279 lines
6.7 KiB
C
279 lines
6.7 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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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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int state;
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/* Continuous voltage */
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int volt_uV;
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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 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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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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unsigned int pwm_reg_period;
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int dutycycle;
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int ret;
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pwm_reg_period = pwm_get_period(drvdata->pwm);
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dutycycle = (pwm_reg_period *
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drvdata->duty_cycle_table[selector].dutycycle) / 100;
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ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
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if (ret) {
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dev_err(&rdev->dev, "Failed to configure PWM\n");
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return ret;
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}
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drvdata->state = selector;
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ret = pwm_enable(drvdata->pwm);
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if (ret) {
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dev_err(&rdev->dev, "Failed to enable PWM\n");
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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 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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/**
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* Continuous voltage call-backs
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*/
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static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV)
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{
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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 = max_uV - min_uV;
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return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
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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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return drvdata->volt_uV;
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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 period = pwm_get_period(drvdata->pwm);
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int duty_cycle;
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int ret;
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duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV);
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ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period);
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if (ret) {
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dev_err(&rdev->dev, "Failed to configure PWM\n");
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return ret;
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}
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ret = pwm_enable(drvdata->pwm);
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if (ret) {
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dev_err(&rdev->dev, "Failed to enable PWM\n");
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return ret;
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}
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drvdata->volt_uV = min_uV;
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/* Delay required by PWM regulator to settle to the new voltage */
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usleep_range(ramp_delay, ramp_delay + 1000);
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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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};
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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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};
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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,
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"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\n");
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return ret;
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}
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drvdata->duty_cycle_table = duty_cycle_table;
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pwm_regulator_desc.ops = &pwm_regulator_voltage_table_ops;
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pwm_regulator_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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pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops;
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pwm_regulator_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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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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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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&pwm_regulator_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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dev_err(&pdev->dev, "Failed to get PWM\n");
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return PTR_ERR(drvdata->pwm);
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}
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regulator = devm_regulator_register(&pdev->dev,
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&pwm_regulator_desc, &config);
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if (IS_ERR(regulator)) {
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dev_err(&pdev->dev, "Failed to register regulator %s\n",
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pwm_regulator_desc.name);
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return PTR_ERR(regulator);
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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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