drivers/pwm/pwm-bfin.c

   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
  17 struct bfin_pwm_chip {
  18         struct pwm_chip chip;
  19 };
  20
  21 struct bfin_pwm {
  22         unsigned short pin;
  23 };
  24
  25 static 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
  30 static 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
  55 static 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
  65 static 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
  90 static 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
  99 static 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
 106 static 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
 115 static 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
 142 static 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
 149 static struct platform_driver bfin_pwm_driver = {
 150         .driver = {
 151                 .name = "bfin-pwm",
 152                 .owner = THIS_MODULE,
 153         },
 154         .probe = bfin_pwm_probe,
 155         .remove = bfin_pwm_remove,
 156 };
 157
 158 module_platform_driver(bfin_pwm_driver);
 159
 160 MODULE_LICENSE("GPL");