linux-kernel - [PATCH v3 10/14] regulator: pwm: Switch to the atomic PWM API

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Message-Id: <1465895602-31008-11-git-send-email-boris.brezillon@free-electrons.com>
Date:	Tue, 14 Jun 2016 11:13:18 +0200
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Thierry Reding <thierry.reding@...il.com>,
	linux-pwm@...r.kernel.org, Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>
Cc:	Heiko Stuebner <heiko@...ech.de>,
	linux-rockchip@...ts.infradead.org,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Milo Kim <milo.kim@...com>,
	Doug Anderson <dianders@...gle.com>,
	Caesar Wang <wxt@...k-chips.com>,
	Stephen Barber <smbarber@...omium.org>,
	Brian Norris <briannorris@...omium.org>,
	Ajit Pal Singh <ajitpal.singh@...com>,
	Srinivas Kandagatla <srinivas.kandagatla@...il.com>,
	Maxime Coquelin <maxime.coquelin@...com>,
	Patrice Chotard <patrice.chotard@...com>, kernel@...inux.com,
	Laxman Dewangan <ldewangan@...dia.com>,
	Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH v3 10/14] regulator: pwm: Switch to the atomic PWM API

Use the atomic API wherever appropriate and get rid of pwm_apply_args()
call (the reference period and polarity are now explicitly set when
calling pwm_apply_state()).

We also make use of the pwm_set_relative_duty_cycle() helper to ease
relative to absolute duty_cycle conversion.

Note that changes introduced by commit fd786fb0276a ("regulator: pwm:
Try to avoid voltage error in duty cycle calculation") are no longer
needed because pwm_set_relative_duty_cycle() takes care of all rounding
approximation for us.

Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Reviewed-by: Brian Norris <briannorris@...omium.org>
Tested-by: Brian Norris <briannorris@...omium.org>
Acked-by: Laxman Dewangan <ldewangan@...dia.com>
Tested-by: Heiko Stuebner <heiko@...ech.de>
---
 drivers/regulator/pwm-regulator.c | 38 ++++++++++----------------------------
 1 file changed, 10 insertions(+), 28 deletions(-)

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 524b43f..ad75360 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -59,16 +59,14 @@ static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
 					 unsigned selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
-	struct pwm_args pargs;
-	int dutycycle;
+	struct pwm_state pstate;
 	int ret;
 
-	pwm_get_args(drvdata->pwm, &pargs);
+	pwm_init_state(drvdata->pwm, &pstate);
+	pwm_set_relative_duty_cycle(&pstate,
+			drvdata->duty_cycle_table[selector].dutycycle, 100);
 
-	dutycycle = (pargs.period *
-		    drvdata->duty_cycle_table[selector].dutycycle) / 100;
-
-	ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
+	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
@@ -126,34 +124,18 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	unsigned int ramp_delay = rdev->constraints->ramp_delay;
-	struct pwm_args pargs;
 	unsigned int req_diff = min_uV - rdev->constraints->min_uV;
+	struct pwm_state pstate;
 	unsigned int diff;
-	unsigned int duty_pulse;
-	u64 req_period;
-	u32 rem;
 	int ret;
 
-	pwm_get_args(drvdata->pwm, &pargs);
+	pwm_init_state(drvdata->pwm, &pstate);
 	diff = rdev->constraints->max_uV - rdev->constraints->min_uV;
 
-	/* First try to find out if we get the iduty cycle time which is
-	 * factor of PWM period time. If (request_diff_to_min * pwm_period)
-	 * is perfect divided by voltage_range_diff then it is possible to
-	 * get duty cycle time which is factor of PWM period. This will help
-	 * to get output voltage nearer to requested value as there is no
-	 * calculation loss.
-	 */
-	req_period = req_diff * pargs.period;
-	div_u64_rem(req_period, diff, &rem);
-	if (!rem) {
-		do_div(req_period, diff);
-		duty_pulse = (unsigned int)req_period;
-	} else {
-		duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
-	}
+	/* We pass diff as the scale to get a uV precision. */
+	pwm_set_relative_duty_cycle(&pstate, req_diff, diff);
 
-	ret = pwm_config(drvdata->pwm, duty_pulse, pargs.period);
+	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
-- 
2.7.4