linux-kernel - [PATCH] hwmon: (pwm-fan) Explicitly switch off fan power when setting pwm1

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Date:   Thu, 13 Oct 2022 15:59:51 +0200
From:   Matthias Schiffer <matthias.schiffer@...tq-group.com>
To:     Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>
Cc:     Alexander Stein <alexander.stein@...tq-group.com>,
        linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org,
        Matthias Schiffer <matthias.schiffer@...tq-group.com>
Subject: [PATCH] hwmon: (pwm-fan) Explicitly switch off fan power when setting pwm1_enable to 0

When pwm1_enable is changed from 1 to 0 while pwm1 == 0, the regulator
is not switched off as expected. The reason is that when the fan is
already off, ctx->enabled is false, so pwm_fan_power_off() will be a
no-op.

Handle this case explicitly in pwm_fan_update_enable() by calling
pwm_fan_switch_power() directly.

Fixes: b99152d4f04b ("hwmon: (pwm-fan) Switch regulator dynamically")
Signed-off-by: Matthias Schiffer <matthias.schiffer@...tq-group.com>
---
 drivers/hwmon/pwm-fan.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index dc3d9a22d917..83a347ca35da 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -257,7 +257,10 @@ static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val)
 
 	if (val == 0) {
 		/* Disable pwm-fan unconditionally */
-		ret = __set_pwm(ctx, 0);
+		if (ctx->enabled)
+			ret = __set_pwm(ctx, 0);
+		else
+			ret = pwm_fan_switch_power(ctx, false);
 		if (ret)
 			ctx->enable_mode = old_val;
 		pwm_fan_update_state(ctx, 0);
-- 
2.25.1