[RFT,0/4] platform/x86: int3472: don't use gpiod_toggle_active_low()

  From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

gpiod_toggle_active_low() is a badly designed API that should have never
been used elsewhere then in the MMC code. And even there we should find
a better solution.

Replace the uses of it in the int3472 driver with the good old temporary
lookup table trick. This is not very pretty either but it's the lesser
evil.

Bartosz Golaszewski (4):
  platform/x86: int3472: provide a helper for getting GPIOs from lookups
  platform/x86: int3472: led: don't use gpiod_toggle_active_low()
  platform/x86: int3472: clk_and_regulator: use GPIO lookup tables
  gpio: acpi: remove acpi_get_and_request_gpiod()

 drivers/gpio/gpiolib-acpi.c                   | 28 ------------------
 .../x86/intel/int3472/clk_and_regulator.c     | 22 ++++++--------
 drivers/platform/x86/intel/int3472/common.c   | 29 +++++++++++++++++++
 drivers/platform/x86/intel/int3472/common.h   |  9 ++++++
 drivers/platform/x86/intel/int3472/led.c      | 12 +++-----
 include/linux/gpio/consumer.h                 |  8 -----
 6 files changed, 51 insertions(+), 57 deletions(-)
  

On Tue, Sep 26, 2023 at 04:59:43PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> With no more users, we can remove acpi_get_and_request_gpiod().

The best patch in the series!
Reviewed-by: From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  

On Tue, Sep 26, 2023 at 04:59:39PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> gpiod_toggle_active_low() is a badly designed API that should have never
> been used elsewhere then in the MMC code. And even there we should find
> a better solution.
> 
> Replace the uses of it in the int3472 driver with the good old temporary
> lookup table trick. This is not very pretty either but it's the lesser
> evil.

Good jon!
I have only style issues, otherwise
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
  

Hi Bartosz,

On 9/26/23 16:59, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> gpiod_toggle_active_low() is a badly designed API that should have never
> been used elsewhere then in the MMC code. And even there we should find
> a better solution.
> 
> Replace the uses of it in the int3472 driver with the good old temporary
> lookup table trick. This is not very pretty either but it's the lesser
> evil.

I saw your previous proposal which added a new api to directly set
the active_low flag, rather then toggle it.

I intended to reply to that thread to say that I liked that approach,
but I don't remember if I actually did reply.

I wonder what made you abandon the new function to directly set
the active-low flag on a gpio_desc?

For the int3472 code that would work pretty well and it would
be much cleaner then the temp gpio-lookup approach.

Regards,

Hans



> 
> Bartosz Golaszewski (4):
>   platform/x86: int3472: provide a helper for getting GPIOs from lookups
>   platform/x86: int3472: led: don't use gpiod_toggle_active_low()
>   platform/x86: int3472: clk_and_regulator: use GPIO lookup tables
>   gpio: acpi: remove acpi_get_and_request_gpiod()
> 
>  drivers/gpio/gpiolib-acpi.c                   | 28 ------------------
>  .../x86/intel/int3472/clk_and_regulator.c     | 22 ++++++--------
>  drivers/platform/x86/intel/int3472/common.c   | 29 +++++++++++++++++++
>  drivers/platform/x86/intel/int3472/common.h   |  9 ++++++
>  drivers/platform/x86/intel/int3472/led.c      | 12 +++-----
>  include/linux/gpio/consumer.h                 |  8 -----
>  6 files changed, 51 insertions(+), 57 deletions(-)
>
  

Hi,

On 9/27/23 10:38, Hans de Goede wrote:
> Hi Bartosz,
> 
> On 9/26/23 16:59, Bartosz Golaszewski wrote:
>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>
>> gpiod_toggle_active_low() is a badly designed API that should have never
>> been used elsewhere then in the MMC code. And even there we should find
>> a better solution.
>>
>> Replace the uses of it in the int3472 driver with the good old temporary
>> lookup table trick. This is not very pretty either but it's the lesser
>> evil.
> 
> I saw your previous proposal which added a new api to directly set
> the active_low flag, rather then toggle it.
> 
> I intended to reply to that thread to say that I liked that approach,
> but I don't remember if I actually did reply.
> 
> I wonder what made you abandon the new function to directly set
> the active-low flag on a gpio_desc?
> 
> For the int3472 code that would work pretty well and it would
> be much cleaner then the temp gpio-lookup approach.

I missed that 4/4 removes acpi_get_and_request_gpiod(),
so I guess that this is not just only about removing gpiod_toggle_active_low()
but also about removing gpiod_toggle_active_low() ?

Regards,

Hans



>>
>> Bartosz Golaszewski (4):
>>   platform/x86: int3472: provide a helper for getting GPIOs from lookups
>>   platform/x86: int3472: led: don't use gpiod_toggle_active_low()
>>   platform/x86: int3472: clk_and_regulator: use GPIO lookup tables
>>   gpio: acpi: remove acpi_get_and_request_gpiod()
>>
>>  drivers/gpio/gpiolib-acpi.c                   | 28 ------------------
>>  .../x86/intel/int3472/clk_and_regulator.c     | 22 ++++++--------
>>  drivers/platform/x86/intel/int3472/common.c   | 29 +++++++++++++++++++
>>  drivers/platform/x86/intel/int3472/common.h   |  9 ++++++
>>  drivers/platform/x86/intel/int3472/led.c      | 12 +++-----
>>  include/linux/gpio/consumer.h                 |  8 -----
>>  6 files changed, 51 insertions(+), 57 deletions(-)
>>
  

On Wed, Sep 27, 2023 at 10:38 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Bartosz,
>
> On 9/26/23 16:59, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > gpiod_toggle_active_low() is a badly designed API that should have never
> > been used elsewhere then in the MMC code. And even there we should find
> > a better solution.
> >
> > Replace the uses of it in the int3472 driver with the good old temporary
> > lookup table trick. This is not very pretty either but it's the lesser
> > evil.
>
> I saw your previous proposal which added a new api to directly set
> the active_low flag, rather then toggle it.
>
> I intended to reply to that thread to say that I liked that approach,
> but I don't remember if I actually did reply.
>
> I wonder what made you abandon the new function to directly set
> the active-low flag on a gpio_desc?
>
> For the int3472 code that would work pretty well and it would
> be much cleaner then the temp gpio-lookup approach.
>

You did reply, yes. Under one of the other patches Linus W stated that
first: adding the ability for consumers to toggle the polarity was
added to handle the MMC slot quirk, then it was used unknowingly to
GPIO maintainers in other places (including this driver). I then
acknowledged the fact that it should have never existed in the first
place as this is HW description and should be defined in ACPI, DT or
lookup flags.

I'm not sure why this information needs to be hard-coded in the driver
in int3472_get_func_and_polarity() but maybe it could be pulled into
gpiolib-acpi.c with other quirks?

Bart
  

Hi Bartosz,

On 9/27/23 10:48, Bartosz Golaszewski wrote:
> On Wed, Sep 27, 2023 at 10:38 AM Hans de Goede <hdegoede@redhat.com> wrote:
>>
>> Hi Bartosz,
>>
>> On 9/26/23 16:59, Bartosz Golaszewski wrote:
>>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>>>
>>> gpiod_toggle_active_low() is a badly designed API that should have never
>>> been used elsewhere then in the MMC code. And even there we should find
>>> a better solution.
>>>
>>> Replace the uses of it in the int3472 driver with the good old temporary
>>> lookup table trick. This is not very pretty either but it's the lesser
>>> evil.
>>
>> I saw your previous proposal which added a new api to directly set
>> the active_low flag, rather then toggle it.
>>
>> I intended to reply to that thread to say that I liked that approach,
>> but I don't remember if I actually did reply.
>>
>> I wonder what made you abandon the new function to directly set
>> the active-low flag on a gpio_desc?
>>
>> For the int3472 code that would work pretty well and it would
>> be much cleaner then the temp gpio-lookup approach.
>>
> 
> You did reply, yes. Under one of the other patches Linus W stated that
> first: adding the ability for consumers to toggle the polarity was
> added to handle the MMC slot quirk, then it was used unknowingly to
> GPIO maintainers in other places (including this driver). I then
> acknowledged the fact that it should have never existed in the first
> place as this is HW description and should be defined in ACPI, DT or
> lookup flags.

I see and I understand.

> I'm not sure why this information needs to be hard-coded in the driver
> in int3472_get_func_and_polarity() but maybe it could be pulled into
> gpiolib-acpi.c with other quirks?

The problem is that for camera sensors Intel uses this special
INT3472 ACPI device with a custom _DSM to list GPIOs, with the _DSM
returning an u32 and one of the bits in the u32 is the polarity.

We really do not want to deal with this Intel camera team hack
inside gpiolib-acpi and I can understand why you and Linus W
want to get rid of functions which allow drivers to meddle
with a gpio_desc's active-low flag.

So using a temporary gpio-lookup in the int3472 code as
you are proposing is the best (least bad) thing to do
here then.

I'll try to make some time to test this sometime
the coming days.

Other then the discussion we just had is there any specific
reason why this should be considered a RFC / why this would
not be ready for merging?  (I still need to review these,
but lets assume that goes well)

Regards,

Hans
  

On Wed, Sep 27, 2023 at 11:02 AM Hans de Goede <hdegoede@redhat.com> wrote:
>
> Hi Bartosz,
>
> On 9/27/23 10:48, Bartosz Golaszewski wrote:
> > On Wed, Sep 27, 2023 at 10:38 AM Hans de Goede <hdegoede@redhat.com> wrote:
> >>
> >> Hi Bartosz,
> >>
> >> On 9/26/23 16:59, Bartosz Golaszewski wrote:
> >>> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >>>
> >>> gpiod_toggle_active_low() is a badly designed API that should have never
> >>> been used elsewhere then in the MMC code. And even there we should find
> >>> a better solution.
> >>>
> >>> Replace the uses of it in the int3472 driver with the good old temporary
> >>> lookup table trick. This is not very pretty either but it's the lesser
> >>> evil.
> >>
> >> I saw your previous proposal which added a new api to directly set
> >> the active_low flag, rather then toggle it.
> >>
> >> I intended to reply to that thread to say that I liked that approach,
> >> but I don't remember if I actually did reply.
> >>
> >> I wonder what made you abandon the new function to directly set
> >> the active-low flag on a gpio_desc?
> >>
> >> For the int3472 code that would work pretty well and it would
> >> be much cleaner then the temp gpio-lookup approach.
> >>
> >
> > You did reply, yes. Under one of the other patches Linus W stated that
> > first: adding the ability for consumers to toggle the polarity was
> > added to handle the MMC slot quirk, then it was used unknowingly to
> > GPIO maintainers in other places (including this driver). I then
> > acknowledged the fact that it should have never existed in the first
> > place as this is HW description and should be defined in ACPI, DT or
> > lookup flags.
>
> I see and I understand.
>
> > I'm not sure why this information needs to be hard-coded in the driver
> > in int3472_get_func_and_polarity() but maybe it could be pulled into
> > gpiolib-acpi.c with other quirks?
>
> The problem is that for camera sensors Intel uses this special
> INT3472 ACPI device with a custom _DSM to list GPIOs, with the _DSM
> returning an u32 and one of the bits in the u32 is the polarity.
>
> We really do not want to deal with this Intel camera team hack
> inside gpiolib-acpi and I can understand why you and Linus W
> want to get rid of functions which allow drivers to meddle
> with a gpio_desc's active-low flag.
>
> So using a temporary gpio-lookup in the int3472 code as
> you are proposing is the best (least bad) thing to do
> here then.
>
> I'll try to make some time to test this sometime
> the coming days.
>
> Other then the discussion we just had is there any specific
> reason why this should be considered a RFC / why this would
> not be ready for merging?  (I still need to review these,
> but lets assume that goes well)
>

This is not an RFC but rather RFT - Request For Testing. I don't have
any HW to test those with so I only built it.

Bart