drivers/input/rmi4/rmi_smbus.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2015 - 2016 Red Hat, Inc
   4  * Copyright (c) 2011, 2012 Synaptics Incorporated
   5  * Copyright (c) 2011 Unixphere
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/delay.h>
  10 #include <linux/i2c.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/kconfig.h>
  13 #include <linux/lockdep.h>
  14 #include <linux/module.h>
  15 #include <linux/pm.h>
  16 #include <linux/rmi.h>
  17 #include <linux/slab.h>
  18 #include "rmi_driver.h"
  19
  20 #define SMB_PROTOCOL_VERSION_ADDRESS    0xfd
  21 #define SMB_MAX_COUNT                   32
  22 #define RMI_SMB2_MAP_SIZE               8 /* 8 entry of 4 bytes each */
  23 #define RMI_SMB2_MAP_FLAGS_WE           0x01
  24
  25 struct mapping_table_entry {
  26         __le16 rmiaddr;
  27         u8 readcount;
  28         u8 flags;
  29 };
  30
  31 struct rmi_smb_xport {
  32         struct rmi_transport_dev xport;
  33         struct i2c_client *client;
  34
  35         struct mutex page_mutex;
  36         int page;
  37         u8 table_index;
  38         struct mutex mappingtable_mutex;
  39         struct mapping_table_entry mapping_table[RMI_SMB2_MAP_SIZE];
  40 };
  41
  42 static int rmi_smb_get_version(struct rmi_smb_xport *rmi_smb)
  43 {
  44         struct i2c_client *client = rmi_smb->client;
  45         int retval;
  46
  47         /* Check if for SMBus new version device by reading version byte. */
  48         retval = i2c_smbus_read_byte_data(client, SMB_PROTOCOL_VERSION_ADDRESS);
  49         if (retval < 0) {
  50                 dev_err(&client->dev, "failed to get SMBus version number!\n");
  51                 return retval;
  52         }
  53
  54         return retval + 1;
  55 }
  56
  57 /* SMB block write - wrapper over ic2_smb_write_block */
  58 static int smb_block_write(struct rmi_transport_dev *xport,
  59                               u8 commandcode, const void *buf, size_t len)
  60 {
  61         struct rmi_smb_xport *rmi_smb =
  62                 container_of(xport, struct rmi_smb_xport, xport);
  63         struct i2c_client *client = rmi_smb->client;
  64         int retval;
  65
  66         retval = i2c_smbus_write_block_data(client, commandcode, len, buf);
  67
  68         rmi_dbg(RMI_DEBUG_XPORT, &client->dev,
  69                 "wrote %zd bytes at %#04x: %d (%*ph)\n",
  70                 len, commandcode, retval, (int)len, buf);
  71
  72         return retval;
  73 }
  74
  75 /*
  76  * The function to get command code for smbus operations and keeps
  77  * records to the driver mapping table
  78  */
  79 static int rmi_smb_get_command_code(struct rmi_transport_dev *xport,
  80                 u16 rmiaddr, int bytecount, bool isread, u8 *commandcode)
  81 {
  82         struct rmi_smb_xport *rmi_smb =
  83                 container_of(xport, struct rmi_smb_xport, xport);
  84         struct mapping_table_entry new_map;
  85         int i;
  86         int retval = 0;
  87
  88         mutex_lock(&rmi_smb->mappingtable_mutex);
  89
  90         for (i = 0; i < RMI_SMB2_MAP_SIZE; i++) {
  91                 struct mapping_table_entry *entry = &rmi_smb->mapping_table[i];
  92
  93                 if (le16_to_cpu(entry->rmiaddr) == rmiaddr) {
  94                         if (isread) {
  95                                 if (entry->readcount == bytecount)
  96                                         goto exit;
  97                         } else {
  98                                 if (entry->flags & RMI_SMB2_MAP_FLAGS_WE) {
  99                                         goto exit;
 100                                 }
 101                         }
 102                 }
 103         }
 104
 105         i = rmi_smb->table_index;
 106         rmi_smb->table_index = (i + 1) % RMI_SMB2_MAP_SIZE;
 107
 108         /* constructs mapping table data entry. 4 bytes each entry */
 109         memset(&new_map, 0, sizeof(new_map));
 110         new_map.rmiaddr = cpu_to_le16(rmiaddr);
 111         new_map.readcount = bytecount;
 112         new_map.flags = !isread ? RMI_SMB2_MAP_FLAGS_WE : 0;
 113
 114         retval = smb_block_write(xport, i + 0x80, &new_map, sizeof(new_map));
 115         if (retval < 0) {
 116                 /*
 117                  * if not written to device mapping table
 118                  * clear the driver mapping table records
 119                  */
 120                 memset(&new_map, 0, sizeof(new_map));
 121         }
 122
 123         /* save to the driver level mapping table */
 124         rmi_smb->mapping_table[i] = new_map;
 125
 126 exit:
 127         mutex_unlock(&rmi_smb->mappingtable_mutex);
 128
 129         if (retval < 0)
 130                 return retval;
 131
 132         *commandcode = i;
 133         return 0;
 134 }
 135
 136 static int rmi_smb_write_block(struct rmi_transport_dev *xport, u16 rmiaddr,
 137                                 const void *databuff, size_t len)
 138 {
 139         int retval = 0;
 140         u8 commandcode;
 141         struct rmi_smb_xport *rmi_smb =
 142                 container_of(xport, struct rmi_smb_xport, xport);
 143         int cur_len = (int)len;
 144
 145         mutex_lock(&rmi_smb->page_mutex);
 146
 147         while (cur_len > 0) {
 148                 /*
 149                  * break into 32 bytes chunks to write get command code
 150                  */
 151                 int block_len = min_t(int, len, SMB_MAX_COUNT);
 152
 153                 retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
 154                                                   false, &commandcode);
 155                 if (retval < 0)
 156                         goto exit;
 157
 158                 retval = smb_block_write(xport, commandcode,
 159                                          databuff, block_len);
 160                 if (retval < 0)
 161                         goto exit;
 162
 163                 /* prepare to write next block of bytes */
 164                 cur_len -= SMB_MAX_COUNT;
 165                 databuff += SMB_MAX_COUNT;
 166                 rmiaddr += SMB_MAX_COUNT;
 167         }
 168 exit:
 169         mutex_unlock(&rmi_smb->page_mutex);
 170         return retval;
 171 }
 172
 173 /* SMB block read - wrapper over ic2_smb_read_block */
 174 static int smb_block_read(struct rmi_transport_dev *xport,
 175                              u8 commandcode, void *buf, size_t len)
 176 {
 177         struct rmi_smb_xport *rmi_smb =
 178                 container_of(xport, struct rmi_smb_xport, xport);
 179         struct i2c_client *client = rmi_smb->client;
 180         int retval;
 181
 182         retval = i2c_smbus_read_block_data(client, commandcode, buf);
 183         if (retval < 0)
 184                 return retval;
 185
 186         return retval;
 187 }
 188
 189 static int rmi_smb_read_block(struct rmi_transport_dev *xport, u16 rmiaddr,
 190                               void *databuff, size_t len)
 191 {
 192         struct rmi_smb_xport *rmi_smb =
 193                 container_of(xport, struct rmi_smb_xport, xport);
 194         int retval;
 195         u8 commandcode;
 196         int cur_len = (int)len;
 197
 198         mutex_lock(&rmi_smb->page_mutex);
 199         memset(databuff, 0, len);
 200
 201         while (cur_len > 0) {
 202                 /* break into 32 bytes chunks to write get command code */
 203                 int block_len =  min_t(int, cur_len, SMB_MAX_COUNT);
 204
 205                 retval = rmi_smb_get_command_code(xport, rmiaddr, block_len,
 206                                                   true, &commandcode);
 207                 if (retval < 0)
 208                         goto exit;
 209
 210                 retval = smb_block_read(xport, commandcode,
 211                                         databuff, block_len);
 212                 if (retval < 0)
 213                         goto exit;
 214
 215                 /* prepare to read next block of bytes */
 216                 cur_len -= SMB_MAX_COUNT;
 217                 databuff += SMB_MAX_COUNT;
 218                 rmiaddr += SMB_MAX_COUNT;
 219         }
 220
 221         retval = 0;
 222
 223 exit:
 224         mutex_unlock(&rmi_smb->page_mutex);
 225         return retval;
 226 }
 227
 228 static void rmi_smb_clear_state(struct rmi_smb_xport *rmi_smb)
 229 {
 230         /* the mapping table has been flushed, discard the current one */
 231         mutex_lock(&rmi_smb->mappingtable_mutex);
 232         memset(rmi_smb->mapping_table, 0, sizeof(rmi_smb->mapping_table));
 233         mutex_unlock(&rmi_smb->mappingtable_mutex);
 234 }
 235
 236 static int rmi_smb_enable_smbus_mode(struct rmi_smb_xport *rmi_smb)
 237 {
 238         int retval;
 239
 240         /* we need to get the smbus version to activate the touchpad */
 241         retval = rmi_smb_get_version(rmi_smb);
 242         if (retval < 0)
 243                 return retval;
 244
 245         return 0;
 246 }
 247
 248 static int rmi_smb_reset(struct rmi_transport_dev *xport, u16 reset_addr)
 249 {
 250         struct rmi_smb_xport *rmi_smb =
 251                 container_of(xport, struct rmi_smb_xport, xport);
 252
 253         rmi_smb_clear_state(rmi_smb);
 254
 255         /*
 256          * we do not call the actual reset command, it has to be handled in
 257          * PS/2 or there will be races between PS/2 and SMBus.
 258          * PS/2 should ensure that a psmouse_reset is called before
 259          * intializing the device and after it has been removed to be in a known
 260          * state.
 261          */
 262         return rmi_smb_enable_smbus_mode(rmi_smb);
 263 }
 264
 265 static const struct rmi_transport_ops rmi_smb_ops = {
 266         .write_block    = rmi_smb_write_block,
 267         .read_block     = rmi_smb_read_block,
 268         .reset          = rmi_smb_reset,
 269 };
 270
 271 static int rmi_smb_probe(struct i2c_client *client,
 272                          const struct i2c_device_id *id)
 273 {
 274         struct rmi_device_platform_data *pdata = dev_get_platdata(&client->dev);
 275         struct rmi_smb_xport *rmi_smb;
 276         int smbus_version;
 277         int error;
 278
 279         if (!pdata) {
 280                 dev_err(&client->dev, "no platform data, aborting\n");
 281                 return -ENOMEM;
 282         }
 283
 284         if (!i2c_check_functionality(client->adapter,
 285                                      I2C_FUNC_SMBUS_READ_BLOCK_DATA |
 286                                      I2C_FUNC_SMBUS_HOST_NOTIFY)) {
 287                 dev_err(&client->dev,
 288                         "adapter does not support required functionality\n");
 289                 return -ENODEV;
 290         }
 291
 292         if (client->irq <= 0) {
 293                 dev_err(&client->dev, "no IRQ provided, giving up\n");
 294                 return client->irq ? client->irq : -ENODEV;
 295         }
 296
 297         rmi_smb = devm_kzalloc(&client->dev, sizeof(struct rmi_smb_xport),
 298                                 GFP_KERNEL);
 299         if (!rmi_smb)
 300                 return -ENOMEM;
 301
 302         rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Probing %s\n",
 303                 dev_name(&client->dev));
 304
 305         rmi_smb->client = client;
 306         mutex_init(&rmi_smb->page_mutex);
 307         mutex_init(&rmi_smb->mappingtable_mutex);
 308
 309         rmi_smb->xport.dev = &client->dev;
 310         rmi_smb->xport.pdata = *pdata;
 311         rmi_smb->xport.pdata.irq = client->irq;
 312         rmi_smb->xport.proto_name = "smb";
 313         rmi_smb->xport.ops = &rmi_smb_ops;
 314
 315         smbus_version = rmi_smb_get_version(rmi_smb);
 316         if (smbus_version < 0)
 317                 return smbus_version;
 318
 319         rmi_dbg(RMI_DEBUG_XPORT, &client->dev, "Smbus version is %d",
 320                 smbus_version);
 321
 322         if (smbus_version != 2 && smbus_version != 3) {
 323                 dev_err(&client->dev, "Unrecognized SMB version %d\n",
 324                                 smbus_version);
 325                 return -ENODEV;
 326         }
 327
 328         i2c_set_clientdata(client, rmi_smb);
 329
 330         dev_info(&client->dev, "registering SMbus-connected sensor\n");
 331
 332         error = rmi_register_transport_device(&rmi_smb->xport);
 333         if (error) {
 334                 dev_err(&client->dev, "failed to register sensor: %d\n", error);
 335                 return error;
 336         }
 337
 338         return 0;
 339 }
 340
 341 static int rmi_smb_remove(struct i2c_client *client)
 342 {
 343         struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
 344
 345         rmi_unregister_transport_device(&rmi_smb->xport);
 346
 347         return 0;
 348 }
 349
 350 static int __maybe_unused rmi_smb_suspend(struct device *dev)
 351 {
 352         struct i2c_client *client = to_i2c_client(dev);
 353         struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
 354         int ret;
 355
 356         ret = rmi_driver_suspend(rmi_smb->xport.rmi_dev, true);
 357         if (ret)
 358                 dev_warn(dev, "Failed to suspend device: %d\n", ret);
 359
 360         return ret;
 361 }
 362
 363 static int __maybe_unused rmi_smb_runtime_suspend(struct device *dev)
 364 {
 365         struct i2c_client *client = to_i2c_client(dev);
 366         struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
 367         int ret;
 368
 369         ret = rmi_driver_suspend(rmi_smb->xport.rmi_dev, false);
 370         if (ret)
 371                 dev_warn(dev, "Failed to suspend device: %d\n", ret);
 372
 373         return ret;
 374 }
 375
 376 static int __maybe_unused rmi_smb_resume(struct device *dev)
 377 {
 378         struct i2c_client *client = container_of(dev, struct i2c_client, dev);
 379         struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
 380         struct rmi_device *rmi_dev = rmi_smb->xport.rmi_dev;
 381         int ret;
 382
 383         rmi_smb_reset(&rmi_smb->xport, 0);
 384
 385         rmi_reset(rmi_dev);
 386
 387         ret = rmi_driver_resume(rmi_smb->xport.rmi_dev, true);
 388         if (ret)
 389                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 390
 391         return 0;
 392 }
 393
 394 static int __maybe_unused rmi_smb_runtime_resume(struct device *dev)
 395 {
 396         struct i2c_client *client = to_i2c_client(dev);
 397         struct rmi_smb_xport *rmi_smb = i2c_get_clientdata(client);
 398         int ret;
 399
 400         ret = rmi_driver_resume(rmi_smb->xport.rmi_dev, false);
 401         if (ret)
 402                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 403
 404         return 0;
 405 }
 406
 407 static const struct dev_pm_ops rmi_smb_pm = {
 408         SET_SYSTEM_SLEEP_PM_OPS(rmi_smb_suspend, rmi_smb_resume)
 409         SET_RUNTIME_PM_OPS(rmi_smb_runtime_suspend, rmi_smb_runtime_resume,
 410                            NULL)
 411 };
 412
 413 static const struct i2c_device_id rmi_id[] = {
 414         { "rmi4_smbus", 0 },
 415         { }
 416 };
 417 MODULE_DEVICE_TABLE(i2c, rmi_id);
 418
 419 static struct i2c_driver rmi_smb_driver = {
 420         .driver = {
 421                 .name   = "rmi4_smbus",
 422                 .pm     = &rmi_smb_pm,
 423         },
 424         .id_table       = rmi_id,
 425         .probe          = rmi_smb_probe,
 426         .remove         = rmi_smb_remove,
 427 };
 428
 429 module_i2c_driver(rmi_smb_driver);
 430
 431 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 432 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
 433 MODULE_DESCRIPTION("RMI4 SMBus driver");
 434 MODULE_LICENSE("GPL");