pwm: pwm-tiecap: Add support for configuring polarity of PWM

ECAP APWM hardware supports polarity configuration of PWM output.
This commit adds support for polarity configuration of ECAP APWM.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/pwm/pwm-tiecap.c b/drivers/pwm/pwm-tiecap.c
index 4b6688909fee..081471fbb097 100644
--- a/drivers/pwm/pwm-tiecap.c
+++ b/drivers/pwm/pwm-tiecap.c
@@ -32,6 +32,7 @@
 #define CAP3                    0x10
 #define CAP4                    0x14
 #define ECCTL2                  0x2A
+#define ECCTL2_APWM_POL_LOW     BIT(10)
 #define ECCTL2_APWM_MODE        BIT(9)
 #define ECCTL2_SYNC_SEL_DISA    (BIT(7) | BIT(6))
 #define ECCTL2_TSCTR_FREERUN    BIT(4)
@@ -111,6 +112,26 @@ static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
         return 0;
 }
 
+static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+                enum pwm_polarity polarity)
+{
+        struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
+        unsigned short reg_val;
+
+        pm_runtime_get_sync(pc->chip.dev);
+        reg_val = readw(pc->mmio_base + ECCTL2);
+        if (polarity == PWM_POLARITY_INVERSED)
+                /* Duty cycle defines LOW period of PWM */
+                reg_val |= ECCTL2_APWM_POL_LOW;
+        else
+                /* Duty cycle defines HIGH period of PWM */
+                reg_val &= ~ECCTL2_APWM_POL_LOW;
+
+        writew(reg_val, pc->mmio_base + ECCTL2);
+        pm_runtime_put_sync(pc->chip.dev);
+        return 0;
+}
+
 static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
         struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
@@ -157,6 +178,7 @@ static void ecap_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 static const struct pwm_ops ecap_pwm_ops = {
         .free           = ecap_pwm_free,
         .config         = ecap_pwm_config,
+        .set_polarity   = ecap_pwm_set_polarity,
         .enable         = ecap_pwm_enable,
         .disable        = ecap_pwm_disable,
         .owner          = THIS_MODULE,