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        val = (unsigned long long)get_sclk() * period_ns;
  73        do_div(val, NSEC_PER_SEC);
  74        period = val;
  75
  76        val = (unsigned long long)period * duty_ns;
  77        do_div(val, period_ns);
  78        duty = period - val;
  79
  80        if (duty >= period)
  81                duty = period - 1;
  82
  83        set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
  84        set_gptimer_pwidth(priv->pin, duty);
  85        set_gptimer_period(priv->pin, period);
  86
  87        return 0;
  88}
  89
  90static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  91{
  92        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  93
  94        enable_gptimer(priv->pin);
  95
  96        return 0;
  97}
  98
  99static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 100{
 101        struct bfin_pwm *priv = pwm_get_chip_data(pwm);
 102
 103        disable_gptimer(priv->pin);
 104}
 105
 106static struct pwm_ops bfin_pwm_ops = {
 107        .request = bfin_pwm_request,
 108        .free = bfin_pwm_free,
 109        .config = bfin_pwm_config,
 110        .enable = bfin_pwm_enable,
 111        .disable = bfin_pwm_disable,
 112        .owner = THIS_MODULE,
 113};
 114
 115static int bfin_pwm_probe(struct platform_device *pdev)
 116{
 117        struct bfin_pwm_chip *pwm;
 118        int ret;
 119
 120        pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
 121        if (!pwm) {
 122                dev_err(&pdev->dev, "failed to allocate memory\n");
 123                return -ENOMEM;
 124        }
 125
 126        platform_set_drvdata(pdev, pwm);
 127
 128        pwm->chip.dev = &pdev->dev;
 129        pwm->chip.ops = &bfin_pwm_ops;
 130        pwm->chip.base = -1;
 131        pwm->chip.npwm = 12;
 132
 133        ret = pwmchip_add(&pwm->chip);
 134        if (ret < 0) {
 135                dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
 136                return ret;
 137        }
 138
 139        return 0;
 140}
 141
 142static int bfin_pwm_remove(struct platform_device *pdev)
 143{
 144        struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);
 145
 146        return pwmchip_remove(&pwm->chip);
 147}
 148
 149static struct platform_driver bfin_pwm_driver = {
 150        .driver = {
 151                .name = "bfin-pwm",
 152        },
 153        .probe = bfin_pwm_probe,
 154        .remove = bfin_pwm_remove,
 155};
 156
 157module_platform_driver(bfin_pwm_driver);
 158
 159MODULE_LICENSE("GPL");
 160
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