drivers/pwm/pwm-clps711x.c

   1 /*
   2  * Cirrus Logic CLPS711X PWM driver
   3  *
   4  * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/pwm.h>
  18
  19 struct clps711x_chip {
  20         struct pwm_chip chip;
  21         void __iomem *pmpcon;
  22         struct clk *clk;
  23         spinlock_t lock;
  24 };
  25
  26 static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
  27 {
  28         return container_of(chip, struct clps711x_chip, chip);
  29 }
  30
  31 static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
  32 {
  33         /* PWM0 - bits 4..7, PWM1 - bits 8..11 */
  34         u32 shift = (n + 1) * 4;
  35         unsigned long flags;
  36         u32 tmp;
  37
  38         spin_lock_irqsave(&priv->lock, flags);
  39
  40         tmp = readl(priv->pmpcon);
  41         tmp &= ~(0xf << shift);
  42         tmp |= v << shift;
  43         writel(tmp, priv->pmpcon);
  44
  45         spin_unlock_irqrestore(&priv->lock, flags);
  46 }
  47
  48 static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
  49 {
  50         /* Duty cycle 0..15 max */
  51         return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
  52 }
  53
  54 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  55 {
  56         struct clps711x_chip *priv = to_clps711x_chip(chip);
  57         unsigned int freq = clk_get_rate(priv->clk);
  58
  59         if (!freq)
  60                 return -EINVAL;
  61
  62         /* Store constant period value */
  63         pwm->args.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq);
  64
  65         return 0;
  66 }
  67
  68 static int clps711x_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  69                                int duty_ns, int period_ns)
  70 {
  71         struct clps711x_chip *priv = to_clps711x_chip(chip);
  72         unsigned int duty;
  73
  74         if (period_ns != pwm->args.period)
  75                 return -EINVAL;
  76
  77         duty = clps711x_get_duty(pwm, duty_ns);
  78         clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
  79
  80         return 0;
  81 }
  82
  83 static int clps711x_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  84 {
  85         struct clps711x_chip *priv = to_clps711x_chip(chip);
  86         unsigned int duty;
  87
  88         duty = clps711x_get_duty(pwm, pwm_get_duty_cycle(pwm));
  89         clps711x_pwm_update_val(priv, pwm->hwpwm, duty);
  90
  91         return 0;
  92 }
  93
  94 static void clps711x_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  95 {
  96         struct clps711x_chip *priv = to_clps711x_chip(chip);
  97
  98         clps711x_pwm_update_val(priv, pwm->hwpwm, 0);
  99 }
 100
 101 static const struct pwm_ops clps711x_pwm_ops = {
 102         .request = clps711x_pwm_request,
 103         .config = clps711x_pwm_config,
 104         .enable = clps711x_pwm_enable,
 105         .disable = clps711x_pwm_disable,
 106         .owner = THIS_MODULE,
 107 };
 108
 109 static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
 110                                              const struct of_phandle_args *args)
 111 {
 112         if (args->args[0] >= chip->npwm)
 113                 return ERR_PTR(-EINVAL);
 114
 115         return pwm_request_from_chip(chip, args->args[0], NULL);
 116 }
 117
 118 static int clps711x_pwm_probe(struct platform_device *pdev)
 119 {
 120         struct clps711x_chip *priv;
 121         struct resource *res;
 122
 123         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 124         if (!priv)
 125                 return -ENOMEM;
 126
 127         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 128         priv->pmpcon = devm_ioremap_resource(&pdev->dev, res);
 129         if (IS_ERR(priv->pmpcon))
 130                 return PTR_ERR(priv->pmpcon);
 131
 132         priv->clk = devm_clk_get(&pdev->dev, NULL);
 133         if (IS_ERR(priv->clk))
 134                 return PTR_ERR(priv->clk);
 135
 136         priv->chip.ops = &clps711x_pwm_ops;
 137         priv->chip.dev = &pdev->dev;
 138         priv->chip.base = -1;
 139         priv->chip.npwm = 2;
 140         priv->chip.of_xlate = clps711x_pwm_xlate;
 141         priv->chip.of_pwm_n_cells = 1;
 142
 143         spin_lock_init(&priv->lock);
 144
 145         platform_set_drvdata(pdev, priv);
 146
 147         return pwmchip_add(&priv->chip);
 148 }
 149
 150 static int clps711x_pwm_remove(struct platform_device *pdev)
 151 {
 152         struct clps711x_chip *priv = platform_get_drvdata(pdev);
 153
 154         return pwmchip_remove(&priv->chip);
 155 }
 156
 157 static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
 158         { .compatible = "cirrus,ep7209-pwm", },
 159         { }
 160 };
 161 MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 162
 163 static struct platform_driver clps711x_pwm_driver = {
 164         .driver = {
 165                 .name = "clps711x-pwm",
 166                 .of_match_table = of_match_ptr(clps711x_pwm_dt_ids),
 167         },
 168         .probe = clps711x_pwm_probe,
 169         .remove = clps711x_pwm_remove,
 170 };
 171 module_platform_driver(clps711x_pwm_driver);
 172
 173 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 174 MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
 175 MODULE_LICENSE("GPL");