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  * @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  */
  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
  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
 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
 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
 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
 201 static int rmi_i2c_probe(struct i2c_client *client)
 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 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
 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
 362 static const struct dev_pm_ops rmi_i2c_pm = {
 363         SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
 364         RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume, NULL)
 365 };
 366
 367 static const struct i2c_device_id rmi_id[] = {
 368         { "rmi4_i2c", 0 },
 369         { }
 370 };
 371 MODULE_DEVICE_TABLE(i2c, rmi_id);
 372
 373 static struct i2c_driver rmi_i2c_driver = {
 374         .driver = {
 375                 .name   = "rmi4_i2c",
 376                 .pm     = pm_ptr(&rmi_i2c_pm),
 377                 .of_match_table = of_match_ptr(rmi_i2c_of_match),
 378         },
 379         .id_table       = rmi_id,
 380         .probe_new      = rmi_i2c_probe,
 381 };
 382
 383 module_i2c_driver(rmi_i2c_driver);
 384
 385 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
 386 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 387 MODULE_DESCRIPTION("RMI I2C driver");
 388 MODULE_LICENSE("GPL");