On Tue, 2011-08-30 at 16:05 -0400, Jean Delvare wrote:
> Word reads can cause trouble with some I2C devices, so do as much
> detection as we can using only byte reads, and only use a word read in
> the end to confirm the positive match. Also properly handle read
> errors.
>
> Signed-off-by: Jean Delvare <khali@xxxxxxxxxxxx>
> Cc: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> Cc: Robert Casanova <robertcasanova@xxxxxxxxxxxxxx>
> ---
> drivers/hwmon/lm73.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> --- linux-3.1-rc4.orig/drivers/hwmon/lm73.c 2011-07-22 04:17:23.000000000 +0200
> +++ linux-3.1-rc4/drivers/hwmon/lm73.c 2011-08-30 21:13:46.000000000 +0200
> @@ -150,17 +150,31 @@ static int lm73_detect(struct i2c_client
> struct i2c_board_info *info)
> {
> struct i2c_adapter *adapter = new_client->adapter;
> - u16 id;
> - u8 ctrl;
> + int id, ctrl, conf;
>
> if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> I2C_FUNC_SMBUS_WORD_DATA))
> return -ENODEV;
>
> + /*
> + * Do as much detection as possible with byte reads first, as word
> + * reads can confuse other devices.
> + */
> + ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
> + if (ctrl < 0 || (ctrl & 0x10))
> + return -ENODEV;
> +
> + conf = i2c_smbus_read_byte_data(new_client, LM73_REG_CONF);
> + if (conf < 0 || (conf & 0x0c))
> + return -ENODEV;
> +
> + id = i2c_smbus_read_byte_data(new_client, LM73_REG_ID);
> + if (id < 0 || id != (LM73_ID & 0xff))
> + return -ENODEV;
> +
> /* Check device ID */
> id = i2c_smbus_read_word_data(new_client, LM73_REG_ID);
> - ctrl = i2c_smbus_read_byte_data(new_client, LM73_REG_CTRL);
> - if ((id != LM73_ID) || (ctrl & 0x10))
> + if (id < 0 || id != LM73_ID)
> return -ENODEV;
>
> strlcpy(info->type, "lm73", I2C_NAME_SIZE);
>
>
Looks good.
Acked-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
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