Re: [PATCH 0/6 v2] gpiolib: Add GPIO name support

[Markus Pargmann <mpa@pengutronix.de>]

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On Tue, Aug 04, 2015 at 11:23:17AM +0200, Markus Pargmann wrote:
> Hi,
> 
> Changes in v2:

Sorry, forgot to add v2 into the subject.

Best regards,

Markus

>  - Removed patch 'gpiolib: Fix possible use of wrong name'
>  - Removed discussed patch 'gpio: Allow hogged gpios to be requested' from this
>    series
>  - Fixed show gpio name patch (locks, (null) printing, and getting the descriptor)
>  - Merged gpio name patch into gpio_name_to_desc() patch
> 
> Description from v1:
> 
> This is a proposal to add GPIO names to the kernel based on devicetree
> descriptions.
> 
> This series adds GPIO name support. Until now it is only possible to use names
> for already requested GPIOs (for example what they are used for). It is not
> possible to identify GPIOs by a name although most of them have a name for
> example in the schematics of the board. This makes it difficult to identify
> a specific GPIO from userspace.
> 
> As the GPIO name information is a hardware description this series uses the
> devicetree bindings introduced by the GPIO hogging mechanism, specifically
> 'line-name', to identify GPIOs. The sysfs 'export' file is changed to accept
> names as fallback. The gpio numbers still have a higher priority to ensure
> backwards compatibility.
> 
> Exported GPIOs are still using their number as directory name (gpio<ID>). But the
> directories now contain a 'name' file which is '' for non-existent names and
> the name otherwise.
> 
> This series can be used to have an easy name mapping for udev with a quite
> simple rule similar to this:
> 	SUBSYSTEM=="gpio", KERNEL=="gpio*", ATTR{name}!="(null)", ACTION=="add", \
> 	PROGRAM+="/bin/sh -c 'mkdir -p /dev/gpios; rm -f /dev/gpios/$attr{name}; ln -s /sys%p/ /dev/gpios/$attr{name}"
> With this rule udev adds a link for each exported GPIO with a name into
> /dev/gpios/. This way it is not necessary to know the number of a GPIO to use
> it.
> 
> Best Regards,
> 
> Markus
> 
> 
> Markus Pargmann (6):
>   gpiolib-of: Rename gpio_hog functions to be generic
>   gpio: Introduce gpio descriptor 'name'
>   gpiolib-of: Reuse 'line-name' from DT as gpio descriptor name
>   gpiolib-sysfs: Add gpio name parsing for sysfs export
>   gpiolib-sysfs: Show gpio-name in /sys/class/gpio/gpio*/name
>   gpiolib: Add gpio name information to /sys/kernel/debug/gpio
> 
>  drivers/gpio/gpiolib-of.c     | 41 ++++++++++++++++++------------
>  drivers/gpio/gpiolib-sysfs.c  | 59 +++++++++++++++++++++++++++++++++----------
>  drivers/gpio/gpiolib.c        | 43 ++++++++++++++++++++++++++++---
>  drivers/gpio/gpiolib.h        |  3 +++
>  include/linux/gpio/consumer.h |  7 +++++
>  5 files changed, 121 insertions(+), 32 deletions(-)
> 
> -- 
> 2.1.4
> 
> 

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