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.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #include <linux/kernel.h>
23 #include <linux/kmod.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/cache.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/mutex.h>
30 #include <linux/of_device.h>
31 #include <linux/of_irq.h>
32 #include <linux/clk/clk-conf.h>
33 #include <linux/slab.h>
34 #include <linux/mod_devicetable.h>
35 #include <linux/spi/spi.h>
36 #include <linux/of_gpio.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/export.h>
39 #include <linux/sched/rt.h>
40 #include <linux/delay.h>
41 #include <linux/kthread.h>
42 #include <linux/ioport.h>
43 #include <linux/acpi.h>
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/spi.h>
48 static void spidev_release(struct device
*dev
)
50 struct spi_device
*spi
= to_spi_device(dev
);
52 /* spi masters may cleanup for released devices */
53 if (spi
->master
->cleanup
)
54 spi
->master
->cleanup(spi
);
56 spi_master_put(spi
->master
);
61 modalias_show(struct device
*dev
, struct device_attribute
*a
, char *buf
)
63 const struct spi_device
*spi
= to_spi_device(dev
);
66 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
- 1);
70 return sprintf(buf
, "%s%s\n", SPI_MODULE_PREFIX
, spi
->modalias
);
72 static DEVICE_ATTR_RO(modalias
);
74 static struct attribute
*spi_dev_attrs
[] = {
75 &dev_attr_modalias
.attr
,
78 ATTRIBUTE_GROUPS(spi_dev
);
80 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
81 * and the sysfs version makes coldplug work too.
84 static const struct spi_device_id
*spi_match_id(const struct spi_device_id
*id
,
85 const struct spi_device
*sdev
)
88 if (!strcmp(sdev
->modalias
, id
->name
))
95 const struct spi_device_id
*spi_get_device_id(const struct spi_device
*sdev
)
97 const struct spi_driver
*sdrv
= to_spi_driver(sdev
->dev
.driver
);
99 return spi_match_id(sdrv
->id_table
, sdev
);
101 EXPORT_SYMBOL_GPL(spi_get_device_id
);
103 static int spi_match_device(struct device
*dev
, struct device_driver
*drv
)
105 const struct spi_device
*spi
= to_spi_device(dev
);
106 const struct spi_driver
*sdrv
= to_spi_driver(drv
);
108 /* Attempt an OF style match */
109 if (of_driver_match_device(dev
, drv
))
113 if (acpi_driver_match_device(dev
, drv
))
117 return !!spi_match_id(sdrv
->id_table
, spi
);
119 return strcmp(spi
->modalias
, drv
->name
) == 0;
122 static int spi_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
124 const struct spi_device
*spi
= to_spi_device(dev
);
127 rc
= acpi_device_uevent_modalias(dev
, env
);
131 add_uevent_var(env
, "MODALIAS=%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
135 #ifdef CONFIG_PM_SLEEP
136 static int spi_legacy_suspend(struct device
*dev
, pm_message_t message
)
139 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
141 /* suspend will stop irqs and dma; no more i/o */
144 value
= drv
->suspend(to_spi_device(dev
), message
);
146 dev_dbg(dev
, "... can't suspend\n");
151 static int spi_legacy_resume(struct device
*dev
)
154 struct spi_driver
*drv
= to_spi_driver(dev
->driver
);
156 /* resume may restart the i/o queue */
159 value
= drv
->resume(to_spi_device(dev
));
161 dev_dbg(dev
, "... can't resume\n");
166 static int spi_pm_suspend(struct device
*dev
)
168 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
171 return pm_generic_suspend(dev
);
173 return spi_legacy_suspend(dev
, PMSG_SUSPEND
);
176 static int spi_pm_resume(struct device
*dev
)
178 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
181 return pm_generic_resume(dev
);
183 return spi_legacy_resume(dev
);
186 static int spi_pm_freeze(struct device
*dev
)
188 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
191 return pm_generic_freeze(dev
);
193 return spi_legacy_suspend(dev
, PMSG_FREEZE
);
196 static int spi_pm_thaw(struct device
*dev
)
198 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
201 return pm_generic_thaw(dev
);
203 return spi_legacy_resume(dev
);
206 static int spi_pm_poweroff(struct device
*dev
)
208 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
211 return pm_generic_poweroff(dev
);
213 return spi_legacy_suspend(dev
, PMSG_HIBERNATE
);
216 static int spi_pm_restore(struct device
*dev
)
218 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
221 return pm_generic_restore(dev
);
223 return spi_legacy_resume(dev
);
226 #define spi_pm_suspend NULL
227 #define spi_pm_resume NULL
228 #define spi_pm_freeze NULL
229 #define spi_pm_thaw NULL
230 #define spi_pm_poweroff NULL
231 #define spi_pm_restore NULL
234 static const struct dev_pm_ops spi_pm
= {
235 .suspend
= spi_pm_suspend
,
236 .resume
= spi_pm_resume
,
237 .freeze
= spi_pm_freeze
,
239 .poweroff
= spi_pm_poweroff
,
240 .restore
= spi_pm_restore
,
242 pm_generic_runtime_suspend
,
243 pm_generic_runtime_resume
,
248 struct bus_type spi_bus_type
= {
250 .dev_groups
= spi_dev_groups
,
251 .match
= spi_match_device
,
252 .uevent
= spi_uevent
,
255 EXPORT_SYMBOL_GPL(spi_bus_type
);
258 static int spi_drv_probe(struct device
*dev
)
260 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
263 ret
= of_clk_set_defaults(dev
->of_node
, false);
267 acpi_dev_pm_attach(dev
, true);
268 ret
= sdrv
->probe(to_spi_device(dev
));
270 acpi_dev_pm_detach(dev
, true);
275 static int spi_drv_remove(struct device
*dev
)
277 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
280 ret
= sdrv
->remove(to_spi_device(dev
));
281 acpi_dev_pm_detach(dev
, true);
286 static void spi_drv_shutdown(struct device
*dev
)
288 const struct spi_driver
*sdrv
= to_spi_driver(dev
->driver
);
290 sdrv
->shutdown(to_spi_device(dev
));
294 * spi_register_driver - register a SPI driver
295 * @sdrv: the driver to register
298 int spi_register_driver(struct spi_driver
*sdrv
)
300 sdrv
->driver
.bus
= &spi_bus_type
;
302 sdrv
->driver
.probe
= spi_drv_probe
;
304 sdrv
->driver
.remove
= spi_drv_remove
;
306 sdrv
->driver
.shutdown
= spi_drv_shutdown
;
307 return driver_register(&sdrv
->driver
);
309 EXPORT_SYMBOL_GPL(spi_register_driver
);
311 /*-------------------------------------------------------------------------*/
313 /* SPI devices should normally not be created by SPI device drivers; that
314 * would make them board-specific. Similarly with SPI master drivers.
315 * Device registration normally goes into like arch/.../mach.../board-YYY.c
316 * with other readonly (flashable) information about mainboard devices.
320 struct list_head list
;
321 struct spi_board_info board_info
;
324 static LIST_HEAD(board_list
);
325 static LIST_HEAD(spi_master_list
);
328 * Used to protect add/del opertion for board_info list and
329 * spi_master list, and their matching process
331 static DEFINE_MUTEX(board_lock
);
334 * spi_alloc_device - Allocate a new SPI device
335 * @master: Controller to which device is connected
338 * Allows a driver to allocate and initialize a spi_device without
339 * registering it immediately. This allows a driver to directly
340 * fill the spi_device with device parameters before calling
341 * spi_add_device() on it.
343 * Caller is responsible to call spi_add_device() on the returned
344 * spi_device structure to add it to the SPI master. If the caller
345 * needs to discard the spi_device without adding it, then it should
346 * call spi_dev_put() on it.
348 * Returns a pointer to the new device, or NULL.
350 struct spi_device
*spi_alloc_device(struct spi_master
*master
)
352 struct spi_device
*spi
;
354 if (!spi_master_get(master
))
357 spi
= kzalloc(sizeof(*spi
), GFP_KERNEL
);
359 spi_master_put(master
);
363 spi
->master
= master
;
364 spi
->dev
.parent
= &master
->dev
;
365 spi
->dev
.bus
= &spi_bus_type
;
366 spi
->dev
.release
= spidev_release
;
367 spi
->cs_gpio
= -ENOENT
;
368 device_initialize(&spi
->dev
);
371 EXPORT_SYMBOL_GPL(spi_alloc_device
);
373 static void spi_dev_set_name(struct spi_device
*spi
)
375 struct acpi_device
*adev
= ACPI_COMPANION(&spi
->dev
);
378 dev_set_name(&spi
->dev
, "spi-%s", acpi_dev_name(adev
));
382 dev_set_name(&spi
->dev
, "%s.%u", dev_name(&spi
->master
->dev
),
386 static int spi_dev_check(struct device
*dev
, void *data
)
388 struct spi_device
*spi
= to_spi_device(dev
);
389 struct spi_device
*new_spi
= data
;
391 if (spi
->master
== new_spi
->master
&&
392 spi
->chip_select
== new_spi
->chip_select
)
398 * spi_add_device - Add spi_device allocated with spi_alloc_device
399 * @spi: spi_device to register
401 * Companion function to spi_alloc_device. Devices allocated with
402 * spi_alloc_device can be added onto the spi bus with this function.
404 * Returns 0 on success; negative errno on failure
406 int spi_add_device(struct spi_device
*spi
)
408 static DEFINE_MUTEX(spi_add_lock
);
409 struct spi_master
*master
= spi
->master
;
410 struct device
*dev
= master
->dev
.parent
;
413 /* Chipselects are numbered 0..max; validate. */
414 if (spi
->chip_select
>= master
->num_chipselect
) {
415 dev_err(dev
, "cs%d >= max %d\n",
417 master
->num_chipselect
);
421 /* Set the bus ID string */
422 spi_dev_set_name(spi
);
424 /* We need to make sure there's no other device with this
425 * chipselect **BEFORE** we call setup(), else we'll trash
426 * its configuration. Lock against concurrent add() calls.
428 mutex_lock(&spi_add_lock
);
430 status
= bus_for_each_dev(&spi_bus_type
, NULL
, spi
, spi_dev_check
);
432 dev_err(dev
, "chipselect %d already in use\n",
437 if (master
->cs_gpios
)
438 spi
->cs_gpio
= master
->cs_gpios
[spi
->chip_select
];
440 /* Drivers may modify this initial i/o setup, but will
441 * normally rely on the device being setup. Devices
442 * using SPI_CS_HIGH can't coexist well otherwise...
444 status
= spi_setup(spi
);
446 dev_err(dev
, "can't setup %s, status %d\n",
447 dev_name(&spi
->dev
), status
);
451 /* Device may be bound to an active driver when this returns */
452 status
= device_add(&spi
->dev
);
454 dev_err(dev
, "can't add %s, status %d\n",
455 dev_name(&spi
->dev
), status
);
457 dev_dbg(dev
, "registered child %s\n", dev_name(&spi
->dev
));
460 mutex_unlock(&spi_add_lock
);
463 EXPORT_SYMBOL_GPL(spi_add_device
);
466 * spi_new_device - instantiate one new SPI device
467 * @master: Controller to which device is connected
468 * @chip: Describes the SPI device
471 * On typical mainboards, this is purely internal; and it's not needed
472 * after board init creates the hard-wired devices. Some development
473 * platforms may not be able to use spi_register_board_info though, and
474 * this is exported so that for example a USB or parport based adapter
475 * driver could add devices (which it would learn about out-of-band).
477 * Returns the new device, or NULL.
479 struct spi_device
*spi_new_device(struct spi_master
*master
,
480 struct spi_board_info
*chip
)
482 struct spi_device
*proxy
;
485 /* NOTE: caller did any chip->bus_num checks necessary.
487 * Also, unless we change the return value convention to use
488 * error-or-pointer (not NULL-or-pointer), troubleshootability
489 * suggests syslogged diagnostics are best here (ugh).
492 proxy
= spi_alloc_device(master
);
496 WARN_ON(strlen(chip
->modalias
) >= sizeof(proxy
->modalias
));
498 proxy
->chip_select
= chip
->chip_select
;
499 proxy
->max_speed_hz
= chip
->max_speed_hz
;
500 proxy
->mode
= chip
->mode
;
501 proxy
->irq
= chip
->irq
;
502 strlcpy(proxy
->modalias
, chip
->modalias
, sizeof(proxy
->modalias
));
503 proxy
->dev
.platform_data
= (void *) chip
->platform_data
;
504 proxy
->controller_data
= chip
->controller_data
;
505 proxy
->controller_state
= NULL
;
507 status
= spi_add_device(proxy
);
515 EXPORT_SYMBOL_GPL(spi_new_device
);
517 static void spi_match_master_to_boardinfo(struct spi_master
*master
,
518 struct spi_board_info
*bi
)
520 struct spi_device
*dev
;
522 if (master
->bus_num
!= bi
->bus_num
)
525 dev
= spi_new_device(master
, bi
);
527 dev_err(master
->dev
.parent
, "can't create new device for %s\n",
532 * spi_register_board_info - register SPI devices for a given board
533 * @info: array of chip descriptors
534 * @n: how many descriptors are provided
537 * Board-specific early init code calls this (probably during arch_initcall)
538 * with segments of the SPI device table. Any device nodes are created later,
539 * after the relevant parent SPI controller (bus_num) is defined. We keep
540 * this table of devices forever, so that reloading a controller driver will
541 * not make Linux forget about these hard-wired devices.
543 * Other code can also call this, e.g. a particular add-on board might provide
544 * SPI devices through its expansion connector, so code initializing that board
545 * would naturally declare its SPI devices.
547 * The board info passed can safely be __initdata ... but be careful of
548 * any embedded pointers (platform_data, etc), they're copied as-is.
550 int spi_register_board_info(struct spi_board_info
const *info
, unsigned n
)
552 struct boardinfo
*bi
;
555 bi
= kzalloc(n
* sizeof(*bi
), GFP_KERNEL
);
559 for (i
= 0; i
< n
; i
++, bi
++, info
++) {
560 struct spi_master
*master
;
562 memcpy(&bi
->board_info
, info
, sizeof(*info
));
563 mutex_lock(&board_lock
);
564 list_add_tail(&bi
->list
, &board_list
);
565 list_for_each_entry(master
, &spi_master_list
, list
)
566 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
567 mutex_unlock(&board_lock
);
573 /*-------------------------------------------------------------------------*/
575 static void spi_set_cs(struct spi_device
*spi
, bool enable
)
577 if (spi
->mode
& SPI_CS_HIGH
)
580 if (spi
->cs_gpio
>= 0)
581 gpio_set_value(spi
->cs_gpio
, !enable
);
582 else if (spi
->master
->set_cs
)
583 spi
->master
->set_cs(spi
, !enable
);
586 #ifdef CONFIG_HAS_DMA
587 static int spi_map_buf(struct spi_master
*master
, struct device
*dev
,
588 struct sg_table
*sgt
, void *buf
, size_t len
,
589 enum dma_data_direction dir
)
591 const bool vmalloced_buf
= is_vmalloc_addr(buf
);
592 const int desc_len
= vmalloced_buf
? PAGE_SIZE
: master
->max_dma_len
;
593 const int sgs
= DIV_ROUND_UP(len
, desc_len
);
594 struct page
*vm_page
;
599 ret
= sg_alloc_table(sgt
, sgs
, GFP_KERNEL
);
603 for (i
= 0; i
< sgs
; i
++) {
604 min
= min_t(size_t, len
, desc_len
);
607 vm_page
= vmalloc_to_page(buf
);
612 sg_buf
= page_address(vm_page
) +
613 ((size_t)buf
& ~PAGE_MASK
);
618 sg_set_buf(&sgt
->sgl
[i
], sg_buf
, min
);
624 ret
= dma_map_sg(dev
, sgt
->sgl
, sgt
->nents
, dir
);
637 static void spi_unmap_buf(struct spi_master
*master
, struct device
*dev
,
638 struct sg_table
*sgt
, enum dma_data_direction dir
)
640 if (sgt
->orig_nents
) {
641 dma_unmap_sg(dev
, sgt
->sgl
, sgt
->orig_nents
, dir
);
646 static int __spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
648 struct device
*tx_dev
, *rx_dev
;
649 struct spi_transfer
*xfer
;
652 if (!master
->can_dma
)
655 tx_dev
= master
->dma_tx
->device
->dev
;
656 rx_dev
= master
->dma_rx
->device
->dev
;
658 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
659 if (!master
->can_dma(master
, msg
->spi
, xfer
))
662 if (xfer
->tx_buf
!= NULL
) {
663 ret
= spi_map_buf(master
, tx_dev
, &xfer
->tx_sg
,
664 (void *)xfer
->tx_buf
, xfer
->len
,
670 if (xfer
->rx_buf
!= NULL
) {
671 ret
= spi_map_buf(master
, rx_dev
, &xfer
->rx_sg
,
672 xfer
->rx_buf
, xfer
->len
,
675 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
,
682 master
->cur_msg_mapped
= true;
687 static int spi_unmap_msg(struct spi_master
*master
, struct spi_message
*msg
)
689 struct spi_transfer
*xfer
;
690 struct device
*tx_dev
, *rx_dev
;
692 if (!master
->cur_msg_mapped
|| !master
->can_dma
)
695 tx_dev
= master
->dma_tx
->device
->dev
;
696 rx_dev
= master
->dma_rx
->device
->dev
;
698 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
699 if (!master
->can_dma(master
, msg
->spi
, xfer
))
702 spi_unmap_buf(master
, rx_dev
, &xfer
->rx_sg
, DMA_FROM_DEVICE
);
703 spi_unmap_buf(master
, tx_dev
, &xfer
->tx_sg
, DMA_TO_DEVICE
);
708 #else /* !CONFIG_HAS_DMA */
709 static inline int __spi_map_msg(struct spi_master
*master
,
710 struct spi_message
*msg
)
715 static inline int spi_unmap_msg(struct spi_master
*master
,
716 struct spi_message
*msg
)
720 #endif /* !CONFIG_HAS_DMA */
722 static int spi_map_msg(struct spi_master
*master
, struct spi_message
*msg
)
724 struct spi_transfer
*xfer
;
726 unsigned int max_tx
, max_rx
;
728 if (master
->flags
& (SPI_MASTER_MUST_RX
| SPI_MASTER_MUST_TX
)) {
732 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
733 if ((master
->flags
& SPI_MASTER_MUST_TX
) &&
735 max_tx
= max(xfer
->len
, max_tx
);
736 if ((master
->flags
& SPI_MASTER_MUST_RX
) &&
738 max_rx
= max(xfer
->len
, max_rx
);
742 tmp
= krealloc(master
->dummy_tx
, max_tx
,
743 GFP_KERNEL
| GFP_DMA
);
746 master
->dummy_tx
= tmp
;
747 memset(tmp
, 0, max_tx
);
751 tmp
= krealloc(master
->dummy_rx
, max_rx
,
752 GFP_KERNEL
| GFP_DMA
);
755 master
->dummy_rx
= tmp
;
758 if (max_tx
|| max_rx
) {
759 list_for_each_entry(xfer
, &msg
->transfers
,
762 xfer
->tx_buf
= master
->dummy_tx
;
764 xfer
->rx_buf
= master
->dummy_rx
;
769 return __spi_map_msg(master
, msg
);
773 * spi_transfer_one_message - Default implementation of transfer_one_message()
775 * This is a standard implementation of transfer_one_message() for
776 * drivers which impelment a transfer_one() operation. It provides
777 * standard handling of delays and chip select management.
779 static int spi_transfer_one_message(struct spi_master
*master
,
780 struct spi_message
*msg
)
782 struct spi_transfer
*xfer
;
783 bool keep_cs
= false;
787 spi_set_cs(msg
->spi
, true);
789 list_for_each_entry(xfer
, &msg
->transfers
, transfer_list
) {
790 trace_spi_transfer_start(msg
, xfer
);
792 reinit_completion(&master
->xfer_completion
);
794 ret
= master
->transfer_one(master
, msg
->spi
, xfer
);
796 dev_err(&msg
->spi
->dev
,
797 "SPI transfer failed: %d\n", ret
);
803 ms
= xfer
->len
* 8 * 1000 / xfer
->speed_hz
;
804 ms
+= ms
+ 100; /* some tolerance */
806 ms
= wait_for_completion_timeout(&master
->xfer_completion
,
807 msecs_to_jiffies(ms
));
811 dev_err(&msg
->spi
->dev
, "SPI transfer timed out\n");
812 msg
->status
= -ETIMEDOUT
;
815 trace_spi_transfer_stop(msg
, xfer
);
817 if (msg
->status
!= -EINPROGRESS
)
820 if (xfer
->delay_usecs
)
821 udelay(xfer
->delay_usecs
);
823 if (xfer
->cs_change
) {
824 if (list_is_last(&xfer
->transfer_list
,
828 spi_set_cs(msg
->spi
, false);
830 spi_set_cs(msg
->spi
, true);
834 msg
->actual_length
+= xfer
->len
;
838 if (ret
!= 0 || !keep_cs
)
839 spi_set_cs(msg
->spi
, false);
841 if (msg
->status
== -EINPROGRESS
)
844 spi_finalize_current_message(master
);
850 * spi_finalize_current_transfer - report completion of a transfer
851 * @master: the master reporting completion
853 * Called by SPI drivers using the core transfer_one_message()
854 * implementation to notify it that the current interrupt driven
855 * transfer has finished and the next one may be scheduled.
857 void spi_finalize_current_transfer(struct spi_master
*master
)
859 complete(&master
->xfer_completion
);
861 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer
);
864 * spi_pump_messages - kthread work function which processes spi message queue
865 * @work: pointer to kthread work struct contained in the master struct
867 * This function checks if there is any spi message in the queue that
868 * needs processing and if so call out to the driver to initialize hardware
869 * and transfer each message.
872 static void spi_pump_messages(struct kthread_work
*work
)
874 struct spi_master
*master
=
875 container_of(work
, struct spi_master
, pump_messages
);
877 bool was_busy
= false;
880 /* Lock queue and check for queue work */
881 spin_lock_irqsave(&master
->queue_lock
, flags
);
882 if (list_empty(&master
->queue
) || !master
->running
) {
884 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
887 master
->busy
= false;
888 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
889 kfree(master
->dummy_rx
);
890 master
->dummy_rx
= NULL
;
891 kfree(master
->dummy_tx
);
892 master
->dummy_tx
= NULL
;
893 if (master
->unprepare_transfer_hardware
&&
894 master
->unprepare_transfer_hardware(master
))
895 dev_err(&master
->dev
,
896 "failed to unprepare transfer hardware\n");
897 if (master
->auto_runtime_pm
) {
898 pm_runtime_mark_last_busy(master
->dev
.parent
);
899 pm_runtime_put_autosuspend(master
->dev
.parent
);
901 trace_spi_master_idle(master
);
905 /* Make sure we are not already running a message */
906 if (master
->cur_msg
) {
907 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
910 /* Extract head of queue */
912 list_first_entry(&master
->queue
, struct spi_message
, queue
);
914 list_del_init(&master
->cur_msg
->queue
);
919 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
921 if (!was_busy
&& master
->auto_runtime_pm
) {
922 ret
= pm_runtime_get_sync(master
->dev
.parent
);
924 dev_err(&master
->dev
, "Failed to power device: %d\n",
931 trace_spi_master_busy(master
);
933 if (!was_busy
&& master
->prepare_transfer_hardware
) {
934 ret
= master
->prepare_transfer_hardware(master
);
936 dev_err(&master
->dev
,
937 "failed to prepare transfer hardware\n");
939 if (master
->auto_runtime_pm
)
940 pm_runtime_put(master
->dev
.parent
);
945 trace_spi_message_start(master
->cur_msg
);
947 if (master
->prepare_message
) {
948 ret
= master
->prepare_message(master
, master
->cur_msg
);
950 dev_err(&master
->dev
,
951 "failed to prepare message: %d\n", ret
);
952 master
->cur_msg
->status
= ret
;
953 spi_finalize_current_message(master
);
956 master
->cur_msg_prepared
= true;
959 ret
= spi_map_msg(master
, master
->cur_msg
);
961 master
->cur_msg
->status
= ret
;
962 spi_finalize_current_message(master
);
966 ret
= master
->transfer_one_message(master
, master
->cur_msg
);
968 dev_err(&master
->dev
,
969 "failed to transfer one message from queue\n");
974 static int spi_init_queue(struct spi_master
*master
)
976 struct sched_param param
= { .sched_priority
= MAX_RT_PRIO
- 1 };
978 INIT_LIST_HEAD(&master
->queue
);
979 spin_lock_init(&master
->queue_lock
);
981 master
->running
= false;
982 master
->busy
= false;
984 init_kthread_worker(&master
->kworker
);
985 master
->kworker_task
= kthread_run(kthread_worker_fn
,
986 &master
->kworker
, "%s",
987 dev_name(&master
->dev
));
988 if (IS_ERR(master
->kworker_task
)) {
989 dev_err(&master
->dev
, "failed to create message pump task\n");
992 init_kthread_work(&master
->pump_messages
, spi_pump_messages
);
995 * Master config will indicate if this controller should run the
996 * message pump with high (realtime) priority to reduce the transfer
997 * latency on the bus by minimising the delay between a transfer
998 * request and the scheduling of the message pump thread. Without this
999 * setting the message pump thread will remain at default priority.
1002 dev_info(&master
->dev
,
1003 "will run message pump with realtime priority\n");
1004 sched_setscheduler(master
->kworker_task
, SCHED_FIFO
, ¶m
);
1011 * spi_get_next_queued_message() - called by driver to check for queued
1013 * @master: the master to check for queued messages
1015 * If there are more messages in the queue, the next message is returned from
1018 struct spi_message
*spi_get_next_queued_message(struct spi_master
*master
)
1020 struct spi_message
*next
;
1021 unsigned long flags
;
1023 /* get a pointer to the next message, if any */
1024 spin_lock_irqsave(&master
->queue_lock
, flags
);
1025 next
= list_first_entry_or_null(&master
->queue
, struct spi_message
,
1027 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1031 EXPORT_SYMBOL_GPL(spi_get_next_queued_message
);
1034 * spi_finalize_current_message() - the current message is complete
1035 * @master: the master to return the message to
1037 * Called by the driver to notify the core that the message in the front of the
1038 * queue is complete and can be removed from the queue.
1040 void spi_finalize_current_message(struct spi_master
*master
)
1042 struct spi_message
*mesg
;
1043 unsigned long flags
;
1046 spin_lock_irqsave(&master
->queue_lock
, flags
);
1047 mesg
= master
->cur_msg
;
1048 master
->cur_msg
= NULL
;
1050 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1051 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1053 spi_unmap_msg(master
, mesg
);
1055 if (master
->cur_msg_prepared
&& master
->unprepare_message
) {
1056 ret
= master
->unprepare_message(master
, mesg
);
1058 dev_err(&master
->dev
,
1059 "failed to unprepare message: %d\n", ret
);
1062 master
->cur_msg_prepared
= false;
1066 mesg
->complete(mesg
->context
);
1068 trace_spi_message_done(mesg
);
1070 EXPORT_SYMBOL_GPL(spi_finalize_current_message
);
1072 static int spi_start_queue(struct spi_master
*master
)
1074 unsigned long flags
;
1076 spin_lock_irqsave(&master
->queue_lock
, flags
);
1078 if (master
->running
|| master
->busy
) {
1079 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1083 master
->running
= true;
1084 master
->cur_msg
= NULL
;
1085 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1087 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1092 static int spi_stop_queue(struct spi_master
*master
)
1094 unsigned long flags
;
1095 unsigned limit
= 500;
1098 spin_lock_irqsave(&master
->queue_lock
, flags
);
1101 * This is a bit lame, but is optimized for the common execution path.
1102 * A wait_queue on the master->busy could be used, but then the common
1103 * execution path (pump_messages) would be required to call wake_up or
1104 * friends on every SPI message. Do this instead.
1106 while ((!list_empty(&master
->queue
) || master
->busy
) && limit
--) {
1107 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1108 usleep_range(10000, 11000);
1109 spin_lock_irqsave(&master
->queue_lock
, flags
);
1112 if (!list_empty(&master
->queue
) || master
->busy
)
1115 master
->running
= false;
1117 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1120 dev_warn(&master
->dev
,
1121 "could not stop message queue\n");
1127 static int spi_destroy_queue(struct spi_master
*master
)
1131 ret
= spi_stop_queue(master
);
1134 * flush_kthread_worker will block until all work is done.
1135 * If the reason that stop_queue timed out is that the work will never
1136 * finish, then it does no good to call flush/stop thread, so
1140 dev_err(&master
->dev
, "problem destroying queue\n");
1144 flush_kthread_worker(&master
->kworker
);
1145 kthread_stop(master
->kworker_task
);
1151 * spi_queued_transfer - transfer function for queued transfers
1152 * @spi: spi device which is requesting transfer
1153 * @msg: spi message which is to handled is queued to driver queue
1155 static int spi_queued_transfer(struct spi_device
*spi
, struct spi_message
*msg
)
1157 struct spi_master
*master
= spi
->master
;
1158 unsigned long flags
;
1160 spin_lock_irqsave(&master
->queue_lock
, flags
);
1162 if (!master
->running
) {
1163 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1166 msg
->actual_length
= 0;
1167 msg
->status
= -EINPROGRESS
;
1169 list_add_tail(&msg
->queue
, &master
->queue
);
1171 queue_kthread_work(&master
->kworker
, &master
->pump_messages
);
1173 spin_unlock_irqrestore(&master
->queue_lock
, flags
);
1177 static int spi_master_initialize_queue(struct spi_master
*master
)
1181 master
->transfer
= spi_queued_transfer
;
1182 if (!master
->transfer_one_message
)
1183 master
->transfer_one_message
= spi_transfer_one_message
;
1185 /* Initialize and start queue */
1186 ret
= spi_init_queue(master
);
1188 dev_err(&master
->dev
, "problem initializing queue\n");
1189 goto err_init_queue
;
1191 master
->queued
= true;
1192 ret
= spi_start_queue(master
);
1194 dev_err(&master
->dev
, "problem starting queue\n");
1195 goto err_start_queue
;
1201 spi_destroy_queue(master
);
1206 /*-------------------------------------------------------------------------*/
1208 #if defined(CONFIG_OF)
1210 * of_register_spi_devices() - Register child devices onto the SPI bus
1211 * @master: Pointer to spi_master device
1213 * Registers an spi_device for each child node of master node which has a 'reg'
1216 static void of_register_spi_devices(struct spi_master
*master
)
1218 struct spi_device
*spi
;
1219 struct device_node
*nc
;
1223 if (!master
->dev
.of_node
)
1226 for_each_available_child_of_node(master
->dev
.of_node
, nc
) {
1227 /* Alloc an spi_device */
1228 spi
= spi_alloc_device(master
);
1230 dev_err(&master
->dev
, "spi_device alloc error for %s\n",
1236 /* Select device driver */
1237 if (of_modalias_node(nc
, spi
->modalias
,
1238 sizeof(spi
->modalias
)) < 0) {
1239 dev_err(&master
->dev
, "cannot find modalias for %s\n",
1245 /* Device address */
1246 rc
= of_property_read_u32(nc
, "reg", &value
);
1248 dev_err(&master
->dev
, "%s has no valid 'reg' property (%d)\n",
1253 spi
->chip_select
= value
;
1255 /* Mode (clock phase/polarity/etc.) */
1256 if (of_find_property(nc
, "spi-cpha", NULL
))
1257 spi
->mode
|= SPI_CPHA
;
1258 if (of_find_property(nc
, "spi-cpol", NULL
))
1259 spi
->mode
|= SPI_CPOL
;
1260 if (of_find_property(nc
, "spi-cs-high", NULL
))
1261 spi
->mode
|= SPI_CS_HIGH
;
1262 if (of_find_property(nc
, "spi-3wire", NULL
))
1263 spi
->mode
|= SPI_3WIRE
;
1264 if (of_find_property(nc
, "spi-lsb-first", NULL
))
1265 spi
->mode
|= SPI_LSB_FIRST
;
1267 /* Device DUAL/QUAD mode */
1268 if (!of_property_read_u32(nc
, "spi-tx-bus-width", &value
)) {
1273 spi
->mode
|= SPI_TX_DUAL
;
1276 spi
->mode
|= SPI_TX_QUAD
;
1279 dev_warn(&master
->dev
,
1280 "spi-tx-bus-width %d not supported\n",
1286 if (!of_property_read_u32(nc
, "spi-rx-bus-width", &value
)) {
1291 spi
->mode
|= SPI_RX_DUAL
;
1294 spi
->mode
|= SPI_RX_QUAD
;
1297 dev_warn(&master
->dev
,
1298 "spi-rx-bus-width %d not supported\n",
1305 rc
= of_property_read_u32(nc
, "spi-max-frequency", &value
);
1307 dev_err(&master
->dev
, "%s has no valid 'spi-max-frequency' property (%d)\n",
1312 spi
->max_speed_hz
= value
;
1315 spi
->irq
= irq_of_parse_and_map(nc
, 0);
1317 /* Store a pointer to the node in the device structure */
1319 spi
->dev
.of_node
= nc
;
1321 /* Register the new device */
1322 request_module("%s%s", SPI_MODULE_PREFIX
, spi
->modalias
);
1323 rc
= spi_add_device(spi
);
1325 dev_err(&master
->dev
, "spi_device register error %s\n",
1333 static void of_register_spi_devices(struct spi_master
*master
) { }
1337 static int acpi_spi_add_resource(struct acpi_resource
*ares
, void *data
)
1339 struct spi_device
*spi
= data
;
1341 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
1342 struct acpi_resource_spi_serialbus
*sb
;
1344 sb
= &ares
->data
.spi_serial_bus
;
1345 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_SPI
) {
1346 spi
->chip_select
= sb
->device_selection
;
1347 spi
->max_speed_hz
= sb
->connection_speed
;
1349 if (sb
->clock_phase
== ACPI_SPI_SECOND_PHASE
)
1350 spi
->mode
|= SPI_CPHA
;
1351 if (sb
->clock_polarity
== ACPI_SPI_START_HIGH
)
1352 spi
->mode
|= SPI_CPOL
;
1353 if (sb
->device_polarity
== ACPI_SPI_ACTIVE_HIGH
)
1354 spi
->mode
|= SPI_CS_HIGH
;
1356 } else if (spi
->irq
< 0) {
1359 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
1363 /* Always tell the ACPI core to skip this resource */
1367 static acpi_status
acpi_spi_add_device(acpi_handle handle
, u32 level
,
1368 void *data
, void **return_value
)
1370 struct spi_master
*master
= data
;
1371 struct list_head resource_list
;
1372 struct acpi_device
*adev
;
1373 struct spi_device
*spi
;
1376 if (acpi_bus_get_device(handle
, &adev
))
1378 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
1381 spi
= spi_alloc_device(master
);
1383 dev_err(&master
->dev
, "failed to allocate SPI device for %s\n",
1384 dev_name(&adev
->dev
));
1385 return AE_NO_MEMORY
;
1388 ACPI_COMPANION_SET(&spi
->dev
, adev
);
1391 INIT_LIST_HEAD(&resource_list
);
1392 ret
= acpi_dev_get_resources(adev
, &resource_list
,
1393 acpi_spi_add_resource
, spi
);
1394 acpi_dev_free_resource_list(&resource_list
);
1396 if (ret
< 0 || !spi
->max_speed_hz
) {
1401 adev
->power
.flags
.ignore_parent
= true;
1402 strlcpy(spi
->modalias
, acpi_device_hid(adev
), sizeof(spi
->modalias
));
1403 if (spi_add_device(spi
)) {
1404 adev
->power
.flags
.ignore_parent
= false;
1405 dev_err(&master
->dev
, "failed to add SPI device %s from ACPI\n",
1406 dev_name(&adev
->dev
));
1413 static void acpi_register_spi_devices(struct spi_master
*master
)
1418 handle
= ACPI_HANDLE(master
->dev
.parent
);
1422 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
1423 acpi_spi_add_device
, NULL
,
1425 if (ACPI_FAILURE(status
))
1426 dev_warn(&master
->dev
, "failed to enumerate SPI slaves\n");
1429 static inline void acpi_register_spi_devices(struct spi_master
*master
) {}
1430 #endif /* CONFIG_ACPI */
1432 static void spi_master_release(struct device
*dev
)
1434 struct spi_master
*master
;
1436 master
= container_of(dev
, struct spi_master
, dev
);
1440 static struct class spi_master_class
= {
1441 .name
= "spi_master",
1442 .owner
= THIS_MODULE
,
1443 .dev_release
= spi_master_release
,
1449 * spi_alloc_master - allocate SPI master controller
1450 * @dev: the controller, possibly using the platform_bus
1451 * @size: how much zeroed driver-private data to allocate; the pointer to this
1452 * memory is in the driver_data field of the returned device,
1453 * accessible with spi_master_get_devdata().
1454 * Context: can sleep
1456 * This call is used only by SPI master controller drivers, which are the
1457 * only ones directly touching chip registers. It's how they allocate
1458 * an spi_master structure, prior to calling spi_register_master().
1460 * This must be called from context that can sleep. It returns the SPI
1461 * master structure on success, else NULL.
1463 * The caller is responsible for assigning the bus number and initializing
1464 * the master's methods before calling spi_register_master(); and (after errors
1465 * adding the device) calling spi_master_put() and kfree() to prevent a memory
1468 struct spi_master
*spi_alloc_master(struct device
*dev
, unsigned size
)
1470 struct spi_master
*master
;
1475 master
= kzalloc(size
+ sizeof(*master
), GFP_KERNEL
);
1479 device_initialize(&master
->dev
);
1480 master
->bus_num
= -1;
1481 master
->num_chipselect
= 1;
1482 master
->dev
.class = &spi_master_class
;
1483 master
->dev
.parent
= get_device(dev
);
1484 spi_master_set_devdata(master
, &master
[1]);
1488 EXPORT_SYMBOL_GPL(spi_alloc_master
);
1491 static int of_spi_register_master(struct spi_master
*master
)
1494 struct device_node
*np
= master
->dev
.of_node
;
1499 nb
= of_gpio_named_count(np
, "cs-gpios");
1500 master
->num_chipselect
= max_t(int, nb
, master
->num_chipselect
);
1502 /* Return error only for an incorrectly formed cs-gpios property */
1503 if (nb
== 0 || nb
== -ENOENT
)
1508 cs
= devm_kzalloc(&master
->dev
,
1509 sizeof(int) * master
->num_chipselect
,
1511 master
->cs_gpios
= cs
;
1513 if (!master
->cs_gpios
)
1516 for (i
= 0; i
< master
->num_chipselect
; i
++)
1519 for (i
= 0; i
< nb
; i
++)
1520 cs
[i
] = of_get_named_gpio(np
, "cs-gpios", i
);
1525 static int of_spi_register_master(struct spi_master
*master
)
1532 * spi_register_master - register SPI master controller
1533 * @master: initialized master, originally from spi_alloc_master()
1534 * Context: can sleep
1536 * SPI master controllers connect to their drivers using some non-SPI bus,
1537 * such as the platform bus. The final stage of probe() in that code
1538 * includes calling spi_register_master() to hook up to this SPI bus glue.
1540 * SPI controllers use board specific (often SOC specific) bus numbers,
1541 * and board-specific addressing for SPI devices combines those numbers
1542 * with chip select numbers. Since SPI does not directly support dynamic
1543 * device identification, boards need configuration tables telling which
1544 * chip is at which address.
1546 * This must be called from context that can sleep. It returns zero on
1547 * success, else a negative error code (dropping the master's refcount).
1548 * After a successful return, the caller is responsible for calling
1549 * spi_unregister_master().
1551 int spi_register_master(struct spi_master
*master
)
1553 static atomic_t dyn_bus_id
= ATOMIC_INIT((1<<15) - 1);
1554 struct device
*dev
= master
->dev
.parent
;
1555 struct boardinfo
*bi
;
1556 int status
= -ENODEV
;
1562 status
= of_spi_register_master(master
);
1566 /* even if it's just one always-selected device, there must
1567 * be at least one chipselect
1569 if (master
->num_chipselect
== 0)
1572 if ((master
->bus_num
< 0) && master
->dev
.of_node
)
1573 master
->bus_num
= of_alias_get_id(master
->dev
.of_node
, "spi");
1575 /* convention: dynamically assigned bus IDs count down from the max */
1576 if (master
->bus_num
< 0) {
1577 /* FIXME switch to an IDR based scheme, something like
1578 * I2C now uses, so we can't run out of "dynamic" IDs
1580 master
->bus_num
= atomic_dec_return(&dyn_bus_id
);
1584 spin_lock_init(&master
->bus_lock_spinlock
);
1585 mutex_init(&master
->bus_lock_mutex
);
1586 master
->bus_lock_flag
= 0;
1587 init_completion(&master
->xfer_completion
);
1588 if (!master
->max_dma_len
)
1589 master
->max_dma_len
= INT_MAX
;
1591 /* register the device, then userspace will see it.
1592 * registration fails if the bus ID is in use.
1594 dev_set_name(&master
->dev
, "spi%u", master
->bus_num
);
1595 status
= device_add(&master
->dev
);
1598 dev_dbg(dev
, "registered master %s%s\n", dev_name(&master
->dev
),
1599 dynamic
? " (dynamic)" : "");
1601 /* If we're using a queued driver, start the queue */
1602 if (master
->transfer
)
1603 dev_info(dev
, "master is unqueued, this is deprecated\n");
1605 status
= spi_master_initialize_queue(master
);
1607 device_del(&master
->dev
);
1612 mutex_lock(&board_lock
);
1613 list_add_tail(&master
->list
, &spi_master_list
);
1614 list_for_each_entry(bi
, &board_list
, list
)
1615 spi_match_master_to_boardinfo(master
, &bi
->board_info
);
1616 mutex_unlock(&board_lock
);
1618 /* Register devices from the device tree and ACPI */
1619 of_register_spi_devices(master
);
1620 acpi_register_spi_devices(master
);
1624 EXPORT_SYMBOL_GPL(spi_register_master
);
1626 static void devm_spi_unregister(struct device
*dev
, void *res
)
1628 spi_unregister_master(*(struct spi_master
**)res
);
1632 * dev_spi_register_master - register managed SPI master controller
1633 * @dev: device managing SPI master
1634 * @master: initialized master, originally from spi_alloc_master()
1635 * Context: can sleep
1637 * Register a SPI device as with spi_register_master() which will
1638 * automatically be unregister
1640 int devm_spi_register_master(struct device
*dev
, struct spi_master
*master
)
1642 struct spi_master
**ptr
;
1645 ptr
= devres_alloc(devm_spi_unregister
, sizeof(*ptr
), GFP_KERNEL
);
1649 ret
= spi_register_master(master
);
1652 devres_add(dev
, ptr
);
1659 EXPORT_SYMBOL_GPL(devm_spi_register_master
);
1661 static int __unregister(struct device
*dev
, void *null
)
1663 spi_unregister_device(to_spi_device(dev
));
1668 * spi_unregister_master - unregister SPI master controller
1669 * @master: the master being unregistered
1670 * Context: can sleep
1672 * This call is used only by SPI master controller drivers, which are the
1673 * only ones directly touching chip registers.
1675 * This must be called from context that can sleep.
1677 void spi_unregister_master(struct spi_master
*master
)
1681 if (master
->queued
) {
1682 if (spi_destroy_queue(master
))
1683 dev_err(&master
->dev
, "queue remove failed\n");
1686 mutex_lock(&board_lock
);
1687 list_del(&master
->list
);
1688 mutex_unlock(&board_lock
);
1690 dummy
= device_for_each_child(&master
->dev
, NULL
, __unregister
);
1691 device_unregister(&master
->dev
);
1693 EXPORT_SYMBOL_GPL(spi_unregister_master
);
1695 int spi_master_suspend(struct spi_master
*master
)
1699 /* Basically no-ops for non-queued masters */
1700 if (!master
->queued
)
1703 ret
= spi_stop_queue(master
);
1705 dev_err(&master
->dev
, "queue stop failed\n");
1709 EXPORT_SYMBOL_GPL(spi_master_suspend
);
1711 int spi_master_resume(struct spi_master
*master
)
1715 if (!master
->queued
)
1718 ret
= spi_start_queue(master
);
1720 dev_err(&master
->dev
, "queue restart failed\n");
1724 EXPORT_SYMBOL_GPL(spi_master_resume
);
1726 static int __spi_master_match(struct device
*dev
, const void *data
)
1728 struct spi_master
*m
;
1729 const u16
*bus_num
= data
;
1731 m
= container_of(dev
, struct spi_master
, dev
);
1732 return m
->bus_num
== *bus_num
;
1736 * spi_busnum_to_master - look up master associated with bus_num
1737 * @bus_num: the master's bus number
1738 * Context: can sleep
1740 * This call may be used with devices that are registered after
1741 * arch init time. It returns a refcounted pointer to the relevant
1742 * spi_master (which the caller must release), or NULL if there is
1743 * no such master registered.
1745 struct spi_master
*spi_busnum_to_master(u16 bus_num
)
1748 struct spi_master
*master
= NULL
;
1750 dev
= class_find_device(&spi_master_class
, NULL
, &bus_num
,
1751 __spi_master_match
);
1753 master
= container_of(dev
, struct spi_master
, dev
);
1754 /* reference got in class_find_device */
1757 EXPORT_SYMBOL_GPL(spi_busnum_to_master
);
1760 /*-------------------------------------------------------------------------*/
1762 /* Core methods for SPI master protocol drivers. Some of the
1763 * other core methods are currently defined as inline functions.
1767 * spi_setup - setup SPI mode and clock rate
1768 * @spi: the device whose settings are being modified
1769 * Context: can sleep, and no requests are queued to the device
1771 * SPI protocol drivers may need to update the transfer mode if the
1772 * device doesn't work with its default. They may likewise need
1773 * to update clock rates or word sizes from initial values. This function
1774 * changes those settings, and must be called from a context that can sleep.
1775 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
1776 * effect the next time the device is selected and data is transferred to
1777 * or from it. When this function returns, the spi device is deselected.
1779 * Note that this call will fail if the protocol driver specifies an option
1780 * that the underlying controller or its driver does not support. For
1781 * example, not all hardware supports wire transfers using nine bit words,
1782 * LSB-first wire encoding, or active-high chipselects.
1784 int spi_setup(struct spi_device
*spi
)
1786 unsigned bad_bits
, ugly_bits
;
1789 /* check mode to prevent that DUAL and QUAD set at the same time
1791 if (((spi
->mode
& SPI_TX_DUAL
) && (spi
->mode
& SPI_TX_QUAD
)) ||
1792 ((spi
->mode
& SPI_RX_DUAL
) && (spi
->mode
& SPI_RX_QUAD
))) {
1794 "setup: can not select dual and quad at the same time\n");
1797 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
1799 if ((spi
->mode
& SPI_3WIRE
) && (spi
->mode
&
1800 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
)))
1802 /* help drivers fail *cleanly* when they need options
1803 * that aren't supported with their current master
1805 bad_bits
= spi
->mode
& ~spi
->master
->mode_bits
;
1806 ugly_bits
= bad_bits
&
1807 (SPI_TX_DUAL
| SPI_TX_QUAD
| SPI_RX_DUAL
| SPI_RX_QUAD
);
1810 "setup: ignoring unsupported mode bits %x\n",
1812 spi
->mode
&= ~ugly_bits
;
1813 bad_bits
&= ~ugly_bits
;
1816 dev_err(&spi
->dev
, "setup: unsupported mode bits %x\n",
1821 if (!spi
->bits_per_word
)
1822 spi
->bits_per_word
= 8;
1824 if (!spi
->max_speed_hz
)
1825 spi
->max_speed_hz
= spi
->master
->max_speed_hz
;
1827 if (spi
->master
->setup
)
1828 status
= spi
->master
->setup(spi
);
1830 dev_dbg(&spi
->dev
, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
1831 (int) (spi
->mode
& (SPI_CPOL
| SPI_CPHA
)),
1832 (spi
->mode
& SPI_CS_HIGH
) ? "cs_high, " : "",
1833 (spi
->mode
& SPI_LSB_FIRST
) ? "lsb, " : "",
1834 (spi
->mode
& SPI_3WIRE
) ? "3wire, " : "",
1835 (spi
->mode
& SPI_LOOP
) ? "loopback, " : "",
1836 spi
->bits_per_word
, spi
->max_speed_hz
,
1841 EXPORT_SYMBOL_GPL(spi_setup
);
1843 static int __spi_validate(struct spi_device
*spi
, struct spi_message
*message
)
1845 struct spi_master
*master
= spi
->master
;
1846 struct spi_transfer
*xfer
;
1849 if (list_empty(&message
->transfers
))
1852 /* Half-duplex links include original MicroWire, and ones with
1853 * only one data pin like SPI_3WIRE (switches direction) or where
1854 * either MOSI or MISO is missing. They can also be caused by
1855 * software limitations.
1857 if ((master
->flags
& SPI_MASTER_HALF_DUPLEX
)
1858 || (spi
->mode
& SPI_3WIRE
)) {
1859 unsigned flags
= master
->flags
;
1861 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1862 if (xfer
->rx_buf
&& xfer
->tx_buf
)
1864 if ((flags
& SPI_MASTER_NO_TX
) && xfer
->tx_buf
)
1866 if ((flags
& SPI_MASTER_NO_RX
) && xfer
->rx_buf
)
1872 * Set transfer bits_per_word and max speed as spi device default if
1873 * it is not set for this transfer.
1874 * Set transfer tx_nbits and rx_nbits as single transfer default
1875 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
1877 list_for_each_entry(xfer
, &message
->transfers
, transfer_list
) {
1878 message
->frame_length
+= xfer
->len
;
1879 if (!xfer
->bits_per_word
)
1880 xfer
->bits_per_word
= spi
->bits_per_word
;
1882 if (!xfer
->speed_hz
)
1883 xfer
->speed_hz
= spi
->max_speed_hz
;
1885 if (master
->max_speed_hz
&&
1886 xfer
->speed_hz
> master
->max_speed_hz
)
1887 xfer
->speed_hz
= master
->max_speed_hz
;
1889 if (master
->bits_per_word_mask
) {
1890 /* Only 32 bits fit in the mask */
1891 if (xfer
->bits_per_word
> 32)
1893 if (!(master
->bits_per_word_mask
&
1894 BIT(xfer
->bits_per_word
- 1)))
1899 * SPI transfer length should be multiple of SPI word size
1900 * where SPI word size should be power-of-two multiple
1902 if (xfer
->bits_per_word
<= 8)
1904 else if (xfer
->bits_per_word
<= 16)
1909 /* No partial transfers accepted */
1910 if (xfer
->len
% w_size
)
1913 if (xfer
->speed_hz
&& master
->min_speed_hz
&&
1914 xfer
->speed_hz
< master
->min_speed_hz
)
1917 if (xfer
->tx_buf
&& !xfer
->tx_nbits
)
1918 xfer
->tx_nbits
= SPI_NBITS_SINGLE
;
1919 if (xfer
->rx_buf
&& !xfer
->rx_nbits
)
1920 xfer
->rx_nbits
= SPI_NBITS_SINGLE
;
1921 /* check transfer tx/rx_nbits:
1922 * 1. check the value matches one of single, dual and quad
1923 * 2. check tx/rx_nbits match the mode in spi_device
1926 if (xfer
->tx_nbits
!= SPI_NBITS_SINGLE
&&
1927 xfer
->tx_nbits
!= SPI_NBITS_DUAL
&&
1928 xfer
->tx_nbits
!= SPI_NBITS_QUAD
)
1930 if ((xfer
->tx_nbits
== SPI_NBITS_DUAL
) &&
1931 !(spi
->mode
& (SPI_TX_DUAL
| SPI_TX_QUAD
)))
1933 if ((xfer
->tx_nbits
== SPI_NBITS_QUAD
) &&
1934 !(spi
->mode
& SPI_TX_QUAD
))
1937 /* check transfer rx_nbits */
1939 if (xfer
->rx_nbits
!= SPI_NBITS_SINGLE
&&
1940 xfer
->rx_nbits
!= SPI_NBITS_DUAL
&&
1941 xfer
->rx_nbits
!= SPI_NBITS_QUAD
)
1943 if ((xfer
->rx_nbits
== SPI_NBITS_DUAL
) &&
1944 !(spi
->mode
& (SPI_RX_DUAL
| SPI_RX_QUAD
)))
1946 if ((xfer
->rx_nbits
== SPI_NBITS_QUAD
) &&
1947 !(spi
->mode
& SPI_RX_QUAD
))
1952 message
->status
= -EINPROGRESS
;
1957 static int __spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1959 struct spi_master
*master
= spi
->master
;
1963 trace_spi_message_submit(message
);
1965 return master
->transfer(spi
, message
);
1969 * spi_async - asynchronous SPI transfer
1970 * @spi: device with which data will be exchanged
1971 * @message: describes the data transfers, including completion callback
1972 * Context: any (irqs may be blocked, etc)
1974 * This call may be used in_irq and other contexts which can't sleep,
1975 * as well as from task contexts which can sleep.
1977 * The completion callback is invoked in a context which can't sleep.
1978 * Before that invocation, the value of message->status is undefined.
1979 * When the callback is issued, message->status holds either zero (to
1980 * indicate complete success) or a negative error code. After that
1981 * callback returns, the driver which issued the transfer request may
1982 * deallocate the associated memory; it's no longer in use by any SPI
1983 * core or controller driver code.
1985 * Note that although all messages to a spi_device are handled in
1986 * FIFO order, messages may go to different devices in other orders.
1987 * Some device might be higher priority, or have various "hard" access
1988 * time requirements, for example.
1990 * On detection of any fault during the transfer, processing of
1991 * the entire message is aborted, and the device is deselected.
1992 * Until returning from the associated message completion callback,
1993 * no other spi_message queued to that device will be processed.
1994 * (This rule applies equally to all the synchronous transfer calls,
1995 * which are wrappers around this core asynchronous primitive.)
1997 int spi_async(struct spi_device
*spi
, struct spi_message
*message
)
1999 struct spi_master
*master
= spi
->master
;
2001 unsigned long flags
;
2003 ret
= __spi_validate(spi
, message
);
2007 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2009 if (master
->bus_lock_flag
)
2012 ret
= __spi_async(spi
, message
);
2014 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2018 EXPORT_SYMBOL_GPL(spi_async
);
2021 * spi_async_locked - version of spi_async with exclusive bus usage
2022 * @spi: device with which data will be exchanged
2023 * @message: describes the data transfers, including completion callback
2024 * Context: any (irqs may be blocked, etc)
2026 * This call may be used in_irq and other contexts which can't sleep,
2027 * as well as from task contexts which can sleep.
2029 * The completion callback is invoked in a context which can't sleep.
2030 * Before that invocation, the value of message->status is undefined.
2031 * When the callback is issued, message->status holds either zero (to
2032 * indicate complete success) or a negative error code. After that
2033 * callback returns, the driver which issued the transfer request may
2034 * deallocate the associated memory; it's no longer in use by any SPI
2035 * core or controller driver code.
2037 * Note that although all messages to a spi_device are handled in
2038 * FIFO order, messages may go to different devices in other orders.
2039 * Some device might be higher priority, or have various "hard" access
2040 * time requirements, for example.
2042 * On detection of any fault during the transfer, processing of
2043 * the entire message is aborted, and the device is deselected.
2044 * Until returning from the associated message completion callback,
2045 * no other spi_message queued to that device will be processed.
2046 * (This rule applies equally to all the synchronous transfer calls,
2047 * which are wrappers around this core asynchronous primitive.)
2049 int spi_async_locked(struct spi_device
*spi
, struct spi_message
*message
)
2051 struct spi_master
*master
= spi
->master
;
2053 unsigned long flags
;
2055 ret
= __spi_validate(spi
, message
);
2059 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2061 ret
= __spi_async(spi
, message
);
2063 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2068 EXPORT_SYMBOL_GPL(spi_async_locked
);
2071 /*-------------------------------------------------------------------------*/
2073 /* Utility methods for SPI master protocol drivers, layered on
2074 * top of the core. Some other utility methods are defined as
2078 static void spi_complete(void *arg
)
2083 static int __spi_sync(struct spi_device
*spi
, struct spi_message
*message
,
2086 DECLARE_COMPLETION_ONSTACK(done
);
2088 struct spi_master
*master
= spi
->master
;
2090 message
->complete
= spi_complete
;
2091 message
->context
= &done
;
2094 mutex_lock(&master
->bus_lock_mutex
);
2096 status
= spi_async_locked(spi
, message
);
2099 mutex_unlock(&master
->bus_lock_mutex
);
2102 wait_for_completion(&done
);
2103 status
= message
->status
;
2105 message
->context
= NULL
;
2110 * spi_sync - blocking/synchronous SPI data transfers
2111 * @spi: device with which data will be exchanged
2112 * @message: describes the data transfers
2113 * Context: can sleep
2115 * This call may only be used from a context that may sleep. The sleep
2116 * is non-interruptible, and has no timeout. Low-overhead controller
2117 * drivers may DMA directly into and out of the message buffers.
2119 * Note that the SPI device's chip select is active during the message,
2120 * and then is normally disabled between messages. Drivers for some
2121 * frequently-used devices may want to minimize costs of selecting a chip,
2122 * by leaving it selected in anticipation that the next message will go
2123 * to the same chip. (That may increase power usage.)
2125 * Also, the caller is guaranteeing that the memory associated with the
2126 * message will not be freed before this call returns.
2128 * It returns zero on success, else a negative error code.
2130 int spi_sync(struct spi_device
*spi
, struct spi_message
*message
)
2132 return __spi_sync(spi
, message
, 0);
2134 EXPORT_SYMBOL_GPL(spi_sync
);
2137 * spi_sync_locked - version of spi_sync with exclusive bus usage
2138 * @spi: device with which data will be exchanged
2139 * @message: describes the data transfers
2140 * Context: can sleep
2142 * This call may only be used from a context that may sleep. The sleep
2143 * is non-interruptible, and has no timeout. Low-overhead controller
2144 * drivers may DMA directly into and out of the message buffers.
2146 * This call should be used by drivers that require exclusive access to the
2147 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2148 * be released by a spi_bus_unlock call when the exclusive access is over.
2150 * It returns zero on success, else a negative error code.
2152 int spi_sync_locked(struct spi_device
*spi
, struct spi_message
*message
)
2154 return __spi_sync(spi
, message
, 1);
2156 EXPORT_SYMBOL_GPL(spi_sync_locked
);
2159 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2160 * @master: SPI bus master that should be locked for exclusive bus access
2161 * Context: can sleep
2163 * This call may only be used from a context that may sleep. The sleep
2164 * is non-interruptible, and has no timeout.
2166 * This call should be used by drivers that require exclusive access to the
2167 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2168 * exclusive access is over. Data transfer must be done by spi_sync_locked
2169 * and spi_async_locked calls when the SPI bus lock is held.
2171 * It returns zero on success, else a negative error code.
2173 int spi_bus_lock(struct spi_master
*master
)
2175 unsigned long flags
;
2177 mutex_lock(&master
->bus_lock_mutex
);
2179 spin_lock_irqsave(&master
->bus_lock_spinlock
, flags
);
2180 master
->bus_lock_flag
= 1;
2181 spin_unlock_irqrestore(&master
->bus_lock_spinlock
, flags
);
2183 /* mutex remains locked until spi_bus_unlock is called */
2187 EXPORT_SYMBOL_GPL(spi_bus_lock
);
2190 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2191 * @master: SPI bus master that was locked for exclusive bus access
2192 * Context: can sleep
2194 * This call may only be used from a context that may sleep. The sleep
2195 * is non-interruptible, and has no timeout.
2197 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2200 * It returns zero on success, else a negative error code.
2202 int spi_bus_unlock(struct spi_master
*master
)
2204 master
->bus_lock_flag
= 0;
2206 mutex_unlock(&master
->bus_lock_mutex
);
2210 EXPORT_SYMBOL_GPL(spi_bus_unlock
);
2212 /* portable code must never pass more than 32 bytes */
2213 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2218 * spi_write_then_read - SPI synchronous write followed by read
2219 * @spi: device with which data will be exchanged
2220 * @txbuf: data to be written (need not be dma-safe)
2221 * @n_tx: size of txbuf, in bytes
2222 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2223 * @n_rx: size of rxbuf, in bytes
2224 * Context: can sleep
2226 * This performs a half duplex MicroWire style transaction with the
2227 * device, sending txbuf and then reading rxbuf. The return value
2228 * is zero for success, else a negative errno status code.
2229 * This call may only be used from a context that may sleep.
2231 * Parameters to this routine are always copied using a small buffer;
2232 * portable code should never use this for more than 32 bytes.
2233 * Performance-sensitive or bulk transfer code should instead use
2234 * spi_{async,sync}() calls with dma-safe buffers.
2236 int spi_write_then_read(struct spi_device
*spi
,
2237 const void *txbuf
, unsigned n_tx
,
2238 void *rxbuf
, unsigned n_rx
)
2240 static DEFINE_MUTEX(lock
);
2243 struct spi_message message
;
2244 struct spi_transfer x
[2];
2247 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2248 * copying here, (as a pure convenience thing), but we can
2249 * keep heap costs out of the hot path unless someone else is
2250 * using the pre-allocated buffer or the transfer is too large.
2252 if ((n_tx
+ n_rx
) > SPI_BUFSIZ
|| !mutex_trylock(&lock
)) {
2253 local_buf
= kmalloc(max((unsigned)SPI_BUFSIZ
, n_tx
+ n_rx
),
2254 GFP_KERNEL
| GFP_DMA
);
2261 spi_message_init(&message
);
2262 memset(x
, 0, sizeof(x
));
2265 spi_message_add_tail(&x
[0], &message
);
2269 spi_message_add_tail(&x
[1], &message
);
2272 memcpy(local_buf
, txbuf
, n_tx
);
2273 x
[0].tx_buf
= local_buf
;
2274 x
[1].rx_buf
= local_buf
+ n_tx
;
2277 status
= spi_sync(spi
, &message
);
2279 memcpy(rxbuf
, x
[1].rx_buf
, n_rx
);
2281 if (x
[0].tx_buf
== buf
)
2282 mutex_unlock(&lock
);
2288 EXPORT_SYMBOL_GPL(spi_write_then_read
);
2290 /*-------------------------------------------------------------------------*/
2292 static int __init
spi_init(void)
2296 buf
= kmalloc(SPI_BUFSIZ
, GFP_KERNEL
);
2302 status
= bus_register(&spi_bus_type
);
2306 status
= class_register(&spi_master_class
);
2312 bus_unregister(&spi_bus_type
);
2320 /* board_info is normally registered in arch_initcall(),
2321 * but even essential drivers wait till later
2323 * REVISIT only boardinfo really needs static linking. the rest (device and
2324 * driver registration) _could_ be dynamically linked (modular) ... costs
2325 * include needing to have boardinfo data structures be much more public.
2327 postcore_initcall(spi_init
);