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/irq.h>
  13 #include <linux/of.h>
  14 #include "rmi_driver.h"
  15
  16 #define BUFFER_SIZE_INCREMENT 32
  17
  18 /**
  19  * struct rmi_i2c_xport - stores information for i2c communication
  20  *
  21  * @xport: The transport interface structure
  22  *
  23  * @page_mutex: Locks current page to avoid changing pages in unexpected ways.
  24  * @page: Keeps track of the current virtual page
  25  *
  26  * @tx_buf: Buffer used for transmitting data to the sensor over i2c.
  27  * @tx_buf_size: Size of the buffer
  28  */
  29 struct rmi_i2c_xport {
  30         struct rmi_transport_dev xport;
  31         struct i2c_client *client;
  32
  33         struct mutex page_mutex;
  34         int page;
  35
  36         int irq;
  37
  38         u8 *tx_buf;
  39         size_t tx_buf_size;
  40 };
  41
  42 #define RMI_PAGE_SELECT_REGISTER 0xff
  43 #define RMI_I2C_PAGE(addr) (((addr) >> 8) & 0xff)
  44
  45 /*
  46  * rmi_set_page - Set RMI page
  47  * @xport: The pointer to the rmi_transport_dev struct
  48  * @page: The new page address.
  49  *
  50  * RMI devices have 16-bit addressing, but some of the transport
  51  * implementations (like SMBus) only have 8-bit addressing. So RMI implements
  52  * a page address at 0xff of every page so we can reliable page addresses
  53  * every 256 registers.
  54  *
  55  * The page_mutex lock must be held when this function is entered.
  56  *
  57  * Returns zero on success, non-zero on failure.
  58  */
  59 static int rmi_set_page(struct rmi_i2c_xport *rmi_i2c, u8 page)
  60 {
  61         struct i2c_client *client = rmi_i2c->client;
  62         u8 txbuf[2] = {RMI_PAGE_SELECT_REGISTER, page};
  63         int retval;
  64
  65         retval = i2c_master_send(client, txbuf, sizeof(txbuf));
  66         if (retval != sizeof(txbuf)) {
  67                 dev_err(&client->dev,
  68                         "%s: set page failed: %d.", __func__, retval);
  69                 return (retval < 0) ? retval : -EIO;
  70         }
  71
  72         rmi_i2c->page = page;
  73         return 0;
  74 }
  75
  76 static int rmi_i2c_write_block(struct rmi_transport_dev *xport, u16 addr,
  77                                const void *buf, size_t len)
  78 {
  79         struct rmi_i2c_xport *rmi_i2c =
  80                 container_of(xport, struct rmi_i2c_xport, xport);
  81         struct i2c_client *client = rmi_i2c->client;
  82         size_t tx_size = len + 1;
  83         int retval;
  84
  85         mutex_lock(&rmi_i2c->page_mutex);
  86
  87         if (!rmi_i2c->tx_buf || rmi_i2c->tx_buf_size < tx_size) {
  88                 if (rmi_i2c->tx_buf)
  89                         devm_kfree(&client->dev, rmi_i2c->tx_buf);
  90                 rmi_i2c->tx_buf_size = tx_size + BUFFER_SIZE_INCREMENT;
  91                 rmi_i2c->tx_buf = devm_kzalloc(&client->dev,
  92                                                rmi_i2c->tx_buf_size,
  93                                                GFP_KERNEL);
  94                 if (!rmi_i2c->tx_buf) {
  95                         rmi_i2c->tx_buf_size = 0;
  96                         retval = -ENOMEM;
  97                         goto exit;
  98                 }
  99         }
 100
 101         rmi_i2c->tx_buf[0] = addr & 0xff;
 102         memcpy(rmi_i2c->tx_buf + 1, buf, len);
 103
 104         if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
 105                 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
 106                 if (retval)
 107                         goto exit;
 108         }
 109
 110         retval = i2c_master_send(client, rmi_i2c->tx_buf, tx_size);
 111         if (retval == tx_size)
 112                 retval = 0;
 113         else if (retval >= 0)
 114                 retval = -EIO;
 115
 116 exit:
 117         rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
 118                 "write %zd bytes at %#06x: %d (%*ph)\n",
 119                 len, addr, retval, (int)len, buf);
 120
 121         mutex_unlock(&rmi_i2c->page_mutex);
 122         return retval;
 123 }
 124
 125 static int rmi_i2c_read_block(struct rmi_transport_dev *xport, u16 addr,
 126                               void *buf, size_t len)
 127 {
 128         struct rmi_i2c_xport *rmi_i2c =
 129                 container_of(xport, struct rmi_i2c_xport, xport);
 130         struct i2c_client *client = rmi_i2c->client;
 131         u8 addr_offset = addr & 0xff;
 132         int retval;
 133         struct i2c_msg msgs[] = {
 134                 {
 135                         .addr   = client->addr,
 136                         .len    = sizeof(addr_offset),
 137                         .buf    = &addr_offset,
 138                 },
 139                 {
 140                         .addr   = client->addr,
 141                         .flags  = I2C_M_RD,
 142                         .len    = len,
 143                         .buf    = buf,
 144                 },
 145         };
 146
 147         mutex_lock(&rmi_i2c->page_mutex);
 148
 149         if (RMI_I2C_PAGE(addr) != rmi_i2c->page) {
 150                 retval = rmi_set_page(rmi_i2c, RMI_I2C_PAGE(addr));
 151                 if (retval)
 152                         goto exit;
 153         }
 154
 155         retval = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 156         if (retval == ARRAY_SIZE(msgs))
 157                 retval = 0; /* success */
 158         else if (retval >= 0)
 159                 retval = -EIO;
 160
 161 exit:
 162         rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
 163                 "read %zd bytes at %#06x: %d (%*ph)\n",
 164                 len, addr, retval, (int)len, buf);
 165
 166         mutex_unlock(&rmi_i2c->page_mutex);
 167         return retval;
 168 }
 169
 170 static const struct rmi_transport_ops rmi_i2c_ops = {
 171         .write_block    = rmi_i2c_write_block,
 172         .read_block     = rmi_i2c_read_block,
 173 };
 174
 175 static irqreturn_t rmi_i2c_irq(int irq, void *dev_id)
 176 {
 177         struct rmi_i2c_xport *rmi_i2c = dev_id;
 178         struct rmi_device *rmi_dev = rmi_i2c->xport.rmi_dev;
 179         int ret;
 180
 181         ret = rmi_process_interrupt_requests(rmi_dev);
 182         if (ret)
 183                 rmi_dbg(RMI_DEBUG_XPORT, &rmi_dev->dev,
 184                         "Failed to process interrupt request: %d\n", ret);
 185
 186         return IRQ_HANDLED;
 187 }
 188
 189 static int rmi_i2c_init_irq(struct i2c_client *client)
 190 {
 191         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 192         int irq_flags = irqd_get_trigger_type(irq_get_irq_data(rmi_i2c->irq));
 193         int ret;
 194
 195         if (!irq_flags)
 196                 irq_flags = IRQF_TRIGGER_LOW;
 197
 198         ret = devm_request_threaded_irq(&client->dev, rmi_i2c->irq, NULL,
 199                         rmi_i2c_irq, irq_flags | IRQF_ONESHOT, client->name,
 200                         rmi_i2c);
 201         if (ret < 0) {
 202                 dev_warn(&client->dev, "Failed to register interrupt %d\n",
 203                         rmi_i2c->irq);
 204
 205                 return ret;
 206         }
 207
 208         return 0;
 209 }
 210
 211 #ifdef CONFIG_OF
 212 static const struct of_device_id rmi_i2c_of_match[] = {
 213         { .compatible = "syna,rmi4-i2c" },
 214         {},
 215 };
 216 MODULE_DEVICE_TABLE(of, rmi_i2c_of_match);
 217 #endif
 218
 219 static int rmi_i2c_probe(struct i2c_client *client,
 220                          const struct i2c_device_id *id)
 221 {
 222         struct rmi_device_platform_data *pdata;
 223         struct rmi_device_platform_data *client_pdata =
 224                                         dev_get_platdata(&client->dev);
 225         struct rmi_i2c_xport *rmi_i2c;
 226         int retval;
 227
 228         rmi_i2c = devm_kzalloc(&client->dev, sizeof(struct rmi_i2c_xport),
 229                                 GFP_KERNEL);
 230         if (!rmi_i2c)
 231                 return -ENOMEM;
 232
 233         pdata = &rmi_i2c->xport.pdata;
 234
 235         if (!client->dev.of_node && client_pdata)
 236                 *pdata = *client_pdata;
 237
 238         if (client->irq > 0)
 239                 rmi_i2c->irq = client->irq;
 240
 241         rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s.\n",
 242                         dev_name(&client->dev));
 243         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 244                 dev_err(&client->dev,
 245                         "adapter does not support required functionality.\n");
 246                 return -ENODEV;
 247         }
 248
 249         rmi_i2c->client = client;
 250         mutex_init(&rmi_i2c->page_mutex);
 251
 252         rmi_i2c->xport.dev = &client->dev;
 253         rmi_i2c->xport.proto_name = "i2c";
 254         rmi_i2c->xport.ops = &rmi_i2c_ops;
 255
 256         i2c_set_clientdata(client, rmi_i2c);
 257
 258         /*
 259          * Setting the page to zero will (a) make sure the PSR is in a
 260          * known state, and (b) make sure we can talk to the device.
 261          */
 262         retval = rmi_set_page(rmi_i2c, 0);
 263         if (retval) {
 264                 dev_err(&client->dev, "Failed to set page select to 0.\n");
 265                 return retval;
 266         }
 267
 268         retval = rmi_register_transport_device(&rmi_i2c->xport);
 269         if (retval) {
 270                 dev_err(&client->dev, "Failed to register transport driver at 0x%.2X.\n",
 271                         client->addr);
 272                 return retval;
 273         }
 274
 275         retval = rmi_i2c_init_irq(client);
 276         if (retval < 0)
 277                 return retval;
 278
 279         dev_info(&client->dev, "registered rmi i2c driver at %#04x.\n",
 280                         client->addr);
 281         return 0;
 282 }
 283
 284 static int rmi_i2c_remove(struct i2c_client *client)
 285 {
 286         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 287
 288         rmi_unregister_transport_device(&rmi_i2c->xport);
 289
 290         return 0;
 291 }
 292
 293 #ifdef CONFIG_PM_SLEEP
 294 static int rmi_i2c_suspend(struct device *dev)
 295 {
 296         struct i2c_client *client = to_i2c_client(dev);
 297         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 298         int ret;
 299
 300         ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);
 301         if (ret)
 302                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 303
 304         disable_irq(rmi_i2c->irq);
 305         if (device_may_wakeup(&client->dev)) {
 306                 ret = enable_irq_wake(rmi_i2c->irq);
 307                 if (!ret)
 308                         dev_warn(dev, "Failed to enable irq for wake: %d\n",
 309                                 ret);
 310         }
 311         return ret;
 312 }
 313
 314 static int rmi_i2c_resume(struct device *dev)
 315 {
 316         struct i2c_client *client = to_i2c_client(dev);
 317         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 318         int ret;
 319
 320         enable_irq(rmi_i2c->irq);
 321         if (device_may_wakeup(&client->dev)) {
 322                 ret = disable_irq_wake(rmi_i2c->irq);
 323                 if (!ret)
 324                         dev_warn(dev, "Failed to disable irq for wake: %d\n",
 325                                 ret);
 326         }
 327
 328         ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);
 329         if (ret)
 330                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 331
 332         return ret;
 333 }
 334 #endif
 335
 336 #ifdef CONFIG_PM
 337 static int rmi_i2c_runtime_suspend(struct device *dev)
 338 {
 339         struct i2c_client *client = to_i2c_client(dev);
 340         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 341         int ret;
 342
 343         ret = rmi_driver_suspend(rmi_i2c->xport.rmi_dev);
 344         if (ret)
 345                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 346
 347         disable_irq(rmi_i2c->irq);
 348
 349         return 0;
 350 }
 351
 352 static int rmi_i2c_runtime_resume(struct device *dev)
 353 {
 354         struct i2c_client *client = to_i2c_client(dev);
 355         struct rmi_i2c_xport *rmi_i2c = i2c_get_clientdata(client);
 356         int ret;
 357
 358         enable_irq(rmi_i2c->irq);
 359
 360         ret = rmi_driver_resume(rmi_i2c->xport.rmi_dev);
 361         if (ret)
 362                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 363
 364         return 0;
 365 }
 366 #endif
 367
 368 static const struct dev_pm_ops rmi_i2c_pm = {
 369         SET_SYSTEM_SLEEP_PM_OPS(rmi_i2c_suspend, rmi_i2c_resume)
 370         SET_RUNTIME_PM_OPS(rmi_i2c_runtime_suspend, rmi_i2c_runtime_resume,
 371                            NULL)
 372 };
 373
 374 static const struct i2c_device_id rmi_id[] = {
 375         { "rmi4_i2c", 0 },
 376         { }
 377 };
 378 MODULE_DEVICE_TABLE(i2c, rmi_id);
 379
 380 static struct i2c_driver rmi_i2c_driver = {
 381         .driver = {
 382                 .name   = "rmi4_i2c",
 383                 .pm     = &rmi_i2c_pm,
 384                 .of_match_table = of_match_ptr(rmi_i2c_of_match),
 385         },
 386         .id_table       = rmi_id,
 387         .probe          = rmi_i2c_probe,
 388         .remove         = rmi_i2c_remove,
 389 };
 390
 391 module_i2c_driver(rmi_i2c_driver);
 392
 393 MODULE_AUTHOR("Christopher Heiny <[email protected]>");
 394 MODULE_AUTHOR("Andrew Duggan <[email protected]>");
 395 MODULE_DESCRIPTION("RMI I2C driver");
 396 MODULE_LICENSE("GPL");
 397 MODULE_VERSION(RMI_DRIVER_VERSION);