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         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 void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
  27 {
  28         /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
  29         u32 shift = (n + 1) * 4;
  30         unsigned long flags;
  31         u32 tmp;
  32
  33         spin_lock_irqsave(&priv->lock, flags);
  34
  35         tmp = readl(priv->pmpcon);
  36         tmp &= ~(0xf << shift);
  37         tmp |= v << shift;
  38         writel(tmp, priv->pmpcon);
  39
  40         spin_unlock_irqrestore(&priv->lock, flags);
  41 }
  42
  43 static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
  44 {
  45         /* Duty cycle 0..15 max */
  46         return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
  47 }
  48
  49 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  50 {
  51         struct clps711x_chip *priv = to_clps711x_chip(chip);
  52         unsigned int freq = clk_get_rate(priv->clk);
  53
  54         if (!freq)
  55                 return -EINVAL;
  56
  57         /* Store constant period value */
  58         pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
  59
  60         return 0;
  61 }
  62
  63 static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  64                                int duty_ns, int period_ns)
  65 {
  66         struct clps711x_chip *priv = to_clps711x_chip(chip);
  67         unsigned int duty;
  68
  69         if (period_ns != pwm->args.period)
  70                 return -EINVAL;
  71
  72         duty = clps711x_get_duty(pwm, duty_ns);
  73         clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
  74
  75         return 0;
  76 }
  77
  78 static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  79 {
  80         struct clps711x_chip *priv = to_clps711x_chip(chip);
  81         unsigned int duty;
  82
  83         duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm));
  84         clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
  85
  86         return 0;
  87 }
  88
  89 static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  90 {
  91         struct clps711x_chip *priv = to_clps711x_chip(chip);
  92
  93         clps711x_pwm_update_val(priv, pwm->hwpwm, 0);
  94 }
  95
  96 static const struct pwm_ops clps711x_pwm_ops = {
  97         .request = clps711x_pwm_request,
  98         .config = clps711x_pwm_config,
  99         .enable = clps711x_pwm_enable,
 100         .disable = clps711x_pwm_disable,
 101         .owner = THIS_MODULE,
 102 };
 103
 104 static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
 105                                              const struct of_phandle_args *args)
 106 {
 107         if (args->args[0] >= chip->npwm)
 108                 return ERR_PTR(-EINVAL);
 109
 110         return pwm_request_from_chip(chip, args->args[0], NULL);
 111 }
 112
 113 static int clps711x_pwm_probe(struct platform_device *pdev)
 114 {
 115         struct clps711x_chip *priv;
 116         struct resource *res;
 117
 118         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 119         if (!priv)
 120                 return -ENOMEM;
 121
 122         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 123         priv->pmpcon = devm_ioremap_resource(&pdev->dev, res);
 124         if (IS_ERR(priv->pmpcon))
 125                 return PTR_ERR(priv->pmpcon);
 126
 127         priv->clk = devm_clk_get(&pdev->dev, NULL);
 128         if (IS_ERR(priv->clk))
 129                 return PTR_ERR(priv->clk);
 130
 131         priv->chip.ops = &clps711x_pwm_ops;
 132         priv->chip.dev = &pdev->dev;
 133         priv->chip.base = -1;
 134         priv->chip.npwm = 2;
 135         priv->chip.of_xlate = clps711x_pwm_xlate;
 136         priv->chip.of_pwm_n_cells = 1;
 137
 138         spin_lock_init(&priv->lock);
 139
 140         platform_set_drvdata(pdev, priv);
 141
 142         return pwmchip_add(&priv->chip);
 143 }
 144
 145 static int clps711x_pwm_remove(struct platform_device *pdev)
 146 {
 147         struct clps711x_chip *priv = platform_get_drvdata(pdev);
 148
 149         return pwmchip_remove(&priv->chip);
 150 }
 151
 152 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
 153         { .compatible = "cirrus,ep7209-pwm", },
 154         { }
 155 };
 156 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 157
 158 static struct platform_driver clps711x_pwm_driver = {
 159         .driver = {
 160                 .name = "clps711x-pwm",
 161                 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
 162         },
 163         .probe = clps711x_pwm_probe,
 164         .remove = clps711x_pwm_remove,
 165 };
 166 module_platform_driver(clps711x_pwm_driver);
 167
 168 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 169 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
 170 MODULE_LICENSE("GPL");