hwmon: (tmp421) Strengthen detect function
Not all supported chips support the entire I2C address range.
Only accept specific chips at the addresses supported by that chip.
Check for invalid values in conversion rate and status registers.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
index 7bab7a9..9438c1b 100644
--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -42,6 +42,7 @@
enum chips { tmp421, tmp422, tmp423 };
/* The TMP421 registers */
+#define TMP421_STATUS_REG 0x08
#define TMP421_CONFIG_REG_1 0x09
#define TMP421_CONVERSION_RATE_REG 0x0B
#define TMP421_MANUFACTURER_ID_REG 0xFE
@@ -235,6 +236,7 @@
enum chips kind;
struct i2c_adapter *adapter = client->adapter;
const char *names[] = { "TMP421", "TMP422", "TMP423" };
+ int addr = client->addr;
u8 reg;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
@@ -244,15 +246,27 @@
if (reg != TMP421_MANUFACTURER_ID)
return -ENODEV;
+ reg = i2c_smbus_read_byte_data(client, TMP421_CONVERSION_RATE_REG);
+ if (reg & 0xf8)
+ return -ENODEV;
+
+ reg = i2c_smbus_read_byte_data(client, TMP421_STATUS_REG);
+ if (reg & 0x7f)
+ return -ENODEV;
+
reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
switch (reg) {
case TMP421_DEVICE_ID:
kind = tmp421;
break;
case TMP422_DEVICE_ID:
+ if (addr == 0x2a)
+ return -ENODEV;
kind = tmp422;
break;
case TMP423_DEVICE_ID:
+ if (addr != 0x4c && addr != 0x4d)
+ return -ENODEV;
kind = tmp423;
break;
default: