linux/drivers/regulator/ad5398.c
<<
>>
Prefs
   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
  21struct 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
  31static 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
  39static 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
  54static 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
  67static 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
  83static 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
 123static 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
 140static 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
 161static 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
 182static 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
 190static 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
 198struct ad5398_current_data_format {
 199        int current_bits;
 200        int current_offset;
 201        int min_uA;
 202        int max_uA;
 203};
 204
 205static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
 206
 207static 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};
 212MODULE_DEVICE_TABLE(i2c, ad5398_id);
 213
 214static int __devinit ad5398_probe(struct i2c_client *client,
 215                                const struct i2c_device_id *id)
 216{
 217        struct regulator_init_data *init_data = client->dev.platform_data;
 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        int ret;
 223
 224        if (!init_data)
 225                return -EINVAL;
 226
 227        chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
 228        if (!chip)
 229                return -ENOMEM;
 230
 231        config.dev = &client->dev;
 232        config.init_data = init_data;
 233        config.driver_data = chip;
 234
 235        chip->client = client;
 236
 237        chip->min_uA = df->min_uA;
 238        chip->max_uA = df->max_uA;
 239        chip->current_level = 1 << df->current_bits;
 240        chip->current_offset = df->current_offset;
 241        chip->current_mask = (chip->current_level - 1) << chip->current_offset;
 242
 243        chip->rdev = regulator_register(&ad5398_reg, &config);
 244        if (IS_ERR(chip->rdev)) {
 245                ret = PTR_ERR(chip->rdev);
 246                dev_err(&client->dev, "failed to register %s %s\n",
 247                        id->name, ad5398_reg.name);
 248                goto err;
 249        }
 250
 251        i2c_set_clientdata(client, chip);
 252        dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
 253        return 0;
 254
 255err:
 256        return ret;
 257}
 258
 259static int __devexit ad5398_remove(struct i2c_client *client)
 260{
 261        struct ad5398_chip_info *chip = i2c_get_clientdata(client);
 262
 263        regulator_unregister(chip->rdev);
 264        return 0;
 265}
 266
 267static struct i2c_driver ad5398_driver = {
 268        .probe = ad5398_probe,
 269        .remove = __devexit_p(ad5398_remove),
 270        .driver         = {
 271                .name   = "ad5398",
 272        },
 273        .id_table       = ad5398_id,
 274};
 275
 276static int __init ad5398_init(void)
 277{
 278        return i2c_add_driver(&ad5398_driver);
 279}
 280subsys_initcall(ad5398_init);
 281
 282static void __exit ad5398_exit(void)
 283{
 284        i2c_del_driver(&ad5398_driver);
 285}
 286module_exit(ad5398_exit);
 287
 288MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
 289MODULE_AUTHOR("Sonic Zhang");
 290MODULE_LICENSE("GPL");
 291MODULE_ALIAS("i2c:ad5398-regulator");
 292
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.