pwm: atmel: Fix incorrect CDTY value after enabling

CUPD is not flushed before enabling the channel so it will update
CDTY/CPRD just after one period. So we always set CUPD, even when the
channel is not enabled.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 18 insertions, 17 deletions

diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index d3c22de9ee47..89f9ca41d9af 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -155,24 +155,25 @@ static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm,
         struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
         unsigned int val;
 
-        if (test_bit(PWMF_ENABLED, &pwm->flags)) {
-                /*
-                 * If the PWM channel is enabled, using the update register,
-                 * it needs to set bit 10 of CMR to 0
-                 */
-                atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty);
 
-                val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
-                val &= ~PWM_CMR_UPD_CDTY;
-                atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
-        } else {
-                /*
-                 * If the PWM channel is disabled, write value to duty and
-                 * period registers directly.
-                 */
-                atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty);
-                atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd);
-        }
+        atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty);
+
+        val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
+        val &= ~PWM_CMR_UPD_CDTY;
+        atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
+
+        /*
+         * If the PWM channel is enabled, only update CDTY by using the update
+         * register, it needs to set bit 10 of CMR to 0
+         */
+        if (test_bit(PWMF_ENABLED, &pwm->flags))
+                return;
+        /*
+         * If the PWM channel is disabled, write value to duty and period
+         * registers directly.
+         */
+        atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty);
+        atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd);
 }
 
 static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm,