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 != 2) {
  62                 dev_err(&client->dev, "I2C write error\n");
  63                 return ret < 0 ? ret : -EIO;
  64         }
  65
  66         return 0;
  67 }
  68
  69 static int ad5398_get_current_limit(struct regulator_dev *rdev)
  70 {
  71         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
  72         struct i2c_client *client = chip->client;
  73         unsigned short data;
  74         int ret;
  75
  76         ret = ad5398_read_reg(client, &data);
  77         if (ret < 0)
  78                 return ret;
  79
  80         ret = (data & chip->current_mask) >> chip->current_offset;
  81
  82         return ad5398_calc_current(chip, ret);
  83 }
  84
  85 static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
  86 {
  87         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
  88         struct i2c_client *client = chip->client;
  89         unsigned range_uA = chip->max_uA - chip->min_uA;
  90         unsigned selector;
  91         unsigned short data;
  92         int ret;
  93
  94         if (min_uA < chip->min_uA)
  95                 min_uA = chip->min_uA;
  96         if (max_uA > chip->max_uA)
  97                 max_uA = chip->max_uA;
  98
  99         if (min_uA > chip->max_uA || max_uA < chip->min_uA)
 100                 return -EINVAL;
 101
 102         selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
 103                                 range_uA);
 104         if (ad5398_calc_current(chip, selector) > max_uA)
 105                 return -EINVAL;
 106
 107         dev_dbg(&client->dev, "changing current %duA\n",
 108                 ad5398_calc_current(chip, selector));
 109
 110         /* read chip enable bit */
 111         ret = ad5398_read_reg(client, &data);
 112         if (ret < 0)
 113                 return ret;
 114
 115         /* prepare register data */
 116         selector = (selector << chip->current_offset) & chip->current_mask;
 117         data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
 118
 119         /* write the new current value back as well as enable bit */
 120         ret = ad5398_write_reg(client, data);
 121
 122         return ret;
 123 }
 124
 125 static int ad5398_is_enabled(struct regulator_dev *rdev)
 126 {
 127         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 128         struct i2c_client *client = chip->client;
 129         unsigned short data;
 130         int ret;
 131
 132         ret = ad5398_read_reg(client, &data);
 133         if (ret < 0)
 134                 return ret;
 135
 136         if (data & AD5398_CURRENT_EN_MASK)
 137                 return 1;
 138         else
 139                 return 0;
 140 }
 141
 142 static int ad5398_enable(struct regulator_dev *rdev)
 143 {
 144         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 145         struct i2c_client *client = chip->client;
 146         unsigned short data;
 147         int ret;
 148
 149         ret = ad5398_read_reg(client, &data);
 150         if (ret < 0)
 151                 return ret;
 152
 153         if (data & AD5398_CURRENT_EN_MASK)
 154                 return 0;
 155
 156         data |= AD5398_CURRENT_EN_MASK;
 157
 158         ret = ad5398_write_reg(client, data);
 159
 160         return ret;
 161 }
 162
 163 static int ad5398_disable(struct regulator_dev *rdev)
 164 {
 165         struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
 166         struct i2c_client *client = chip->client;
 167         unsigned short data;
 168         int ret;
 169
 170         ret = ad5398_read_reg(client, &data);
 171         if (ret < 0)
 172                 return ret;
 173
 174         if (!(data & AD5398_CURRENT_EN_MASK))
 175                 return 0;
 176
 177         data &= ~AD5398_CURRENT_EN_MASK;
 178
 179         ret = ad5398_write_reg(client, data);
 180
 181         return ret;
 182 }
 183
 184 static const struct regulator_ops ad5398_ops = {
 185         .get_current_limit = ad5398_get_current_limit,
 186         .set_current_limit = ad5398_set_current_limit,
 187         .enable = ad5398_enable,
 188         .disable = ad5398_disable,
 189         .is_enabled = ad5398_is_enabled,
 190 };
 191
 192 static const struct regulator_desc ad5398_reg = {
 193         .name = "isink",
 194         .id = 0,
 195         .ops = &ad5398_ops,
 196         .type = REGULATOR_CURRENT,
 197         .owner = THIS_MODULE,
 198 };
 199
 200 struct ad5398_current_data_format {
 201         int current_bits;
 202         int current_offset;
 203         int min_uA;
 204         int max_uA;
 205 };
 206
 207 static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
 208
 209 static const struct i2c_device_id ad5398_id[] = {
 210         { "ad5398", (kernel_ulong_t)&df_10_4_120 },
 211         { "ad5821", (kernel_ulong_t)&df_10_4_120 },
 212         { }
 213 };
 214 MODULE_DEVICE_TABLE(i2c, ad5398_id);
 215
 216 static int ad5398_probe(struct i2c_client *client,
 217                                 const struct i2c_device_id *id)
 218 {
 219         struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
 220         struct regulator_config config = { };
 221         struct ad5398_chip_info *chip;
 222         const struct ad5398_current_data_format *df =
 223                         (struct ad5398_current_data_format *)id->driver_data;
 224
 225         if (!init_data)
 226                 return -EINVAL;
 227
 228         chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 229         if (!chip)
 230                 return -ENOMEM;
 231
 232         config.dev = &client->dev;
 233         config.init_data = init_data;
 234         config.driver_data = chip;
 235
 236         chip->client = client;
 237
 238         chip->min_uA = df->min_uA;
 239         chip->max_uA = df->max_uA;
 240         chip->current_level = 1 << df->current_bits;
 241         chip->current_offset = df->current_offset;
 242         chip->current_mask = (chip->current_level - 1) << chip->current_offset;
 243
 244         chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
 245                                              &config);
 246         if (IS_ERR(chip->rdev)) {
 247                 dev_err(&client->dev, "failed to register %s %s\n",
 248                         id->name, ad5398_reg.name);
 249                 return PTR_ERR(chip->rdev);
 250         }
 251
 252         i2c_set_clientdata(client, chip);
 253         dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
 254         return 0;
 255 }
 256
 257 static struct i2c_driver ad5398_driver = {
 258         .probe = ad5398_probe,
 259         .driver         = {
 260                 .name   = "ad5398",
 261         },
 262         .id_table       = ad5398_id,
 263 };
 264
 265 static int __init ad5398_init(void)
 266 {
 267         return i2c_add_driver(&ad5398_driver);
 268 }
 269 subsys_initcall(ad5398_init);
 270
 271 static void __exit ad5398_exit(void)
 272 {
 273         i2c_del_driver(&ad5398_driver);
 274 }
 275 module_exit(ad5398_exit);
 276
 277 MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
 278 MODULE_AUTHOR("Sonic Zhang");
 279 MODULE_LICENSE("GPL");