drivers/pwm/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
  14 struct clps711x_chip {
  15         void __iomem *pmpcon;
  16         struct clk *clk;
  17         spinlock_t lock;
  18 };
  19
  20 static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
  21 {
  22         return pwmchip_get_drvdata(chip);
  23 }
  24
  25 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  26 {
  27         struct clps711x_chip *priv = to_clps711x_chip(chip);
  28         unsigned int freq = clk_get_rate(priv->clk);
  29
  30         if (!freq)
  31                 return -EINVAL;
  32
  33         /* Store constant period value */
  34         pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
  35
  36         return 0;
  37 }
  38
  39 static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
  40                               const struct pwm_state *state)
  41 {
  42         struct clps711x_chip *priv = to_clps711x_chip(chip);
  43         /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
  44         u32 shift = (pwm->hwpwm + 1) * 4;
  45         unsigned long flags;
  46         u32 pmpcon, val;
  47
  48         if (state->polarity != PWM_POLARITY_NORMAL)
  49                 return -EINVAL;
  50
  51         if (state->period != pwm->args.period)
  52                 return -EINVAL;
  53
  54         if (state->enabled)
  55                 val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
  56         else
  57                 val = 0;
  58
  59         spin_lock_irqsave(&priv->lock, flags);
  60
  61         pmpcon = readl(priv->pmpcon);
  62         pmpcon &= ~(0xf << shift);
  63         pmpcon |= val << shift;
  64         writel(pmpcon, priv->pmpcon);
  65
  66         spin_unlock_irqrestore(&priv->lock, flags);
  67
  68         return 0;
  69 }
  70
  71 static const struct pwm_ops clps711x_pwm_ops = {
  72         .request = clps711x_pwm_request,
  73         .apply = clps711x_pwm_apply,
  74 };
  75
  76 static int clps711x_pwm_probe(struct platform_device *pdev)
  77 {
  78         struct pwm_chip *chip;
  79         struct clps711x_chip *priv;
  80
  81         chip = devm_pwmchip_alloc(&pdev->dev, 2, sizeof(*priv));
  82         if (IS_ERR(chip))
  83                 return PTR_ERR(chip);
  84         priv = to_clps711x_chip(chip);
  85
  86         priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
  87         if (IS_ERR(priv->pmpcon))
  88                 return PTR_ERR(priv->pmpcon);
  89
  90         priv->clk = devm_clk_get(&pdev->dev, NULL);
  91         if (IS_ERR(priv->clk))
  92                 return PTR_ERR(priv->clk);
  93
  94         chip->ops = &clps711x_pwm_ops;
  95
  96         spin_lock_init(&priv->lock);
  97
  98         return devm_pwmchip_add(&pdev->dev, chip);
  99 }
 100
 101 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
 102         { .compatible = "cirrus,ep7209-pwm", },
 103         { }
 104 };
 105 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 106
 107 static struct platform_driver clps711x_pwm_driver = {
 108         .driver = {
 109                 .name = "clps711x-pwm",
 110                 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
 111         },
 112         .probe = clps711x_pwm_probe,
 113 };
 114 module_platform_driver(clps711x_pwm_driver);
 115
 116 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 117 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
 118 MODULE_LICENSE("GPL");