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From: Timur Tabi <timur@codeaurora.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>
Cc: linux-arm-msm@vger.kernel.org,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	linux-gpio@vger.kernel.org,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	David Brown <david.brown@linaro.org>,
	Andy Gross <andy.gross@linaro.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Varadarajan Narayanan <varada@codeaurora.org>,
	Archit Taneja <architt@codeaurora.org>
Subject: Re: [PATCH 4/4] [v4] pinctrl: qcom: qdf2xxx: add support for new ACPI HID QCOM8002
Date: Tue, 12 Dec 2017 14:27:10 -0600	[thread overview]
Message-ID: <88349f2e-5243-8061-cc72-d01fa70e6f2e@codeaurora.org> (raw)
In-Reply-To: <1513076836.25007.641.camel@linux.intel.com>

On 12/12/2017 05:07 AM, Andy Shevchenko wrote:

> Not ACPI standards as of my knowledge. ACPI standard defines a common
> scheme how to define properties, it doesn't tell anything about property
> names or any mappings between names to values or names to "OS
> subsystem").

There was an attempt a while back to standardize this like we do for 
device tree, but it fell apart.  Device-specific ACPI-only properties 
are not standarized.  This driver is initialized only on ACPI systems. 
It has no device tree binding.

> As for GPIO we just follow *de facto* what DT has right now, i.e. "xxx-
> gpio" or "xxx-gpios" pattern is used to map ACPI standard resource to a
> GPIO name. That's how GPIO ACPI lib is being developed.

GPIOs in device tree are defined completely differently than in ACPI. 
On DT, the kernel controls the pin muxing.  On ACPI, pins are muxed by 
firmware and never re-muxed by the operating system.  So all this driver 
does is expose a few pins as simple GPIOs.

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

WARNING: multiple messages have this Message-ID (diff)
From: timur@codeaurora.org (Timur Tabi)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/4] [v4] pinctrl: qcom: qdf2xxx: add support for new ACPI HID QCOM8002
Date: Tue, 12 Dec 2017 14:27:10 -0600	[thread overview]
Message-ID: <88349f2e-5243-8061-cc72-d01fa70e6f2e@codeaurora.org> (raw)
In-Reply-To: <1513076836.25007.641.camel@linux.intel.com>

On 12/12/2017 05:07 AM, Andy Shevchenko wrote:

> Not ACPI standards as of my knowledge. ACPI standard defines a common
> scheme how to define properties, it doesn't tell anything about property
> names or any mappings between names to values or names to "OS
> subsystem").

There was an attempt a while back to standardize this like we do for 
device tree, but it fell apart.  Device-specific ACPI-only properties 
are not standarized.  This driver is initialized only on ACPI systems. 
It has no device tree binding.

> As for GPIO we just follow *de facto* what DT has right now, i.e. "xxx-
> gpio" or "xxx-gpios" pattern is used to map ACPI standard resource to a
> GPIO name. That's how GPIO ACPI lib is being developed.

GPIOs in device tree are defined completely differently than in ACPI. 
On DT, the kernel controls the pin muxing.  On ACPI, pins are muxed by 
firmware and never re-muxed by the operating system.  So all this driver 
does is expose a few pins as simple GPIOs.

-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm
Technologies, Inc.  Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.

  reply	other threads:[~2017-12-12 20:27 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01 23:28 [PATCH 0/4] [v8] pinctrl: qcom: add support for sparse GPIOs Timur Tabi
2017-12-01 23:28 ` Timur Tabi
2017-12-01 23:28 ` [PATCH 1/4] [v2] Revert "gpio: set up initial state from .get_direction()" Timur Tabi
2017-12-01 23:28   ` Timur Tabi
2017-12-01 23:28 ` [PATCH 2/4] [v2] gpiolib: add bitmask for valid GPIO lines Timur Tabi
2017-12-01 23:28   ` Timur Tabi
2017-12-12  9:58   ` Andy Shevchenko
2017-12-12  9:58     ` Andy Shevchenko
2017-12-12 20:16     ` Timur Tabi
2017-12-12 20:16       ` Timur Tabi
2017-12-01 23:28 ` [PATCH 3/4] [v7] pinctrl: qcom: disable GPIO groups with no pins Timur Tabi
2017-12-01 23:28   ` Timur Tabi
2017-12-01 23:28 ` [PATCH 4/4] [v4] pinctrl: qcom: qdf2xxx: add support for new ACPI HID QCOM8002 Timur Tabi
2017-12-01 23:28   ` Timur Tabi
2017-12-12 10:05   ` Andy Shevchenko
2017-12-12 10:05     ` Andy Shevchenko
2017-12-12 20:17     ` Timur Tabi
2017-12-12 20:17       ` Timur Tabi
2017-12-13 14:32       ` Andy Shevchenko
2017-12-13 14:32         ` Andy Shevchenko
2017-12-13 14:46         ` Timur Tabi
2017-12-13 14:46           ` Timur Tabi
2017-12-13 15:18           ` Timur Tabi
2017-12-13 15:18             ` Timur Tabi
2017-12-13 15:40             ` Andy Shevchenko
2017-12-13 15:40               ` Andy Shevchenko
     [not found]   ` <1512170904-4749-5-git-send-email-timur-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2017-12-12 10:42     ` Linus Walleij
2017-12-12 10:42       ` Linus Walleij
2017-12-12 11:07       ` Andy Shevchenko
2017-12-12 11:07         ` Andy Shevchenko
2017-12-12 20:27         ` Timur Tabi [this message]
2017-12-12 20:27           ` Timur Tabi
2017-12-13 14:36           ` Andy Shevchenko
2017-12-13 14:36             ` Andy Shevchenko
2017-12-13 14:47             ` Timur Tabi
2017-12-13 14:47               ` Timur Tabi

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