Hi Linus,
On Mon, May 13, 2013 at 12:26:23AM +0200, Linus Walleij wrote:
> Cc: Rob Herring <rob.herring@xxxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> I would need some device tree core people to confirm that I am
> on the right track with this. I was soooo confused when I found
> that .of_match_table could not be used with I2C devices...
> ---
> drivers/i2c/i2c-core.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 6b63cc7..30b5bb2 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -240,7 +240,7 @@ static int i2c_device_probe(struct device *dev)
> return 0;
>
> driver = to_i2c_driver(dev->driver);
> - if (!driver->probe || !driver->id_table)
> + if (!driver->probe || (!driver->id_table && !dev->driver->of_match_table))
> return -ENODEV;
> client->driver = driver;
> if (!device_can_wakeup(&client->dev))
> @@ -248,7 +248,12 @@ static int i2c_device_probe(struct device *dev)
> client->flags & I2C_CLIENT_WAKE);
> dev_dbg(dev, "probe\n");
>
> - status = driver->probe(client, i2c_match_id(driver->id_table, client));
> + if (dev->driver->of_match_table)
> + /* Device tree matching */
> + status = driver->probe(client, NULL);
> + else
> + /* Fall back to matching the id_table */
> + status = driver->probe(client, i2c_match_id(driver->id_table, client));
If you correctly register a device with "vendor,product" in the devicetree
the driver can already fetch the of_device_id using of_match_device(dt_ids, &client->dev)
just like a platform driver would do aswell.
i2c_match_id will return a NULL pointer if called with "vendor,product",
because nothing matches in the drivers id_table, so for this case you
change nothing.
If anything, you introduce the problem that a devicetree capable driver
no longer gets a i2c_device_id if the device was instantiated with
i2c_board_info.
See how the mc13xxx driver does it:
if (client->dev.of_node) {
const struct of_device_id *of_id =
of_match_device(mc13xxx_dt_ids, &client->dev);
mc13xxx->variant = of_id->data;
} else {
mc13xxx->variant = (void *)id->driver_data;
}
This works.
Sascha
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