On Tuesday, May 19, 2015 05:03:29 PM Robert Dolca wrote:
> For i2c devices enumerated with ACPI you need to declare both
> acpi_match_table and id_table. When using ACPI, the i2c_device_id structure
> supplied to the probe function is null and you have to handle this case
> in the driver.
>
> The current name for the i2c client when using ACPI is "HID:UID" where the
> UID has 7 or 8 characters and the UID has 2 characters. The UID is not
> relevant for identifying the chip so it does not have any practical
> purpose.
>
> Modifying i2c_match_id we make the comparison by ignoring the UID from the
> client name when the device was discovered using ACPI. The comparison is
> case insensitive because the ACPI names are uppercase and the DT and ID
> table names are lowercase. It would not make sense to have two different
> chips with the same name and the only diference being the capitalized
> letters.
>
> With these changes the probe function gets a valid i2c_device_id and the
> driver doesn't have to declare acpi_match_table.
>
> Signed-off-by: Robert Dolca <robert.dolca@xxxxxxxxx>
> ---
> drivers/i2c/i2c-core.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index fec0e0d..c9b30b7 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -447,8 +447,18 @@ static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
> static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
> const struct i2c_client *client)
> {
> + char name[I2C_NAME_SIZE], *c;
> +
> + strlcpy(name, client->name, sizeof(name));
> +
> + if (ACPI_HANDLE(&client->dev)) {
If you don't need to use the handle, it is better to call has_acpi_companion() here.
> + c = strchr(name, ':');
> + if (c)
> + *c = 0;
> + }
> +
> while (id->name[0]) {
> - if (strcmp(client->name, id->name) == 0)
> + if (strncasecmp(name, id->name, sizeof(id->name)) == 0)
> return id;
> id++;
> }
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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