Re: [PATCH 4/6] hwmon: (lm95234) Convert to with_info hwmon API

[Guenter Roeck <linux@roeck-us.net>]

On 7/18/24 09:40, Tzung-Bi Shih wrote:
> On Wed, Jul 17, 2024 at 08:39:33PM -0700, Guenter Roeck wrote:
>> +static int lm95234_temp_write(struct device *dev, u32 attr, int channel, long val)
>>   {
> [...]
>> +	case hwmon_temp_max:
>> +		val = clamp_val(val, 0, channel ? 255000 : 127000);
> 
> Perhaps I am misunderstanding, but this looks weird to me.  By applying
> the patch, the maximum values are:
> 
> static SENSOR_DEVICE_ATTR_RW(temp1_max, tcrit1, 0); -> 127000
> static SENSOR_DEVICE_ATTR_RW(temp2_max, tcrit2, 0); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp3_max, tcrit2, 1); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp4_max, tcrit1, 3); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp5_max, tcrit1, 4); -> 255000
> 
> 
> However, it was originally:
> 
> static ssize_t tcrit1_store(struct device *dev, struct device_attribute *attr,
> 	        const char *buf, size_t count)
> {
> [...]
>      val = DIV_ROUND_CLOSEST(clamp_val(val, 0, 255000), 1000);
> 
> static ssize_t tcrit2_store(struct device *dev, struct device_attribute *attr,
> 	        const char *buf, size_t count)
> {
> [...]
>      val = DIV_ROUND_CLOSEST(clamp_val(val, 0, (index ? 255 : 127) * 1000),
> 		    1000);
> 
> static SENSOR_DEVICE_ATTR_RW(temp1_max, tcrit1, 0); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp2_max, tcrit2, 0); -> 127000
> static SENSOR_DEVICE_ATTR_RW(temp3_max, tcrit2, 1); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp4_max, tcrit1, 3); -> 255000
> static SENSOR_DEVICE_ATTR_RW(temp5_max, tcrit1, 4); -> 255000
> 
>> +		val = DIV_ROUND_CLOSEST(val, 1000);
>> +		return regmap_write(regmap, lm95234_crit_reg(channel), val);
> 

That is indeed a bug. Here is the fix:

diff --git a/drivers/hwmon/lm95234.c b/drivers/hwmon/lm95234.c
index c3c68c196479..7da6c8f07332 100644
--- a/drivers/hwmon/lm95234.c
+++ b/drivers/hwmon/lm95234.c
@@ -150,7 +150,7 @@ static int lm95234_temp_write(struct device *dev, u32 attr, int channel, long va
                 val = DIV_ROUND_CLOSEST(clamp_val(val, -64000, 63500), 500);
                 return regmap_write(regmap, LM95234_REG_OFFSET(channel - 1), val);
         case hwmon_temp_max:
-               val = clamp_val(val, 0, channel ? 255000 : 127000);
+               val = clamp_val(val, 0, channel == 1 ? 127000 : 255000);
                 val = DIV_ROUND_CLOSEST(val, 1000);
                 return regmap_write(regmap, lm95234_crit_reg(channel), val);
         case hwmon_temp_max_hyst:

Thanks a lot for the detailed review!

Guenter