pwm-clps711x.c

  1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Cirrus Logic CLPS711X PWM driver
  4 * Author: Alexander Shiyan <shc_work@mail.ru>
  5 */
  6
  7#include <linux/clk.h>
  8#include <linux/io.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/platform_device.h>
 12#include <linux/pwm.h>
 13
 14struct clps711x_chip {
 15	void __iomem *pmpcon;
 16	struct clk *clk;
 17};
 18
 19static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
 20{
 21	return pwmchip_get_drvdata(chip);
 22}
 23
 24static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 25{
 26	struct clps711x_chip *priv = to_clps711x_chip(chip);
 27	unsigned int freq = clk_get_rate(priv->clk);
 28
 29	if (!freq)
 30		return -EINVAL;
 31
 32	/* Store constant period value */
 33	pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
 34
 35	return 0;
 36}
 37
 38static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 39			      const struct pwm_state *state)
 40{
 41	struct clps711x_chip *priv = to_clps711x_chip(chip);
 42	/* PWM0 - bits 4..7, PWM1 - bits 8..11 */
 43	u32 shift = (pwm->hwpwm + 1) * 4;
 44	u32 pmpcon, val;
 45
 46	if (state->polarity != PWM_POLARITY_NORMAL)
 47		return -EINVAL;
 48
 49	if (state->period != pwm->args.period)
 50		return -EINVAL;
 51
 52	if (state->enabled)
 53		val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
 54	else
 55		val = 0;
 56
 57	pmpcon = readl(priv->pmpcon);
 58	pmpcon &= ~(0xf << shift);
 59	pmpcon |= val << shift;
 60	writel(pmpcon, priv->pmpcon);
 61
 62	return 0;
 63}
 64
 65static const struct pwm_ops clps711x_pwm_ops = {
 66	.request = clps711x_pwm_request,
 67	.apply = clps711x_pwm_apply,
 68};
 69
 70static int clps711x_pwm_probe(struct platform_device *pdev)
 71{
 72	struct pwm_chip *chip;
 73	struct clps711x_chip *priv;
 74
 75	chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*priv));
 76	if (IS_ERR(chip))
 77		return PTR_ERR(chip);
 78	priv = to_clps711x_chip(chip);
 79
 80	priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
 81	if (IS_ERR(priv->pmpcon))
 82		return PTR_ERR(priv->pmpcon);
 83
 84	priv->clk = devm_clk_get(&pdev->dev, NULL);
 85	if (IS_ERR(priv->clk))
 86		return PTR_ERR(priv->clk);
 87
 88	chip->ops = &clps711x_pwm_ops;
 89
 90	return devm_pwmchip_add(&pdev->dev, chip);
 91}
 92
 93static const struct of_device_id clps711x_pwm_dt_ids[] = {
 94	{ .compatible = "cirrus,ep7209-pwm", },
 95	{ }
 96};
 97MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 98
 99static struct platform_driver clps711x_pwm_driver = {
100	.driver = {
101		.name = "clps711x-pwm",
102		.of_match_table = clps711x_pwm_dt_ids,
103	},
104	.probe = clps711x_pwm_probe,
105};
106module_platform_driver(clps711x_pwm_driver);
107
108MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
109MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
110MODULE_LICENSE("GPL");