diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/regulator/pwm-regulator.c | 418 |
1 files changed, 418 insertions, 0 deletions
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c new file mode 100644 index 000000000..34f3b9778 --- /dev/null +++ b/drivers/regulator/pwm-regulator.c @@ -0,0 +1,418 @@ +/* + * Regulator driver for PWM Regulators + * + * Copyright (C) 2014 - STMicroelectronics Inc. + * + * Author: Lee Jones <lee.jones@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/err.h> +#include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> +#include <linux/regulator/of_regulator.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/pwm.h> +#include <linux/gpio/consumer.h> + +struct pwm_continuous_reg_data { + unsigned int min_uV_dutycycle; + unsigned int max_uV_dutycycle; + unsigned int dutycycle_unit; +}; + +struct pwm_regulator_data { + /* Shared */ + struct pwm_device *pwm; + + /* Voltage table */ + struct pwm_voltages *duty_cycle_table; + + /* Continuous mode info */ + struct pwm_continuous_reg_data continuous; + + /* regulator descriptor */ + struct regulator_desc desc; + + /* Regulator ops */ + struct regulator_ops ops; + + int state; + + /* Enable GPIO */ + struct gpio_desc *enb_gpio; +}; + +struct pwm_voltages { + unsigned int uV; + unsigned int dutycycle; +}; + +/** + * Voltage table call-backs + */ +static void pwm_regulator_init_state(struct regulator_dev *rdev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + struct pwm_state pwm_state; + unsigned int dutycycle; + int i; + + pwm_get_state(drvdata->pwm, &pwm_state); + dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100); + + for (i = 0; i < rdev->desc->n_voltages; i++) { + if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) { + drvdata->state = i; + return; + } + } +} + +static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + + if (drvdata->state < 0) + pwm_regulator_init_state(rdev); + + return drvdata->state; +} + +static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev, + unsigned selector) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + struct pwm_state pstate; + int ret; + + pwm_init_state(drvdata->pwm, &pstate); + pwm_set_relative_duty_cycle(&pstate, + drvdata->duty_cycle_table[selector].dutycycle, 100); + + ret = pwm_apply_state(drvdata->pwm, &pstate); + if (ret) { + dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); + return ret; + } + + drvdata->state = selector; + + return 0; +} + +static int pwm_regulator_list_voltage(struct regulator_dev *rdev, + unsigned selector) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + + if (selector >= rdev->desc->n_voltages) + return -EINVAL; + + return drvdata->duty_cycle_table[selector].uV; +} + +static int pwm_regulator_enable(struct regulator_dev *dev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + gpiod_set_value_cansleep(drvdata->enb_gpio, 1); + + return pwm_enable(drvdata->pwm); +} + +static int pwm_regulator_disable(struct regulator_dev *dev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + pwm_disable(drvdata->pwm); + + gpiod_set_value_cansleep(drvdata->enb_gpio, 0); + + return 0; +} + +static int pwm_regulator_is_enabled(struct regulator_dev *dev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio)) + return false; + + return pwm_is_enabled(drvdata->pwm); +} + +static int pwm_regulator_get_voltage(struct regulator_dev *rdev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; + unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; + unsigned int duty_unit = drvdata->continuous.dutycycle_unit; + int min_uV = rdev->constraints->min_uV; + int max_uV = rdev->constraints->max_uV; + int diff_uV = max_uV - min_uV; + struct pwm_state pstate; + unsigned int diff_duty; + unsigned int voltage; + + pwm_get_state(drvdata->pwm, &pstate); + + voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit); + + /* + * The dutycycle for min_uV might be greater than the one for max_uV. + * This is happening when the user needs an inversed polarity, but the + * PWM device does not support inversing it in hardware. + */ + if (max_uV_duty < min_uV_duty) { + voltage = min_uV_duty - voltage; + diff_duty = min_uV_duty - max_uV_duty; + } else { + voltage = voltage - min_uV_duty; + diff_duty = max_uV_duty - min_uV_duty; + } + + voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty); + + return voltage + min_uV; +} + +static int pwm_regulator_set_voltage(struct regulator_dev *rdev, + int req_min_uV, int req_max_uV, + unsigned int *selector) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev); + unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle; + unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle; + unsigned int duty_unit = drvdata->continuous.dutycycle_unit; + int min_uV = rdev->constraints->min_uV; + int max_uV = rdev->constraints->max_uV; + int diff_uV = max_uV - min_uV; + struct pwm_state pstate; + unsigned int diff_duty; + unsigned int dutycycle; + int ret; + + pwm_init_state(drvdata->pwm, &pstate); + + /* + * The dutycycle for min_uV might be greater than the one for max_uV. + * This is happening when the user needs an inversed polarity, but the + * PWM device does not support inversing it in hardware. + */ + if (max_uV_duty < min_uV_duty) + diff_duty = min_uV_duty - max_uV_duty; + else + diff_duty = max_uV_duty - min_uV_duty; + + dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) * + diff_duty, + diff_uV); + + if (max_uV_duty < min_uV_duty) + dutycycle = min_uV_duty - dutycycle; + else + dutycycle = min_uV_duty + dutycycle; + + pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit); + + ret = pwm_apply_state(drvdata->pwm, &pstate); + if (ret) { + dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret); + return ret; + } + + return 0; +} + +static struct regulator_ops pwm_regulator_voltage_table_ops = { + .set_voltage_sel = pwm_regulator_set_voltage_sel, + .get_voltage_sel = pwm_regulator_get_voltage_sel, + .list_voltage = pwm_regulator_list_voltage, + .map_voltage = regulator_map_voltage_iterate, + .enable = pwm_regulator_enable, + .disable = pwm_regulator_disable, + .is_enabled = pwm_regulator_is_enabled, +}; + +static struct regulator_ops pwm_regulator_voltage_continuous_ops = { + .get_voltage = pwm_regulator_get_voltage, + .set_voltage = pwm_regulator_set_voltage, + .enable = pwm_regulator_enable, + .disable = pwm_regulator_disable, + .is_enabled = pwm_regulator_is_enabled, +}; + +static struct regulator_desc pwm_regulator_desc = { + .name = "pwm-regulator", + .type = REGULATOR_VOLTAGE, + .owner = THIS_MODULE, + .supply_name = "pwm", +}; + +static int pwm_regulator_init_table(struct platform_device *pdev, + struct pwm_regulator_data *drvdata) +{ + struct device_node *np = pdev->dev.of_node; + struct pwm_voltages *duty_cycle_table; + unsigned int length = 0; + int ret; + + of_find_property(np, "voltage-table", &length); + + if ((length < sizeof(*duty_cycle_table)) || + (length % sizeof(*duty_cycle_table))) { + dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n", + length); + return -EINVAL; + } + + duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL); + if (!duty_cycle_table) + return -ENOMEM; + + ret = of_property_read_u32_array(np, "voltage-table", + (u32 *)duty_cycle_table, + length / sizeof(u32)); + if (ret) { + dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret); + return ret; + } + + drvdata->state = -ENOTRECOVERABLE; + drvdata->duty_cycle_table = duty_cycle_table; + memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops, + sizeof(drvdata->ops)); + drvdata->desc.ops = &drvdata->ops; + drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table); + + return 0; +} + +static int pwm_regulator_init_continuous(struct platform_device *pdev, + struct pwm_regulator_data *drvdata) +{ + u32 dutycycle_range[2] = { 0, 100 }; + u32 dutycycle_unit = 100; + + memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops, + sizeof(drvdata->ops)); + drvdata->desc.ops = &drvdata->ops; + drvdata->desc.continuous_voltage_range = true; + + of_property_read_u32_array(pdev->dev.of_node, + "pwm-dutycycle-range", + dutycycle_range, 2); + of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit", + &dutycycle_unit); + + if (dutycycle_range[0] > dutycycle_unit || + dutycycle_range[1] > dutycycle_unit) + return -EINVAL; + + drvdata->continuous.dutycycle_unit = dutycycle_unit; + drvdata->continuous.min_uV_dutycycle = dutycycle_range[0]; + drvdata->continuous.max_uV_dutycycle = dutycycle_range[1]; + + return 0; +} + +static int pwm_regulator_probe(struct platform_device *pdev) +{ + const struct regulator_init_data *init_data; + struct pwm_regulator_data *drvdata; + struct regulator_dev *regulator; + struct regulator_config config = { }; + struct device_node *np = pdev->dev.of_node; + enum gpiod_flags gpio_flags; + int ret; + + if (!np) { + dev_err(&pdev->dev, "Device Tree node missing\n"); + return -EINVAL; + } + + drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL); + if (!drvdata) + return -ENOMEM; + + memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc)); + + if (of_find_property(np, "voltage-table", NULL)) + ret = pwm_regulator_init_table(pdev, drvdata); + else + ret = pwm_regulator_init_continuous(pdev, drvdata); + if (ret) + return ret; + + init_data = of_get_regulator_init_data(&pdev->dev, np, + &drvdata->desc); + if (!init_data) + return -ENOMEM; + + config.of_node = np; + config.dev = &pdev->dev; + config.driver_data = drvdata; + config.init_data = init_data; + + drvdata->pwm = devm_pwm_get(&pdev->dev, NULL); + if (IS_ERR(drvdata->pwm)) { + ret = PTR_ERR(drvdata->pwm); + dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret); + return ret; + } + + if (init_data->constraints.boot_on || init_data->constraints.always_on) + gpio_flags = GPIOD_OUT_HIGH; + else + gpio_flags = GPIOD_OUT_LOW; + drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", + gpio_flags); + if (IS_ERR(drvdata->enb_gpio)) { + ret = PTR_ERR(drvdata->enb_gpio); + dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret); + return ret; + } + + ret = pwm_adjust_config(drvdata->pwm); + if (ret) + return ret; + + regulator = devm_regulator_register(&pdev->dev, + &drvdata->desc, &config); + if (IS_ERR(regulator)) { + ret = PTR_ERR(regulator); + dev_err(&pdev->dev, "Failed to register regulator %s: %d\n", + drvdata->desc.name, ret); + return ret; + } + + return 0; +} + +static const struct of_device_id pwm_of_match[] = { + { .compatible = "pwm-regulator" }, + { }, +}; +MODULE_DEVICE_TABLE(of, pwm_of_match); + +static struct platform_driver pwm_regulator_driver = { + .driver = { + .name = "pwm-regulator", + .of_match_table = of_match_ptr(pwm_of_match), + }, + .probe = pwm_regulator_probe, +}; + +module_platform_driver(pwm_regulator_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); +MODULE_DESCRIPTION("PWM Regulator Driver"); +MODULE_ALIAS("platform:pwm-regulator"); |