Messages in this thread | | | Date | Thu, 23 Feb 2023 09:19:57 +0100 | From | Robin van der Gracht <> | Subject | Re: [PATCH v1 2/3] auxdisplay: ht16k33: Make use of device_get_match_data() |
| |
On 2023-02-22 18:20, Andy Shevchenko wrote: > + Cc: OF bindings people for the mess with the IDs. > > On Wed, Feb 22, 2023 at 07:01:40PM +0200, Andy Shevchenko wrote: >> On Wed, Feb 22, 2023 at 05:46:00PM +0100, Robin van der Gracht wrote: >> > On 2023-02-21 18:48, Andy Shevchenko wrote: >> > > 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: > > ... > >> > > > > > - 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. >> >> ^^^^^ (1) >> >> > > > > 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 >> > >> > For my understanding, please correct me if I'm wrong; >> > >> > For all methods of instantiation during ht16k33 probe, i2c_of_match_device() >> > matches the compatible strings in the OF ID table due to a call to >> > i2c_of_match_device_sysfs(). >> > >> > device_get_match_data() only matches the compatible strings in the OF ID >> > table for devicetree instantiation because of_match_device() won't match >> > is there is no actual of_node. >> >> That's half-true. On ACPI based platforms we may have no of_node and >> match >> against OF ID table. >> >> > So with only device_get_match_data() and a non devicetree instantiation, >> > priv->type will always be (uintptr_t)NULL = 0 = DISP_MATRIX. >> >> Yes. >> >> > Which effectively breaks i.e. user-space instantiation for other display >> > types which now do work due to i2c_of_match_device(). >> > (so my suggestion above is not sufficient). >> > >> > Are you proposing extending and searching the I2C ID table to work around >> > that? >> >> See (1) above. This is the downside I have noticed after sending this >> series. >> So, the I²C ID table match has to be restored, but the above mentioned >> issues >> with existing table are not gone, hence they need to be addressed in >> the next >> version. > > I see now what you mean. So, we have even more issues in this driver: > - I²C table is not in sync with all devices supported > - the OF ID table seems has something really badly formed for adafruit > (just a number after a comma) > > The latter shows how broken it is. The I²C ID table mechanism is used > as > a backward compatibility to the OF. Unfortunately, user space may not > provide > the data except in form of DT overlays, so for the legacy enumeration > we > have only device name, which is a set of 4 digits for adafruit case. > > Now imagine if by some reason we will get adafruit2 (you name it) with > the same schema. How I²C framework can understand that you meant > adafruit > and not adafruit2? Or did I miss something?
I agree.
I've added Geert Uytterhoeven to the CC. He added support for the adafruit segment displays. Maybe he has a comment on this.
Kind regards, Robin van der Gracht
| |