From 48b9d5b4f408259cd6800c4b17d4fe5025435da2 Mon Sep 17 00:00:00 2001
From: Kamil Debski <k.debski@samsung.com>
Date: Mon, 3 Nov 2014 15:42:55 +0100
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@samsung.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
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 823c877a1ec09..1991d9032c384 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
--
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