diff options
Diffstat (limited to 'drivers/regulator/max8973-regulator.c')
| -rw-r--r-- | drivers/regulator/max8973-regulator.c | 507 |
1 files changed, 507 insertions, 0 deletions
diff --git a/drivers/regulator/max8973-regulator.c b/drivers/regulator/max8973-regulator.c new file mode 100644 index 00000000000..dbedf1768db --- /dev/null +++ b/drivers/regulator/max8973-regulator.c @@ -0,0 +1,507 @@ +/* + * max8973-regulator.c -- Maxim max8973 + * + * Regulator driver for MAXIM 8973 DC-DC step-down switching regulator. + * + * Copyright (c) 2012, NVIDIA Corporation. + * + * Author: Laxman Dewangan <ldewangan@nvidia.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind, + * whether express or implied; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + * 02111-1307, USA + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> +#include <linux/regulator/max8973-regulator.h> +#include <linux/regulator/of_regulator.h> +#include <linux/gpio.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/regmap.h> + +/* Register definitions */ +#define MAX8973_VOUT 0x0 +#define MAX8973_VOUT_DVS 0x1 +#define MAX8973_CONTROL1 0x2 +#define MAX8973_CONTROL2 0x3 +#define MAX8973_CHIPID1 0x4 +#define MAX8973_CHIPID2 0x5 + +#define MAX8973_MAX_VOUT_REG 2 + +/* MAX8973_VOUT */ +#define MAX8973_VOUT_ENABLE BIT(7) +#define MAX8973_VOUT_MASK 0x7F + +/* MAX8973_VOUT_DVS */ +#define MAX8973_DVS_VOUT_MASK 0x7F + +/* MAX8973_CONTROL1 */ +#define MAX8973_SNS_ENABLE BIT(7) +#define MAX8973_FPWM_EN_M BIT(6) +#define MAX8973_NFSR_ENABLE BIT(5) +#define MAX8973_AD_ENABLE BIT(4) +#define MAX8973_BIAS_ENABLE BIT(3) +#define MAX8973_FREQSHIFT_9PER BIT(2) + +#define MAX8973_RAMP_12mV_PER_US 0x0 +#define MAX8973_RAMP_25mV_PER_US 0x1 +#define MAX8973_RAMP_50mV_PER_US 0x2 +#define MAX8973_RAMP_200mV_PER_US 0x3 + +/* MAX8973_CONTROL2 */ +#define MAX8973_WDTMR_ENABLE BIT(6) +#define MAX8973_DISCH_ENBABLE BIT(5) +#define MAX8973_FT_ENABLE BIT(4) + +#define MAX8973_CKKADV_TRIP_DISABLE 0xC +#define MAX8973_CKKADV_TRIP_75mV_PER_US 0x0 +#define MAX8973_CKKADV_TRIP_150mV_PER_US 0x4 +#define MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS 0x8 +#define MAX8973_CONTROL_CLKADV_TRIP_MASK 0x00030000 + +#define MAX8973_INDUCTOR_MIN_30_PER 0x0 +#define MAX8973_INDUCTOR_NOMINAL 0x1 +#define MAX8973_INDUCTOR_PLUS_30_PER 0x2 +#define MAX8973_INDUCTOR_PLUS_60_PER 0x3 +#define MAX8973_CONTROL_INDUCTOR_VALUE_MASK 0x00300000 + +#define MAX8973_MIN_VOLATGE 606250 +#define MAX8973_MAX_VOLATGE 1400000 +#define MAX8973_VOLATGE_STEP 6250 +#define MAX8973_BUCK_N_VOLTAGE 0x80 + +/* Maxim 8973 chip information */ +struct max8973_chip { + struct device *dev; + struct regulator_desc desc; + struct regmap *regmap; + bool enable_external_control; + int dvs_gpio; + int lru_index[MAX8973_MAX_VOUT_REG]; + int curr_vout_val[MAX8973_MAX_VOUT_REG]; + int curr_vout_reg; + int curr_gpio_val; + bool valid_dvs_gpio; + struct regulator_ops ops; +}; + +/* + * find_voltage_set_register: Find new voltage configuration register (VOUT). + * The finding of the new VOUT register will be based on the LRU mechanism. + * Each VOUT register will have different voltage configured . This + * Function will look if any of the VOUT register have requested voltage set + * or not. + * - If it is already there then it will make that register as most + * recently used and return as found so that caller need not to set + * the VOUT register but need to set the proper gpios to select this + * VOUT register. + * - If requested voltage is not found then it will use the least + * recently mechanism to get new VOUT register for new configuration + * and will return not_found so that caller need to set new VOUT + * register and then gpios (both). + */ +static bool find_voltage_set_register(struct max8973_chip *tps, + int req_vsel, int *vout_reg, int *gpio_val) +{ + int i; + bool found = false; + int new_vout_reg = tps->lru_index[MAX8973_MAX_VOUT_REG - 1]; + int found_index = MAX8973_MAX_VOUT_REG - 1; + + for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) { + if (tps->curr_vout_val[tps->lru_index[i]] == req_vsel) { + new_vout_reg = tps->lru_index[i]; + found_index = i; + found = true; + goto update_lru_index; + } + } + +update_lru_index: + for (i = found_index; i > 0; i--) + tps->lru_index[i] = tps->lru_index[i - 1]; + + tps->lru_index[0] = new_vout_reg; + *gpio_val = new_vout_reg; + *vout_reg = MAX8973_VOUT + new_vout_reg; + return found; +} + +static int max8973_dcdc_get_voltage_sel(struct regulator_dev *rdev) +{ + struct max8973_chip *max = rdev_get_drvdata(rdev); + unsigned int data; + int ret; + + ret = regmap_read(max->regmap, max->curr_vout_reg, &data); + if (ret < 0) { + dev_err(max->dev, "register %d read failed, err = %d\n", + max->curr_vout_reg, ret); + return ret; + } + return data & MAX8973_VOUT_MASK; +} + +static int max8973_dcdc_set_voltage_sel(struct regulator_dev *rdev, + unsigned vsel) +{ + struct max8973_chip *max = rdev_get_drvdata(rdev); + int ret; + bool found = false; + int vout_reg = max->curr_vout_reg; + int gpio_val = max->curr_gpio_val; + + /* + * If gpios are available to select the VOUT register then least + * recently used register for new configuration. + */ + if (max->valid_dvs_gpio) + found = find_voltage_set_register(max, vsel, + &vout_reg, &gpio_val); + + if (!found) { + ret = regmap_update_bits(max->regmap, vout_reg, + MAX8973_VOUT_MASK, vsel); + if (ret < 0) { + dev_err(max->dev, "register %d update failed, err %d\n", + vout_reg, ret); + return ret; + } + max->curr_vout_reg = vout_reg; + max->curr_vout_val[gpio_val] = vsel; + } + + /* Select proper VOUT register vio gpios */ + if (max->valid_dvs_gpio) { + gpio_set_value_cansleep(max->dvs_gpio, gpio_val & 0x1); + max->curr_gpio_val = gpio_val; + } + return 0; +} + +static int max8973_dcdc_set_mode(struct regulator_dev *rdev, unsigned int mode) +{ + struct max8973_chip *max = rdev_get_drvdata(rdev); + int ret; + int pwm; + + /* Enable force PWM mode in FAST mode only. */ + switch (mode) { + case REGULATOR_MODE_FAST: + pwm = MAX8973_FPWM_EN_M; + break; + + case REGULATOR_MODE_NORMAL: + pwm = 0; + break; + + default: + return -EINVAL; + } + + ret = regmap_update_bits(max->regmap, MAX8973_CONTROL1, + MAX8973_FPWM_EN_M, pwm); + if (ret < 0) + dev_err(max->dev, "register %d update failed, err %d\n", + MAX8973_CONTROL1, ret); + return ret; +} + +static unsigned int max8973_dcdc_get_mode(struct regulator_dev *rdev) +{ + struct max8973_chip *max = rdev_get_drvdata(rdev); + unsigned int data; + int ret; + + ret = regmap_read(max->regmap, MAX8973_CONTROL1, &data); + if (ret < 0) { + dev_err(max->dev, "register %d read failed, err %d\n", + MAX8973_CONTROL1, ret); + return ret; + } + return (data & MAX8973_FPWM_EN_M) ? + REGULATOR_MODE_FAST : REGULATOR_MODE_NORMAL; +} + +static const struct regulator_ops max8973_dcdc_ops = { + .get_voltage_sel = max8973_dcdc_get_voltage_sel, + .set_voltage_sel = max8973_dcdc_set_voltage_sel, + .list_voltage = regulator_list_voltage_linear, + .set_mode = max8973_dcdc_set_mode, + .get_mode = max8973_dcdc_get_mode, +}; + +static int max8973_init_dcdc(struct max8973_chip *max, + struct max8973_regulator_platform_data *pdata) +{ + int ret; + uint8_t control1 = 0; + uint8_t control2 = 0; + + if (pdata->control_flags & MAX8973_CONTROL_REMOTE_SENSE_ENABLE) + control1 |= MAX8973_SNS_ENABLE; + + if (!(pdata->control_flags & MAX8973_CONTROL_FALLING_SLEW_RATE_ENABLE)) + control1 |= MAX8973_NFSR_ENABLE; + + if (pdata->control_flags & MAX8973_CONTROL_OUTPUT_ACTIVE_DISCH_ENABLE) + control1 |= MAX8973_AD_ENABLE; + + if (pdata->control_flags & MAX8973_CONTROL_BIAS_ENABLE) + control1 |= MAX8973_BIAS_ENABLE; + + if (pdata->control_flags & MAX8973_CONTROL_FREQ_SHIFT_9PER_ENABLE) + control1 |= MAX8973_FREQSHIFT_9PER; + + /* Set ramp delay */ + if (pdata->reg_init_data && + pdata->reg_init_data->constraints.ramp_delay) { + if (pdata->reg_init_data->constraints.ramp_delay < 25000) + control1 |= MAX8973_RAMP_12mV_PER_US; + else if (pdata->reg_init_data->constraints.ramp_delay < 50000) + control1 |= MAX8973_RAMP_25mV_PER_US; + else if (pdata->reg_init_data->constraints.ramp_delay < 200000) + control1 |= MAX8973_RAMP_50mV_PER_US; + else + control1 |= MAX8973_RAMP_200mV_PER_US; + } else { + control1 |= MAX8973_RAMP_12mV_PER_US; + max->desc.ramp_delay = 12500; + } + + if (!(pdata->control_flags & MAX8973_CONTROL_PULL_DOWN_ENABLE)) + control2 |= MAX8973_DISCH_ENBABLE; + + /* Clock advance trip configuration */ + switch (pdata->control_flags & MAX8973_CONTROL_CLKADV_TRIP_MASK) { + case MAX8973_CONTROL_CLKADV_TRIP_DISABLED: + control2 |= MAX8973_CKKADV_TRIP_DISABLE; + break; + + case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US: + control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US; + break; + + case MAX8973_CONTROL_CLKADV_TRIP_150mV_PER_US: + control2 |= MAX8973_CKKADV_TRIP_150mV_PER_US; + break; + + case MAX8973_CONTROL_CLKADV_TRIP_75mV_PER_US_HIST_DIS: + control2 |= MAX8973_CKKADV_TRIP_75mV_PER_US_HIST_DIS; + break; + } + + /* Configure inductor value */ + switch (pdata->control_flags & MAX8973_CONTROL_INDUCTOR_VALUE_MASK) { + case MAX8973_CONTROL_INDUCTOR_VALUE_NOMINAL: + control2 |= MAX8973_INDUCTOR_NOMINAL; + break; + + case MAX8973_CONTROL_INDUCTOR_VALUE_MINUS_30_PER: + control2 |= MAX8973_INDUCTOR_MIN_30_PER; + break; + + case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_30_PER: + control2 |= MAX8973_INDUCTOR_PLUS_30_PER; + break; + + case MAX8973_CONTROL_INDUCTOR_VALUE_PLUS_60_PER: + control2 |= MAX8973_INDUCTOR_PLUS_60_PER; + break; + } + + ret = regmap_write(max->regmap, MAX8973_CONTROL1, control1); + if (ret < 0) { + dev_err(max->dev, "register %d write failed, err = %d", + MAX8973_CONTROL1, ret); + return ret; + } + + ret = regmap_write(max->regmap, MAX8973_CONTROL2, control2); + if (ret < 0) { + dev_err(max->dev, "register %d write failed, err = %d", + MAX8973_CONTROL2, ret); + return ret; + } + + /* If external control is enabled then disable EN bit */ + if (max->enable_external_control) { + ret = regmap_update_bits(max->regmap, MAX8973_VOUT, + MAX8973_VOUT_ENABLE, 0); + if (ret < 0) + dev_err(max->dev, "register %d update failed, err = %d", + MAX8973_VOUT, ret); + } + return ret; +} + +static const struct regmap_config max8973_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MAX8973_CHIPID2, + .cache_type = REGCACHE_RBTREE, +}; + +static int max8973_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct max8973_regulator_platform_data *pdata; + struct regulator_config config = { }; + struct regulator_dev *rdev; + struct max8973_chip *max; + int ret; + + pdata = dev_get_platdata(&client->dev); + + if (!pdata && !client->dev.of_node) { + dev_err(&client->dev, "No Platform data"); + return -EIO; + } + + max = devm_kzalloc(&client->dev, sizeof(*max), GFP_KERNEL); + if (!max) + return -ENOMEM; + + max->regmap = devm_regmap_init_i2c(client, &max8973_regmap_config); + if (IS_ERR(max->regmap)) { + ret = PTR_ERR(max->regmap); + dev_err(&client->dev, "regmap init failed, err %d\n", ret); + return ret; + } + + i2c_set_clientdata(client, max); + max->ops = max8973_dcdc_ops; + max->dev = &client->dev; + max->desc.name = id->name; + max->desc.id = 0; + max->desc.ops = &max->ops; + max->desc.type = REGULATOR_VOLTAGE; + max->desc.owner = THIS_MODULE; + max->desc.min_uV = MAX8973_MIN_VOLATGE; + max->desc.uV_step = MAX8973_VOLATGE_STEP; + max->desc.n_voltages = MAX8973_BUCK_N_VOLTAGE; + + if (!pdata || !pdata->enable_ext_control) { + max->desc.enable_reg = MAX8973_VOUT; + max->desc.enable_mask = MAX8973_VOUT_ENABLE; + max->ops.enable = regulator_enable_regmap; + max->ops.disable = regulator_disable_regmap; + max->ops.is_enabled = regulator_is_enabled_regmap; + } + + if (pdata) { + max->dvs_gpio = pdata->dvs_gpio; + max->enable_external_control = pdata->enable_ext_control; + max->curr_gpio_val = pdata->dvs_def_state; + max->curr_vout_reg = MAX8973_VOUT + pdata->dvs_def_state; + } else { + max->dvs_gpio = -EINVAL; + max->curr_vout_reg = MAX8973_VOUT; + } + + max->lru_index[0] = max->curr_vout_reg; + + if (gpio_is_valid(max->dvs_gpio)) { + int gpio_flags; + int i; + + gpio_flags = (pdata->dvs_def_state) ? + GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW; + ret = devm_gpio_request_one(&client->dev, max->dvs_gpio, + gpio_flags, "max8973-dvs"); + if (ret) { + dev_err(&client->dev, + "gpio_request for gpio %d failed, err = %d\n", + max->dvs_gpio, ret); + return ret; + } + max->valid_dvs_gpio = true; + + /* + * Initialize the lru index with vout_reg id + * The index 0 will be most recently used and + * set with the max->curr_vout_reg */ + for (i = 0; i < MAX8973_MAX_VOUT_REG; ++i) + max->lru_index[i] = i; + max->lru_index[0] = max->curr_vout_reg; + max->lru_index[max->curr_vout_reg] = 0; + } else { + max->valid_dvs_gpio = false; + } + + if (pdata) { + ret = max8973_init_dcdc(max, pdata); + if (ret < 0) { + dev_err(max->dev, "Max8973 Init failed, err = %d\n", ret); + return ret; + } + } + + config.dev = &client->dev; + config.init_data = pdata ? pdata->reg_init_data : + of_get_regulator_init_data(&client->dev, client->dev.of_node); + config.driver_data = max; + config.of_node = client->dev.of_node; + config.regmap = max->regmap; + + /* Register the regulators */ + rdev = devm_regulator_register(&client->dev, &max->desc, &config); + if (IS_ERR(rdev)) { + ret = PTR_ERR(rdev); + dev_err(max->dev, "regulator register failed, err %d\n", ret); + return ret; + } + + return 0; +} + +static const struct i2c_device_id max8973_id[] = { + {.name = "max8973",}, + {}, +}; + +MODULE_DEVICE_TABLE(i2c, max8973_id); + +static struct i2c_driver max8973_i2c_driver = { + .driver = { + .name = "max8973", + .owner = THIS_MODULE, + }, + .probe = max8973_probe, + .id_table = max8973_id, +}; + +static int __init max8973_init(void) +{ + return i2c_add_driver(&max8973_i2c_driver); +} +subsys_initcall(max8973_init); + +static void __exit max8973_cleanup(void) +{ + i2c_del_driver(&max8973_i2c_driver); +} +module_exit(max8973_cleanup); + +MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>"); +MODULE_DESCRIPTION("MAX8973 voltage regulator driver"); +MODULE_LICENSE("GPL v2"); |