drivers/regulator/ad5398.c

   1 /*
   2  * Voltage and current regulation for AD5398 and AD5821
   3  *
   4  * Copyright 2010 Analog Devices Inc.
   5  *
   6  * Enter bugs at http://blackfin.uclinux.org/
   7  *
   8  * Licensed under the GPL-2 or later.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/err.h>
  13 #include <linux/i2c.h>
  14 #include <linux/slab.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regulator/driver.h>
  17 #include <linux/regulator/machine.h>
  18
  19 #define AD5398_CURRENT_EN_MASK  0x8000
  20
  21 struct ad5398_chip_info {
  22         struct i2c_client *client;
  23         int min_uA;
  24         int max_uA;
  25         unsigned int current_level;
  26         unsigned int current_mask;
  27         unsigned int current_offset;
  28         struct regulator_dev *rdev;
  29 };
  30
  31 static int ad5398_calc_current(struct ad5398_chip_info *chip,
  32         unsigned selector)
  33 {
  34         unsigned range_uA = chip->max_uA - chip->min_uA;
  35
  36         return chip->min_uA + (selector * range_uA / chip->current_level);
  37 }
  38
  39 static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
  40 {
  41         unsigned short val;
  42         int ret;
  43
  44         ret = i2c_master_recv(client, (char *)&val, 2);
  45         if (ret < 0) {
  46                 dev_err(&client->dev, "I2C read error\n");
  47                 return ret;
  48         }
  49         *data = be16_to_cpu(val);
  50
  51         return ret;
  52 }
  53
  54 static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
  55 {
  56         unsigned short val;
  57         int ret;
  58
  59         val = cpu_to_be16(data);
  60         ret = i2c_master_send(client, (char *)&val, 2);
  61         if (ret < 0)
  62                 dev_err(&client->dev, "I2C write error\n");
  63
  64         return ret;
  65 }
  66
  67 static int ad5398_get_current_limit(struct regulator_dev *rdev)
  68 {
  69         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
  70         struct i2c_client *client = chip->client;
  71         unsigned short data;
  72         int ret;
  73
  74         ret = ad5398_read_reg(client, &data);
  75         if (ret < 0)
  76                 return ret;
  77
  78         ret = (data & chip->current_mask) >> chip->current_offset;
  79
  80         return ad5398_calc_current(chip, ret);
  81 }
  82
  83 static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
  84 {
  85         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
  86         struct i2c_client *client = chip->client;
  87         unsigned range_uA = chip->max_uA - chip->min_uA;
  88         unsigned selector;
  89         unsigned short data;
  90         int ret;
  91
  92         if (min_uA < chip->min_uA)
  93                 min_uA = chip->min_uA;
  94         if (max_uA > chip->max_uA)
  95                 max_uA = chip->max_uA;
  96
  97         if (min_uA > chip->max_uA || max_uA < chip->min_uA)
  98                 return -EINVAL;
  99
 100         selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
 101                                 range_uA);
 102         if (ad5398_calc_current(chip, selector) > max_uA)
 103                 return -EINVAL;
 104
 105         dev_dbg(&client->dev, "changing current %duA\n",
 106                 ad5398_calc_current(chip, selector));
 107
 108         /* read chip enable bit */
 109         ret = ad5398_read_reg(client, &data);
 110         if (ret < 0)
 111                 return ret;
 112
 113         /* prepare register data */
 114         selector = (selector << chip->current_offset) & chip->current_mask;
 115         data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
 116
 117         /* write the new current value back as well as enable bit */
 118         ret = ad5398_write_reg(client, data);
 119
 120         return ret;
 121 }
 122
 123 static int ad5398_is_enabled(struct regulator_dev *rdev)
 124 {
 125         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 126         struct i2c_client *client = chip->client;
 127         unsigned short data;
 128         int ret;
 129
 130         ret = ad5398_read_reg(client, &data);
 131         if (ret < 0)
 132                 return ret;
 133
 134         if (data & AD5398_CURRENT_EN_MASK)
 135                 return 1;
 136         else
 137                 return 0;
 138 }
 139
 140 static int ad5398_enable(struct regulator_dev *rdev)
 141 {
 142         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 143         struct i2c_client *client = chip->client;
 144         unsigned short data;
 145         int ret;
 146
 147         ret = ad5398_read_reg(client, &data);
 148         if (ret < 0)
 149                 return ret;
 150
 151         if (data & AD5398_CURRENT_EN_MASK)
 152                 return 0;
 153
 154         data |= AD5398_CURRENT_EN_MASK;
 155
 156         ret = ad5398_write_reg(client, data);
 157
 158         return ret;
 159 }
 160
 161 static int ad5398_disable(struct regulator_dev *rdev)
 162 {
 163         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 164         struct i2c_client *client = chip->client;
 165         unsigned short data;
 166         int ret;
 167
 168         ret = ad5398_read_reg(client, &data);
 169         if (ret < 0)
 170                 return ret;
 171
 172         if (!(data & AD5398_CURRENT_EN_MASK))
 173                 return 0;
 174
 175         data &= ~AD5398_CURRENT_EN_MASK;
 176
 177         ret = ad5398_write_reg(client, data);
 178
 179         return ret;
 180 }
 181
 182 static struct regulator_ops ad5398_ops = {
 183         .get_current_limit = ad5398_get_current_limit,
 184         .set_current_limit = ad5398_set_current_limit,
 185         .enable = ad5398_enable,
 186         .disable = ad5398_disable,
 187         .is_enabled = ad5398_is_enabled,
 188 };
 189
 190 static const struct regulator_desc ad5398_reg = {
 191         .name = "isink",
 192         .id = 0,
 193         .ops = &ad5398_ops,
 194         .type = REGULATOR_CURRENT,
 195         .owner = THIS_MODULE,
 196 };
 197
 198 struct ad5398_current_data_format {
 199         int current_bits;
 200         int current_offset;
 201         int min_uA;
 202         int max_uA;
 203 };
 204
 205 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
 206
 207 static const struct i2c_device_id ad5398_id[] = {
 208         { "ad5398", (kernel_ulong_t)&df_10_4_120 },
 209         { "ad5821", (kernel_ulong_t)&df_10_4_120 },
 210         { }
 211 };
 212 MODULE_DEVICE_TABLE(i2c, ad5398_id);
 213
 214 static int ad5398_probe(struct i2c_client *client,
 215                                 const struct i2c_device_id *id)
 216 {
 217         struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
 218         struct regulator_config config = { };
 219         struct ad5398_chip_info *chip;
 220         const struct ad5398_current_data_format *df =
 221                         (struct ad5398_current_data_format *)id->driver_data;
 222
 223         if (!init_data)
 224                 return -EINVAL;
 225
 226         chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 227         if (!chip)
 228                 return -ENOMEM;
 229
 230         config.dev = &client->dev;
 231         config.init_data = init_data;
 232         config.driver_data = chip;
 233
 234         chip->client = client;
 235
 236         chip->min_uA = df->min_uA;
 237         chip->max_uA = df->max_uA;
 238         chip->current_level = 1 << df->current_bits;
 239         chip->current_offset = df->current_offset;
 240         chip->current_mask = (chip->current_level - 1) << chip->current_offset;
 241
 242         chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
 243                                              &config);
 244         if (IS_ERR(chip->rdev)) {
 245                 dev_err(&client->dev, "failed to register %s %s\n",
 246                         id->name, ad5398_reg.name);
 247                 return PTR_ERR(chip->rdev);
 248         }
 249
 250         i2c_set_clientdata(client, chip);
 251         dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
 252         return 0;
 253 }
 254
 255 static struct i2c_driver ad5398_driver = {
 256         .probe = ad5398_probe,
 257         .driver         = {
 258                 .name   = "ad5398",
 259         },
 260         .id_table       = ad5398_id,
 261 };
 262
 263 static int __init ad5398_init(void)
 264 {
 265         return i2c_add_driver(&ad5398_driver);
 266 }
 267 subsys_initcall(ad5398_init);
 268
 269 static void __exit ad5398_exit(void)
 270 {
 271         i2c_del_driver(&ad5398_driver);
 272 }
 273 module_exit(ad5398_exit);
 274
 275 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
 276 MODULE_AUTHOR("Sonic Zhang");
 277 MODULE_LICENSE("GPL");