hwmon: (w83795) Improve detection routine
Check for additional identification registers. Improve debugging
messages on failed detection.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index c7f6b1fd..6596303 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -48,6 +48,7 @@
#define W83795_REG_VENDORID 0xfd
#define W83795_REG_CHIPID 0xfe
#define W83795_REG_DEVICEID 0xfb
+#define W83795_REG_DEVICEID_A 0xff
#define W83795_REG_I2C_ADDR 0xfc
#define W83795_REG_CONFIG 0x01
@@ -1684,11 +1685,31 @@
w83795_read(client, W83795_REG_CONFIG) | 0x01);
}
+static int w83795_get_device_id(struct i2c_client *client)
+{
+ int device_id;
+
+ device_id = i2c_smbus_read_byte_data(client, W83795_REG_DEVICEID);
+
+ /* Special case for rev. A chips; can't be checked first because later
+ revisions emulate this for compatibility */
+ if (device_id < 0 || (device_id & 0xf0) != 0x50) {
+ int alt_id;
+
+ alt_id = i2c_smbus_read_byte_data(client,
+ W83795_REG_DEVICEID_A);
+ if (alt_id == 0x50)
+ device_id = alt_id;
+ }
+
+ return device_id;
+}
+
/* Return 0 if detection is successful, -ENODEV otherwise */
static int w83795_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
- u8 tmp, bank;
+ int bank, vendor_id, device_id, expected, i2c_addr, config;
struct i2c_adapter *adapter = client->adapter;
unsigned short address = client->addr;
const char *chip_name;
@@ -1696,32 +1717,44 @@
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
bank = i2c_smbus_read_byte_data(client, W83795_REG_BANKSEL);
+ if (bank < 0 || (bank & 0x7c)) {
+ dev_dbg(&adapter->dev,
+ "w83795: Detection failed at addr 0x%02hx, check %s\n",
+ address, "bank");
+ return -ENODEV;
+ }
- tmp = bank & 0x80 ? 0x5c : 0xa3;
/* Check Nuvoton vendor ID */
- if (tmp != i2c_smbus_read_byte_data(client,
- W83795_REG_VENDORID)) {
- pr_debug("w83795: Detection failed at check "
- "vendor id\n");
+ vendor_id = i2c_smbus_read_byte_data(client, W83795_REG_VENDORID);
+ expected = bank & 0x80 ? 0x5c : 0xa3;
+ if (vendor_id != expected) {
+ dev_dbg(&adapter->dev,
+ "w83795: Detection failed at addr 0x%02hx, check %s\n",
+ address, "vendor id");
+ return -ENODEV;
+ }
+
+ /* Check device ID */
+ device_id = w83795_get_device_id(client) |
+ (i2c_smbus_read_byte_data(client, W83795_REG_CHIPID) << 8);
+ if ((device_id >> 4) != 0x795) {
+ dev_dbg(&adapter->dev,
+ "w83795: Detection failed at addr 0x%02hx, check %s\n",
+ address, "device id\n");
return -ENODEV;
}
/* If Nuvoton chip, address of chip and W83795_REG_I2C_ADDR
should match */
- if ((bank & 0x07) == 0
- && (i2c_smbus_read_byte_data(client, W83795_REG_I2C_ADDR) & 0x7f) !=
- address) {
- pr_debug("w83795: Detection failed at check "
- "i2c addr\n");
- return -ENODEV;
- }
-
- /* Determine the chip type now */
- if (0x79 != i2c_smbus_read_byte_data(client,
- W83795_REG_CHIPID)) {
- pr_debug("w83795: Detection failed at check "
- "chip id\n");
- return -ENODEV;
+ if ((bank & 0x07) == 0) {
+ i2c_addr = i2c_smbus_read_byte_data(client,
+ W83795_REG_I2C_ADDR);
+ if ((i2c_addr & 0x7f) != address) {
+ dev_dbg(&adapter->dev,
+ "w83795: Detection failed at addr 0x%02hx, "
+ "check %s\n", address, "i2c addr");
+ return -ENODEV;
+ }
}
/* Check 795 chip type: 795G or 795ADG
@@ -1731,14 +1764,15 @@
if ((bank & 0x07) != 0)
i2c_smbus_write_byte_data(client, W83795_REG_BANKSEL,
bank & ~0x07);
- if (W83795_REG_CONFIG_CONFIG48 &
- i2c_smbus_read_byte_data(client, W83795_REG_CONFIG)) {
+ config = i2c_smbus_read_byte_data(client, W83795_REG_CONFIG);
+ if (config & W83795_REG_CONFIG_CONFIG48)
chip_name = "w83795adg";
- } else {
+ else
chip_name = "w83795g";
- }
strlcpy(info->type, chip_name, I2C_NAME_SIZE);
+ dev_info(&adapter->dev, "Found %s rev. %c at 0x%02hx\n", chip_name,
+ 'A' + (device_id & 0xf), address);
return 0;
}