linux/drivers/pwm/pwm-bfin.c
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   1/*
   2 * Blackfin Pulse Width Modulation (PWM) core
   3 *
   4 * Copyright (c) 2011 Analog Devices Inc.
   5 *
   6 * Licensed under the GPL-2 or later.
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/platform_device.h>
  11#include <linux/pwm.h>
  12#include <linux/slab.h>
  13
  14#include <asm/gptimers.h>
  15#include <asm/portmux.h>
  16
  17struct bfin_pwm_chip {
  18        struct pwm_chip chip;
  19};
  20
  21struct bfin_pwm {
  22        unsigned short pin;
  23};
  24
  25static const unsigned short pwm_to_gptimer_per[] = {
  26        P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
  27        P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
  28};
  29
  30static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  31{
  32        struct bfin_pwm *priv;
  33        int ret;
  34
  35        if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per))
  36                return -EINVAL;
  37
  38        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  39        if (!priv)
  40                return -ENOMEM;
  41
  42        priv->pin = pwm_to_gptimer_per[pwm->hwpwm];
  43
  44        ret = peripheral_request(priv->pin, NULL);
  45        if (ret) {
  46                kfree(priv);
  47                return ret;
  48        }
  49
  50        pwm_set_chip_data(pwm, priv);
  51
  52        return 0;
  53}
  54
  55static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  56{
  57        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  58
  59        if (priv) {
  60                peripheral_free(priv->pin);
  61                kfree(priv);
  62        }
  63}
  64
  65static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  66                int duty_ns, int period_ns)
  67{
  68        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  69        unsigned long period, duty;
  70        unsigned long long val;
  71
  72        if (duty_ns < 0 || duty_ns > period_ns)
  73                return -EINVAL;
  74
  75        val = (unsigned long long)get_sclk() * period_ns;
  76        do_div(val, NSEC_PER_SEC);
  77        period = val;
  78
  79        val = (unsigned long long)period * duty_ns;
  80        do_div(val, period_ns);
  81        duty = period - val;
  82
  83        if (duty >= period)
  84                duty = period - 1;
  85
  86        set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
  87        set_gptimer_pwidth(priv->pin, duty);
  88        set_gptimer_period(priv->pin, period);
  89
  90        return 0;
  91}
  92
  93static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  94{
  95        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  96
  97        enable_gptimer(priv->pin);
  98
  99        return 0;
 100}
 101
 102static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 103{
 104        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
 105
 106        disable_gptimer(priv->pin);
 107}
 108
 109static struct pwm_ops bfin_pwm_ops = {
 110        .request = bfin_pwm_request,
 111        .free = bfin_pwm_free,
 112        .config = bfin_pwm_config,
 113        .enable = bfin_pwm_enable,
 114        .disable = bfin_pwm_disable,
 115        .owner = THIS_MODULE,
 116};
 117
 118static int bfin_pwm_probe(struct platform_device *pdev)
 119{
 120        struct bfin_pwm_chip *pwm;
 121        int ret;
 122
 123        pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 124        if (!pwm) {
 125                dev_err(&pdev->dev, "failed to allocate memory\n");
 126                return -ENOMEM;
 127        }
 128
 129        platform_set_drvdata(pdev, pwm);
 130
 131        pwm->chip.dev = &pdev->dev;
 132        pwm->chip.ops = &bfin_pwm_ops;
 133        pwm->chip.base = -1;
 134        pwm->chip.npwm = 12;
 135
 136        ret = pwmchip_add(&pwm->chip);
 137        if (ret < 0) {
 138                dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 139                return ret;
 140        }
 141
 142        return 0;
 143}
 144
 145static int __devexit bfin_pwm_remove(struct platform_device *pdev)
 146{
 147        struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);
 148
 149        return pwmchip_remove(&pwm->chip);
 150}
 151
 152static struct platform_driver bfin_pwm_driver = {
 153        .driver = {
 154                .name = "bfin-pwm",
 155        },
 156        .probe = bfin_pwm_probe,
 157        .remove = __devexit_p(bfin_pwm_remove),
 158};
 159
 160module_platform_driver(bfin_pwm_driver);
 161
 162MODULE_LICENSE("GPL");
 163
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