Re: [PATCH] ACPI: LPSS: Add pwm_lookup_table entry for second PWM on CHT/BSW devices

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Tue, May 9, 2023 at 3:35 PM Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxxxx> wrote:
>
> On Tue, May 09, 2023 at 01:52:26PM +0200, Hans de Goede wrote:
> > BSW PWM2 is used for backlight control for fixed (etched into the glass)
> > touch controls on some models.
> >
> > Add an entry for the second PWM controller to bsw_pwm_lookup,
> > so that drivers can use pwm_get() to get a referene to it.
> >
> > These touch-controls have specialized drivers which bind to different
> > devices on different models, so the consumer-device-name in the lookup
> > table entry is set to NULL, so that only con-id matching is used.
> >
> > The con-id is set to "pwm_soc_lpss_2" which describes the PWM controller
> > rather then the usual approach of describing its function.
> > The specialized (model specific) drivers which need access to the PWM
> > controller know they need the "pwm_soc_lpss_2" con-id.
> >
> > Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>
> I don't understand the conditional before the call to pwm_add_table, but
> I guess that's ok.

There is a comment.
The _UID can be different for the _HID (so on some devices we have the
same _HID, but different _UIDs, i.e. '80862288 / 1', '80862288 / n'),
this is to prevent duplication for those, on the other hand the
devices where there are two different IDs, i.e. '80862288 / 1',
'80862289 / n', we expect to have the second one only when the first
one is present. At the same time we have no callback for the second
one at all. I.o.w. for the '80862289' we add the table when '80862288
/ 1' is enumerated.


-- 
With Best Regards,
Andy Shevchenko




[Index of Archives]     [Linux IBM ACPI]     [Linux Power Management]     [Linux Kernel]     [Linux Laptop]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]
  Powered by Linux