In order to disable the PWM we need to update using following sequence.
pwm_config(pwm, 0, period);
pwm_disable(pwm);
pwm_config() with a zero duty cycle to make it clear the timer and update the PWM registers.
pwm_disable will clear the TCON_AUTORELOAD(tcon_chan) and update the PWM register.
Next change in state will get trigger unless a new PWM cycle happened.
pwm_config(pwm, duty, period);
pwm_enable(pwm);
Through pwm_config we update the duty cycle and period and update the PWM register.
pwm_enable will update the state to TCON_MANUALUPDATE(tcon_chan)
and TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan) and update the PWM register.
Reported-by: Markus Reichl <m.reichl@xxxxxxxxxxxxx>
Tested-by: Markus Reichl <m.reichl@xxxxxxxxxxxxx>
Reviewed-by: Lukasz Majewski <l.majewski@xxxxxxxxxxx>
Reviewed-by: Sjoerd Simons <sjoerd.simons@xxxxxxxxxxxxxxx>
Signed-off-by: Anand Moon <linux.amoon@xxxxxxxxx>
---
drivers/hwmon/pwm-fan.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 7c83dc4..f25c841 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -44,26 +44,24 @@ static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
int ret = 0;
mutex_lock(&ctx->lock);
+
if (ctx->pwm_value == pwm)
goto exit_set_pwm_err;
- if (pwm == 0) {
- pwm_disable(ctx->pwm);
- goto exit_set_pwm;
- }
-
duty = DIV_ROUND_UP(pwm * (ctx->pwm->period - 1), MAX_PWM);
ret = pwm_config(ctx->pwm, duty, ctx->pwm->period);
if (ret)
goto exit_set_pwm_err;
+ if (pwm == 0)
+ pwm_disable(ctx->pwm);
+
if (ctx->pwm_value == 0) {
ret = pwm_enable(ctx->pwm);
if (ret)
goto exit_set_pwm_err;
}
-exit_set_pwm:
ctx->pwm_value = pwm;
exit_set_pwm_err:
mutex_unlock(&ctx->lock);
--
1.9.1
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