drivers/input/rmi4/rmi_i2c.c

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