![Boris Brezillon](/assets/img/avatar_default.png)
The continuous PWM voltage regulator is caching the voltage value in the ->volt_uV field. While most of the time this value should reflect the real voltage, sometime it can be sightly different if the PWM device rounded the set_duty_cycle request. Moreover, this value is not valid until someone has modified the regulator output. Remove the ->volt_uV field and always rely on the PWM state to calculate the regulator output. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Reviewed-by: Brian Norris <briannorris@chromium.org> Tested-by: Brian Norris <briannorris@chromium.org> Tested-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Mark Brown <broonie@kernel.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
359 lines
9 KiB
C
359 lines
9 KiB
C
/*
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* Regulator driver for PWM Regulators
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*
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* Copyright (C) 2014 - STMicroelectronics Inc.
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*
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* Author: Lee Jones <lee.jones@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/delay.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/err.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/machine.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/pwm.h>
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#include <linux/gpio/consumer.h>
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struct pwm_regulator_data {
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/* Shared */
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struct pwm_device *pwm;
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/* Voltage table */
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struct pwm_voltages *duty_cycle_table;
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/* regulator descriptor */
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struct regulator_desc desc;
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/* Regulator ops */
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struct regulator_ops ops;
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int state;
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/* Enable GPIO */
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struct gpio_desc *enb_gpio;
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};
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struct pwm_voltages {
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unsigned int uV;
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unsigned int dutycycle;
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};
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/**
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* Voltage table call-backs
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*/
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static void pwm_regulator_init_state(struct regulator_dev *rdev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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struct pwm_state pwm_state;
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unsigned int dutycycle;
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int i;
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pwm_get_state(drvdata->pwm, &pwm_state);
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dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
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for (i = 0; i < rdev->desc->n_voltages; i++) {
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if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
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drvdata->state = i;
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return;
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}
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}
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}
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static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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if (drvdata->state < 0)
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pwm_regulator_init_state(rdev);
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return drvdata->state;
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}
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static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
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unsigned selector)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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struct pwm_state pstate;
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int ret;
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pwm_init_state(drvdata->pwm, &pstate);
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pwm_set_relative_duty_cycle(&pstate,
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drvdata->duty_cycle_table[selector].dutycycle, 100);
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ret = pwm_apply_state(drvdata->pwm, &pstate);
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if (ret) {
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dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
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return ret;
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}
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drvdata->state = selector;
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return 0;
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}
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static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
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unsigned selector)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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if (selector >= rdev->desc->n_voltages)
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return -EINVAL;
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return drvdata->duty_cycle_table[selector].uV;
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}
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static int pwm_regulator_enable(struct regulator_dev *dev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
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if (drvdata->enb_gpio)
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gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
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return pwm_enable(drvdata->pwm);
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}
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static int pwm_regulator_disable(struct regulator_dev *dev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
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pwm_disable(drvdata->pwm);
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if (drvdata->enb_gpio)
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gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
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return 0;
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}
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static int pwm_regulator_is_enabled(struct regulator_dev *dev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
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if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
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return false;
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return pwm_is_enabled(drvdata->pwm);
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}
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static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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int min_uV = rdev->constraints->min_uV;
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int diff = rdev->constraints->max_uV - min_uV;
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struct pwm_state pstate;
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pwm_get_state(drvdata->pwm, &pstate);
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return min_uV + pwm_get_relative_duty_cycle(&pstate, diff);
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}
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static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
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int min_uV, int max_uV,
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unsigned *selector)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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unsigned int ramp_delay = rdev->constraints->ramp_delay;
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unsigned int req_diff = min_uV - rdev->constraints->min_uV;
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struct pwm_state pstate;
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unsigned int diff;
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int old_uV = pwm_regulator_get_voltage(rdev);
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int ret;
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pwm_init_state(drvdata->pwm, &pstate);
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diff = rdev->constraints->max_uV - rdev->constraints->min_uV;
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/* We pass diff as the scale to get a uV precision. */
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pwm_set_relative_duty_cycle(&pstate, req_diff, diff);
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ret = pwm_apply_state(drvdata->pwm, &pstate);
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if (ret) {
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dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
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return ret;
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}
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if ((ramp_delay == 0) || !pwm_regulator_is_enabled(rdev))
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return 0;
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/* Ramp delay is in uV/uS. Adjust to uS and delay */
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ramp_delay = DIV_ROUND_UP(abs(min_uV - old_uV), ramp_delay);
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usleep_range(ramp_delay, ramp_delay + DIV_ROUND_UP(ramp_delay, 10));
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return 0;
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}
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static struct regulator_ops pwm_regulator_voltage_table_ops = {
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.set_voltage_sel = pwm_regulator_set_voltage_sel,
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.get_voltage_sel = pwm_regulator_get_voltage_sel,
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.list_voltage = pwm_regulator_list_voltage,
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.map_voltage = regulator_map_voltage_iterate,
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.enable = pwm_regulator_enable,
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.disable = pwm_regulator_disable,
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.is_enabled = pwm_regulator_is_enabled,
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};
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static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
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.get_voltage = pwm_regulator_get_voltage,
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.set_voltage = pwm_regulator_set_voltage,
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.enable = pwm_regulator_enable,
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.disable = pwm_regulator_disable,
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.is_enabled = pwm_regulator_is_enabled,
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};
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static struct regulator_desc pwm_regulator_desc = {
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.name = "pwm-regulator",
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.type = REGULATOR_VOLTAGE,
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.owner = THIS_MODULE,
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.supply_name = "pwm",
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};
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static int pwm_regulator_init_table(struct platform_device *pdev,
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struct pwm_regulator_data *drvdata)
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{
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struct device_node *np = pdev->dev.of_node;
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struct pwm_voltages *duty_cycle_table;
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unsigned int length = 0;
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int ret;
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of_find_property(np, "voltage-table", &length);
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if ((length < sizeof(*duty_cycle_table)) ||
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(length % sizeof(*duty_cycle_table))) {
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dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
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length);
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return -EINVAL;
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}
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duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
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if (!duty_cycle_table)
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return -ENOMEM;
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ret = of_property_read_u32_array(np, "voltage-table",
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(u32 *)duty_cycle_table,
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length / sizeof(u32));
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if (ret) {
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dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
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return ret;
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}
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drvdata->state = -EINVAL;
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drvdata->duty_cycle_table = duty_cycle_table;
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memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
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sizeof(drvdata->ops));
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drvdata->desc.ops = &drvdata->ops;
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drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
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return 0;
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}
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static int pwm_regulator_init_continuous(struct platform_device *pdev,
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struct pwm_regulator_data *drvdata)
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{
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memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
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sizeof(drvdata->ops));
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drvdata->desc.ops = &drvdata->ops;
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drvdata->desc.continuous_voltage_range = true;
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return 0;
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}
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static int pwm_regulator_probe(struct platform_device *pdev)
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{
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const struct regulator_init_data *init_data;
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struct pwm_regulator_data *drvdata;
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struct regulator_dev *regulator;
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struct regulator_config config = { };
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struct device_node *np = pdev->dev.of_node;
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enum gpiod_flags gpio_flags;
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int ret;
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if (!np) {
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dev_err(&pdev->dev, "Device Tree node missing\n");
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return -EINVAL;
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}
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drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
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if (!drvdata)
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return -ENOMEM;
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memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
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if (of_find_property(np, "voltage-table", NULL))
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ret = pwm_regulator_init_table(pdev, drvdata);
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else
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ret = pwm_regulator_init_continuous(pdev, drvdata);
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if (ret)
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return ret;
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init_data = of_get_regulator_init_data(&pdev->dev, np,
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&drvdata->desc);
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if (!init_data)
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return -ENOMEM;
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config.of_node = np;
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config.dev = &pdev->dev;
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config.driver_data = drvdata;
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config.init_data = init_data;
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drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
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if (IS_ERR(drvdata->pwm)) {
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ret = PTR_ERR(drvdata->pwm);
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dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
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return ret;
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}
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if (init_data->constraints.boot_on || init_data->constraints.always_on)
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gpio_flags = GPIOD_OUT_HIGH;
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else
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gpio_flags = GPIOD_OUT_LOW;
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drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
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gpio_flags);
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if (IS_ERR(drvdata->enb_gpio)) {
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ret = PTR_ERR(drvdata->enb_gpio);
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dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
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return ret;
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}
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ret = pwm_adjust_config(drvdata->pwm);
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if (ret)
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return ret;
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regulator = devm_regulator_register(&pdev->dev,
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&drvdata->desc, &config);
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if (IS_ERR(regulator)) {
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ret = PTR_ERR(regulator);
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dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
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drvdata->desc.name, ret);
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return ret;
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}
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return 0;
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}
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static const struct of_device_id pwm_of_match[] = {
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{ .compatible = "pwm-regulator" },
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{ },
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};
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MODULE_DEVICE_TABLE(of, pwm_of_match);
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static struct platform_driver pwm_regulator_driver = {
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.driver = {
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.name = "pwm-regulator",
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.of_match_table = of_match_ptr(pwm_of_match),
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},
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.probe = pwm_regulator_probe,
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};
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module_platform_driver(pwm_regulator_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
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MODULE_DESCRIPTION("PWM Regulator Driver");
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MODULE_ALIAS("platform:pwm-regulator");
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