From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>, Lukas Wunner <lukas@wunner.de>
Cc: Mark Brown <broonie@kernel.org>,
Florian Fainelli <florian.fainelli@broadcom.com>,
Linus Walleij <linus.walleij@linaro.org>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@broadcom.com>,
linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Subject: Re: [RFT PATCH] spi: bcm2835: reduce the abuse of the GPIO API
Date: Fri, 1 Sep 2023 11:55:48 +0300 [thread overview]
Message-ID: <ZPGnFHgtK1wE6Ppf@smile.fi.intel.com> (raw)
In-Reply-To: <CAMRc=Md-6i+nqDtYiUUtZExA32c0nJxhevYsiZqmd1PP8aaMng@mail.gmail.com>
On Fri, Sep 01, 2023 at 09:40:11AM +0200, Bartosz Golaszewski wrote:
> On Fri, Sep 1, 2023 at 1:25 AM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> >
> > On Thu, Aug 31, 2023 at 09:49:34PM +0200, Bartosz Golaszewski wrote:
> > > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > >
> > > Currently the bcm2835 SPI driver uses functions meant for GPIO providers
> > > exclusively to locate the GPIO chip it gets its CS pins from and request
> > > the relevant pin. I don't know the background and what bug forced this.
...
> > > /*
> > > + * TODO: The code below is a slightly better alternative to the utter
> > > + * abuse of the GPIO API that I found here before. It creates a
> > > + * temporary lookup table, assigns it to the SPI device, gets the GPIO
> > > + * descriptor and then releases the lookup table.
> > > *
> > > + * Still the real problem is unsolved. Looks like the cs_gpiods table
> > > + * is not assigned correctly from DT?
> > > */
> >
> > I'm not sure why this quirk is here. AFAIR the SPI CS quirks are located in
> > gpiolib-of.c.
> >
>
> I'm not sure this is a good candidate for the GPIOLIB quirks. This is
> the SPI setup callback (which makes me think - I should have used
> gpiod_get(), not devm_gpiod_get() and then put the descriptor in
> .cleanup()) and not probe. It would be great to get some background on
> why this is even needed in the first place. The only reason I see is
> booting the driver with an invalid device-tree that doesn't assign the
> GPIO to the SPI controller.
Maybe Lukas knows more?
--
With Best Regards,
Andy Shevchenko
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next prev parent reply other threads:[~2023-09-01 8:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-31 19:49 [RFT PATCH] spi: bcm2835: reduce the abuse of the GPIO API Bartosz Golaszewski
2023-08-31 22:51 ` kernel test robot
2023-08-31 23:24 ` Andy Shevchenko
2023-09-01 7:40 ` Bartosz Golaszewski
2023-09-01 8:55 ` Andy Shevchenko [this message]
2023-09-01 9:22 ` Linus Walleij
2023-09-01 9:34 ` Bartosz Golaszewski
2023-08-31 23:27 ` Andy Shevchenko
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