Commit 7f68ce82 authored by Yoshihiro Shimoda's avatar Yoshihiro Shimoda Committed by Thierry Reding
Browse files

pwm: rcar: Add support "atomic" API 



This patch adds support for "atomic" API. This behavior differs with
legacy APIs a little.

 Legacy APIs:
  The PWMCNT register will be updated in rcar_pwm_config() even if
  the PWM state is disabled.

 Atomic API:
  The PWMCNT register will be updated in rcar_pwm_apply() only if
  the PWM state is enabled. Otherwize, if a PWM runs with 30% duty
  cycles and the pwm_apply_state() is called with state->enabled = 0,
  ->duty_cycle = 60 and ->period = 100, this is possible to output
  a 60% duty cycle.

Signed-off-by: default avatarYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 74d0c3b2

drivers/pwm/pwm-rcar.c

+37 −0
Original line number Diff line number Diff line
@@ -192,12 +192,49 @@ static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 
	rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);

}



static int rcar_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,

			  struct pwm_state *state)

{

	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);

	struct pwm_state cur_state;

	int div, ret;



	/* This HW/driver only supports normal polarity */

	pwm_get_state(pwm, &cur_state);

	if (state->polarity != PWM_POLARITY_NORMAL)

		return -ENOTSUPP;



	if (!state->enabled) {

		rcar_pwm_disable(chip, pwm);

		return 0;

	}



	div = rcar_pwm_get_clock_division(rp, state->period);

	if (div < 0)

		return div;



	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);



	ret = rcar_pwm_set_counter(rp, div, state->duty_cycle, state->period);

	if (!ret)

		rcar_pwm_set_clock_control(rp, div);



	/* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */

	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);



	if (!ret && state->enabled)

		ret = rcar_pwm_enable(chip, pwm);



	return ret;

}



static const struct pwm_ops rcar_pwm_ops = {

	.request = rcar_pwm_request,

	.free = rcar_pwm_free,

	.config = rcar_pwm_config,

	.enable = rcar_pwm_enable,

	.disable = rcar_pwm_disable,

	.apply = rcar_pwm_apply,

	.owner = THIS_MODULE,

};