1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2011-2016 Synaptics Incorporated
4 * Copyright (c) 2011 Unixphere
5 */
6
7 #include <linux/i2c.h>
8 #include <linux/rmi.h>
9 #include <linux/of.h>
10 #include <linux/delay.h>
11 #include <linux/regulator/consumer.h>
12 #include "rmi_driver.h"
13
14 #define BUFFER_SIZE_INCREMENT 32
15
16 /**
17 * struct rmi_i2c_xport - stores information for i2c communication
18 *
19 * @xport: The transport interface structure
20 * @client: The I2C client device structure
21 *
22 * @page_mutex: Locks current page to avoid changing pages in unexpected ways.
23 * @page: Keeps track of the current virtual page
24 *
25 * @tx_buf: Buffer used for transmitting data to the sensor over i2c.
26 * @tx_buf_size: Size of the buffer
27 *
28 * @supplies: Array of voltage regulators
29 * @startup_delay: Milliseconds to pause after powering up the regulators
30 */
31 struct rmi_i2c_xport {
32 struct rmi_transport_dev xport;
33 struct i2c_client *client;
34
35 struct mutex page_mutex;
36 int page;
37
38 u8 *tx_buf;
39 size_t tx_buf_size;
40
41 struct regulator_bulk_data supplies[2];
42 u32 startup_delay;
43 };
44
45 #define RMI_PAGE_SELECT_REGISTER 0xff
46 #define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)
47
48 /*
49 * rmi_set_page - Set RMI page
50 * @xport: The pointer to the rmi_transport_dev struct
51 * @page: The new page address.
52 *
53 * RMI devices have 16-bit addressing, but some of the transport
54 * implementations (like SMBus) only have 8-bit addressing. So RMI implements
55 * a page address at 0xff of every page so we can reliable page addresses
56 * every 256 registers.
57 *
58 * The page_mutex lock must be held when this function is entered.
59 *
60 * Returns zero on success, non-zero on failure.
61 */
rmi_set_page(struct rmi_i2c_xport * rmi_i2c,u8 page)62 static int rmi_set_page(struct rmi_i2c_xport *rmi_i2c, u8 page)
63 {
64 struct i2c_client *client = rmi_i2c->client;
65 u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
66 int retval;
67
68 retval = i2c_master_send(client, txbuf, sizeof(txbuf));
69 if (retval != sizeof(txbuf)) {
70 dev_err(&client->dev,
71 "%s: set page failed: %d.", __func__, retval);
72 return (retval < 0) ? retval : -EIO;
73 }
74
75 rmi_i2c->page = page;
76 return 0;
77 }
78
rmi_i2c_write_block(struct rmi_transport_dev * xport,u16 addr,const void * buf,size_t len)79 static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
80 const void *buf, size_t len)
81 {
82 struct rmi_i2c_xport *rmi_i2c =
83 container_of(xport, struct rmi_i2c_xport, xport);
84 struct i2c_client *client = rmi_i2c->client;
85 size_t tx_size = len + 1;
86 int retval;
87
88 mutex_lock(&rmi_i2c->page_mutex);
89
90 if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {
91 if (rmi_i2c->tx_buf)
92 devm_kfree(&client->dev, rmi_i2c->tx_buf);
93 rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;
94 rmi_i2c->tx_buf = devm_kzalloc(&client->dev,
95 rmi_i2c->tx_buf_size,
96 GFP_KERNEL);
97 if (!rmi_i2c->tx_buf) {
98 rmi_i2c->tx_buf_size = 0;
99 retval = -ENOMEM;
100 goto exit;
101 }
102 }
103
104 rmi_i2c->tx_buf[0] = addr & 0xff;
105 memcpy(rmi_i2c->tx_buf + 1, buf, len);
106
107 if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
108 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
109 if (retval)
110 goto exit;
111 }
112
113 retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);
114 if (retval == tx_size)
115 retval = 0;
116 else if (retval >= 0)
117 retval = -EIO;
118
119 exit:
120 rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
121 "write %zd bytes at %#06x: %d (%*ph)\n",
122 len, addr, retval, (int)len, buf);
123
124 mutex_unlock(&rmi_i2c->page_mutex);
125 return retval;
126 }
127
rmi_i2c_read_block(struct rmi_transport_dev * xport,u16 addr,void * buf,size_t len)128 static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
129 void *buf, size_t len)
130 {
131 struct rmi_i2c_xport *rmi_i2c =
132 container_of(xport, struct rmi_i2c_xport, xport);
133 struct i2c_client *client = rmi_i2c->client;
134 u8 addr_offset = addr & 0xff;
135 int retval;
136 struct i2c_msg msgs[] = {
137 {
138 .addr = client->addr,
139 .len = sizeof(addr_offset),
140 .buf = &addr_offset,
141 },
142 {
143 .addr = client->addr,
144 .flags = I2C_M_RD,
145 .len = len,
146 .buf = buf,
147 },
148 };
149
150 mutex_lock(&rmi_i2c->page_mutex);
151
152 if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
153 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
154 if (retval)
155 goto exit;
156 }
157
158 retval = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
159 if (retval == ARRAY_SIZE(msgs))
160 retval = 0; /* success */
161 else if (retval >= 0)
162 retval = -EIO;
163
164 exit:
165 rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
166 "read %zd bytes at %#06x: %d (%*ph)\n",
167 len, addr, retval, (int)len, buf);
168
169 mutex_unlock(&rmi_i2c->page_mutex);
170 return retval;
171 }
172
173 static const struct rmi_transport_ops rmi_i2c_ops = {
174 .write_block = rmi_i2c_write_block,
175 .read_block = rmi_i2c_read_block,
176 };
177
178 #ifdef CONFIG_OF
179 static const struct of_device_id rmi_i2c_of_match[] = {
180 { .compatible = "syna,rmi4-i2c" },
181 {},
182 };
183 MODULE_DEVICE_TABLE(of, rmi_i2c_of_match);
184 #endif
185
rmi_i2c_regulator_bulk_disable(void * data)186 static void rmi_i2c_regulator_bulk_disable(void *data)
187 {
188 struct rmi_i2c_xport *rmi_i2c = data;
189
190 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
191 rmi_i2c->supplies);
192 }
193
rmi_i2c_unregister_transport(void * data)194 static void rmi_i2c_unregister_transport(void *data)
195 {
196 struct rmi_i2c_xport *rmi_i2c = data;
197
198 rmi_unregister_transport_device(&rmi_i2c->xport);
199 }
200
rmi_i2c_probe(struct i2c_client * client,const struct i2c_device_id * id)201 static int rmi_i2c_probe(struct i2c_client *client,
202 const struct i2c_device_id *id)
203 {
204 struct rmi_device_platform_data *pdata;
205 struct rmi_device_platform_data *client_pdata =
206 dev_get_platdata(&client->dev);
207 struct rmi_i2c_xport *rmi_i2c;
208 int error;
209
210 rmi_i2c = devm_kzalloc(&client->dev, sizeof(struct rmi_i2c_xport),
211 GFP_KERNEL);
212 if (!rmi_i2c)
213 return -ENOMEM;
214
215 pdata = &rmi_i2c->xport.pdata;
216
217 if (!client->dev.of_node && client_pdata)
218 *pdata = *client_pdata;
219
220 pdata->irq = client->irq;
221
222 rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
223 dev_name(&client->dev));
224
225 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
226 dev_err(&client->dev,
227 "adapter does not support required functionality\n");
228 return -ENODEV;
229 }
230
231 rmi_i2c->supplies[0].supply = "vdd";
232 rmi_i2c->supplies[1].supply = "vio";
233 error = devm_regulator_bulk_get(&client->dev,
234 ARRAY_SIZE(rmi_i2c->supplies),
235 rmi_i2c->supplies);
236 if (error < 0)
237 return error;
238
239 error = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
240 rmi_i2c->supplies);
241 if (error < 0)
242 return error;
243
244 error = devm_add_action_or_reset(&client->dev,
245 rmi_i2c_regulator_bulk_disable,
246 rmi_i2c);
247 if (error)
248 return error;
249
250 of_property_read_u32(client->dev.of_node, "syna,startup-delay-ms",
251 &rmi_i2c->startup_delay);
252
253 msleep(rmi_i2c->startup_delay);
254
255 rmi_i2c->client = client;
256 mutex_init(&rmi_i2c->page_mutex);
257
258 rmi_i2c->xport.dev = &client->dev;
259 rmi_i2c->xport.proto_name = "i2c";
260 rmi_i2c->xport.ops = &rmi_i2c_ops;
261
262 i2c_set_clientdata(client, rmi_i2c);
263
264 /*
265 * Setting the page to zero will (a) make sure the PSR is in a
266 * known state, and (b) make sure we can talk to the device.
267 */
268 error = rmi_set_page(rmi_i2c, 0);
269 if (error) {
270 dev_err(&client->dev, "Failed to set page select to 0\n");
271 return error;
272 }
273
274 dev_info(&client->dev, "registering I2C-connected sensor\n");
275
276 error = rmi_register_transport_device(&rmi_i2c->xport);
277 if (error) {
278 dev_err(&client->dev, "failed to register sensor: %d\n", error);
279 return error;
280 }
281
282 error = devm_add_action_or_reset(&client->dev,
283 rmi_i2c_unregister_transport,
284 rmi_i2c);
285 if (error)
286 return error;
287
288 return 0;
289 }
290
291 #ifdef CONFIG_PM_SLEEP
rmi_i2c_suspend(struct device * dev)292 static int rmi_i2c_suspend(struct device *dev)
293 {
294 struct i2c_client *client = to_i2c_client(dev);
295 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
296 int ret;
297
298 ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, true);
299 if (ret)
300 dev_warn(dev, "Failed to resume device: %d\n", ret);
301
302 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
303 rmi_i2c->supplies);
304
305 return ret;
306 }
307
rmi_i2c_resume(struct device * dev)308 static int rmi_i2c_resume(struct device *dev)
309 {
310 struct i2c_client *client = to_i2c_client(dev);
311 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
312 int ret;
313
314 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
315 rmi_i2c->supplies);
316 if (ret)
317 return ret;
318
319 msleep(rmi_i2c->startup_delay);
320
321 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, true);
322 if (ret)
323 dev_warn(dev, "Failed to resume device: %d\n", ret);
324
325 return ret;
326 }
327 #endif
328
329 #ifdef CONFIG_PM
rmi_i2c_runtime_suspend(struct device * dev)330 static int rmi_i2c_runtime_suspend(struct device *dev)
331 {
332 struct i2c_client *client = to_i2c_client(dev);
333 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
334 int ret;
335
336 ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, false);
337 if (ret)
338 dev_warn(dev, "Failed to resume device: %d\n", ret);
339
340 regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
341 rmi_i2c->supplies);
342
343 return 0;
344 }
345
rmi_i2c_runtime_resume(struct device * dev)346 static int rmi_i2c_runtime_resume(struct device *dev)
347 {
348 struct i2c_client *client = to_i2c_client(dev);
349 struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
350 int ret;
351
352 ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
353 rmi_i2c->supplies);
354 if (ret)
355 return ret;
356
357 msleep(rmi_i2c->startup_delay);
358
359 ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, false);
360 if (ret)
361 dev_warn(dev, "Failed to resume device: %d\n", ret);
362
363 return 0;
364 }
365 #endif
366
367 static const struct dev_pm_ops rmi_i2c_pm = {
368 SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
369 SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,
370 NULL)
371 };
372
373 static const struct i2c_device_id rmi_id[] = {
374 { "rmi4_i2c", 0 },
375 { }
376 };
377 MODULE_DEVICE_TABLE(i2c, rmi_id);
378
379 static struct i2c_driver rmi_i2c_driver = {
380 .driver = {
381 .name = "rmi4_i2c",
382 .pm = &rmi_i2c_pm,
383 .of_match_table = of_match_ptr(rmi_i2c_of_match),
384 },
385 .id_table = rmi_id,
386 .probe = rmi_i2c_probe,
387 };
388
389 module_i2c_driver(rmi_i2c_driver);
390
391 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
392 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
393 MODULE_DESCRIPTION("RMI I2C driver");
394 MODULE_LICENSE("GPL");
395