Hi Brian,
On Mon, May 18, 2015 at 8:34 PM, Brian Norris
<computersforpeace@xxxxxxxxx> wrote:
> On Mon, May 18, 2015 at 11:45:01AM +0100, Mark Rutland wrote:
>> On Fri, May 15, 2015 at 08:55:41PM +0100, Brian Norris wrote:
>> > It really helps if I test patches...
>> >
>> > On Thu, May 14, 2015 at 10:32:53AM -0700, Brian Norris wrote:
> [...]
>> > > @@ -305,7 +305,7 @@ static const struct spi_device_id m25p_ids[] = {
>> > > * Generic support for SPI NOR that can be identified by the JEDEC READ
>> > > * ID opcode (0x9F). Use this, if possible.
>> > > */
>> > > - {"nor-jedec"},
>> > > + {"jedec,spi-nor"},
>> >
>> > So I forgot (again; we hit this before) that the SPI/OF framework strips
>> > everything before the first comma before binding devices. See
>> > of_modalias_node(). So I'll have to squash in the patch below to get a
>> > usable binding.
>>
>> Is it not possible to use the of_match_table on spi_driver::driver? If
>> not, we really should make it so.
>
> Hmm, it does look like spi.c supports multiple matching mechanisms, so I
> guess m25p80.c could match some with of_match_table and some with
> modalias/spi_driver.id_table. See:
>
> static int spi_match_device(struct device *dev, struct device_driver *drv)
> {
> const struct spi_device *spi = to_spi_device(dev);
> const struct spi_driver *sdrv = to_spi_driver(drv);
>
> /* Attempt an OF style match */
> if (of_driver_match_device(dev, drv))
> return 1;
> // ^^^^ we aren't yet (but could be) using this
>
> /* Then try ACPI */
> if (acpi_driver_match_device(dev, drv))
> return 1;
>
> if (sdrv->id_table)
> return !!spi_match_id(sdrv->id_table, spi);
> // ^^^^ we're currently only using this
>
> return strcmp(spi->modalias, drv->name) == 0;
> }
>
> I'll see about patching this for 4.2. We have a working solution for
> 4.1 at least.
When using DT:
- spi_driver.id_table is used to match with vendor-stripped DT "compatible"
entries.
- spi_driver.driver.of_match_table is used to match with full DT "compatible"
entries.
Note that stripping of vendor names from DT "compatible" entries is done
for the _first_ "compatible" entry in the device node only!
Hence
compatible = "myvendor,m25p80";
will match against "m25p80" in m25p_ids[], while
compatible = "myvendor,shinynewdevice", "st,m25p80";
will _not_ match against "m25p80" in m25p_ids[], and fail to probe in
the absence of a driver entry for the first (real) "compatible" entry.
I2c behaves similarly.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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