From: Stephen Warren <swarren@wwwdotorg.org>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 09/14] fdt: Add polarity-aware gpio functions to fdtdec
Date: Wed, 31 Oct 2012 22:50:19 -0600 [thread overview]
Message-ID: <5091FF8B.7040109@wwwdotorg.org> (raw)
In-Reply-To: <CAPnjgZ0x=1mgwZ049amB1G4ADM_bBke3TY33Co7cNnHhc3V5zg@mail.gmail.com>
On 10/31/2012 05:59 PM, Simon Glass wrote:
> Hi,
>
> On Fri, Oct 26, 2012 at 12:17 AM, Lucas Stach <dev@lynxeye.de> wrote:
>> Am Donnerstag, den 25.10.2012, 19:31 -0700 schrieb Simon Glass:
>>> From: Sean Paul <seanpaul@chromium.org>
>>>
>>> Add get and set gpio functions to fdtdec that take into account the
>>> polarity field in fdtdec_gpio_state.flags.
>>>
>> In another thread Stephen Warren and I came to the conclusion that we
>> most likely should remove this polarity flag from the GPIO bindings.
>>
>> Currently it is only for the USB VBUS GPIO which should move over to
>> regulators once they land in U-Boot. Do you have any other applications
>> for this flag, so we might reconsider removing it?
>>
>
> Well, any time you have a flag which is inverted in meaning, it can be
> useful. We have several switches on the board which can be active high
> or low, and polarity is used for that.
>
> In fact, it would be nice IMO to be able to specify input/output as
> well. I know the exynos bindings do this. There is a noddy function
> called fdtdec_setup_gpio() in U-Boot which really needs to be sorted
> out. I discussed with Stephen some time ago how GPIOs should be
> SOC-specific and it should be possible to set up a GPIO with a single
> call, as Linux does. The more information there is in the binding, the
> more it can do automatically.
>
> Does the Tegra Linux GPIO binding still have a polarity?
Yes it does, although in practice it can't be used (and hence should
really be removed), since not all GPIO bindings have such a flag, so
there is always a need for a separate property to indicate the polarity
(c.f. fixed-regulator with GPIO control bindings for example).
next prev parent reply other threads:[~2012-11-01 4:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 2:30 [U-Boot] [PATCH 0/14] fdt: Add various device tree utilities and features Simon Glass
2012-10-26 2:30 ` [U-Boot] [PATCH 01/14] fdt: Add function to get config int from device tree Simon Glass
2012-10-26 2:30 ` [U-Boot] [PATCH 02/14] fdt: Add function to get a config string " Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 03/14] fdt: Add fdtdec_decode_region() to decode memory region Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 04/14] fdt: Add function for decoding multiple gpios globally available Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 05/14] fdt: Export fdtdec_find_alias_node() function Simon Glass
2012-10-26 4:24 ` David Gibson
2012-10-31 23:50 ` Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 06/14] fdt: Export fdtdec_lookup() and fix the name Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 07/14] fdt: Add function to read boolean property Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 08/14] fdt: Add fdtdec_get_uint64 to decode a 64-bit value from a property Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 09/14] fdt: Add polarity-aware gpio functions to fdtdec Simon Glass
2012-10-26 7:17 ` Lucas Stach
2012-10-31 23:59 ` Simon Glass
2012-11-01 4:50 ` Stephen Warren [this message]
2012-11-15 23:31 ` Simon Glass
2012-11-15 23:46 ` Stephen Warren
2012-11-16 0:01 ` Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 10/14] fdt: Load boot command from device tree Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 11/14] fdt: Tell the FDT library where the device tree is Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 12/14] fdt: Allow device tree to specify secure booting Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 13/14] fdt: Add option to default to most compatible conf in a fit image Simon Glass
2012-10-26 2:31 ` [U-Boot] [PATCH 14/14] fdt: Set kernaddr if fdt indicates a kernel is present Simon Glass
2012-11-28 14:30 ` Dennis Lan
2012-11-28 15:16 ` Simon Glass
2012-11-18 1:35 ` [U-Boot] [PATCH 0/14] fdt: Add various device tree utilities and features Jerry Van Baren
2012-11-19 17:08 ` Simon Glass
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5091FF8B.7040109@wwwdotorg.org \
--to=swarren@wwwdotorg.org \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox