/* * 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->min_uA) min_uA = chip->min_uA; if (max_uA > chip->max_uA) max_uA = chip->max_uA; if (min_uA > chip->max_uA || max_uA < chip->min_uA) return -EINVAL; selector = DIV_ROUND_UP((min_uA - chip->min_uA) * chip->current_level, range_uA); if (ad5398_calc_current(chip, selector) > max_uA) return -EINVAL; dev_dbg(&client->dev, "changing current %duA\n", ad5398_calc_current(chip, selector)); /* 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 const 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_init_data *init_data = client->dev.platform_data; struct regulator_config config = { }; 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 = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; config.dev = &client->dev; config.init_data = init_data; config.driver_data = chip; 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; chip->rdev = regulator_register(&ad5398_reg, &config); if (IS_ERR(chip->rdev)) { ret = PTR_ERR(chip->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: return ret; } static int __devexit ad5398_remove(struct i2c_client *client) { struct ad5398_chip_info *chip = i2c_get_clientdata(client); regulator_unregister(chip->rdev); 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); } subsys_initcall(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");