[PATCH 3/4] pwm: mxs: add support for inverse polarity
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: 2019-09-23 08:14:01
Also in:
linux-devicetree, linux-pwm, lkml
Subsystem:
pwm subsystem, the rest · Maintainers:
Uwe Kleine-König, Linus Torvalds
If I'm reading of_pwm_xlate_with_flags() right, existing device trees that set #pwm-cells = 2 will continue to work. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- drivers/pwm/pwm-mxs.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c
index 284107784dad..c46697acaf11 100644
--- a/drivers/pwm/pwm-mxs.c
+++ b/drivers/pwm/pwm-mxs.c@@ -25,8 +25,11 @@ #define PERIOD_PERIOD(p) ((p) & 0xffff) #define PERIOD_PERIOD_MAX 0x10000 #define PERIOD_ACTIVE_HIGH (3 << 16) +#define PERIOD_ACTIVE_LOW (2 << 16) +#define PERIOD_INACTIVE_HIGH (3 << 18) #define PERIOD_INACTIVE_LOW (2 << 18) #define PERIOD_POLARITY_NORMAL (PERIOD_ACTIVE_HIGH | PERIOD_INACTIVE_LOW) +#define PERIOD_POLARITY_INVERSE (PERIOD_ACTIVE_LOW | PERIOD_INACTIVE_HIGH) #define PERIOD_CDIV(div) (((div) & 0x7) << 20) #define PERIOD_CDIV_MAX 8
@@ -50,9 +53,7 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, unsigned int period_cycles, duty_cycles; unsigned long rate; unsigned long long c; - - if (state->polarity != PWM_POLARITY_NORMAL) - return -ENOTSUPP; + unsigned int pol_bits; rate = clk_get_rate(mxs->clk); while (1) {
@@ -81,9 +82,12 @@ static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, return ret; } + pol_bits = state->polarity == PWM_POLARITY_NORMAL ? + PERIOD_POLARITY_NORMAL : PERIOD_POLARITY_INVERSE; + writel(duty_cycles << 16, mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); - writel(PERIOD_PERIOD(period_cycles) | PERIOD_POLARITY_NORMAL | PERIOD_CDIV(div), + writel(PERIOD_PERIOD(period_cycles) | pol_bits | PERIOD_CDIV(div), mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); if (state->enabled) {
@@ -129,6 +133,8 @@ static int mxs_pwm_probe(struct platform_device *pdev) mxs->chip.dev = &pdev->dev; mxs->chip.ops = &mxs_pwm_ops; + mxs->chip.of_xlate = of_pwm_xlate_with_flags; + mxs->chip.of_pwm_n_cells = 3; mxs->chip.base = -1; ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
--
2.20.1
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