/*
   * Blackfin Pulse Width Modulation (PWM) core
   *
   * Copyright (c) 2011 Analog Devices Inc.
   *
   * Licensed under the GPL-2 or later.
   */
  
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/pwm.h>
  #include <linux/slab.h>
  
  #include <asm/gptimers.h>
  #include <asm/portmux.h>
  
  struct bfin_pwm_chip {
  	struct pwm_chip chip;
  };
  
  struct bfin_pwm {
  	unsigned short pin;
  };
  
  static const unsigned short pwm_to_gptimer_per[] = {
  	P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
  	P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
  };
  
  static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
  {
  	struct bfin_pwm *priv;
  	int ret;
  
  	if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per))
  		return -EINVAL;
  
  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	priv->pin = pwm_to_gptimer_per[pwm->hwpwm];
  
  	ret = peripheral_request(priv->pin, NULL);
  	if (ret) {
  		kfree(priv);
  		return ret;
  	}
  
  	pwm_set_chip_data(pwm, priv);
  
  	return 0;
  }
  
  static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
  {
  	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  
  	if (priv) {
  		peripheral_free(priv->pin);
  		kfree(priv);
  	}
  }
  
  static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
  		int duty_ns, int period_ns)
  {
  	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  	unsigned long period, duty;
  	unsigned long long val;

  	val = (unsigned long long)get_sclk() * period_ns;
  	do_div(val, NSEC_PER_SEC);
  	period = val;
  
  	val = (unsigned long long)period * duty_ns;
  	do_div(val, period_ns);
  	duty = period - val;
  
  	if (duty >= period)
  		duty = period - 1;
  
  	set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
  	set_gptimer_pwidth(priv->pin, duty);
  	set_gptimer_period(priv->pin, period);
  
  	return 0;
  }
  
  static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
  {
  	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  
  	enable_gptimer(priv->pin);
  
  	return 0;
  }
  
  static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
  {
  	struct bfin_pwm *priv = pwm_get_chip_data(pwm);
  
  	disable_gptimer(priv->pin);
  }
  
  static struct pwm_ops bfin_pwm_ops = {
  	.request = bfin_pwm_request,
  	.free = bfin_pwm_free,
  	.config = bfin_pwm_config,
  	.enable = bfin_pwm_enable,
  	.disable = bfin_pwm_disable,
  	.owner = THIS_MODULE,
  };
  
  static int bfin_pwm_probe(struct platform_device *pdev)
  {
  	struct bfin_pwm_chip *pwm;
  	int ret;
  
  	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
  	if (!pwm) {
  		dev_err(&pdev->dev, "failed to allocate memory
  ");
  		return -ENOMEM;
  	}
  
  	platform_set_drvdata(pdev, pwm);
  
  	pwm->chip.dev = &pdev->dev;
  	pwm->chip.ops = &bfin_pwm_ops;
  	pwm->chip.base = -1;
  	pwm->chip.npwm = 12;
  
  	ret = pwmchip_add(&pwm->chip);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "pwmchip_add() failed: %d
  ", ret);
  		return ret;
  	}
  
  	return 0;
  }

  static int bfin_pwm_remove(struct platform_device *pdev)

  {
  	struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);

  	return pwmchip_remove(&pwm->chip);

  }
  
  static struct platform_driver bfin_pwm_driver = {
  	.driver = {
  		.name = "bfin-pwm",
  	},
  	.probe = bfin_pwm_probe,

  	.remove = bfin_pwm_remove,

  };
  
  module_platform_driver(bfin_pwm_driver);
  
  MODULE_LICENSE("GPL");