diff mbox

[v5,27/46] regulator: pwm: adjust PWM config at probe time

Message ID 1459368249-13241-28-git-send-email-boris.brezillon@free-electrons.com (mailing list archive)
State New, archived
Headers show

Commit Message

Boris BREZILLON March 30, 2016, 8:03 p.m. UTC
The PWM attached to a PWM regulator device might have been previously
configured by the bootloader.
Make sure the bootloader and linux config are in sync, and adjust the PWM
config if that's not the case.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
 drivers/regulator/pwm-regulator.c | 50 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

Comments

Mark Brown March 30, 2016, 9:22 p.m. UTC | #1
On Wed, Mar 30, 2016 at 10:03:50PM +0200, Boris Brezillon wrote:
> The PWM attached to a PWM regulator device might have been previously
> configured by the bootloader.
> Make sure the bootloader and linux config are in sync, and adjust the PWM
> config if that's not the case.

Acked-by: Mark Brown <broonie@kernel.org>
diff mbox

Patch

diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 9154c47..9590fb0 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -240,6 +240,52 @@  static int pwm_regulator_init_continuous(struct platform_device *pdev,
 	return 0;
 }
 
+static int pwm_regulator_adjust_pwm_config(struct pwm_regulator_data *drvdata)
+{
+	struct pwm_state pstate = { };
+	struct pwm_args pargs = { };
+
+	pwm_get_args(drvdata->pwm, &pargs);
+	pwm_get_state(drvdata->pwm, &pstate);
+
+	/*
+	 * if the current period is zero this either means the PWM driver
+	 * does not support initial state retrieval or the PWM was not
+	 * configured.
+	 * In any case, we setup the new period and poloarity, and assign a
+	 * duty_cycle of 0.
+	 */
+	if (!pstate.period) {
+		pstate.duty_cycle = 0;
+		pstate.period = pargs.period;
+		pstate.polarity = pargs.polarity;
+
+		return pwm_apply_state(drvdata->pwm, &pstate);
+	}
+
+	/*
+	 * Adjust the PWM dutycycle/period based on the period value provided
+	 * in PWM args.
+	 */
+	if (pargs.period != pstate.period) {
+		u64 dutycycle = (u64)pstate.duty_cycle * pargs.period;
+
+		do_div(dutycycle, pstate.period);
+		pstate.duty_cycle = dutycycle;
+		pstate.period = pargs.period;
+	}
+
+	/*
+	 * If the polarity changed, we should also change the dutycycle value.
+	 */
+	if (pargs.polarity != pstate.polarity) {
+		pstate.polarity = pargs.polarity;
+		pstate.duty_cycle = pstate.period - pstate.duty_cycle;
+	}
+
+	return pwm_apply_state(drvdata->pwm, &pstate);
+}
+
 static int pwm_regulator_probe(struct platform_device *pdev)
 {
 	const struct regulator_init_data *init_data;
@@ -283,6 +329,10 @@  static int pwm_regulator_probe(struct platform_device *pdev)
 		return PTR_ERR(drvdata->pwm);
 	}
 
+	ret = pwm_regulator_adjust_pwm_config(drvdata);
+	if (ret)
+		return ret;
+
 	regulator = devm_regulator_register(&pdev->dev,
 					    &drvdata->desc, &config);
 	if (IS_ERR(regulator)) {