From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Octavian Purdila <octavian.purdila@intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Lars-Peter Clausen <lars@metafoo.de>,
Robert Dolca <robert.dolca@gmail.com>,
Robert Dolca <robert.dolca@intel.com>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
Jonathan Cameron <jic23@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Hartmut Knaack <knaack.h@gmx.de>,
Peter Meerwald <pmeerw@pmeerw.net>,
Denis CIOCCA <denis.ciocca@st.com>
Subject: Re: [PATCH] IIO: Adds ACPI support for ST gyroscopes
Date: Mon, 30 Mar 2015 16:33:07 +0300 [thread overview]
Message-ID: <20150330133307.GE1524@lahna.fi.intel.com> (raw)
In-Reply-To: <CAE1zotJCo2oUJLb3ETozxutFCXUD8gKZeUL-qWj-Y8gW0idr8Q@mail.gmail.com>
On Mon, Mar 30, 2015 at 03:55:14PM +0300, Octavian Purdila wrote:
> On Mon, Mar 30, 2015 at 12:52 PM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> > On Fri, Mar 27, 2015 at 11:36:25AM +0100, Linus Walleij wrote:
> >> On Fri, Mar 27, 2015 at 11:06 AM, Mika Westerberg
> >> <mika.westerberg@linux.intel.com> wrote:
> >> > On Thu, Mar 26, 2015 at 06:28:19PM +0200, Octavian Purdila wrote:
> >>
> >> >> For the sleep case I think the GPIO controller needs to do the pin
> >> >> enable and set input direction operation in it's irq_bus_sync_unlock.
> >> >
> >> > I wonder how DT handles all this? Is it the boot firmware that sets up
> >> > the pins accordingly or is there something we are missing?
> >>
> >> DT systems mostly do not have firmware for power usecases, they
> >> handle it all using pin control. I would more say that is a feature of
> >> all-SW systems without power-firmware ideas, without ACPI and
> >> without PSCI (well PSCI systems do not care about much more
> >> than CPU power down in firmware anyway...)
> >
> > OK, thanks.
> >
> > In case of ACPI (where firmware does lot more) it is supposed to
> > configure pins based on what is connected, if the firmware knows that.
> > Due to bugs in the boot firmware that obviously does not happen in all
> > cases (like this one).
> >
>
> Ah, interesting, I was not aware that the firmware was supposed to do
> the pin configuration. In this case I think your patch can be merged
> as it is Mika, mine doesn't make sense anymore.
Unfortunately because of bugs we can't rely that the firmware (BIOS)
gets those always right :-(
> This particular case is special since we did not performed the tests
> on a full system that has the component integrated. We instead used
> and I2C to USB bridge to which we connected the component and we
> loaded the ACPI table dynamically.
Regardless of how did the device appear this always works:
1) request the GPIO (with GPIOD_IN)
2) convert it to IRQ using gpiod_to_irq()
Since we cannot be sure that the firmware has configured the pin
properly, rather than adding automatic IRQ <-> GPIO translation for ACPI
GpioInt I think we are better off if drivers explictly request their
GPIOs and configure them as needed.
next prev parent reply other threads:[~2015-03-30 13:33 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-23 13:40 [PATCH] IIO: Adds ACPI support for ST gyroscopes Robert Dolca
2015-03-23 13:40 ` [PATCH] IIO: Add support for L3GD20H gyroscope Robert Dolca
2015-03-24 10:29 ` Linus Walleij
2015-03-28 11:14 ` Jonathan Cameron
2015-03-23 15:18 ` [PATCH] IIO: Adds ACPI support for ST gyroscopes Mika Westerberg
2015-03-24 11:51 ` Daniel Baluta
2015-03-24 10:22 ` Linus Walleij
2015-03-24 10:37 ` Linus Walleij
2015-03-24 10:44 ` Linus Walleij
2015-03-24 12:17 ` Lars-Peter Clausen
2015-03-24 13:26 ` Robert Dolca
2015-03-24 13:38 ` Lars-Peter Clausen
2015-03-24 13:57 ` Linus Walleij
2015-03-24 15:06 ` Mika Westerberg
2015-03-24 15:22 ` Lars-Peter Clausen
2015-03-24 15:28 ` Daniel Baluta
2015-03-24 15:55 ` Mika Westerberg
2015-03-24 16:43 ` Lars-Peter Clausen
2015-03-24 16:55 ` Mika Westerberg
2015-03-25 8:44 ` Linus Walleij
2015-03-25 9:43 ` Mika Westerberg
2015-03-25 12:25 ` Mika Westerberg
2015-03-25 13:21 ` Mika Westerberg
2015-03-25 13:42 ` Robert Dolca
2015-03-25 18:05 ` sathyanarayanan kuppuswamy
2015-03-25 18:08 ` Lars-Peter Clausen
2015-03-25 21:12 ` Octavian Purdila
2015-03-26 10:06 ` Robert Dolca
2015-03-26 10:36 ` Mika Westerberg
2015-03-26 10:16 ` Mika Westerberg
2015-03-26 12:04 ` Octavian Purdila
2015-03-26 14:04 ` Mika Westerberg
2015-03-26 14:37 ` Octavian Purdila
2015-03-26 14:47 ` Mika Westerberg
2015-03-26 15:00 ` Octavian Purdila
2015-03-26 16:28 ` Octavian Purdila
2015-03-27 10:06 ` Mika Westerberg
2015-03-27 10:36 ` Linus Walleij
2015-03-30 9:52 ` Mika Westerberg
2015-03-30 12:55 ` Octavian Purdila
2015-03-30 13:33 ` Mika Westerberg [this message]
2015-03-30 13:52 ` Octavian Purdila
2015-03-30 14:18 ` Mika Westerberg
2015-04-07 9:35 ` Linus Walleij
2015-04-07 9:39 ` Lars-Peter Clausen
2015-03-26 18:32 ` Jonathan Cameron
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