280 lines
6.3 KiB
C
280 lines
6.3 KiB
C
/*
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* Voltage and current regulation for AD5398 and AD5821
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*
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* Copyright 2010 Analog Devices Inc.
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*
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* Enter bugs at http://blackfin.uclinux.org/
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/machine.h>
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#define AD5398_CURRENT_EN_MASK 0x8000
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struct ad5398_chip_info {
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struct i2c_client *client;
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int min_uA;
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int max_uA;
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unsigned int current_level;
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unsigned int current_mask;
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unsigned int current_offset;
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struct regulator_dev *rdev;
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};
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static int ad5398_calc_current(struct ad5398_chip_info *chip,
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unsigned selector)
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{
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unsigned range_uA = chip->max_uA - chip->min_uA;
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return chip->min_uA + (selector * range_uA / chip->current_level);
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}
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static int ad5398_read_reg(struct i2c_client *client, unsigned short *data)
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{
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unsigned short val;
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int ret;
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ret = i2c_master_recv(client, (char *)&val, 2);
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if (ret < 0) {
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dev_err(&client->dev, "I2C read error\n");
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return ret;
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}
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*data = be16_to_cpu(val);
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return ret;
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}
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static int ad5398_write_reg(struct i2c_client *client, const unsigned short data)
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{
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unsigned short val;
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int ret;
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val = cpu_to_be16(data);
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ret = i2c_master_send(client, (char *)&val, 2);
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if (ret != 2) {
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dev_err(&client->dev, "I2C write error\n");
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return ret < 0 ? ret : -EIO;
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}
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return 0;
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}
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static int ad5398_get_current_limit(struct regulator_dev *rdev)
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{
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struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
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struct i2c_client *client = chip->client;
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unsigned short data;
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int ret;
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ret = ad5398_read_reg(client, &data);
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if (ret < 0)
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return ret;
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ret = (data & chip->current_mask) >> chip->current_offset;
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return ad5398_calc_current(chip, ret);
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}
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static int ad5398_set_current_limit(struct regulator_dev *rdev, int min_uA, int max_uA)
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{
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struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
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struct i2c_client *client = chip->client;
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unsigned range_uA = chip->max_uA - chip->min_uA;
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unsigned selector;
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unsigned short data;
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int ret;
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if (min_uA < chip->min_uA)
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min_uA = chip->min_uA;
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if (max_uA > chip->max_uA)
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max_uA = chip->max_uA;
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if (min_uA > chip->max_uA || max_uA < chip->min_uA)
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return -EINVAL;
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selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level,
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range_uA);
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if (ad5398_calc_current(chip, selector) > max_uA)
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return -EINVAL;
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dev_dbg(&client->dev, "changing current %duA\n",
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ad5398_calc_current(chip, selector));
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/* read chip enable bit */
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ret = ad5398_read_reg(client, &data);
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if (ret < 0)
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return ret;
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/* prepare register data */
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selector = (selector << chip->current_offset) & chip->current_mask;
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data = (unsigned short)selector | (data & AD5398_CURRENT_EN_MASK);
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/* write the new current value back as well as enable bit */
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ret = ad5398_write_reg(client, data);
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return ret;
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}
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static int ad5398_is_enabled(struct regulator_dev *rdev)
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{
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struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
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struct i2c_client *client = chip->client;
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unsigned short data;
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int ret;
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ret = ad5398_read_reg(client, &data);
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if (ret < 0)
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return ret;
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if (data & AD5398_CURRENT_EN_MASK)
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return 1;
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else
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return 0;
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}
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static int ad5398_enable(struct regulator_dev *rdev)
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{
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struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
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struct i2c_client *client = chip->client;
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unsigned short data;
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int ret;
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ret = ad5398_read_reg(client, &data);
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if (ret < 0)
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return ret;
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if (data & AD5398_CURRENT_EN_MASK)
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return 0;
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data |= AD5398_CURRENT_EN_MASK;
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ret = ad5398_write_reg(client, data);
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return ret;
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}
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static int ad5398_disable(struct regulator_dev *rdev)
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{
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struct ad5398_chip_info *chip = rdev_get_drvdata(rdev);
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struct i2c_client *client = chip->client;
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unsigned short data;
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int ret;
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ret = ad5398_read_reg(client, &data);
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if (ret < 0)
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return ret;
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if (!(data & AD5398_CURRENT_EN_MASK))
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return 0;
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data &= ~AD5398_CURRENT_EN_MASK;
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ret = ad5398_write_reg(client, data);
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return ret;
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}
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static const struct regulator_ops ad5398_ops = {
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.get_current_limit = ad5398_get_current_limit,
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.set_current_limit = ad5398_set_current_limit,
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.enable = ad5398_enable,
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.disable = ad5398_disable,
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.is_enabled = ad5398_is_enabled,
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};
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static const struct regulator_desc ad5398_reg = {
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.name = "isink",
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.id = 0,
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.ops = &ad5398_ops,
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.type = REGULATOR_CURRENT,
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.owner = THIS_MODULE,
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};
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struct ad5398_current_data_format {
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int current_bits;
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int current_offset;
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int min_uA;
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int max_uA;
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};
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static const struct ad5398_current_data_format df_10_4_120 = {10, 4, 0, 120000};
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static const struct i2c_device_id ad5398_id[] = {
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{ "ad5398", (kernel_ulong_t)&df_10_4_120 },
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{ "ad5821", (kernel_ulong_t)&df_10_4_120 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ad5398_id);
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static int ad5398_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct regulator_init_data *init_data = dev_get_platdata(&client->dev);
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struct regulator_config config = { };
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struct ad5398_chip_info *chip;
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const struct ad5398_current_data_format *df =
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(struct ad5398_current_data_format *)id->driver_data;
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if (!init_data)
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return -EINVAL;
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chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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config.dev = &client->dev;
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config.init_data = init_data;
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config.driver_data = chip;
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chip->client = client;
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chip->min_uA = df->min_uA;
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chip->max_uA = df->max_uA;
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chip->current_level = 1 << df->current_bits;
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chip->current_offset = df->current_offset;
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chip->current_mask = (chip->current_level - 1) << chip->current_offset;
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chip->rdev = devm_regulator_register(&client->dev, &ad5398_reg,
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&config);
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if (IS_ERR(chip->rdev)) {
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dev_err(&client->dev, "failed to register %s %s\n",
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id->name, ad5398_reg.name);
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return PTR_ERR(chip->rdev);
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}
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i2c_set_clientdata(client, chip);
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dev_dbg(&client->dev, "%s regulator driver is registered.\n", id->name);
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return 0;
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}
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static struct i2c_driver ad5398_driver = {
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.probe = ad5398_probe,
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.driver = {
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.name = "ad5398",
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},
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.id_table = ad5398_id,
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};
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static int __init ad5398_init(void)
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{
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return i2c_add_driver(&ad5398_driver);
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}
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subsys_initcall(ad5398_init);
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static void __exit ad5398_exit(void)
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{
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i2c_del_driver(&ad5398_driver);
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}
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module_exit(ad5398_exit);
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MODULE_DESCRIPTION("AD5398 and AD5821 current regulator driver");
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MODULE_AUTHOR("Sonic Zhang");
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MODULE_LICENSE("GPL");
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