Hi Robert,

On Mon, 20 May 2013 17:29:29 -0700, Robert Coulson wrote:
> v2:
> - removed detect function references in ds1621 documentation
> - replaced deprecated with removed and fixed a spelling error

Note: the patch changes history should go below, between the "---" and
the diffstat, so that it doesn't make it to git.

Almost there, see my comments inline.

>
> Due to a lack of device and vendor identification registers, the
> Dallas/Maxim DS16xx devices cannot be uniquely detected, sometimes
> resulting in false positives. Therefore, the detection function is
> being removed in favor of explicit device instantiation.
>
> These changes are based on the 3.9 source base and intended for
> hwmon-next.
>
> Signed-off-by: Robert Coulson <rob.coulson@gmail.com>
> ---
>  Documentation/hwmon/ds1621 |   13 ++++---------
>  drivers/hwmon/ds1621.c     |   43 -------------------------------------------
>  2 files changed, 4 insertions(+), 52 deletions(-)
>
> diff --git a/Documentation/hwmon/ds1621 b/Documentation/hwmon/ds1621
> index 140eab5..009aabb 100644
> --- a/Documentation/hwmon/ds1621
> +++ b/Documentation/hwmon/ds1621
> @@ -8,9 +8,7 @@ Supported chips:
>      Datasheet: Publicly available from www.maximintegrated.com
>
>    * Dallas Semiconductor DS1625
> -    Prefix:
> -     'ds1621' - if binding via _detect function
> -     'ds1625' - explicit instantiation
> +    Prefix: 'ds1625'
>      Addresses scanned: I2C 0x48 - 0x4f

You much change these lists to "none", as the driver will no longer
scan any address.

>      Datasheet: Publicly available from www.datasheetarchive.com
>
> @@ -77,12 +75,9 @@ The DS1625 is pin compatible and functionally equivalent with the DS1621,
>  but the DS1621 is meant to replace it. The DS1631 and DS1721 are also
>  pin compatible with the DS1621, but provide multi-resolution support.
>
> -Since there is no version register, there is no unique identification
> -for these devices. In addition, the DS1631 and DS1721 will emulate a
> -DS1621 device, if not explicitly instantiated (why? because the detect
> -function compares the temperature register values bits and checks for a
> -9-bit resolution). Therefore, for correct device identification and
> -functionality, explicit device instantiation is required.
> +Since there is no version or vendor identification register, there is
> +no unique identification for these devices. Therefore, explicit device
> +instantiation is required for correct device identification and functionality.
>
>  The DS1721 is pin compatible with the DS1621, has an accuracy of +/- 1.0
>  degree Celius over a -10 to +85 degree range, a minimum/maximum alarm
> diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c
> index d4f02a8..124fc83 100644
> --- a/drivers/hwmon/ds1621.c
> +++ b/drivers/hwmon/ds1621.c
> @@ -360,48 +360,6 @@ static const struct attribute_group ds1621_group = {
>       .is_visible = ds1621_attribute_visible
>  };
>
> -
> -/* Return 0 if detection is successful, -ENODEV otherwise */
> -static int ds1621_detect(struct i2c_client *client,
> -                      struct i2c_board_info *info)
> -{
> -     struct i2c_adapter *adapter = client->adapter;
> -     int conf, temp;
> -     int i;
> -
> -     if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
> -                                  | I2C_FUNC_SMBUS_WORD_DATA
> -                                  | I2C_FUNC_SMBUS_WRITE_BYTE))
> -             return -ENODEV;
> -
> -     /*
> -      * Now, we do the remaining detection. It is lousy.
> -      *
> -      * The NVB bit should be low if no EEPROM write has been requested
> -      * during the latest 10ms, which is highly improbable in our case.
> -      */
> -     conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
> -     if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
> -             return -ENODEV;
> -     /*
> -      * The ds1621 & ds1625 use 9-bit resolution, so the 7 lowest bits
> -      * of the temperature should always be 0 (NOTE: The other chips
> -      * have multi-resolution support, so if they have 9-bit resolution
> -      * configured and the min/max temperature values set accordingly,
> -      * then if not explicitly instantiated, they *will* appear as and
> -      * emulate a ds1621 device).
> -      */
> -     for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
> -             temp = i2c_smbus_read_word_data(client, DS1621_REG_TEMP[i]);
> -             if (temp < 0 || (temp & 0x7f00))
> -                     return -ENODEV;
> -     }
> -
> -     strlcpy(info->type, "ds1621", I2C_NAME_SIZE);
> -
> -     return 0;
> -}
> -
>  static int ds1621_probe(struct i2c_client *client,
>                       const struct i2c_device_id *id)
>  {
> @@ -467,7 +425,6 @@ static struct i2c_driver ds1621_driver = {
>       .probe          = ds1621_probe,
>       .remove         = ds1621_remove,
>       .id_table       = ds1621_id,
> -     .detect         = ds1621_detect,
>       .address_list   = normal_i2c,

This address list can be removed as well, as it is only used to
determine when the detect callback should be called.

>  };
>

Thanks,
--
Jean Delvare