From: "Uwe Kleine-König" <uwe@kleine-koenig.org>
To: Claudiu Beznea <claudiu.beznea@microchip.com>,
Thierry Reding <thierry.reding@gmail.com>
Cc: linux-pwm@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Ludovic Desroches <ludovic.desroches@microchip.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 6/6] pwm: atmel: implement .get_state()
Date: Sat, 24 Aug 2019 02:10:41 +0200 [thread overview]
Message-ID: <20190824001041.11007-7-uwe@kleine-koenig.org> (raw)
In-Reply-To: <20190824001041.11007-1-uwe@kleine-koenig.org>
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>
---
New in v2
drivers/pwm/pwm-atmel.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index 152c2b7dd6df..f788501ab6ca 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -295,8 +295,47 @@ 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,
};
--
2.20.1
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next prev parent reply other threads:[~2019-08-24 0:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-24 0:10 [PATCH v2 0/6] Updates for the atmel PWM driver Uwe Kleine-König
2019-08-24 0:10 ` [PATCH v2 1/6] pwm: atmel: Add a hint where to find hardware documentation Uwe Kleine-König
2019-08-26 8:19 ` Nicolas.Ferre
2019-08-24 0:10 ` [PATCH v2 2/6] pwm: atmel: use a constant for maximum prescale value Uwe Kleine-König
2019-08-24 0:10 ` [PATCH v2 3/6] pwm: atmel: replace loop in prescale calculation by ad-hoc calculation Uwe Kleine-König
2019-08-24 0:10 ` [PATCH v2 4/6] pwm: atmel: document known weaknesses of both hardware and software Uwe Kleine-König
2019-08-24 0:10 ` [PATCH v2 5/6] pwm: atmel: use atmel_pwm_writel in atmel_pwm_ch_writel; ditto for readl Uwe Kleine-König
2019-08-24 0:10 ` Uwe Kleine-König [this message]
2019-08-28 10:26 ` [PATCH v2 6/6] pwm: atmel: implement .get_state() Claudiu.Beznea
2019-09-02 20:06 ` Uwe Kleine-König
2019-10-24 7:30 ` [PATCH v2 0/6] Updates for the atmel PWM driver Uwe Kleine-König
2020-01-08 13:00 ` Thierry Reding
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