2 * hdm_i2c.c - Hardware Dependent Module for I2C Interface
4 * Copyright (C) 2013-2015, Microchip Technology Germany II GmbH & Co. KG
6 * This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
11 * This file is licensed under GPLv2.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/init.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/i2c.h>
20 #include <linux/sched.h>
21 #include <linux/interrupt.h>
22 #include <linux/err.h>
26 enum { CH_RX
, CH_TX
, NUM_CHANNELS
};
28 #define MAX_BUFFERS_CONTROL 32
29 #define MAX_BUF_SIZE_CONTROL 256
32 * list_first_mbo - get the first mbo from a list
33 * @ptr: the list head to take the mbo from.
35 #define list_first_mbo(ptr) \
36 list_first_entry(ptr, struct mbo, list)
38 /* IRQ / Polling option */
39 static bool polling_req
;
40 module_param(polling_req
, bool, S_IRUGO
);
41 MODULE_PARM_DESC(polling_req
, "Request Polling. Default = 0 (use irq)");
44 static int scan_rate
= 100;
45 module_param(scan_rate
, int, 0644);
46 MODULE_PARM_DESC(scan_rate
, "Polling rate in times/sec. Default = 100");
49 bool is_open
[NUM_CHANNELS
];
51 struct most_interface most_iface
;
52 struct most_channel_capability capabilities
[NUM_CHANNELS
];
53 struct i2c_client
*client
;
55 struct delayed_work dwork
;
56 wait_queue_head_t waitq
;
57 struct list_head list
;
58 struct mutex list_mutex
;
63 #define to_hdm(iface) container_of(iface, struct hdm_i2c, most_iface)
66 * configure_channel - called from MOST core to configure a channel
67 * @iface: interface the channel belongs to
68 * @channel: channel to be configured
69 * @channel_config: structure that holds the configuration information
71 * Return 0 on success, negative on failure.
73 * Receives configuration information from MOST core and initialize the
74 * corresponding channel.
76 static int configure_channel(struct most_interface
*most_iface
,
78 struct most_channel_config
*channel_config
)
80 struct hdm_i2c
*dev
= to_hdm(most_iface
);
82 BUG_ON(ch_idx
< 0 || ch_idx
>= NUM_CHANNELS
);
83 BUG_ON(dev
->is_open
[ch_idx
]);
85 if (channel_config
->data_type
!= MOST_CH_CONTROL
) {
86 pr_err("bad data type for channel %d\n", ch_idx
);
90 if (channel_config
->direction
!= dev
->capabilities
[ch_idx
].direction
) {
91 pr_err("bad direction for channel %d\n", ch_idx
);
95 if ((channel_config
->direction
== MOST_CH_RX
) && (dev
->polling_mode
)) {
96 schedule_delayed_work(&dev
->rx
.dwork
,
97 msecs_to_jiffies(MSEC_PER_SEC
/ 4));
99 dev
->is_open
[ch_idx
] = true;
105 * enqueue - called from MOST core to enqueue a buffer for data transfer
106 * @iface: intended interface
107 * @channel: ID of the channel the buffer is intended for
108 * @mbo: pointer to the buffer object
110 * Return 0 on success, negative on failure.
112 * Transmit the data over I2C if it is a "write" request or push the buffer into
113 * list if it is an "read" request
115 static int enqueue(struct most_interface
*most_iface
,
116 int ch_idx
, struct mbo
*mbo
)
118 struct hdm_i2c
*dev
= to_hdm(most_iface
);
121 BUG_ON(ch_idx
< 0 || ch_idx
>= NUM_CHANNELS
);
122 BUG_ON(!dev
->is_open
[ch_idx
]);
124 if (ch_idx
== CH_RX
) {
126 mutex_lock(&dev
->rx
.list_mutex
);
127 list_add_tail(&mbo
->list
, &dev
->rx
.list
);
128 mutex_unlock(&dev
->rx
.list_mutex
);
129 wake_up_interruptible(&dev
->rx
.waitq
);
132 ret
= i2c_master_send(dev
->client
, mbo
->virt_address
,
135 mbo
->processed_length
= 0;
136 mbo
->status
= MBO_E_INVAL
;
138 mbo
->processed_length
= mbo
->buffer_length
;
139 mbo
->status
= MBO_SUCCESS
;
148 * poison_channel - called from MOST core to poison buffers of a channel
149 * @iface: pointer to the interface the channel to be poisoned belongs to
150 * @channel_id: corresponding channel ID
152 * Return 0 on success, negative on failure.
154 * If channel direction is RX, complete the buffers in list with
157 static int poison_channel(struct most_interface
*most_iface
,
160 struct hdm_i2c
*dev
= to_hdm(most_iface
);
163 BUG_ON(ch_idx
< 0 || ch_idx
>= NUM_CHANNELS
);
164 BUG_ON(!dev
->is_open
[ch_idx
]);
166 dev
->is_open
[ch_idx
] = false;
168 if (ch_idx
== CH_RX
) {
169 mutex_lock(&dev
->rx
.list_mutex
);
170 while (!list_empty(&dev
->rx
.list
)) {
171 mbo
= list_first_mbo(&dev
->rx
.list
);
172 list_del(&mbo
->list
);
173 mutex_unlock(&dev
->rx
.list_mutex
);
175 mbo
->processed_length
= 0;
176 mbo
->status
= MBO_E_CLOSE
;
179 mutex_lock(&dev
->rx
.list_mutex
);
181 mutex_unlock(&dev
->rx
.list_mutex
);
182 wake_up_interruptible(&dev
->rx
.waitq
);
188 static void request_netinfo(struct most_interface
*most_iface
,
191 pr_info("request_netinfo()\n");
194 static void do_rx_work(struct hdm_i2c
*dev
)
197 unsigned char msg
[MAX_BUF_SIZE_CONTROL
];
198 int ret
, ch_idx
= CH_RX
;
201 /* Read PML (2 bytes) */
202 ret
= i2c_master_recv(dev
->client
, msg
, 2);
204 pr_err("Failed to receive PML\n");
208 pml
= (msg
[0] << 8) | msg
[1];
214 /* Read the whole message, including PML */
215 ret
= i2c_master_recv(dev
->client
, msg
, data_size
);
217 pr_err("Failed to receive a Port Message\n");
222 /* Conditions to wait for: poisoned channel or free buffer
223 * available for reading
225 if (wait_event_interruptible(dev
->rx
.waitq
,
226 !dev
->is_open
[ch_idx
] ||
227 !list_empty(&dev
->rx
.list
))) {
228 pr_err("wait_event_interruptible() failed\n");
232 if (!dev
->is_open
[ch_idx
])
235 mutex_lock(&dev
->rx
.list_mutex
);
237 /* list may be empty if poison or remove is called */
238 if (!list_empty(&dev
->rx
.list
))
241 mutex_unlock(&dev
->rx
.list_mutex
);
244 mbo
= list_first_mbo(&dev
->rx
.list
);
245 list_del(&mbo
->list
);
246 mutex_unlock(&dev
->rx
.list_mutex
);
248 mbo
->processed_length
= min(data_size
, mbo
->buffer_length
);
249 memcpy(mbo
->virt_address
, msg
, mbo
->processed_length
);
250 mbo
->status
= MBO_SUCCESS
;
255 * pending_rx_work - Read pending messages through I2C
256 * @work: definition of this work item
258 * Invoked by the Interrupt Service Routine, most_irq_handler()
260 static void pending_rx_work(struct work_struct
*work
)
262 struct hdm_i2c
*dev
= container_of(work
, struct hdm_i2c
, rx
.dwork
.work
);
266 if (dev
->polling_mode
) {
267 if (dev
->is_open
[CH_RX
])
268 schedule_delayed_work(&dev
->rx
.dwork
,
269 msecs_to_jiffies(MSEC_PER_SEC
272 enable_irq(dev
->client
->irq
);
277 * most_irq_handler - Interrupt Service Routine
279 * @_dev: private data
281 * Schedules a delayed work
283 * By default the interrupt line behavior is Active Low. Once an interrupt is
284 * generated by the device, until driver clears the interrupt (by reading
285 * the PMP message), device keeps the interrupt line in low state. Since i2c
286 * read is done in work queue, the interrupt line must be disabled temporarily
287 * to avoid ISR being called repeatedly. Re-enable the interrupt in workqueue,
288 * after reading the message.
290 * Note: If we use the interrupt line in Falling edge mode, there is a
291 * possibility to miss interrupts when ISR is getting executed.
294 static irqreturn_t
most_irq_handler(int irq
, void *_dev
)
296 struct hdm_i2c
*dev
= _dev
;
298 disable_irq_nosync(irq
);
300 schedule_delayed_work(&dev
->rx
.dwork
, 0);
306 * i2c_probe - i2c probe handler
307 * @client: i2c client device structure
308 * @id: i2c client device id
310 * Return 0 on success, negative on failure.
312 * Register the i2c client device as a MOST interface
314 static int i2c_probe(struct i2c_client
*client
, const struct i2c_device_id
*id
)
318 struct kobject
*kobj
;
320 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
324 /* ID format: i2c-<bus>-<address> */
325 snprintf(dev
->name
, sizeof(dev
->name
), "i2c-%d-%04x",
326 client
->adapter
->nr
, client
->addr
);
328 for (i
= 0; i
< NUM_CHANNELS
; i
++) {
329 dev
->is_open
[i
] = false;
330 dev
->capabilities
[i
].data_type
= MOST_CH_CONTROL
;
331 dev
->capabilities
[i
].num_buffers_packet
= MAX_BUFFERS_CONTROL
;
332 dev
->capabilities
[i
].buffer_size_packet
= MAX_BUF_SIZE_CONTROL
;
334 dev
->capabilities
[CH_RX
].direction
= MOST_CH_RX
;
335 dev
->capabilities
[CH_RX
].name_suffix
= "rx";
336 dev
->capabilities
[CH_TX
].direction
= MOST_CH_TX
;
337 dev
->capabilities
[CH_TX
].name_suffix
= "tx";
339 dev
->most_iface
.interface
= ITYPE_I2C
;
340 dev
->most_iface
.description
= dev
->name
;
341 dev
->most_iface
.num_channels
= NUM_CHANNELS
;
342 dev
->most_iface
.channel_vector
= dev
->capabilities
;
343 dev
->most_iface
.configure
= configure_channel
;
344 dev
->most_iface
.enqueue
= enqueue
;
345 dev
->most_iface
.poison_channel
= poison_channel
;
346 dev
->most_iface
.request_netinfo
= request_netinfo
;
348 INIT_LIST_HEAD(&dev
->rx
.list
);
349 mutex_init(&dev
->rx
.list_mutex
);
350 init_waitqueue_head(&dev
->rx
.waitq
);
352 INIT_DELAYED_WORK(&dev
->rx
.dwork
, pending_rx_work
);
354 dev
->client
= client
;
355 i2c_set_clientdata(client
, dev
);
357 kobj
= most_register_interface(&dev
->most_iface
);
359 pr_err("Failed to register i2c as a MOST interface\n");
361 return PTR_ERR(kobj
);
364 dev
->polling_mode
= polling_req
|| client
->irq
<= 0;
365 if (!dev
->polling_mode
) {
366 pr_info("Requesting IRQ: %d\n", client
->irq
);
367 ret
= request_irq(client
->irq
, most_irq_handler
, 0,
370 pr_info("IRQ request failed: %d, falling back to polling\n",
372 dev
->polling_mode
= true;
376 if (dev
->polling_mode
)
377 pr_info("Using polling at rate: %d times/sec\n", scan_rate
);
383 * i2c_remove - i2c remove handler
384 * @client: i2c client device structure
386 * Return 0 on success.
388 * Unregister the i2c client device as a MOST interface
390 static int i2c_remove(struct i2c_client
*client
)
392 struct hdm_i2c
*dev
= i2c_get_clientdata(client
);
395 if (!dev
->polling_mode
)
396 free_irq(client
->irq
, dev
);
398 most_deregister_interface(&dev
->most_iface
);
400 for (i
= 0 ; i
< NUM_CHANNELS
; i
++)
402 poison_channel(&dev
->most_iface
, i
);
403 cancel_delayed_work_sync(&dev
->rx
.dwork
);
409 static const struct i2c_device_id i2c_id
[] = {
411 { }, /* Terminating entry */
414 MODULE_DEVICE_TABLE(i2c
, i2c_id
);
416 static struct i2c_driver i2c_driver
= {
421 .remove
= i2c_remove
,
425 module_i2c_driver(i2c_driver
);
427 MODULE_AUTHOR("Jain Roy Ambi <JainRoy.Ambi@microchip.com>");
428 MODULE_AUTHOR("Andrey Shvetsov <andrey.shvetsov@k2l.de>");
429 MODULE_DESCRIPTION("I2C Hardware Dependent Module");
430 MODULE_LICENSE("GPL");