[PATCH] pwm: meson: compute cnt register value in proper way

[George Stark]

According to the datasheet, the PWM high and low clock count values
should be set to at least one. Therefore, setting the clock count
register to 0 actually means 1 clock count.

Signed-off-by: George Stark <GNStark at sberdevices.ru>
Signed-off-by: Dmitry Rokosov <ddrokosov at sberdevices.ru>
---
This patch is based on currently unmerged patch by Heiner Kallweit
https://lore.kernel.org/linux-amlogic/23fe625e-dc23-4db8-3dce-83167cd3b206@gmail.com
---
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
index 834acd7..57e7d9c 100644
--- a/drivers/pwm/pwm-meson.c
+++ b/drivers/pwm/pwm-meson.c
@@ -206,6 +206,11 @@
 		channel->pre_div = pre_div;
 		channel->hi = duty_cnt;
 		channel->lo = cnt - duty_cnt;
+
+		if (channel->hi)
+			channel->hi--;
+		if (channel->lo)
+			channel->lo--;
 	}
 
 	return 0;
@@ -340,7 +345,8 @@
 	channel->lo = FIELD_GET(PWM_LOW_MASK, value);
 	channel->hi = FIELD_GET(PWM_HIGH_MASK, value);
 
-	state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->lo + channel->hi);
+	state->period = meson_pwm_cnt_to_ns(chip, pwm,
+					    channel->lo + 1 + channel->hi + 1);
 	state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, channel->hi);
 
 	return 0;