thermal/drivers/int340x/processor_thermal: Fix tcc setting

The following fixes are done for tcc sysfs interface:
- TCC is 6 bits only from bit 29-24
- TCC of 0 is valid
- When BIT(31) is set, this register is read only
- Check for invalid tcc value
- Error for negative values

Fixes: fdf4f2f ("drivers: thermal: processor_thermal_device: Export sysfs interface for TCC offset")
Signed-off-by: Srinivas Pandruvada <[email protected]>
Cc: [email protected]
Acked-by: Zhang Rui <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: spandruvada

drivers/thermal/intel/int340x_thermal/processor_thermal_device.c

@@ -78,24 +78,27 @@ static ssize_t tcc_offset_degree_celsius_show(struct device *dev,
 	if (err)
 		return err;
 
-	val = (val >> 24) & 0xff;
+	val = (val >> 24) & 0x3f;
 	return sprintf(buf, "%d\n", (int)val);
 }
 
-static int tcc_offset_update(int tcc)
+static int tcc_offset_update(unsigned int tcc)
 {
 	u64 val;
 	int err;
 
-	if (!tcc)
+	if (tcc > 63)
 		return -EINVAL;
 
 	err = rdmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, &val);
 	if (err)
 		return err;
 
-	val &= ~GENMASK_ULL(31, 24);
-	val |= (tcc & 0xff) << 24;
+	if (val & BIT(31))
+		return -EPERM;
+
+	val &= ~GENMASK_ULL(29, 24);
+	val |= (tcc & 0x3f) << 24;
 
 	err = wrmsrl_safe(MSR_IA32_TEMPERATURE_TARGET, val);
 	if (err)
@@ -104,14 +107,15 @@ static int tcc_offset_update(int tcc)
 	return 0;
 }
 
-static int tcc_offset_save;
+static unsigned int tcc_offset_save;
 
 static ssize_t tcc_offset_degree_celsius_store(struct device *dev,
 				struct device_attribute *attr, const char *buf,
 				size_t count)
 {
+	unsigned int tcc;
 	u64 val;
-	int tcc, err;
+	int err;
 
 	err = rdmsrl_safe(MSR_PLATFORM_INFO, &val);
 	if (err)
@@ -120,7 +124,7 @@ static ssize_t tcc_offset_degree_celsius_store(struct device *dev,
 	if (!(val & BIT(30)))
 		return -EACCES;
 
-	if (kstrtoint(buf, 0, &tcc))
+	if (kstrtouint(buf, 0, &tcc))
 		return -EINVAL;
 
 	err = tcc_offset_update(tcc);