drivers/base/regmap/regmap-w1.c

   1 /*
   2  * Register map access API - W1 (1-Wire) support
   3  *
   4  * Copyright (c) 2017 Radioavionica Corporation
   5  * Author: Alex A. Mihaylov <minimumlaw@rambler.ru>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation
  10  */
  11
  12 #include <linux/regmap.h>
  13 #include <linux/module.h>
  14 #include <linux/w1.h>
  15
  16 #include "internal.h"
  17
  18 #define W1_CMD_READ_DATA        0x69
  19 #define W1_CMD_WRITE_DATA       0x6C
  20
  21 /*
  22  * 1-Wire slaves registers with addess 8 bit and data 8 bit
  23  */
  24
  25 static int w1_reg_a8_v8_read(void *context, unsigned int reg, unsigned int *val)
  26 {
  27         struct device *dev = context;
  28         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  29         int ret = 0;
  30
  31         if (reg > 255)
  32                 return -EINVAL;
  33
  34         mutex_lock(&sl->master->bus_mutex);
  35         if (!w1_reset_select_slave(sl)) {
  36                 w1_write_8(sl->master, W1_CMD_READ_DATA);
  37                 w1_write_8(sl->master, reg);
  38                 *val = w1_read_8(sl->master);
  39         } else {
  40                 ret = -ENODEV;
  41         }
  42         mutex_unlock(&sl->master->bus_mutex);
  43
  44         return ret;
  45 }
  46
  47 static int w1_reg_a8_v8_write(void *context, unsigned int reg, unsigned int val)
  48 {
  49         struct device *dev = context;
  50         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  51         int ret = 0;
  52
  53         if (reg > 255)
  54                 return -EINVAL;
  55
  56         mutex_lock(&sl->master->bus_mutex);
  57         if (!w1_reset_select_slave(sl)) {
  58                 w1_write_8(sl->master, W1_CMD_WRITE_DATA);
  59                 w1_write_8(sl->master, reg);
  60                 w1_write_8(sl->master, val);
  61         } else {
  62                 ret = -ENODEV;
  63         }
  64         mutex_unlock(&sl->master->bus_mutex);
  65
  66         return ret;
  67 }
  68
  69 /*
  70  * 1-Wire slaves registers with addess 8 bit and data 16 bit
  71  */
  72
  73 static int w1_reg_a8_v16_read(void *context, unsigned int reg,
  74                                 unsigned int *val)
  75 {
  76         struct device *dev = context;
  77         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
  78         int ret = 0;
  79
  80         if (reg > 255)
  81                 return -EINVAL;
  82
  83         mutex_lock(&sl->master->bus_mutex);
  84         if (!w1_reset_select_slave(sl)) {
  85                 w1_write_8(sl->master, W1_CMD_READ_DATA);
  86                 w1_write_8(sl->master, reg);
  87                 *val = w1_read_8(sl->master);
  88                 *val |= w1_read_8(sl->master)<<8;
  89         } else {
  90                 ret = -ENODEV;
  91         }
  92         mutex_unlock(&sl->master->bus_mutex);
  93
  94         return ret;
  95 }
  96
  97 static int w1_reg_a8_v16_write(void *context, unsigned int reg,
  98                                 unsigned int val)
  99 {
 100         struct device *dev = context;
 101         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 102         int ret = 0;
 103
 104         if (reg > 255)
 105                 return -EINVAL;
 106
 107         mutex_lock(&sl->master->bus_mutex);
 108         if (!w1_reset_select_slave(sl)) {
 109                 w1_write_8(sl->master, W1_CMD_WRITE_DATA);
 110                 w1_write_8(sl->master, reg);
 111                 w1_write_8(sl->master, val & 0x00FF);
 112                 w1_write_8(sl->master, val>>8 & 0x00FF);
 113         } else {
 114                 ret = -ENODEV;
 115         }
 116         mutex_unlock(&sl->master->bus_mutex);
 117
 118         return ret;
 119 }
 120
 121 /*
 122  * 1-Wire slaves registers with addess 16 bit and data 16 bit
 123  */
 124
 125 static int w1_reg_a16_v16_read(void *context, unsigned int reg,
 126                                 unsigned int *val)
 127 {
 128         struct device *dev = context;
 129         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 130         int ret = 0;
 131
 132         if (reg > 65535)
 133                 return -EINVAL;
 134
 135         mutex_lock(&sl->master->bus_mutex);
 136         if (!w1_reset_select_slave(sl)) {
 137                 w1_write_8(sl->master, W1_CMD_READ_DATA);
 138                 w1_write_8(sl->master, reg & 0x00FF);
 139                 w1_write_8(sl->master, reg>>8 & 0x00FF);
 140                 *val = w1_read_8(sl->master);
 141                 *val |= w1_read_8(sl->master)<<8;
 142         } else {
 143                 ret = -ENODEV;
 144         }
 145         mutex_unlock(&sl->master->bus_mutex);
 146
 147         return ret;
 148 }
 149
 150 static int w1_reg_a16_v16_write(void *context, unsigned int reg,
 151                                 unsigned int val)
 152 {
 153         struct device *dev = context;
 154         struct w1_slave *sl = container_of(dev, struct w1_slave, dev);
 155         int ret = 0;
 156
 157         if (reg > 65535)
 158                 return -EINVAL;
 159
 160         mutex_lock(&sl->master->bus_mutex);
 161         if (!w1_reset_select_slave(sl)) {
 162                 w1_write_8(sl->master, W1_CMD_WRITE_DATA);
 163                 w1_write_8(sl->master, reg & 0x00FF);
 164                 w1_write_8(sl->master, reg>>8 & 0x00FF);
 165                 w1_write_8(sl->master, val & 0x00FF);
 166                 w1_write_8(sl->master, val>>8 & 0x00FF);
 167         } else {
 168                 ret = -ENODEV;
 169         }
 170         mutex_unlock(&sl->master->bus_mutex);
 171
 172         return ret;
 173 }
 174
 175 /*
 176  * Various types of supported bus addressing
 177  */
 178
 179 static struct regmap_bus regmap_w1_bus_a8_v8 = {
 180         .reg_read = w1_reg_a8_v8_read,
 181         .reg_write = w1_reg_a8_v8_write,
 182 };
 183
 184 static struct regmap_bus regmap_w1_bus_a8_v16 = {
 185         .reg_read = w1_reg_a8_v16_read,
 186         .reg_write = w1_reg_a8_v16_write,
 187 };
 188
 189 static struct regmap_bus regmap_w1_bus_a16_v16 = {
 190         .reg_read = w1_reg_a16_v16_read,
 191         .reg_write = w1_reg_a16_v16_write,
 192 };
 193
 194 static const struct regmap_bus *regmap_get_w1_bus(struct device *w1_dev,
 195                                         const struct regmap_config *config)
 196 {
 197         if (config->reg_bits == 8 && config->val_bits == 8)
 198                 return &regmap_w1_bus_a8_v8;
 199
 200         if (config->reg_bits == 8 && config->val_bits == 16)
 201                 return &regmap_w1_bus_a8_v16;
 202
 203         if (config->reg_bits == 16 && config->val_bits == 16)
 204                 return &regmap_w1_bus_a16_v16;
 205
 206         return ERR_PTR(-ENOTSUPP);
 207 }
 208
 209 struct regmap *__regmap_init_w1(struct device *w1_dev,
 210                                  const struct regmap_config *config,
 211                                  struct lock_class_key *lock_key,
 212                                  const char *lock_name)
 213 {
 214
 215         const struct regmap_bus *bus = regmap_get_w1_bus(w1_dev, config);
 216
 217         if (IS_ERR(bus))
 218                 return ERR_CAST(bus);
 219
 220         return __regmap_init(w1_dev, bus, w1_dev, config,
 221                          lock_key, lock_name);
 222
 223         return NULL;
 224 }
 225 EXPORT_SYMBOL_GPL(__regmap_init_w1);
 226
 227 struct regmap *__devm_regmap_init_w1(struct device *w1_dev,
 228                                  const struct regmap_config *config,
 229                                  struct lock_class_key *lock_key,
 230                                  const char *lock_name)
 231 {
 232
 233         const struct regmap_bus *bus = regmap_get_w1_bus(w1_dev, config);
 234
 235         if (IS_ERR(bus))
 236                 return ERR_CAST(bus);
 237
 238         return __devm_regmap_init(w1_dev, bus, w1_dev, config,
 239                                  lock_key, lock_name);
 240
 241         return NULL;
 242 }
 243 EXPORT_SYMBOL_GPL(__devm_regmap_init_w1);
 244
 245 MODULE_LICENSE("GPL");