drivers/pwm/pwm-clps711x.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Cirrus Logic CLPS711X PWM driver
   4  * Author: Alexander Shiyan <[email protected]>
   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         struct pwm_chip chip;
  16         void __iomem *pmpcon;
  17         struct clk *clk;
  18         spinlock_t lock;
  19 };
  20
  21 static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
  22 {
  23         return container_of(chip, struct clps711x_chip, chip);
  24 }
  25
  26 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  27 {
  28         struct clps711x_chip *priv = to_clps711x_chip(chip);
  29         unsigned int freq = clk_get_rate(priv->clk);
  30
  31         if (!freq)
  32                 return -EINVAL;
  33
  34         /* Store constant period value */
  35         pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
  36
  37         return 0;
  38 }
  39
  40 static int clps711x_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
  41                               const struct pwm_state *state)
  42 {
  43         struct clps711x_chip *priv = to_clps711x_chip(chip);
  44         /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
  45         u32 shift = (pwm->hwpwm + 1) * 4;
  46         unsigned long flags;
  47         u32 pmpcon, val;
  48
  49         if (state->polarity != PWM_POLARITY_NORMAL)
  50                 return -EINVAL;
  51
  52         if (state->period != pwm->args.period)
  53                 return -EINVAL;
  54
  55         if (state->enabled)
  56                 val = mul_u64_u64_div_u64(state->duty_cycle, 0xf, state->period);
  57         else
  58                 val = 0;
  59
  60         spin_lock_irqsave(&priv->lock, flags);
  61
  62         pmpcon = readl(priv->pmpcon);
  63         pmpcon &= ~(0xf << shift);
  64         pmpcon |= val << shift;
  65         writel(pmpcon, priv->pmpcon);
  66
  67         spin_unlock_irqrestore(&priv->lock, flags);
  68
  69         return 0;
  70 }
  71
  72 static const struct pwm_ops clps711x_pwm_ops = {
  73         .request = clps711x_pwm_request,
  74         .apply = clps711x_pwm_apply,
  75 };
  76
  77 static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
  78                                              const struct of_phandle_args *args)
  79 {
  80         if (args->args[0] >= chip->npwm)
  81                 return ERR_PTR(-EINVAL);
  82
  83         return pwm_request_from_chip(chip, args->args[0], NULL);
  84 }
  85
  86 static int clps711x_pwm_probe(struct platform_device *pdev)
  87 {
  88         struct clps711x_chip *priv;
  89
  90         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  91         if (!priv)
  92                 return -ENOMEM;
  93
  94         priv->pmpcon = devm_platform_ioremap_resource(pdev, 0);
  95         if (IS_ERR(priv->pmpcon))
  96                 return PTR_ERR(priv->pmpcon);
  97
  98         priv->clk = devm_clk_get(&pdev->dev, NULL);
  99         if (IS_ERR(priv->clk))
 100                 return PTR_ERR(priv->clk);
 101
 102         priv->chip.ops = &clps711x_pwm_ops;
 103         priv->chip.dev = &pdev->dev;
 104         priv->chip.npwm = 2;
 105         priv->chip.of_xlate = clps711x_pwm_xlate;
 106         priv->chip.of_pwm_n_cells = 1;
 107
 108         spin_lock_init(&priv->lock);
 109
 110         return devm_pwmchip_add(&pdev->dev, &priv->chip);
 111 }
 112
 113 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
 114         { .compatible = "cirrus,ep7209-pwm", },
 115         { }
 116 };
 117 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 118
 119 static struct platform_driver clps711x_pwm_driver = {
 120         .driver = {
 121                 .name = "clps711x-pwm",
 122                 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
 123         },
 124         .probe = clps711x_pwm_probe,
 125 };
 126 module_platform_driver(clps711x_pwm_driver);
 127
 128 MODULE_AUTHOR("Alexander Shiyan <[email protected]>");
 129 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
 130 MODULE_LICENSE("GPL");