Eric Lee / smarc-fsl-linux-kernel

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arch/blackfin/kernel/pwm.c 1.86 KB
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006669ec2   Mike Frysinger   Blackfin: pwm: im... 
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  /*
   * 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/pwm.h>
  #include <linux/slab.h>
  
  #include <asm/gptimers.h>
  #include <asm/portmux.h>
  
  struct pwm_device {
  	unsigned id;
  	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,
  };
  
  struct pwm_device *pwm_request(int pwm_id, const char *label)
  {
  	struct pwm_device *pwm;
  	int ret;
  
  	/* XXX: pwm_id really should be unsigned */
  	if (pwm_id < 0)
  		return NULL;
  
  	pwm = kzalloc(sizeof(*pwm), GFP_KERNEL);
  	if (!pwm)
  		return pwm;
  
  	pwm->id = pwm_id;
  	if (pwm->id >= ARRAY_SIZE(pwm_to_gptimer_per))
  		goto err;
  
  	pwm->pin = pwm_to_gptimer_per[pwm->id];
  	ret = peripheral_request(pwm->pin, label);
  	if (ret)
  		goto err;
  
  	return pwm;
   err:
  	kfree(pwm);
  	return NULL;
  }
  EXPORT_SYMBOL(pwm_request);
  
  void pwm_free(struct pwm_device *pwm)
  {
  	peripheral_free(pwm->pin);
  	kfree(pwm);
  }
  EXPORT_SYMBOL(pwm_free);
  
  int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
  {
  	unsigned long period, duty;
  	unsigned long long val;
  
  	if (duty_ns < 0 || duty_ns > period_ns)
  		return -EINVAL;
  
  	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(pwm->id, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
  	set_gptimer_pwidth(pwm->id, duty);
  	set_gptimer_period(pwm->id, period);
  
  	return 0;
  }
  EXPORT_SYMBOL(pwm_config);
  
  int pwm_enable(struct pwm_device *pwm)
  {
  	enable_gptimer(pwm->id);
  	return 0;
  }
  EXPORT_SYMBOL(pwm_enable);
  
  void pwm_disable(struct pwm_device *pwm)
  {
  	disable_gptimer(pwm->id);
  }
  EXPORT_SYMBOL(pwm_disable);