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Message-id: <1415025775-24237-1-git-send-email-k.debski@samsung.com>
Date: Mon, 03 Nov 2014 15:42:55 +0100
From: Kamil Debski <k.debski@...sung.com>
To: linux-kernel@...r.kernel.org, lm-sensors@...sensors.org
Cc: linux@...ck-us.net, Kamil Debski <k.debski@...sung.com>
Subject: [PATCH] hwmon: (pwm-fan) Fix suspend/resume behavior
The state of a PWM output is not clearly defined after resume. Some PWM
drivers do not restore the duty cycle upon resume, thus it is necessary to
manually restore the correct value.
Signed-off-by: Kamil Debski <k.debski@...sung.com>
---
drivers/hwmon/pwm-fan.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 823c877..1991d903 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -161,10 +161,17 @@ static int pwm_fan_suspend(struct device *dev)
static int pwm_fan_resume(struct device *dev)
{
struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+ unsigned long duty;
+ int ret;
- if (ctx->pwm_value)
- return pwm_enable(ctx->pwm);
- return 0;
+ if (ctx->pwm_value == 0)
+ return 0;
+
+ duty = DIV_ROUND_UP(ctx->pwm_value * (ctx->pwm->period - 1), MAX_PWM);
+ ret = pwm_config(ctx->pwm, duty, ctx->pwm->period);
+ if (ret)
+ return ret;
+ return pwm_enable(ctx->pwm);
}
#endif
--
1.7.9.5
--
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