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* [PATCH] hwmon: (emc2103) fix unable to change fan pwm1_enable attribute
@ 2020-07-07 14:27 Vishwas M
  2020-07-07 14:56 ` Guenter Roeck
  0 siblings, 1 reply; 2+ messages in thread
From: Vishwas M @ 2020-07-07 14:27 UTC (permalink / raw)
  Cc: Steve Glendinning, Vishwas M, Jean Delvare, Guenter Roeck,
	linux-hwmon, linux-kernel

This patch fixes a bug which does not let FAN mode to be changed from
sysfs(pwm1_enable). i.e pwm1_enable can not be set to 3, it will always
remain at 0.

This is caused because the device driver handles the result of
"read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg)" incorrectly. The
driver thinks an error has occurred if the (result != 0). This has been
fixed by changing the condition to (result < 0).

Signed-off-by: Vishwas M <vishwas.reddy.vr@gmail.com>
---
 drivers/hwmon/emc2103.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/emc2103.c b/drivers/hwmon/emc2103.c
index 491a570e8e50..924c02c1631d 100644
--- a/drivers/hwmon/emc2103.c
+++ b/drivers/hwmon/emc2103.c
@@ -443,7 +443,7 @@ static ssize_t pwm1_enable_store(struct device *dev,
 	}
 
 	result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
-	if (result) {
+	if (result < 0) {
 		count = result;
 		goto err;
 	}
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] hwmon: (emc2103) fix unable to change fan pwm1_enable attribute
  2020-07-07 14:27 [PATCH] hwmon: (emc2103) fix unable to change fan pwm1_enable attribute Vishwas M
@ 2020-07-07 14:56 ` Guenter Roeck
  0 siblings, 0 replies; 2+ messages in thread
From: Guenter Roeck @ 2020-07-07 14:56 UTC (permalink / raw)
  To: Vishwas M; +Cc: Steve Glendinning, Jean Delvare, linux-hwmon, linux-kernel

On 7/7/20 7:27 AM, Vishwas M wrote:
> This patch fixes a bug which does not let FAN mode to be changed from
> sysfs(pwm1_enable). i.e pwm1_enable can not be set to 3, it will always
> remain at 0.
> 
> This is caused because the device driver handles the result of
> "read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg)" incorrectly. The
> driver thinks an error has occurred if the (result != 0). This has been
> fixed by changing the condition to (result < 0).
> 
> Signed-off-by: Vishwas M <vishwas.reddy.vr@gmail.com>
> ---
>  drivers/hwmon/emc2103.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/emc2103.c b/drivers/hwmon/emc2103.c
> index 491a570e8e50..924c02c1631d 100644
> --- a/drivers/hwmon/emc2103.c
> +++ b/drivers/hwmon/emc2103.c
> @@ -443,7 +443,7 @@ static ssize_t pwm1_enable_store(struct device *dev,
>  	}
>  
>  	result = read_u8_from_i2c(client, REG_FAN_CONF1, &conf_reg);
> -	if (result) {
> +	if (result < 0) {
>  		count = result;
>  		goto err;
>  	}
> 

The underlying problem is really that read_u8_from_i2c()
returns the value twice - once as return code, and once
written into the passed pointer. This unnecessarily complex
and messy. But, still, valid bug and fix. Applied.

Thanks,
Guenter

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2020-07-07 14:27 [PATCH] hwmon: (emc2103) fix unable to change fan pwm1_enable attribute Vishwas M
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