diff options
Diffstat (limited to 'kernel/drivers/regulator/pwm-regulator.c')
| -rw-r--r-- | kernel/drivers/regulator/pwm-regulator.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/kernel/drivers/regulator/pwm-regulator.c b/kernel/drivers/regulator/pwm-regulator.c new file mode 100644 index 000000000..253833ae3 --- /dev/null +++ b/kernel/drivers/regulator/pwm-regulator.c @@ -0,0 +1,197 @@ +/* + * 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> + +struct pwm_regulator_data { + struct regulator_desc desc; + struct pwm_voltages *duty_cycle_table; + struct pwm_device *pwm; + bool enabled; + int state; +}; + +struct pwm_voltages { + unsigned int uV; + unsigned int dutycycle; +}; + +static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + return drvdata->state; +} + +static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev, + unsigned selector) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + unsigned int pwm_reg_period; + int dutycycle; + int ret; + + pwm_reg_period = pwm_get_period(drvdata->pwm); + + dutycycle = (pwm_reg_period * + drvdata->duty_cycle_table[selector].dutycycle) / 100; + + ret = pwm_config(drvdata->pwm, dutycycle, 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 pwm_regulator_list_voltage(struct regulator_dev *dev, + unsigned selector) +{ + struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev); + + if (selector >= drvdata->desc.n_voltages) + return -EINVAL; + + return drvdata->duty_cycle_table[selector].uV; +} + +static struct regulator_ops pwm_regulator_voltage_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, +}; + +static const struct regulator_desc pwm_regulator_desc = { + .name = "pwm-regulator", + .ops = &pwm_regulator_voltage_ops, + .type = REGULATOR_VOLTAGE, + .owner = THIS_MODULE, + .supply_name = "pwm", +}; + +static int pwm_regulator_probe(struct platform_device *pdev) +{ + struct pwm_regulator_data *drvdata; + struct property *prop; + struct regulator_dev *regulator; + struct regulator_config config = { }; + struct device_node *np = pdev->dev.of_node; + int length, 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(pwm_regulator_desc)); + + /* determine the number of voltage-table */ + prop = of_find_property(np, "voltage-table", &length); + if (!prop) { + dev_err(&pdev->dev, "No voltage-table\n"); + return -EINVAL; + } + + if ((length < sizeof(*drvdata->duty_cycle_table)) || + (length % sizeof(*drvdata->duty_cycle_table))) { + dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n", + length); + return -EINVAL; + } + + drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table); + + drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev, + length, GFP_KERNEL); + if (!drvdata->duty_cycle_table) + return -ENOMEM; + + /* read voltage table from DT property */ + ret = of_property_read_u32_array(np, "voltage-table", + (u32 *)drvdata->duty_cycle_table, + length / sizeof(u32)); + if (ret < 0) { + dev_err(&pdev->dev, "read voltage-table failed\n"); + return ret; + } + + config.init_data = of_get_regulator_init_data(&pdev->dev, np, + &drvdata->desc); + 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->desc, &config); + if (IS_ERR(regulator)) { + dev_err(&pdev->dev, "Failed to register regulator %s\n", + drvdata->desc.name); + return PTR_ERR(regulator); + } + + 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"); |