diff options
Diffstat (limited to 'drivers/regulator/ad5398.c')
| -rw-r--r-- | drivers/regulator/ad5398.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/drivers/regulator/ad5398.c b/drivers/regulator/ad5398.c new file mode 100644 index 000000000000..6de6bdaeff7c --- /dev/null +++ b/drivers/regulator/ad5398.c @@ -0,0 +1,288 @@ +/* + * Voltage and current regulation for AD5398 and AD5821 + * + * Copyright 2010 Analog Devices Inc. + * + * Enter bugs at http://blackfin.uclinux.org/ + * + * Licensed under the GPL-2 or later. + */ + +#include <linux/module.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> + +#define AD5398_CURRENT_EN_MASK 0x8000 + +struct ad5398_chip_info { + struct i2c_client *client; + int min_uA; + int max_uA; + unsigned int current_level; + unsigned int current_mask; + unsigned int current_offset; + struct regulator_dev rdev; +}; + +static int ad5398_calc_current(struct ad5398_chip_info *chip, + unsigned selector) +{ + unsigned range_uA = chip->max_uA - chip->min_uA; + + return chip->min_uA + (selector * range_uA / chip->current_level); +} + +static int ad5398_read_reg(struct i2c_client *client, unsigned short *data) +{ + unsigned short val; + int ret; + + ret = i2c_master_recv(client, (char *)&val, 2); + if (ret < 0) { + dev_err(&client->dev, "I2C read error\n"); + return ret; + } + *data = be16_to_cpu(val); + + return ret; +} + +static int ad5398_write_reg(struct i2c_client *client, const unsigned short data) +{ + unsigned short val; + int ret; + + val = cpu_to_be16(data); + ret = i2c_master_send(client, (char *)&val, 2); + if (ret < 0) + dev_err(&client->dev, "I2C write error\n"); + + return ret; +} + +static int ad5398_get_current_limit(struct regulator_dev *rdev) +{ + struct ad5398_chip_info *chip = rdev_get_drvdata(rdev); + struct i2c_client *client = chip->client; + unsigned short data; + int ret; + + ret = ad5398_read_reg(client, &data); + if (ret < 0) + return ret; + + ret = (data & chip->current_mask) >> chip->current_offset; + + return ad5398_calc_current(chip, ret); +} + +static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA) +{ + struct ad5398_chip_info *chip = rdev_get_drvdata(rdev); + struct i2c_client *client = chip->client; + unsigned range_uA = chip->max_uA - chip->min_uA; + unsigned selector; + unsigned short data; + int ret; + + if (min_uA > chip->max_uA || min_uA < chip->min_uA) + return -EINVAL; + if (max_uA > chip->max_uA || max_uA < chip->min_uA) + return -EINVAL; + + selector = ((min_uA - chip->min_uA) * chip->current_level + + range_uA - 1) / range_uA; + if (ad5398_calc_current(chip, selector) > max_uA) + return -EINVAL; + + dev_dbg(&client->dev, "changing current %dmA\n", + ad5398_calc_current(chip, selector) / 1000); + + /* read chip enable bit */ + ret = ad5398_read_reg(client, &data); + if (ret < 0) + return ret; + + /* prepare register data */ + selector = (selector << chip->current_offset) & chip->current_mask; + data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK); + + /* write the new current value back as well as enable bit */ + ret = ad5398_write_reg(client, data); + + return ret; +} + +static int ad5398_is_enabled(struct regulator_dev *rdev) +{ + struct ad5398_chip_info *chip = rdev_get_drvdata(rdev); + struct i2c_client *client = chip->client; + unsigned short data; + int ret; + + ret = ad5398_read_reg(client, &data); + if (ret < 0) + return ret; + + if (data & AD5398_CURRENT_EN_MASK) + return 1; + else + return 0; +} + +static int ad5398_enable(struct regulator_dev *rdev) +{ + struct ad5398_chip_info *chip = rdev_get_drvdata(rdev); + struct i2c_client *client = chip->client; + unsigned short data; + int ret; + + ret = ad5398_read_reg(client, &data); + if (ret < 0) + return ret; + + if (data & AD5398_CURRENT_EN_MASK) + return 0; + + data |= AD5398_CURRENT_EN_MASK; + + ret = ad5398_write_reg(client, data); + + return ret; +} + +static int ad5398_disable(struct regulator_dev *rdev) +{ + struct ad5398_chip_info *chip = rdev_get_drvdata(rdev); + struct i2c_client *client = chip->client; + unsigned short data; + int ret; + + ret = ad5398_read_reg(client, &data); + if (ret < 0) + return ret; + + if (!(data & AD5398_CURRENT_EN_MASK)) + return 0; + + data &= ~AD5398_CURRENT_EN_MASK; + + ret = ad5398_write_reg(client, data); + + return ret; +} + +static struct regulator_ops ad5398_ops = { + .get_current_limit = ad5398_get_current_limit, + .set_current_limit = ad5398_set_current_limit, + .enable = ad5398_enable, + .disable = ad5398_disable, + .is_enabled = ad5398_is_enabled, +}; + +static struct regulator_desc ad5398_reg = { + .name = "isink", + .id = 0, + .ops = &ad5398_ops, + .type = REGULATOR_CURRENT, + .owner = THIS_MODULE, +}; + +struct ad5398_current_data_format { + int current_bits; + int current_offset; + int min_uA; + int max_uA; +}; + +static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000}; + +static const struct i2c_device_id ad5398_id[] = { + { "ad5398", (kernel_ulong_t)&df_10_4_120 }, + { "ad5821", (kernel_ulong_t)&df_10_4_120 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, ad5398_id); + +static int __devinit ad5398_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct regulator_dev *rdev; + struct regulator_init_data *init_data = client->dev.platform_data; + struct ad5398_chip_info *chip; + const struct ad5398_current_data_format *df = + (struct ad5398_current_data_format *)id->driver_data; + int ret; + + if (!init_data) + return -EINVAL; + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + chip->client = client; + + chip->min_uA = df->min_uA; + chip->max_uA = df->max_uA; + chip->current_level = 1 << df->current_bits; + chip->current_offset = df->current_offset; + chip->current_mask = (chip->current_level - 1) << chip->current_offset; + + rdev = regulator_register(&ad5398_reg, &client->dev, init_data, chip); + if (IS_ERR(rdev)) { + ret = PTR_ERR(rdev); + dev_err(&client->dev, "failed to register %s %s\n", + id->name, ad5398_reg.name); + goto err; + } + + i2c_set_clientdata(client, chip); + dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name); + return 0; + +err: + kfree(chip); + return ret; +} + +static int __devexit ad5398_remove(struct i2c_client *client) +{ + struct ad5398_chip_info *chip = i2c_get_clientdata(client); + + regulator_unregister(&chip->rdev); + kfree(chip); + i2c_set_clientdata(client, NULL); + + return 0; +} + +static struct i2c_driver ad5398_driver = { + .probe = ad5398_probe, + .remove = __devexit_p(ad5398_remove), + .driver = { + .name = "ad5398", + }, + .id_table = ad5398_id, +}; + +static int __init ad5398_init(void) +{ + return i2c_add_driver(&ad5398_driver); +} +module_init(ad5398_init); + +static void __exit ad5398_exit(void) +{ + i2c_del_driver(&ad5398_driver); +} +module_exit(ad5398_exit); + +MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver"); +MODULE_AUTHOR("Sonic Zhang"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("i2c:ad5398-regulator"); |