drivers/input/rmi4/rmi_i2c.c

   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  */
  30 struct 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  */
  61 static 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
  78 static 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
 118 exit:
 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
 127 static 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
 163 exit:
 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
 172 static 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
 178 static const struct of_device_id rmi_i2c_of_match[] = {
 179         { .compatible = "syna,rmi4-i2c" },
 180         {},
 181 };
 182 MODULE_DEVICE_TABLE(of, rmi_i2c_of_match);
 183 #endif
 184
 185 static 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
 193 static 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
 200 static 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 retval;
 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         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 224                 dev_err(&client->dev,
 225                         "adapter does not support required functionality.\n");
 226                 return -ENODEV;
 227         }
 228
 229         rmi_i2c->supplies[0].supply = "vdd";
 230         rmi_i2c->supplies[1].supply = "vio";
 231         retval = devm_regulator_bulk_get(&client->dev,
 232                                          ARRAY_SIZE(rmi_i2c->supplies),
 233                                          rmi_i2c->supplies);
 234         if (retval < 0)
 235                 return retval;
 236
 237         retval = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
 238                                        rmi_i2c->supplies);
 239         if (retval < 0)
 240                 return retval;
 241
 242         retval = devm_add_action_or_reset(&client->dev,
 243                                           rmi_i2c_regulator_bulk_disable,
 244                                           rmi_i2c);
 245         if (retval)
 246                 return retval;
 247
 248         of_property_read_u32(client->dev.of_node, "syna,startup-delay-ms",
 249                              &rmi_i2c->startup_delay);
 250
 251         msleep(rmi_i2c->startup_delay);
 252
 253         rmi_i2c->client = client;
 254         mutex_init(&rmi_i2c->page_mutex);
 255
 256         rmi_i2c->xport.dev = &client->dev;
 257         rmi_i2c->xport.proto_name = "i2c";
 258         rmi_i2c->xport.ops = &rmi_i2c_ops;
 259
 260         i2c_set_clientdata(client, rmi_i2c);
 261
 262         /*
 263          * Setting the page to zero will (a) make sure the PSR is in a
 264          * known state, and (b) make sure we can talk to the device.
 265          */
 266         retval = rmi_set_page(rmi_i2c, 0);
 267         if (retval) {
 268                 dev_err(&client->dev, "Failed to set page select to 0.\n");
 269                 return retval;
 270         }
 271
 272         retval = rmi_register_transport_device(&rmi_i2c->xport);
 273         if (retval) {
 274                 dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
 275                         client->addr);
 276                 return retval;
 277         }
 278         retval = devm_add_action_or_reset(&client->dev,
 279                                           rmi_i2c_unregister_transport,
 280                                           rmi_i2c);
 281         if (retval)
 282                 return retval;
 283
 284         dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",
 285                         client->addr);
 286         return 0;
 287 }
 288
 289 #ifdef CONFIG_PM_SLEEP
 290 static int rmi_i2c_suspend(struct device *dev)
 291 {
 292         struct i2c_client *client = to_i2c_client(dev);
 293         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 294         int ret;
 295
 296         ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, true);
 297         if (ret)
 298                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 299
 300         regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
 301                                rmi_i2c->supplies);
 302
 303         return ret;
 304 }
 305
 306 static int rmi_i2c_resume(struct device *dev)
 307 {
 308         struct i2c_client *client = to_i2c_client(dev);
 309         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 310         int ret;
 311
 312         ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
 313                                     rmi_i2c->supplies);
 314         if (ret)
 315                 return ret;
 316
 317         msleep(rmi_i2c->startup_delay);
 318
 319         ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, true);
 320         if (ret)
 321                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 322
 323         return ret;
 324 }
 325 #endif
 326
 327 #ifdef CONFIG_PM
 328 static int rmi_i2c_runtime_suspend(struct device *dev)
 329 {
 330         struct i2c_client *client = to_i2c_client(dev);
 331         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 332         int ret;
 333
 334         ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev, false);
 335         if (ret)
 336                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 337
 338         regulator_bulk_disable(ARRAY_SIZE(rmi_i2c->supplies),
 339                                rmi_i2c->supplies);
 340
 341         return 0;
 342 }
 343
 344 static int rmi_i2c_runtime_resume(struct device *dev)
 345 {
 346         struct i2c_client *client = to_i2c_client(dev);
 347         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 348         int ret;
 349
 350         ret = regulator_bulk_enable(ARRAY_SIZE(rmi_i2c->supplies),
 351                                     rmi_i2c->supplies);
 352         if (ret)
 353                 return ret;
 354
 355         msleep(rmi_i2c->startup_delay);
 356
 357         ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev, false);
 358         if (ret)
 359                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 360
 361         return 0;
 362 }
 363 #endif
 364
 365 static const struct dev_pm_ops rmi_i2c_pm = {
 366         SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
 367         SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,
 368                            NULL)
 369 };
 370
 371 static const struct i2c_device_id rmi_id[] = {
 372         { "rmi4_i2c", 0 },
 373         { }
 374 };
 375 MODULE_DEVICE_TABLE(i2c, rmi_id);
 376
 377 static struct i2c_driver rmi_i2c_driver = {
 378         .driver = {
 379                 .name   = "rmi4_i2c",
 380                 .pm     = &rmi_i2c_pm,
 381                 .of_match_table = of_match_ptr(rmi_i2c_of_match),
 382         },
 383         .id_table       = rmi_id,
 384         .probe          = rmi_i2c_probe,
 385 };
 386
 387 module_i2c_driver(rmi_i2c_driver);
 388
 389 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
 390 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 391 MODULE_DESCRIPTION("RMI I2C driver");
 392 MODULE_LICENSE("GPL");
 393 MODULE_VERSION(RMI_DRIVER_VERSION);