Re: [RCF PATCH,v2,2/2] pwm: imx: Configure output to GPIO in disabled state

Uwe Kleine-König
2018-11-07T09:34:08Z

Hello Michal,

just to state it more explicitly, I think the following patch (not even
compile tested) is much preferable over your approach:

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 1d5242c9cde0..af88644b5efb 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -216,7 +216,14 @@ static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
cr |= MX3_PWMCR_POUTC;

writel(cr, imx->mmio_base + MX3_PWMCR);
- } else if (cstate.enabled) {
+ } else if (cstate.enabled && state->polarity == PWM_POLARITY_NORMAL) {
+ /*
+ * When disabled in hardware the output pin goes to 0
+ * independant of the polarity setting. The expectation of some
+ * people however is that after disabling the pin goes to the
+ * inactive level which isn't given for an inversed pwm, so
+ * only disable for normal polarity.
+ */
writel(0, imx->mmio_base + MX3_PWMCR);

clk_disable_unprepare(imx->clk_per);

I think it solves most if not all problems you want to address with the
pinctrl stuff.

Best regards
Uwe

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