From: Laxman Dewangan <ldewangan@nvidia.com>
To: Stephen Warren <swarren@wwwdotorg.org>
Cc: "linus.walleij@linaro.org" <linus.walleij@linaro.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] pinctrl: palmas: do not abort pin configuration for BIAS_DEFAULT
Date: Sat, 28 Sep 2013 17:08:20 +0530 [thread overview]
Message-ID: <5246BFAC.5020306@nvidia.com> (raw)
In-Reply-To: <5245AD0C.7070206@wwwdotorg.org>
On Friday 27 September 2013 09:36 PM, Stephen Warren wrote:
> On 09/27/2013 07:30 AM, Laxman Dewangan wrote:
>> On Thursday 26 September 2013 09:08 PM, Stephen Warren wrote:
>>> On 09/26/2013 06:48 AM, Laxman Dewangan wrote:
>>>> Recent movement of all configurations of pin in the single call of
>>>> pin_config_set(), it is aborting configuration if BIAS_PULL_PIN_DEFAULT
>>>> is selected as return of configuration.
>>>>
>>>> The original idea was to just avoid any update on register for pull
>>>> up/down
>>>> configuration if this option is selected.
>>> That doesn't sound correct. If a config option is specified in DT or the
>>> mapping table, it should be applied to HW. If someone doesn't want a
>>> particular config option applied, then it simply shouldn't be mentioned
>>> in DT or the mapping table.
>>>
>>> IIUC, BIAS_DEFAULT should be used only on HW where there is a concept of
>>> a true default bias, and in that case, that is what should be applied.
>>>
>> Hmm.. When I added the PIN_DEFAULT, I just though that do not update
>> anything in the register and implemented like that.
>> There is nothing "default" option in HW.
> The description of that pinconfig option is:
>
>> 7970cb77 (Heiko Stübner 2013-06-06 16:44:25 +0200 43) * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down based
>> 70637a6d (Heiko Stübner 2013-06-25 14:55:42 +0200 44) * on embedded knowledge of the controller hardware, like current mux
>> 70637a6d (Heiko Stübner 2013-06-25 14:55:42 +0200 45) * function. The pull direction and possibly strength too will normally
>> 70637a6d (Heiko Stübner 2013-06-25 14:55:42 +0200 46) * be decided completely inside the hardware block and not be readable
>> 70637a6d (Heiko Stübner 2013-06-25 14:55:42 +0200 47) * from the kernel side.
>> 5ca3353b (Linus Walleij 2013-06-16 12:43:06 +0200 48) * If the argument is != 0 pull up/down is enabled, if it is 0, the
>> 5ca3353b (Linus Walleij 2013-06-16 12:43:06 +0200 49) * configuration is ignored. The proper way to disable it is to use
>> 5ca3353b (Linus Walleij 2013-06-16 12:43:06 +0200 50) * @PIN_CONFIG_BIAS_DISABLE.
> If the HW doesn't support any concept of a default pull, I think the
> driver shouldn't support that option; it should return an error if asked
> to program it.
Yes, I will remove this option as I have not seen default option for pins.
>
>
> But what made you come across this issue? Is some pin mapping table or
> DT pinctrl node actually using that value? If so, then presumably that
> needs to be fixed, as well as removing driver support for that option.
When referring the code for the AMSAS3722 pincontrol driver, I just
found that it is breaking the earlier code.
Removing this option makes more reasonable here and will post the next
patch.
next prev parent reply other threads:[~2013-09-28 11:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 12:48 [PATCH 1/2] pinctrl: palmas: do not abort pin configuration for BIAS_DEFAULT Laxman Dewangan
2013-09-26 12:48 ` [PATCH 2/2] pinctrl: palmas: remove non-require function Laxman Dewangan
2013-09-27 13:53 ` Linus Walleij
2013-09-26 15:38 ` [PATCH 1/2] pinctrl: palmas: do not abort pin configuration for BIAS_DEFAULT Stephen Warren
2013-09-27 13:30 ` Laxman Dewangan
2013-09-27 16:06 ` Stephen Warren
2013-09-28 11:38 ` Laxman Dewangan [this message]
2013-10-02 10:40 ` Linus Walleij
2013-10-02 11:10 ` Laxman Dewangan
2013-10-02 11:20 ` Heiko Stübner
2013-10-02 16:10 ` Stephen Warren
2013-09-27 14:25 ` Linus Walleij
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=5246BFAC.5020306@nvidia.com \
--to=ldewangan@nvidia.com \
--cc=linus.walleij@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=swarren@wwwdotorg.org \
/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;
as well as URLs for NNTP newsgroup(s).