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pwm: atmel: Implement .get_state()

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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: Uwe Kleine-König <uwe@kleine-koenig.org>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Uwe Kleine-König 2019-08-24 02:10:41 +02:00 committed by Thierry Reding
parent 02afb811e0
commit 651b510a74
1 changed files with 40 additions and 0 deletions
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40
drivers/pwm/pwm-atmel.c
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@ -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,
};