From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/4] ARM: pinctrl: Add Broadcom Capri pinctrl driver
Date: Wed, 06 Nov 2013 10:00:22 -0700 [thread overview]
Message-ID: <527A75A6.5010904@wwwdotorg.org> (raw)
In-Reply-To: <5279A319.5060701@broadcom.com>
On 11/05/2013 07:02 PM, Sherman Yin wrote:
> On 13-11-04 04:04 PM, Stephen Warren wrote:
>> On 11/04/2013 04:26 PM, Heiko St?bner wrote:
>>
>>> I remember we had a discussion about how things like bias-disable
>>> explicitly
>>> shouldn't have a value, when they are represented in the list-format:
>>>
>>> pcfg_pull_none: pcfg_pull_none {
>>> bias-disable;
>>> };
>>>
>>> so a bias-disable = <1> was explicitly "forbidden" [for a lack of a
>>> better
>>> word]. And it was similar for other options, the parameter not meant
>>> to be
>>> indicating if they are active but really only setting the "strength"
>>> or so.
>>
>> Pure Boolean values should be represented as a valueless property. If
>> the property is present, the value is true, otherwise false.
>>
>> However, pinctrl bindings often don't represent Boolean values, but
>> rather tri-states, with the following values:
>>
>> * Don't touch this configuration option at all (missing)
>> * Enable the option (<1>)
>> * Disable the option (<0>)
>>
>> The reason for using tri-states being that you might want to write:
>>
>> xxx1 {
>> pins = <PINA>, <PINB>, <PINC>;
>> function = <...>;
>> // this node doesn't affect pullup
>> }
>> xxx2 {
>> pins = <PINA>, <PINB>;
>> // this node doesn't affect function
>> pull-up = <1>; // change, and enable
>> }
>> xxx3 {
>> pins = <PINAC>;
>> // this node doesn't affect function
>> pull-up = <0>; // change, and disable
>> }
>
> If I understand correctly, in Stephen's example, if a certain driver
> wants to configure PINA PINB and PINC, the pin configuration nodes
> "xxx1", "xxx2", and "xxx3" will all have to be selected for the
> particular pin state.
You probably don't want to reference the individual xxx1/2/3 nodes in
the client pinctrl properties, but instead wrap them in a higher-level
node that represents the whole pinctrl state. Then, the client pinctrl
properties can reference just that single parent node, instead of many
small nodes. In other words:
pinctrl at ... {
...
sx: state_xxx {
xxx1 { ... };
xxx2 { ... };
xxx3 { ... };
};
sy: state_yyy {
yyy1 { ... };
yyy2 { ... };
};
}
some_client at ... {
...
pinctrl-names = "default";
pinctrl-0 = <&sx>;
};
other_client at ... {
...
pinctrl-names = "default";
pinctrl-0 = <&sy>;
};
rather than:
pinctrl at ... {
...
sx1: xxx1 { ... };
sx2: xxx2 { ... };
sx3: xxx3 { ... };
sy1: yyy1 { ... };
sy2: yyy2 { ... };
}
some_client at ... {
...
pinctrl-names = "default";
pinctrl-0 = <&sx1 &sx2 &sx3>;
};
other_client at ... {
...
pinctrl-names = "default";
pinctrl-0 = <&sy1 &sy2>;
};
This is exactly how the Tegra pinctrl bindings work for example.
> This works fine. However, I'm just thinking that
> it would have been easier if we could specify just one node:
>
> xxx {
> pins = <PINA>, <PINB>, <PINC>;
> function = <...>;
> pull-up = <1 1 0>;
> }
>
> This "feature" seems a bit more concise to me and is what I did for my
> original pinctrl driver. The only downside is that with this method,
> one cannot specify "don't touch this option for this pin" if the same
> property must provide values for other pins.
The other downside is that if the lists get even slightly long, it get
really hard to match up the entries in the t properties.
next prev parent reply other threads:[~2013-11-06 17:00 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-04 0:23 [PATCH 0/4] Add Broadcom Capri pinctrl driver Sherman Yin
2013-10-04 0:23 ` [PATCH 1/4] pinctrl: Add void * to pinctrl_pin_desc Sherman Yin
2013-10-09 8:55 ` Linus Walleij
2013-10-09 22:57 ` Sherman Yin
2013-10-04 0:23 ` [PATCH 2/4] pinctrl: Add pinctrl binding for Broadcom Capri SoCs Sherman Yin
2013-10-04 12:51 ` Matt Porter
2013-10-09 8:53 ` Linus Walleij
2013-10-10 17:57 ` Sherman Yin
2013-10-04 0:23 ` [PATCH 3/4] ARM: pinctrl: Add Broadcom Capri pinctrl driver Sherman Yin
2013-10-09 9:10 ` Linus Walleij
2013-10-10 23:48 ` Sherman Yin
2013-10-11 8:14 ` Linus Walleij
2013-10-11 18:25 ` Sherman Yin
2013-10-22 23:29 ` Sherman Yin
2013-10-25 22:48 ` Sherman Yin
2013-11-04 12:24 ` Linus Walleij
2013-11-04 23:26 ` Heiko Stübner
2013-11-05 0:04 ` Stephen Warren
2013-11-06 2:02 ` Sherman Yin
2013-11-06 9:40 ` Linus Walleij
2013-11-08 0:29 ` Sherman Yin
2013-11-11 10:01 ` Linus Walleij
2013-11-13 23:43 ` Sherman Yin
2013-11-19 20:39 ` Linus Walleij
2013-11-06 17:00 ` Stephen Warren [this message]
2013-11-07 22:01 ` Sherman Yin
2013-11-06 9:29 ` Linus Walleij
2013-10-17 6:03 ` Christian Daudt
2013-10-17 14:54 ` Stephen Warren
2013-10-17 15:31 ` Christian Daudt
2013-12-11 0:05 ` Sherman Yin
2013-12-12 20:43 ` Linus Walleij
2013-10-04 0:23 ` [PATCH 4/4] pinctrl: Enable pinctrl for Broadcom Capri SoCs Sherman Yin
2013-10-09 9:11 ` Linus Walleij
2013-10-07 19:28 ` [PATCH v2 0/4] Add Broadcom Capri pinctrl driver Sherman Yin
2013-10-07 19:28 ` [PATCH v2 1/4] pinctrl: Add void * to pinctrl_pin_desc Sherman Yin
2013-10-07 19:28 ` [PATCH v2 2/4] pinctrl: Add pinctrl binding for Broadcom Capri SoCs Sherman Yin
2013-10-07 19:28 ` [PATCH v2 3/4] ARM: pinctrl: Add Broadcom Capri pinctrl driver Sherman Yin
2013-10-07 19:28 ` [PATCH v2 4/4] pinctrl: Enable pinctrl for Broadcom Capri SoCs Sherman Yin
2013-12-11 18:37 ` [PATCH v3 0/6] Add Broadcom Capri pinctrl driver Sherman Yin
2013-12-11 18:37 ` [PATCH v3 1/6] pinctrl: Add void * to pinctrl_pin_desc Sherman Yin
2013-12-11 18:37 ` [PATCH v3 2/6] pinctrl: Adds slew-rate, input-enable/disable Sherman Yin
2013-12-12 20:41 ` Linus Walleij
2013-12-16 9:55 ` Linus Walleij
2013-12-11 18:37 ` [PATCH v3 3/6] pinctrl: Make PINCTRL selectable by defconfig/menuconfig Sherman Yin
2013-12-12 20:39 ` Linus Walleij
2013-12-12 21:35 ` Christian Daudt
2013-12-16 10:01 ` Linus Walleij
2013-12-17 0:18 ` Bjorn Andersson
2013-12-20 9:37 ` Linus Walleij
2013-12-20 20:58 ` Arnd Bergmann
2013-12-21 2:15 ` Sherman Yin
2013-12-11 18:37 ` [PATCH v3 4/6] pinctrl: Add pinctrl binding for Broadcom Capri SoCs Sherman Yin
2013-12-12 20:37 ` Linus Walleij
2013-12-14 1:16 ` Sherman Yin
2013-12-16 13:17 ` Linus Walleij
2013-12-18 2:02 ` Sherman Yin
2013-12-11 18:37 ` [PATCH v3 5/6] ARM: pinctrl: Add Broadcom Capri pinctrl driver Sherman Yin
2013-12-12 20:54 ` Linus Walleij
2013-12-13 10:22 ` Mark Brown
2013-12-19 0:12 ` Sherman Yin
2013-12-18 23:56 ` Sherman Yin
2013-12-21 2:31 ` Sherman Yin
2013-12-11 18:37 ` [PATCH v3 6/6] pinctrl: Enable pinctrl for Broadcom Capri SoCs Sherman Yin
2013-12-21 2:13 ` [PATCH v4 0/6] Add Broadcom Capri pinctrl driver Sherman Yin
2013-12-21 2:13 ` [PATCH v4 1/4] pinctrl: Add void * to pinctrl_pin_desc Sherman Yin
2014-01-16 13:26 ` Linus Walleij
2013-12-21 2:13 ` [PATCH v4 2/4] pinctrl: Add pinctrl binding for Broadcom Capri SoCs Sherman Yin
2014-01-07 17:15 ` Linus Walleij
2014-01-07 20:45 ` Sherman Yin
2014-01-14 10:16 ` Linus Walleij
2014-01-14 19:00 ` Sherman Yin
2014-01-15 9:40 ` Linus Walleij
2014-01-15 16:39 ` Mark Rutland
2014-01-16 13:24 ` Linus Walleij
2013-12-21 2:13 ` [PATCH v4 3/4] ARM: pinctrl: Add Broadcom Capri pinctrl driver Sherman Yin
2014-01-16 13:19 ` Linus Walleij
2014-01-17 19:59 ` Sherman Yin
2014-01-18 2:56 ` Matt Porter
2014-01-20 8:16 ` Linus Walleij
2014-01-20 19:14 ` Sherman Yin
2014-01-21 12:35 ` Linus Walleij
2014-01-21 13:49 ` Matt Porter
2013-12-21 2:13 ` [PATCH v4 4/4] pinctrl: Enable pinctrl for Broadcom Capri SoCs Sherman Yin
2014-01-16 13:28 ` Linus Walleij
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