1/*
2 * Copyright (c) 2011-2016 Synaptics Incorporated
3 * Copyright (c) 2011 Unixphere
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/i2c.h>
11#include <linux/rmi.h>
12#include <linux/of.h>
13#include <linux/delay.h>
14#include <linux/regulator/consumer.h>
15#include "rmi_driver.h"
16
17#define BUFFER_SIZE_INCREMENT 32
18
19/**
20 * struct rmi_i2c_xport - stores information for i2c communication
21 *
22 * @xport: The transport interface structure
23 *
24 * @page_mutex: Locks current page to avoid changing pages in unexpected ways.
25 * @page: Keeps track of the current virtual page
26 *
27 * @tx_buf: Buffer used for transmitting data to the sensor over i2c.
28 * @tx_buf_size: Size of the buffer
29 */
30struct rmi_i2c_xport {
31 struct rmi_transport_dev xport;
32 struct i2c_client *client;
33
34 struct mutex page_mutex;
35 int page;
36
37 u8 *tx_buf;
38 size_t tx_buf_size;
39
40 struct regulator_bulk_data supplies[2];
41 u32 startup_delay;
42};
43
44#define RMI_PAGE_SELECT_REGISTER 0xff
45#define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)
46
47/*
48 * rmi_set_page - Set RMI page
49 * @xport: The pointer to the rmi_transport_dev struct
50 * @page: The new page address.
51 *
52 * RMI devices have 16-bit addressing, but some of the transport
53 * implementations (like SMBus) only have 8-bit addressing. So RMI implements
54 * a page address at 0xff of every page so we can reliable page addresses
55 * every 256 registers.
56 *
57 * The page_mutex lock must be held when this function is entered.
58 *
59 * Returns zero on success, non-zero on failure.
60 */
61static int rmi_set_page(struct rmi_i2c_xport *rmi_i2c, u8 page)
62{
63 struct i2c_client *client = rmi_i2c->client;
64 u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
65 int retval;
66
67 retval = i2c_master_send(client, txbuf, sizeof(txbuf));
68 if (retval != sizeof(txbuf)) {
69 dev_err(&client->dev,
70 "%s: set page failed: %d.", __func__, retval);
71 return (retval < 0) ? retval : -EIO;
72 }
73
74 rmi_i2c->page = page;
75 return 0;
76}
77
78static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
79 const void *buf, size_t len)
80{
81 struct rmi_i2c_xport *rmi_i2c =
82 container_of(xport, struct rmi_i2c_xport, xport);
83 struct i2c_client *client = rmi_i2c->client;
84 size_t tx_size = len + 1;
85 int retval;
86
87 mutex_lock(&rmi_i2c->page_mutex);
88
89 if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {
90 if (rmi_i2c->tx_buf)
91 devm_kfree(&client->dev, rmi_i2c->tx_buf);
92 rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;
93 rmi_i2c->tx_buf = devm_kzalloc(&client->dev,
94 rmi_i2c->tx_buf_size,
95 GFP_KERNEL);
96 if (!rmi_i2c->tx_buf) {
97 rmi_i2c->tx_buf_size = 0;
98 retval = -ENOMEM;
99 goto exit;
100 }
101 }
102
103 rmi_i2c->tx_buf[0] = addr & 0xff;
104 memcpy(rmi_i2c->tx_buf + 1, buf, len);
105
106 if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
107 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
108 if (retval)
109 goto exit;
110 }
111
112 retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);
113 if (retval == tx_size)
114 retval = 0;
115 else if (retval >= 0)
116 retval = -EIO;
117
118exit:
119 rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
120 "write %zd bytes at %#06x: %d (%*ph)\n",
121 len, addr, retval, (int)len, buf);
122
123 mutex_unlock(&rmi_i2c->page_mutex);
124 return retval;
125}
126
127static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
128 void *buf, size_t len)
129{
130 struct rmi_i2c_xport *rmi_i2c =
131 container_of(xport, struct rmi_i2c_xport, xport);
132 struct i2c_client *client = rmi_i2c->client;
133 u8 addr_offset = addr & 0xff;
134 int retval;
135 struct i2c_msg msgs[] = {
136 {
137 .addr = client->addr,
138 .len = sizeof(addr_offset),
139 .buf = &addr_offset,
140 },
141 {
142 .addr = client->addr,
143 .flags = I2C_M_RD,
144 .len = len,
145 .buf = buf,
146 },
147 };
148
149 mutex_lock(&rmi_i2c->page_mutex);
150
151 if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
152 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
153 if (retval)
154 goto exit;
155 }
156
157 retval = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
158 if (retval == ARRAY_SIZE(msgs))
159 retval = 0; /* success */
160 else if (retval >= 0)
161 retval = -EIO;
162
163exit:
164 rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
165 "read %zd bytes at %#06x: %d (%*ph)\n",
166 len, addr, retval, (int)len, buf);
167
168 mutex_unlock(&rmi_i2c->page_mutex);
169 return retval;
170}
171
172static const struct rmi_transport_ops rmi_i2c_ops = {
173 .write_block = rmi_i2c_write_block,
174 .read_block = rmi_i2c_read_block,
175};
176
177#ifdef CONFIG_OF
178static const struct of_device_id rmi_i2c_of_match[] = {
179 { .compatible = "syna,rmi4-i2c" },
180 {},
181};
182MODULE_DEVICE_TABLE(of, rmi_i2c_of_match);
183#endif
184
185static void rmi_i2c_regulator_bulk_disable(void *data)
186{
187 struct rmi_i2c_xport *rmi_i2c = data;
188
189 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
190 rmi_i2c->supplies);
191}
192
193static void rmi_i2c_unregister_transport(void *data)
194{
195 struct rmi_i2c_xport *rmi_i2c = data;
196
197 rmi_unregister_transport_device(&rmi_i2c->xport);
198}
199
200static int rmi_i2c_probe(struct i2c_client *client,
201 const struct i2c_device_id *id)
202{
203 struct rmi_device_platform_data *pdata;
204 struct rmi_device_platform_data *client_pdata =
205 dev_get_platdata(&client->dev);
206 struct rmi_i2c_xport *rmi_i2c;
207 int error;
208
209 rmi_i2c = devm_kzalloc(&client->dev, sizeof(struct rmi_i2c_xport),
210 GFP_KERNEL);
211 if (!rmi_i2c)
212 return -ENOMEM;
213
214 pdata = &rmi_i2c->xport.pdata;
215
216 if (!client->dev.of_node && client_pdata)
217 *pdata = *client_pdata;
218
219 pdata->irq = client->irq;
220
221 rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
222 dev_name(&client->dev));
223
224 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
225 dev_err(&client->dev,
226 "adapter does not support required functionality\n");
227 return -ENODEV;
228 }
229
230 rmi_i2c->supplies[0].supply = "vdd";
231 rmi_i2c->supplies[1].supply = "vio";
232 error = devm_regulator_bulk_get(&client->dev,
233 ARRAY_SIZE(rmi_i2c->supplies),
234 rmi_i2c->supplies);
235 if (error < 0)
236 return error;
237
238 error = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
239 rmi_i2c->supplies);
240 if (error < 0)
241 return error;
242
243 error = devm_add_action_or_reset(&client->dev,
244 rmi_i2c_regulator_bulk_disable,
245 rmi_i2c);
246 if (error)
247 return error;
248
249 of_property_read_u32(client->dev.of_node, "syna,startup-delay-ms",
250 &rmi_i2c->startup_delay);
251
252 msleep(rmi_i2c->startup_delay);
253
254 rmi_i2c->client = client;
255 mutex_init(&rmi_i2c->page_mutex);
256
257 rmi_i2c->xport.dev = &client->dev;
258 rmi_i2c->xport.proto_name = "i2c";
259 rmi_i2c->xport.ops = &rmi_i2c_ops;
260
261 i2c_set_clientdata(client, rmi_i2c);
262
263 /*
264 * Setting the page to zero will (a) make sure the PSR is in a
265 * known state, and (b) make sure we can talk to the device.
266 */
267 error = rmi_set_page(rmi_i2c, 0);
268 if (error) {
269 dev_err(&client->dev, "Failed to set page select to 0\n");
270 return error;
271 }
272
273 dev_info(&client->dev, "registering I2C-connected sensor\n");
274
275 error = rmi_register_transport_device(&rmi_i2c->xport);
276 if (error) {
277 dev_err(&client->dev, "failed to register sensor: %d\n", error);
278 return error;
279 }
280
281 error = devm_add_action_or_reset(&client->dev,
282 rmi_i2c_unregister_transport,
283 rmi_i2c);
284 if (error)
285 return error;
286
287 return 0;
288}
289
290#ifdef CONFIG_PM_SLEEP
291static int rmi_i2c_suspend(struct device *dev)
292{
293 struct i2c_client *client = to_i2c_client(dev);
294 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
295 int ret;
296
297 ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, true);
298 if (ret)
299 dev_warn(dev, "Failed to resume device: %d\n", ret);
300
301 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
302 rmi_i2c->supplies);
303
304 return ret;
305}
306
307static int rmi_i2c_resume(struct device *dev)
308{
309 struct i2c_client *client = to_i2c_client(dev);
310 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
311 int ret;
312
313 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
314 rmi_i2c->supplies);
315 if (ret)
316 return ret;
317
318 msleep(rmi_i2c->startup_delay);
319
320 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, true);
321 if (ret)
322 dev_warn(dev, "Failed to resume device: %d\n", ret);
323
324 return ret;
325}
326#endif
327
328#ifdef CONFIG_PM
329static int rmi_i2c_runtime_suspend(struct device *dev)
330{
331 struct i2c_client *client = to_i2c_client(dev);
332 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
333 int ret;
334
335 ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, false);
336 if (ret)
337 dev_warn(dev, "Failed to resume device: %d\n", ret);
338
339 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
340 rmi_i2c->supplies);
341
342 return 0;
343}
344
345static int rmi_i2c_runtime_resume(struct device *dev)
346{
347 struct i2c_client *client = to_i2c_client(dev);
348 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
349 int ret;
350
351 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
352 rmi_i2c->supplies);
353 if (ret)
354 return ret;
355
356 msleep(rmi_i2c->startup_delay);
357
358 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, false);
359 if (ret)
360 dev_warn(dev, "Failed to resume device: %d\n", ret);
361
362 return 0;
363}
364#endif
365
366static const struct dev_pm_ops rmi_i2c_pm = {
367 SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
368 SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,
369 NULL)
370};
371
372static const struct i2c_device_id rmi_id[] = {
373 { "rmi4_i2c", 0 },
374 { }
375};
376MODULE_DEVICE_TABLE(i2c, rmi_id);
377
378static struct i2c_driver rmi_i2c_driver = {
379 .driver = {
380 .name = "rmi4_i2c",
381 .pm = &rmi_i2c_pm,
382 .of_match_table = of_match_ptr(rmi_i2c_of_match),
383 },
384 .id_table = rmi_id,
385 .probe = rmi_i2c_probe,
386};
387
388module_i2c_driver(rmi_i2c_driver);
389
390MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
391MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
392MODULE_DESCRIPTION("RMI I2C driver");
393MODULE_LICENSE("GPL");
394