From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH RFC 1/4] ARM: bcm2835: remove sdhci pins from GPIO pinctrl
Date: Thu, 10 Dec 2015 22:15:38 -0700 [thread overview]
Message-ID: <566A5BFA.7010009@wwwdotorg.org> (raw)
In-Reply-To: <213306787.32979.5a38c754-5911-4377-aa1a-501587b3a337.open-xchange@email.1und1.de>
On 12/05/2015 02:12 AM, Stefan Wahren wrote:
>
>> Stephen Warren <swarren@wwwdotorg•org> hat am 2. Dezember 2015 um 04:40
>> geschrieben:
>>
>>
>> On 11/19/2015 09:06 AM, Stefan Wahren wrote:
>>> Currently the pins alt3 (sdhci) are assigned to GPIO pinctrl.
>>> This is bad because a user could export it to sysfs and break
>>> sdhci. In order to avoid that remove those pins from GPIO pintrl.
>>
>>> diff --git a/arch/arm/boot/dts/bcm2835-rpi-a-plus.dts
>>> b/arch/arm/boot/dts/bcm2835-rpi-a-plus.dts
>>
>>> &gpio {
>>> - pinctrl-0 = <&gpioout &alt0 &i2s_alt0 &alt3>;
>>> + pinctrl-0 = <&gpioout &alt0 &i2s_alt0>;
>>
>> This doesn't make sense. The current DT content is configuring those
>> pins as SDHCI, not as GPIO. Admitedly this is redundant since the
>> firmware and/or bootloader already did this in order to boot the system,
>> but irrespective, the current DT causes no issues. Removing the pinctrl
>> setting should not influence whether the pins can be exported via GPIO
>> sysfs either.
>
> You are right.
>
> Is it generally possible to avoid the GPIO sysfs export for SDHCI pins?
> Is it an issue of pinctrl-bcm2835?
I believe this same issue exists on all platforms where GPIO pins can be
mux'd onto the same pins as other functions.
next prev parent reply other threads:[~2015-12-11 5:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-19 16:06 [PATCH RFC 0/4] ARM: bcm2835: assign pins to sdhci pinctrl Stefan Wahren
2015-11-19 16:06 ` [PATCH RFC 1/4] ARM: bcm2835: remove sdhci pins from GPIO pinctrl Stefan Wahren
2015-12-02 3:40 ` Stephen Warren
2015-12-05 9:12 ` Stefan Wahren
2015-12-11 5:15 ` Stephen Warren [this message]
2015-11-19 16:06 ` [PATCH RFC 2/4] ARM: bcm2835: rename sdhci pin group Stefan Wahren
2015-12-02 3:42 ` Stephen Warren
2015-12-05 9:43 ` Stefan Wahren
2015-12-11 5:19 ` Stephen Warren
2015-11-19 16:06 ` [PATCH RFC 3/4] ARM: bcm2835: specify card detect pin for RPi B Stefan Wahren
2015-12-02 3:44 ` Stephen Warren
2015-12-02 16:33 ` Stefan Wahren
2015-11-19 16:06 ` [PATCH RFC 4/4] ARM: bcm2835: assign pins to sdhci pinctrl Stefan Wahren
2015-12-01 23:03 ` Eric Anholt
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