LXR linux/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
  19struct clps711x_chip {
  20        struct pwm_chip chip;
  21        void __iomem *pmpcon;
  22        struct clk *clk;
  23        spinlock_t lock;
  24};
  25
  26static inline struct clps711x_chip *to_clps711x_chip(struct pwm_chip *chip)
  27{
  28        return container_of(chip, struct clps711x_chip, chip);
  29}
  30
  31static 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
  48static 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_get_period(pwm));
  52}
  53
  54static 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_set_period(pwm, DIV_ROUND_CLOSEST(NSEC_PER_SEC, freq));
  64
  65        return 0;
  66}
  67
  68static 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_get_period(pwm))
  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
  83static 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
  94static 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
 101static 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
 109static 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
 118static 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
 150static 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
 157static const struct of_device_id __maybe_unused clps711x_pwm_dt_ids[] = {
 158        { .compatible = "cirrus,clps711x-pwm", },
 159        { }
 160};
 161MODULE_DEVICE_TABLE(of, clps711x_pwm_dt_ids);
 162
 163static 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};
 171module_platform_driver(clps711x_pwm_driver);
 172
 173MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 174MODULE_DESCRIPTION("Cirrus Logic CLPS711X PWM driver");
 175MODULE_LICENSE("GPL");
 176