pwm-crc.c
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/*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Author: Shobhit Kumar <shobhit.kumar@intel.com>
*/
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/mfd/intel_soc_pmic.h>
#include <linux/pwm.h>
#define PWM0_CLK_DIV 0x4B
#define PWM_OUTPUT_ENABLE BIT(7)
#define PWM_DIV_CLK_0 0x00 /* DIVIDECLK = BASECLK */
#define PWM_DIV_CLK_100 0x63 /* DIVIDECLK = BASECLK/100 */
#define PWM_DIV_CLK_128 0x7F /* DIVIDECLK = BASECLK/128 */
#define PWM0_DUTY_CYCLE 0x4E
#define BACKLIGHT_EN 0x51
#define PWM_MAX_LEVEL 0xFF
#define PWM_BASE_CLK 6000000 /* 6 MHz */
#define PWM_MAX_PERIOD_NS 21333 /* 46.875KHz */
/**
* struct crystalcove_pwm - Crystal Cove PWM controller
* @chip: the abstract pwm_chip structure.
* @regmap: the regmap from the parent device.
*/
struct crystalcove_pwm {
struct pwm_chip chip;
struct regmap *regmap;
};
static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *pc)
{
return container_of(pc, struct crystalcove_pwm, chip);
}
static int crc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
return 0;
}
static void crc_pwm_disable(struct pwm_chip *c, struct pwm_device *pwm)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
}
static int crc_pwm_config(struct pwm_chip *c, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(c);
struct device *dev = crc_pwm->chip.dev;
int level;
if (period_ns > PWM_MAX_PERIOD_NS) {
dev_err(dev, "un-supported period_ns\n");
return -EINVAL;
}
if (pwm_get_period(pwm) != period_ns) {
int clk_div;
/* changing the clk divisor, need to disable fisrt */
crc_pwm_disable(c, pwm);
clk_div = PWM_BASE_CLK * period_ns / NSEC_PER_SEC;
regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
clk_div | PWM_OUTPUT_ENABLE);
/* enable back */
crc_pwm_enable(c, pwm);
}
/* change the pwm duty cycle */
level = duty_ns * PWM_MAX_LEVEL / period_ns;
regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
return 0;
}
static const struct pwm_ops crc_pwm_ops = {
.config = crc_pwm_config,
.enable = crc_pwm_enable,
.disable = crc_pwm_disable,
};
static int crystalcove_pwm_probe(struct platform_device *pdev)
{
struct crystalcove_pwm *pwm;
struct device *dev = pdev->dev.parent;
struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
if (!pwm)
return -ENOMEM;
pwm->chip.dev = &pdev->dev;
pwm->chip.ops = &crc_pwm_ops;
pwm->chip.base = -1;
pwm->chip.npwm = 1;
/* get the PMIC regmap */
pwm->regmap = pmic->regmap;
platform_set_drvdata(pdev, pwm);
return pwmchip_add(&pwm->chip);
}
static int crystalcove_pwm_remove(struct platform_device *pdev)
{
struct crystalcove_pwm *pwm = platform_get_drvdata(pdev);
return pwmchip_remove(&pwm->chip);
}
static struct platform_driver crystalcove_pwm_driver = {
.probe = crystalcove_pwm_probe,
.remove = crystalcove_pwm_remove,
.driver = {
.name = "crystal_cove_pwm",
},
};
builtin_platform_driver(crystalcove_pwm_driver);