Commit 651b510a authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Thierry Reding
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pwm: atmel: Implement .get_state() 



This function reads back the configured parameters from the hardware. As
.apply() rounds down (mostly) I'm rounding up in .get_state() to achieve
that applying a state just read from hardware is a no-op.

Signed-off-by: default avatarUwe Kleine-König <uwe@kleine-koenig.org>
Acked-by: default avatarClaudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 02afb811

drivers/pwm/pwm-atmel.c

+40 −0
Original line number Diff line number Diff line
@@ -295,8 +295,48 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 
	return 0;

}



static void atmel_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,

				struct pwm_state *state)

{

	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);

	u32 sr, cmr;



	sr = atmel_pwm_readl(atmel_pwm, PWM_SR);

	cmr = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);



	if (sr & (1 << pwm->hwpwm)) {

		unsigned long rate = clk_get_rate(atmel_pwm->clk);

		u32 cdty, cprd, pres;

		u64 tmp;



		pres = cmr & PWM_CMR_CPRE_MSK;



		cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,

					  atmel_pwm->data->regs.period);

		tmp = (u64)cprd * NSEC_PER_SEC;

		tmp <<= pres;

		state->period = DIV64_U64_ROUND_UP(tmp, rate);



		cdty = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,

					  atmel_pwm->data->regs.duty);

		tmp = (u64)cdty * NSEC_PER_SEC;

		tmp <<= pres;

		state->duty_cycle = DIV64_U64_ROUND_UP(tmp, rate);



		state->enabled = true;

	} else {

		state->enabled = false;

	}



	if (cmr & PWM_CMR_CPOL)

		state->polarity = PWM_POLARITY_INVERSED;

	else

		state->polarity = PWM_POLARITY_NORMAL;

}



static const struct pwm_ops atmel_pwm_ops = {

	.apply = atmel_pwm_apply,

	.get_state = atmel_pwm_get_state,

	.owner = THIS_MODULE,

};