[PATCH v2] hwmon: (pt5161l) Fix invalid temperature reading

[PATCH v2] hwmon: (pt5161l) Fix invalid temperature reading

[Cosmo Chou]

The temperature reading function was using a signed long for the ADC
code, which could lead to mishandling of invalid codes on 32-bit
platforms. This allowed out-of-range ADC codes to be incorrectly
interpreted as valid values and used in temperature calculations.

Change adc_code to u32 to ensure that invalid ADC codes are correctly
identified on all platforms.

Fixes: 1b2ca93cd059 ("hwmon: Add driver for Astera Labs PT5161L retimer")
Signed-off-by: Cosmo Chou <chou.cosmo@gmail.com>
---
Change log:

v2:
  - Fix build warnings of dev_dbg().

---
 drivers/hwmon/pt5161l.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/pt5161l.c b/drivers/hwmon/pt5161l.c
index b0d58a26d499..a9f0b23f9e76 100644
--- a/drivers/hwmon/pt5161l.c
+++ b/drivers/hwmon/pt5161l.c
@@ -427,7 +427,7 @@ static int pt5161l_read(struct device *dev, enum hwmon_sensor_types type,
 	struct pt5161l_data *data = dev_get_drvdata(dev);
 	int ret;
 	u8 buf[8];
-	long adc_code;
+	u32 adc_code;
 
 	switch (attr) {
 	case hwmon_temp_input:
@@ -449,7 +449,7 @@ static int pt5161l_read(struct device *dev, enum hwmon_sensor_types type,
 
 		adc_code = buf[3] << 24 | buf[2] << 16 | buf[1] << 8 | buf[0];
 		if (adc_code == 0 || adc_code >= 0x3ff) {
-			dev_dbg(dev, "Invalid adc_code %lx\n", adc_code);
+			dev_dbg(dev, "Invalid adc_code %x\n", adc_code);
 			return -EIO;
 		}
 
-- 
2.34.1

Re: [PATCH v2] hwmon: (pt5161l) Fix invalid temperature reading

[Guenter Roeck]

On Mon, Aug 19, 2024 at 06:46:30PM +0800, Cosmo Chou wrote:
> The temperature reading function was using a signed long for the ADC
> code, which could lead to mishandling of invalid codes on 32-bit
> platforms. This allowed out-of-range ADC codes to be incorrectly
> interpreted as valid values and used in temperature calculations.
> 
> Change adc_code to u32 to ensure that invalid ADC codes are correctly
> identified on all platforms.
> 
> Fixes: 1b2ca93cd059 ("hwmon: Add driver for Astera Labs PT5161L retimer")
> Signed-off-by: Cosmo Chou <chou.cosmo@gmail.com>

Applied.

Thanks,
Guenter