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->max_uA || min_uA < chip->min_uA)
  93                 return -EINVAL;
  94         if (max_uA > chip->max_uA || max_uA < chip->min_uA)
  95                 return -EINVAL;
  96
  97         selector = ((min_uA - chip->min_uA) * chip->current_level +
  98                         range_uA - 1) / range_uA;
  99         if (ad5398_calc_current(chip, selector) > max_uA)
 100                 return -EINVAL;
 101
 102         dev_dbg(&client->dev, "changing current %dmA\n",
 103                 ad5398_calc_current(chip, selector) / 1000);
 104
 105         /* read chip enable bit */
 106         ret = ad5398_read_reg(client, &data);
 107         if (ret < 0)
 108                 return ret;
 109
 110         /* prepare register data */
 111         selector = (selector << chip->current_offset) & chip->current_mask;
 112         data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
 113
 114         /* write the new current value back as well as enable bit */
 115         ret = ad5398_write_reg(client, data);
 116
 117         return ret;
 118 }
 119
 120 static int ad5398_is_enabled(struct regulator_dev *rdev)
 121 {
 122         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 123         struct i2c_client *client = chip->client;
 124         unsigned short data;
 125         int ret;
 126
 127         ret = ad5398_read_reg(client, &data);
 128         if (ret < 0)
 129                 return ret;
 130
 131         if (data & AD5398_CURRENT_EN_MASK)
 132                 return 1;
 133         else
 134                 return 0;
 135 }
 136
 137 static int ad5398_enable(struct regulator_dev *rdev)
 138 {
 139         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 140         struct i2c_client *client = chip->client;
 141         unsigned short data;
 142         int ret;
 143
 144         ret = ad5398_read_reg(client, &data);
 145         if (ret < 0)
 146                 return ret;
 147
 148         if (data & AD5398_CURRENT_EN_MASK)
 149                 return 0;
 150
 151         data |= AD5398_CURRENT_EN_MASK;
 152
 153         ret = ad5398_write_reg(client, data);
 154
 155         return ret;
 156 }
 157
 158 static int ad5398_disable(struct regulator_dev *rdev)
 159 {
 160         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 161         struct i2c_client *client = chip->client;
 162         unsigned short data;
 163         int ret;
 164
 165         ret = ad5398_read_reg(client, &data);
 166         if (ret < 0)
 167                 return ret;
 168
 169         if (!(data & AD5398_CURRENT_EN_MASK))
 170                 return 0;
 171
 172         data &= ~AD5398_CURRENT_EN_MASK;
 173
 174         ret = ad5398_write_reg(client, data);
 175
 176         return ret;
 177 }
 178
 179 static struct regulator_ops ad5398_ops = {
 180         .get_current_limit = ad5398_get_current_limit,
 181         .set_current_limit = ad5398_set_current_limit,
 182         .enable = ad5398_enable,
 183         .disable = ad5398_disable,
 184         .is_enabled = ad5398_is_enabled,
 185 };
 186
 187 static struct regulator_desc ad5398_reg = {
 188         .name = "isink",
 189         .id = 0,
 190         .ops = &ad5398_ops,
 191         .type = REGULATOR_CURRENT,
 192         .owner = THIS_MODULE,
 193 };
 194
 195 struct ad5398_current_data_format {
 196         int current_bits;
 197         int current_offset;
 198         int min_uA;
 199         int max_uA;
 200 };
 201
 202 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
 203
 204 static const struct i2c_device_id ad5398_id[] = {
 205         { "ad5398", (kernel_ulong_t)&df_10_4_120 },
 206         { "ad5821", (kernel_ulong_t)&df_10_4_120 },
 207         { }
 208 };
 209 MODULE_DEVICE_TABLE(i2c, ad5398_id);
 210
 211 static int __devinit ad5398_probe(struct i2c_client *client,
 212                                 const struct i2c_device_id *id)
 213 {
 214         struct regulator_init_data *init_data = client->dev.platform_data;
 215         struct ad5398_chip_info *chip;
 216         const struct ad5398_current_data_format *df =
 217                         (struct ad5398_current_data_format *)id->driver_data;
 218         int ret;
 219
 220         if (!init_data)
 221                 return -EINVAL;
 222
 223         chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 224         if (!chip)
 225                 return -ENOMEM;
 226
 227         chip->client = client;
 228
 229         chip->min_uA = df->min_uA;
 230         chip->max_uA = df->max_uA;
 231         chip->current_level = 1 << df->current_bits;
 232         chip->current_offset = df->current_offset;
 233         chip->current_mask = (chip->current_level - 1) << chip->current_offset;
 234
 235         chip->rdev = regulator_register(&ad5398_reg, &client->dev,
 236                                         init_data, chip);
 237         if (IS_ERR(chip->rdev)) {
 238                 ret = PTR_ERR(chip->rdev);
 239                 dev_err(&client->dev, "failed to register %s %s\n",
 240                         id->name, ad5398_reg.name);
 241                 goto err;
 242         }
 243
 244         i2c_set_clientdata(client, chip);
 245         dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
 246         return 0;
 247
 248 err:
 249         kfree(chip);
 250         return ret;
 251 }
 252
 253 static int __devexit ad5398_remove(struct i2c_client *client)
 254 {
 255         struct ad5398_chip_info *chip = i2c_get_clientdata(client);
 256
 257         regulator_unregister(chip->rdev);
 258         kfree(chip);
 259
 260         return 0;
 261 }
 262
 263 static struct i2c_driver ad5398_driver = {
 264         .probe = ad5398_probe,
 265         .remove = __devexit_p(ad5398_remove),
 266         .driver         = {
 267                 .name   = "ad5398",
 268         },
 269         .id_table       = ad5398_id,
 270 };
 271
 272 static int __init ad5398_init(void)
 273 {
 274         return i2c_add_driver(&ad5398_driver);
 275 }
 276 subsys_initcall(ad5398_init);
 277
 278 static void __exit ad5398_exit(void)
 279 {
 280         i2c_del_driver(&ad5398_driver);
 281 }
 282 module_exit(ad5398_exit);
 283
 284 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
 285 MODULE_AUTHOR("Sonic Zhang");
 286 MODULE_LICENSE("GPL");
 287 MODULE_ALIAS("i2c:ad5398-regulator");