419 lines
11 KiB
C
419 lines
11 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/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_continuous_reg_data {
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unsigned int min_uV_dutycycle;
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unsigned int max_uV_dutycycle;
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unsigned int dutycycle_unit;
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};
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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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/* Continuous mode info */
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struct pwm_continuous_reg_data continuous;
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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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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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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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unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
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unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
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unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
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int min_uV = rdev->constraints->min_uV;
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int max_uV = rdev->constraints->max_uV;
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int diff_uV = max_uV - min_uV;
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struct pwm_state pstate;
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unsigned int diff_duty;
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unsigned int voltage;
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pwm_get_state(drvdata->pwm, &pstate);
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voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
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/*
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* The dutycycle for min_uV might be greater than the one for max_uV.
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* This is happening when the user needs an inversed polarity, but the
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* PWM device does not support inversing it in hardware.
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*/
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if (max_uV_duty < min_uV_duty) {
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voltage = min_uV_duty - voltage;
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diff_duty = min_uV_duty - max_uV_duty;
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} else {
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voltage = voltage - min_uV_duty;
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diff_duty = max_uV_duty - min_uV_duty;
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}
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voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
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return voltage + min_uV;
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}
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static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
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int req_min_uV, int req_max_uV,
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unsigned int *selector)
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{
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struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
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unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
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unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
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unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
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int min_uV = rdev->constraints->min_uV;
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int max_uV = rdev->constraints->max_uV;
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int diff_uV = max_uV - min_uV;
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struct pwm_state pstate;
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unsigned int diff_duty;
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unsigned int dutycycle;
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int ret;
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pwm_init_state(drvdata->pwm, &pstate);
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/*
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* The dutycycle for min_uV might be greater than the one for max_uV.
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* This is happening when the user needs an inversed polarity, but the
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* PWM device does not support inversing it in hardware.
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*/
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if (max_uV_duty < min_uV_duty)
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diff_duty = min_uV_duty - max_uV_duty;
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else
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diff_duty = max_uV_duty - min_uV_duty;
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dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
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diff_duty,
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diff_uV);
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if (max_uV_duty < min_uV_duty)
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dutycycle = min_uV_duty - dutycycle;
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else
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dutycycle = min_uV_duty + dutycycle;
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pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
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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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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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u32 dutycycle_range[2] = { 0, 100 };
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u32 dutycycle_unit = 100;
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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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of_property_read_u32_array(pdev->dev.of_node,
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"pwm-dutycycle-range",
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dutycycle_range, 2);
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of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
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&dutycycle_unit);
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if (dutycycle_range[0] > dutycycle_unit ||
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dutycycle_range[1] > dutycycle_unit)
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return -EINVAL;
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drvdata->continuous.dutycycle_unit = dutycycle_unit;
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drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
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drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
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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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