Note that although all messages to a spi_device are handled in
2207 * FIFO order, messages may go to different devices in other orders.
2208 * Some device might be higher priority, or have various "hard" access
2209 * time requirements, for example.
2211 * On detection of any fault during the transfer, processing of
2212 * the entire message is aborted, and the device is deselected.
2213 * Until returning from the associated message completion callback,
2214 * no other spi_message queued to that device will be processed.
2215 * (This rule applies equally to all the synchronous transfer calls,
2216 * which are wrappers around this core asynchronous primitive.)
2218 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
2220 struct spi_master
*master
= spi
->master
;
2222 unsigned long flags
;
2224 ret
= __spi_validate(spi
, message
);
2228 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2230 ret
= __spi_async(spi
, message
);
2232 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2237 EXPORT_SYMBOL_GPL(spi_async_locked
);
2240 /*-------------------------------------------------------------------------*/
2242 /* Utility methods for SPI master protocol drivers, layered on
2243 * top of the core. Some other utility methods are defined as
2247 static void spi_complete(void *arg
)
2252 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
2255 DECLARE_COMPLETION_ONSTACK(done
);
2257 struct spi_master
*master
= spi
->master
;
2258 unsigned long flags
;
2260 status
= __spi_validate(spi
, message
);
2264 message
->complete
= spi_complete
;
2265 message
->context
= &done
;
2268 SPI_STATISTICS_INCREMENT_FIELD(&master
->statistics
, spi_sync
);
2269 SPI_STATISTICS_INCREMENT_FIELD(&spi
->statistics
, spi_sync
);
2272 mutex_lock(&master
->bus_lock_mutex
);
2274 /* If we're not using the legacy transfer method then we will
2275 * try to transfer in the calling context so special case.
2276 * This code would be less tricky if we could remove the
2277 * support for driver implemented message queues.
2279 if (master
->transfer
== spi_queued_transfer
) {
2280 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2282 trace_spi_message_submit(message
);
2284 status
= __spi_queued_transfer(spi
, message
, false);
2286 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2288 status
= spi_async_locked(spi
, message
);
2292 mutex_unlock(&master
->bus_lock_mutex
);
2295 /* Push out the messages in the calling context if we
2298 if (master
->transfer
== spi_queued_transfer
) {
2299 SPI_STATISTICS_INCREMENT_FIELD(&master
->statistics
,
2300 spi_sync_immediate
);
2301 SPI_STATISTICS_INCREMENT_FIELD(&spi
->statistics
,
2302 spi_sync_immediate
);
2303 __spi_pump_messages(master
, false);
2306 wait_for_completion(&done
);
2307 status
= message
->status
;
2309 message
->context
= NULL
;
2314 * spi_sync - blocking/synchronous SPI data transfers
2315 * @spi: device with which data will be exchanged
2316 * @message: describes the data transfers
2317 * Context: can sleep
2319 * This call may only be used from a context that may sleep. The sleep
2320 * is non-interruptible, and has no timeout. Low-overhead controller
2321 * drivers may DMA directly into and out of the message buffers.
2323 * Note that the SPI device's chip select is active during the message,
2324 * and then is normally disabled between messages. Drivers for some
2325 * frequently-used devices may want to minimize costs of selecting a chip,
2326 * by leaving it selected in anticipation that the next message will go
2327 * to the same chip. (That may increase power usage.)
2329 * Also, the caller is guaranteeing that the memory associated with the
2330 * message will not be freed before this call returns.
2332 * It returns zero on success, else a negative error code.
2334 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
2336 return __spi_sync(spi
, message
, 0);
2338 EXPORT_SYMBOL_GPL(spi_sync
);
2341 * spi_sync_locked - version of spi_sync with exclusive bus usage
2342 * @spi: device with which data will be exchanged
2343 * @message: describes the data transfers
2344 * Context: can sleep
2346 * This call may only be used from a context that may sleep. The sleep
2347 * is non-interruptible, and has no timeout. Low-overhead controller
2348 * drivers may DMA directly into and out of the message buffers.
2350 * This call should be used by drivers that require exclusive access to the
2351 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2352 * be released by a spi_bus_unlock call when the exclusive access is over.
2354 * It returns zero on success, else a negative error code.
2356 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
2358 return __spi_sync(spi
, message
, 1);
2360 EXPORT_SYMBOL_GPL(spi_sync_locked
);
2363 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2364 * @master: SPI bus master that should be locked for exclusive bus access
2365 * Context: can sleep
2367 * This call may only be used from a context that may sleep. The sleep
2368 * is non-interruptible, and has no timeout.
2370 * This call should be used by drivers that require exclusive access to the
2371 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2372 * exclusive access is over. Data transfer must be done by spi_sync_locked
2373 * and spi_async_locked calls when the SPI bus lock is held.
2375 * It returns zero on success, else a negative error code.
2377 int spi_bus_lock(struct spi_master
*master
)
2379 unsigned long flags
;
2381 mutex_lock(&master
->bus_lock_mutex
);
2383 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2384 master
->bus_lock_flag
= 1;
2385 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2387 /* mutex remains locked until spi_bus_unlock is called */
2391 EXPORT_SYMBOL_GPL(spi_bus_lock
);
2394 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2395 * @master: SPI bus master that was locked for exclusive bus access
2396 * Context: can sleep
2398 * This call may only be used from a context that may sleep. The sleep
2399 * is non-interruptible, and has no timeout.
2401 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2404 * It returns zero on success, else a negative error code.
2406 int spi_bus_unlock(struct spi_master
*master
)
2408 master
->bus_lock_flag
= 0;
2410 mutex_unlock(&master
->bus_lock_mutex
);
2414 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
2416 /* portable code must never pass more than 32 bytes */
2417 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2422 * spi_write_then_read - SPI synchronous write followed by read
2423 * @spi: device with which data will be exchanged
2424 * @txbuf: data to be written (need not be dma-safe)
2425 * @n_tx: size of txbuf, in bytes
2426 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2427 * @n_rx: size of rxbuf, in bytes
2428 * Context: can sleep
2430 * This performs a half duplex MicroWire style transaction with the
2431 * device, sending txbuf and then reading rxbuf. The return value
2432 * is zero for success, else a negative errno status code.
2433 * This call may only be used from a context that may sleep.
2435 * Parameters to this routine are always copied using a small buffer;
2436 * portable code should never use this for more than 32 bytes.
2437 * Performance-sensitive or bulk transfer code should instead use
2438 * spi_{async,sync}() calls with dma-safe buffers.
2440 int spi_write_then_read(struct spi_device
*spi
,
2441 const void *txbuf
, unsigned n_tx
,
2442 void *rxbuf
, unsigned n_rx
)
2444 static DEFINE_MUTEX(lock
);
2447 struct spi_message message
;
2448 struct spi_transfer x
[2];
2451 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2452 * copying here, (as a pure convenience thing), but we can
2453 * keep heap costs out of the hot path unless someone else is
2454 * using the pre-allocated buffer or the transfer is too large.
2456 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
2457 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
2458 GFP_KERNEL
| GFP_DMA
);
2465 spi_message_init(&message
);
2466 memset(x
, 0, sizeof(x
));
2469 spi_message_add_tail(&x
[0], &message
);
2473 spi_message_add_tail(&x
[1], &message
);
2476 memcpy(local_buf
, txbuf
, n_tx
);
2477 x
[0].tx_buf
= local_buf
;
2478 x
[1].rx_buf
= local_buf
+ n_tx
;
2481 status
= spi_sync(spi
, &message
);
2483 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
2485 if (x
[0].tx_buf
== buf
)
2486 mutex_unlock(&lock
);
2492 EXPORT_SYMBOL_GPL(spi_write_then_read
);
2494 /*-------------------------------------------------------------------------*/
2496 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2497 static int __spi_of_device_match(struct device
*dev
, void *data
)
2499 return dev
->of_node
== data
;
2502 /* must call put_device() when done with returned spi_device device */
2503 static struct spi_device
*of_find_spi_device_by_node(struct device_node
*node
)
2505 struct device
*dev
= bus_find_device(&spi_bus_type
, NULL
, node
,
2506 __spi_of_device_match
);
2507 return dev
? to_spi_device(dev
) : NULL
;
2510 static int __spi_of_master_match(struct device
*dev
, const void *data
)
2512 return dev
->of_node
== data
;
2515 /* the spi masters are not using spi_bus, so we find it with another way */
2516 static struct spi_master
*of_find_spi_master_by_node(struct device_node
*node
)
2520 dev
= class_find_device(&spi_master_class
, NULL
, node
,
2521 __spi_of_master_match
);
2525 /* reference got in class_find_device */
2526 return container_of(dev
, struct spi_master
, dev
);
2529 static int of_spi_notify(struct notifier_block
*nb
, unsigned long action
,
2532 struct of_reconfig_data
*rd
= arg
;
2533 struct spi_master
*master
;
2534 struct spi_device
*spi
;
2536 switch (of_reconfig_get_state_change(action
, arg
)) {
2537 case OF_RECONFIG_CHANGE_ADD
:
2538 master
= of_find_spi_master_by_node(rd
->dn
->parent
);
2540 return NOTIFY_OK
; /* not for us */
2542 spi
= of_register_spi_device(master
, rd
->dn
);
2543 put_device(&master
->dev
);
2546 pr_err("%s: failed to create for '%s'\n",
2547 __func__
, rd
->dn
->full_name
);
2548 return notifier_from_errno(PTR_ERR(spi
));
2552 case OF_RECONFIG_CHANGE_REMOVE
:
2553 /* find our device by node */
2554 spi
= of_find_spi_device_by_node(rd
->dn
);
2556 return NOTIFY_OK
; /* no? not meant for us */
2558 /* unregister takes one ref away */
2559 spi_unregister_device(spi
);
2561 /* and put the reference of the find */
2562 put_device(&spi
->dev
);
2569 static struct notifier_block spi_of_notifier
= {
2570 .notifier_call
= of_spi_notify
,
2572 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2573 extern struct notifier_block spi_of_notifier
;
2574 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2576 static int __init
spi_init(void)
2580 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
2586 status
= bus_register(&spi_bus_type
);
2590 status
= class_register(&spi_master_class
);
2594 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
2595 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier
));
2600 bus_unregister(&spi_bus_type
);
2608 /* board_info is normally registered in arch_initcall(),
2609 * but even essential drivers wait till later
2611 * REVISIT only boardinfo really needs static linking. the rest (device and
2612 * driver registration) _could_ be dynamically linked (modular) ... costs
2613 * include needing to have boardinfo data structures be much more public.
2615 postcore_initcall(spi_init
);