Re: [PATCH 7/9] i2c: Switch .probe() to not take an id parameter

Luca Ceresoli
2023-02-24T16:02:42Z

Hi Uwe,

On Fri, 24 Feb 2023 13:05:58 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> Commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new() call-back
> type") introduced a new probe callback to convert i2c init routines to
> not take an i2c_device_id parameter. Now that all in-tree drivers are
> converted to the temporary .probe_new() callback, .probe() can be
> modified to match the desired prototype.
>
> Now that .probe() and .probe_new() have the same semantic, they can be
> defined as members of an anonymous union to save some memory and
> simplify the core code a bit.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thank you, I love this cleanup!

> ---
> drivers/i2c/i2c-core-base.c | 11 ++---------
> include/linux/i2c.h | 14 +++++++++-----
> 2 files changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 087e480b624c..1fbe16221085 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -558,15 +558,8 @@ static int i2c_device_probe(struct device *dev)
> goto err_detach_pm_domain;
> }
>
> - /*
> - * When there are no more users of probe(),
> - * rename probe_new to probe.
> - */
> - if (driver->probe_new)
> - status = driver->probe_new(client);
> - else if (driver->probe)
> - status = driver->probe(client,
> - i2c_match_id(driver->id_table, client));
> + if (driver->probe)
> + status = driver->probe(client);
> else
> status = -EINVAL;
>
> diff --git a/include/linux/i2c.h b/include/linux/i2c.h
> index d84e0e99f084..c3e022d53182 100644
> --- a/include/linux/i2c.h
> +++ b/include/linux/i2c.h
> @@ -272,14 +272,18 @@ enum i2c_driver_flags {
> struct i2c_driver {
> unsigned int class;
>
> + union {
> /* Standard driver model interfaces */
> - int (*probe)(struct i2c_client *client, const struct i2c_device_id *id);
> + int (*probe)(struct i2c_client *client);
> + /*
> + * Legacy callback that was part of a conversion of .probe().
> + * Today it has the same semantic as .probe(). Don't use for new
> + * code.
> + */
> + int (*probe_new)(struct i2c_client *client);
> + };
> void (*remove)(struct i2c_client *client);
>
> - /* New driver model interface to aid the seamless removal of the
> - * current probe()'s, more commonly unused than used second parameter.
> - */
> - int (*probe_new)(struct i2c_client *client);

The kerneldoc for this struct should also be updated:

- * @probe: Callback for device binding - soon to be deprecated
- * @probe_new: New callback for device binding
+ * @probe: Callback for device binding
+ * @probe_new: Transitional callback for device binding - do not use

Otherwise LGTM.

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering