hwmon: (nct7904) Strengthen detect function

The bank register has five unused bits. Verify that those bits are zero
to strengthen the detect function.

Cc: Vadim V. Vlasov <vvlasov@dev.rtsoft.ru>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>

diff --git a/drivers/hwmon/nct7904.c b/drivers/hwmon/nct7904.c
index eaa8234e21d088406850abe4e638dc2f2c3f383a..b77b82f244800628843c103ae7dfcf157bd774ce 100644 (file)
--- a/drivers/hwmon/nct7904.c
+++ b/drivers/hwmon/nct7904.c
@@ -502,7 +502,8 @@ static int nct7904_detect(struct i2c_client *client,
        /* Determine the chip type. */
        if (i2c_smbus_read_byte_data(client, VENDOR_ID_REG) != NUVOTON_ID ||
            i2c_smbus_read_byte_data(client, CHIP_ID_REG) != NCT7904_ID ||
-           (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50)
+           (i2c_smbus_read_byte_data(client, DEVICE_ID_REG) & 0xf0) != 0x50 ||
+           (i2c_smbus_read_byte_data(client, BANK_SEL_REG) & 0xf8) != 0x00)
                return -ENODEV;
 
        strlcpy(info->type, "nct7904", I2C_NAME_SIZE);