diff options
Diffstat (limited to 'drivers/regulator/st-pwm.c')
| -rw-r--r-- | drivers/regulator/st-pwm.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/regulator/st-pwm.c b/drivers/regulator/st-pwm.c new file mode 100644 index 00000000000..5ea78df449f --- /dev/null +++ b/drivers/regulator/st-pwm.c @@ -0,0 +1,190 @@ +/* + * Regulator driver for ST's 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> + +#define ST_PWM_REG_PERIOD 8448 + +struct st_pwm_regulator_pdata { + const struct regulator_desc *desc; + struct st_pwm_voltages *duty_cycle_table; +}; + +struct st_pwm_regulator_data { + const struct st_pwm_regulator_pdata *pdata; + struct pwm_device *pwm; + bool enabled; + int state; +}; + +struct st_pwm_voltages { + unsigned int uV; + unsigned int dutycycle; +}; + +static int st_pwm_regulator_get_voltage_sel(struct regulator_dev *dev) +{ + struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + return drvdata->state; +} + +static int st_pwm_regulator_set_voltage_sel(struct regulator_dev *dev, + unsigned selector) +{ + struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + int dutycycle; + int ret; + + dutycycle = (ST_PWM_REG_PERIOD / 100) * + drvdata->pdata->duty_cycle_table[selector].dutycycle; + + ret = pwm_config(drvdata->pwm, dutycycle, ST_PWM_REG_PERIOD); + if (ret) { + dev_err(&dev->dev, "Failed to configure PWM\n"); + return ret; + } + + drvdata->state = selector; + + if (!drvdata->enabled) { + ret = pwm_enable(drvdata->pwm); + if (ret) { + dev_err(&dev->dev, "Failed to enable PWM\n"); + return ret; + } + drvdata->enabled = true; + } + + return 0; +} + +static int st_pwm_regulator_list_voltage(struct regulator_dev *dev, + unsigned selector) +{ + struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + if (selector >= dev->desc->n_voltages) + return -EINVAL; + + return drvdata->pdata->duty_cycle_table[selector].uV; +} + +static struct regulator_ops st_pwm_regulator_voltage_ops = { + .set_voltage_sel = st_pwm_regulator_set_voltage_sel, + .get_voltage_sel = st_pwm_regulator_get_voltage_sel, + .list_voltage = st_pwm_regulator_list_voltage, + .map_voltage = regulator_map_voltage_iterate, +}; + +static struct st_pwm_voltages b2105_duty_cycle_table[] = { + { .uV = 1114000, .dutycycle = 0, }, + { .uV = 1095000, .dutycycle = 10, }, + { .uV = 1076000, .dutycycle = 20, }, + { .uV = 1056000, .dutycycle = 30, }, + { .uV = 1036000, .dutycycle = 40, }, + { .uV = 1016000, .dutycycle = 50, }, + /* WARNING: Values above 50% duty-cycle cause boot failures. */ +}; + +static const struct regulator_desc b2105_desc = { + .name = "b2105-pwm-regulator", + .ops = &st_pwm_regulator_voltage_ops, + .type = REGULATOR_VOLTAGE, + .owner = THIS_MODULE, + .n_voltages = ARRAY_SIZE(b2105_duty_cycle_table), + .supply_name = "pwm", +}; + +static const struct st_pwm_regulator_pdata b2105_info = { + .desc = &b2105_desc, + .duty_cycle_table = b2105_duty_cycle_table, +}; + +static const struct of_device_id st_pwm_of_match[] = { + { .compatible = "st,b2105-pwm-regulator", .data = &b2105_info, }, + { }, +}; +MODULE_DEVICE_TABLE(of, st_pwm_of_match); + +static int st_pwm_regulator_probe(struct platform_device *pdev) +{ + struct st_pwm_regulator_data *drvdata; + struct regulator_dev *regulator; + struct regulator_config config = { }; + struct device_node *np = pdev->dev.of_node; + const struct of_device_id *of_match; + + 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; + + of_match = of_match_device(st_pwm_of_match, &pdev->dev); + if (!of_match) { + dev_err(&pdev->dev, "failed to match of device\n"); + return -ENODEV; + } + drvdata->pdata = of_match->data; + + config.init_data = of_get_regulator_init_data(&pdev->dev, np); + if (!config.init_data) + return -ENOMEM; + + config.of_node = np; + config.dev = &pdev->dev; + config.driver_data = drvdata; + + drvdata->pwm = devm_pwm_get(&pdev->dev, NULL); + if (IS_ERR(drvdata->pwm)) { + dev_err(&pdev->dev, "Failed to get PWM\n"); + return PTR_ERR(drvdata->pwm); + } + + regulator = devm_regulator_register(&pdev->dev, + drvdata->pdata->desc, &config); + if (IS_ERR(regulator)) { + dev_err(&pdev->dev, "Failed to register regulator %s\n", + drvdata->pdata->desc->name); + return PTR_ERR(regulator); + } + + return 0; +} + +static struct platform_driver st_pwm_regulator_driver = { + .driver = { + .name = "st-pwm-regulator", + .owner = THIS_MODULE, + .of_match_table = of_match_ptr(st_pwm_of_match), + }, + .probe = st_pwm_regulator_probe, +}; + +module_platform_driver(st_pwm_regulator_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>"); +MODULE_DESCRIPTION("ST PWM Regulator Driver"); +MODULE_ALIAS("platform:st_pwm-regulator"); |