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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2015 Intel Corporation. All rights reserved.
*
* 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_MHZ 6 /* 6 MHz */
#define PWM_MAX_PERIOD_NS 5461334 /* 183 Hz */
/**
* 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_calc_clk_div(int period_ns)
{
int clk_div;
clk_div = PWM_BASE_CLK_MHZ * period_ns / (256 * NSEC_PER_USEC);
/* clk_div 1 - 128, maps to register values 0-127 */
if (clk_div > 0)
clk_div--;
return clk_div;
}
static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
struct device *dev = crc_pwm->chip.dev;
int err;
if (state->period > PWM_MAX_PERIOD_NS) {
dev_err(dev, "un-supported period_ns\n");
return -EINVAL;
}
if (state->polarity != PWM_POLARITY_NORMAL)
return -EINVAL;
if (pwm_is_enabled(pwm) && !state->enabled) {
err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 0);
if (err) {
dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
return err;
}
}
if (pwm_get_duty_cycle(pwm) != state->duty_cycle ||
pwm_get_period(pwm) != state->period) {
u64 level = state->duty_cycle * PWM_MAX_LEVEL;
do_div(level, state->period);
err = regmap_write(crc_pwm->regmap, PWM0_DUTY_CYCLE, level);
if (err) {
dev_err(dev, "Error writing PWM0_DUTY_CYCLE %d\n", err);
return err;
}
}
if (pwm_is_enabled(pwm) && state->enabled &&
pwm_get_period(pwm) != state->period) {
/* changing the clk divisor, clear PWM_OUTPUT_ENABLE first */
err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV, 0);
if (err) {
dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
return err;
}
}
if (pwm_get_period(pwm) != state->period ||
pwm_is_enabled(pwm) != state->enabled) {
int clk_div = crc_pwm_calc_clk_div(state->period);
int pwm_output_enable = state->enabled ? PWM_OUTPUT_ENABLE : 0;
err = regmap_write(crc_pwm->regmap, PWM0_CLK_DIV,
clk_div | pwm_output_enable);
if (err) {
dev_err(dev, "Error writing PWM0_CLK_DIV %d\n", err);
return err;
}
}
if (!pwm_is_enabled(pwm) && state->enabled) {
err = regmap_write(crc_pwm->regmap, BACKLIGHT_EN, 1);
if (err) {
dev_err(dev, "Error writing BACKLIGHT_EN %d\n", err);
return err;
}
}
return 0;
}
static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
struct device *dev = crc_pwm->chip.dev;
unsigned int clk_div, clk_div_reg, duty_cycle_reg;
int error;
error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
if (error) {
dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
return;
}
error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
if (error) {
dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
return;
}
clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
state->period =
DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ);
state->duty_cycle =
DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
state->polarity = PWM_POLARITY_NORMAL;
state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
}
static const struct pwm_ops crc_pwm_ops = {
.apply = crc_pwm_apply,
.get_state = crc_pwm_get_state,
};
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.npwm = 1;
/* get the PMIC regmap */
pwm->regmap = pmic->regmap;
return devm_pwmchip_add(&pdev->dev, &pwm->chip);
}
static struct platform_driver crystalcove_pwm_driver = {
.probe = crystalcove_pwm_probe,
.driver = {
.name = "crystal_cove_pwm",
},
};
builtin_platform_driver(crystalcove_pwm_driver);
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