Quelle  pwm-clps711x.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
/*
 * Cirrus Logic CLPS711X PWM driver
 * Author: Alexander Shiyan <shc_work@mail.ru>
 */

#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>

struct clps711x_chip {
 void __iomem *pmpcon;
 struct clk *clk;
};

static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
{
 return pwmchip_get_drvdata(chip);
}

static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
 struct clps711x_chip *priv = to_clps711x_chip(chip);
 unsigned int freq = clk_get_rate(priv->clk);

 if (!freq)
  return -EINVAL;

 /* Store constant period value */
 pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);

 return 0;
}

static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
         const struct pwm_state *state)
{
 struct clps711x_chip *priv = to_clps711x_chip(chip);
 /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
 u32 shift = (pwm->hwpwm + 1) * 4;
 u32 pmpcon, val;

 if (state->polarity != PWM_POLARITY_NORMAL)
  return -EINVAL;

 if (state->period != pwm->args.period)
  return -EINVAL;

 if (state->enabled)
  val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
 else
  val = 0;

 pmpcon = readl(priv->pmpcon);
 pmpcon &= ~(0xf << shift);
 pmpcon |= val << shift;
 writel(pmpcon, priv->pmpcon);

 return 0;
}

static const struct pwm_ops clps711x_pwm_ops = {
 .request = clps711x_pwm_request,
 .apply = clps711x_pwm_apply,
};

static int clps711x_pwm_probe(struct platform_device *pdev)
{
 struct pwm_chip *chip;
 struct clps711x_chip *priv;

 chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*priv));
 if (IS_ERR(chip))
  return PTR_ERR(chip);
 priv = to_clps711x_chip(chip);

 priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
 if (IS_ERR(priv->pmpcon))
  return PTR_ERR(priv->pmpcon);

 priv->clk = devm_clk_get(&pdev->dev, NULL);
 if (IS_ERR(priv->clk))
  return PTR_ERR(priv->clk);

 chip->ops = &clps711x_pwm_ops;

 return devm_pwmchip_add(&pdev->dev, chip);
}

static const struct of_device_id clps711x_pwm_dt_ids[] = {
 { .compatible = "cirrus,ep7209-pwm", },
 { }
};
MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);

static struct platform_driver clps711x_pwm_driver = {
 .driver = {
  .name = "clps711x-pwm",
  .of_match_table = clps711x_pwm_dt_ids,
 },
 .probe = clps711x_pwm_probe,
};
module_platform_driver(clps711x_pwm_driver);

MODULE_AUTHOR("Alexander Shiyan ");
MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
MODULE_LICENSE("GPL");