linux/drivers/pwm/pwm-crc.c
Uwe Kleine-König b1a80d5053 pwm: crc: Make use of devm_pwmchip_alloc() function
This prepares the pwm-crc driver to further changes of the pwm core
outlined in the commit introducing devm_pwmchip_alloc(). There is no
intended semantical change and the driver should behave as before.

Link: https://lore.kernel.org/r/bbe4896eabc240c678c66fabb6329f4e6cd04eda.1707900770.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2024-02-15 12:59:21 +01:00

190 lines
4.8 KiB
C

// 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
* @regmap: the regmap from the parent device.
*/
struct crystalcove_pwm {
struct regmap *regmap;
};
static inline struct crystalcove_pwm *to_crc_pwm(struct pwm_chip *chip)
{
return pwmchip_get_drvdata(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 = pwmchip_parent(chip);
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 int 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 = pwmchip_parent(chip);
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;
}
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 error;
}
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);
return 0;
}
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 pwm_chip *chip;
struct crystalcove_pwm *crc_pwm;
struct device *dev = pdev->dev.parent;
struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*crc_pwm));
if (IS_ERR(chip))
return PTR_ERR(chip);
crc_pwm = to_crc_pwm(chip);
chip->ops = &crc_pwm_ops;
/* get the PMIC regmap */
crc_pwm->regmap = pmic->regmap;
return devm_pwmchip_add(&pdev->dev, chip);
}
static struct platform_driver crystalcove_pwm_driver = {
.probe = crystalcove_pwm_probe,
.driver = {
.name = "crystal_cove_pwm",
},
};
module_platform_driver(crystalcove_pwm_driver);
MODULE_ALIAS("platform:crystal_cove_pwm");
MODULE_DESCRIPTION("Intel Crystalcove (CRC) PWM support");
MODULE_LICENSE("GPL");