Re: [PATCH v1 2/3] auxdisplay: ht16k33: Make use of device_get_match_data()

From: Andy Shevchenko
Date: Tue Feb 21 2023 - 12:48:26 EST


On Tue, Feb 21, 2023 at 05:10:00PM +0100, Robin van der Gracht wrote:
> On 2023-02-21 14:40, Andy Shevchenko wrote:
> > On Tue, Feb 21, 2023 at 03:33:06PM +0200, Andy Shevchenko wrote:
> > > Switching to use device_get_match_data() helps getting of
> > > i2c_of_match_device() API.

...

> > > - id = i2c_of_match_device(dev->driver->of_match_table, client);
> > > - if (id)
> > > - priv->type = (uintptr_t)id->data;
> > > + priv->type = (uintptr_t)device_get_match_data(dev);
> >
> > Looking closer the I²C ID table should provide DISP_MATRIX to keep
> > default and this needs to be not dropped.
> >
> > So, the question is what to do with unknown type then, return -EINVAL
> > from probe()?
>
> If you leave out your addition of the DISP_UNKNOWN type, the default type
> will be DISP_MATRIX if no match is found, which is as it is now.
>
> In that case the following change should suffice:
>
> @@ -713,7 +715,6 @@ static int ht16k33_seg_probe(struct device *dev, struct
> ht16k33_priv *priv,
> static int ht16k33_probe(struct i2c_client *client)
> {
> struct device *dev = &client->dev;
> - const struct of_device_id *id;
> struct ht16k33_priv *priv;
> uint32_t dft_brightness;
> int err;
> @@ -728,9 +729,8 @@ static int ht16k33_probe(struct i2c_client *client)
> return -ENOMEM;
>
> priv->client = client;
> - id = i2c_of_match_device(dev->driver->of_match_table, client);
> - if (id)
> - priv->type = (uintptr_t)id->data;
> + priv->type = (uintptr_t)device_get_match_data(dev);
> +
> i2c_set_clientdata(client, priv);
>
> err = ht16k33_initialize(priv);
>
> Or do you think falling back to DISP_MATRIX if no match is found is wrong?

First of all, the I²C ID table should actually use DISP_MATRIX.

Second, there are two points:

- It would be nice to check if the OF ID table doesn't provide a setting
(shouldn't we try I²C ID table and then, if still nothing, bail out?)

- The I²C ID table can be extended in the future with another entry which
may want to have different default


--
With Best Regards,
Andy Shevchenko