From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes
Date: Mon, 02 Mar 2015 13:01:09 -0700 [thread overview]
Message-ID: <54F4C185.9080808@wwwdotorg.org> (raw)
In-Reply-To: <1425039885-5137-2-git-send-email-sebastian.hesselbarth@gmail.com>
On 02/27/2015 05:24 AM, Sebastian Hesselbarth wrote:
> I2C mux pinctrl driver currently determines the number of sub-busses by
> counting available pinctrl-names. Unfortunately, this requires each
> incarnation of the devicetree node with different available sub-busses
> to be rewritten.
>
> This patch reworks i2c-mux-pinctrl driver to count the number of
> available sub-nodes instead. The rework should be compatible to the old
> way of probing for sub-busses and additionally allows to disable unused
> sub-busses with standard DT property status = "disabled".
>
> This also amends the corresponding devicetree binding documentation to
> reflect the new functionality to disable unused sub-nodes. While at it,
> also fix two references to binding documentation files that miss an "i2c-"
> prefix.
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-pinctrl.txt
> -For each named state defined in the pinctrl-names property, an I2C child bus
> -will be created. I2C child bus numbers are assigned based on the index into
> -the pinctrl-names property.
> +For each enabled child node an I2C child bus will be created. I2C child bus
> +numbers are assigned based on the order of child nodes.
I think that I2C bus numbers are an internal concept for the OS. As
such, we should probably remove any mention re: the bus numbers from the
binding.
> -The only exception is that no bus will be created for a state named "idle". If
> -such a state is defined, it must be the last entry in pinctrl-names. For
> -example:
> +There must be a corresponding pinctrl-names entry for each enabled child
> +node at the position of the child node's "reg" property. Also, there can be
> +an idle pinctrl state defined at the end of possible pinctrl states. If such
> +a state is defined, it must be the last entry in pinctrl-names. For example:
What about gaps in the numbering sequence? IIRC, in a situation with 5
nodes with reg 0, 1, 2, 3, 4 but where only the nodes with reg of 1, 3
enabled, we only want 2 entries in pinctrl-names? If so, "at the
position of the child node's "reg" property" isn't correct, since "at
the position" implies there must be gaps in pinctrl-names. "In the same
order as the reg property values for enabled subnodes" might be a better
description.
Perhaps I'm misremembering and you explicitly didn't want to remove
entries from pinctrl-names if child nodes were disabled? If so, then
surely then in the text above, "for each enabled child" should be
replaced with "for each child"?
> @@ -68,6 +68,7 @@ Example:
> pinctrl-1 = <&state_i2cmux_pta>;
> pinctrl-2 = <&state_i2cmux_idle>;
>
> + /* Enabled child bus 0 */
> i2c at 0 {
> reg = <0>;
> #address-cells = <1>;
> @@ -79,10 +80,12 @@ Example:
> };
> };
>
> + /* Disabled child bus 1 */
> i2c at 1 {
> reg = <1>;
> #address-cells = <1>;
> #size-cells = <0>;
> + status = "disabled";
To make the example cover more cases, perhaps make child node i2c at 0
disabled and i2c at 1 enabled. Then, the example would show what happens to
pinctrl-names when there are gaps in the reg property numbering space of
enabled children?
next prev parent reply other threads:[~2015-03-02 20:01 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-17 18:52 [PATCH 0/8] Add proper support for Compulab CM-A510/SBC-A510 Sebastian Hesselbarth
2015-02-17 18:52 ` [PATCH 1/8] i2c: mux-pinctrl: Rework to honor disabled child nodes Sebastian Hesselbarth
2015-02-17 20:46 ` Stephen Warren
2015-02-17 21:08 ` Sebastian Hesselbarth
2015-02-17 21:15 ` Stephen Warren
2015-02-17 21:19 ` Sebastian Hesselbarth
2015-02-26 21:46 ` Stephen Warren
2015-02-17 18:52 ` [PATCH 2/8] devicetree: vendor-prefixes: Add CompuLab to known vendors Sebastian Hesselbarth
2015-02-17 19:37 ` Rob Herring
2015-02-17 18:52 ` [PATCH 3/8] ARM: dts: dove: Fix uart[23] reg property Sebastian Hesselbarth
2015-02-23 14:54 ` Gregory CLEMENT
2015-02-17 18:52 ` [PATCH 4/8] ARM: dts: dove: Always include gpio and interrupt-controller headers Sebastian Hesselbarth
2015-02-23 14:54 ` Gregory CLEMENT
2015-02-17 18:52 ` [PATCH 5/8] ARM: dts: dove: Add node labels for PCIe ports 0 and 1 Sebastian Hesselbarth
2015-02-23 14:55 ` Gregory CLEMENT
2015-02-17 18:52 ` [PATCH 6/8] ARM: dts: dove: Add some more common pinctrl settings Sebastian Hesselbarth
2015-02-23 14:56 ` Gregory CLEMENT
2015-02-17 18:52 ` [PATCH 7/8] ARM: dts: dove: Add internal i2c multiplexer node Sebastian Hesselbarth
2015-02-23 15:07 ` Gregory CLEMENT
2015-02-17 18:52 ` [PATCH 8/8] ARM: dts: dove: Add proper support for Compulab CM-A510/SBC-A510 Sebastian Hesselbarth
2015-02-26 17:55 ` [PATCH 0/8] " Gregory CLEMENT
2015-02-26 19:39 ` Sebastian Hesselbarth
2015-02-26 20:01 ` Stephen Warren
2015-02-26 20:35 ` Sebastian Hesselbarth
2015-02-27 12:24 ` [PATCH v2 0/4] " Sebastian Hesselbarth
2015-02-27 12:24 ` [PATCH v2 1/4] i2c: mux-pinctrl: Rework to honor disabled child nodes Sebastian Hesselbarth
2015-03-02 20:01 ` Stephen Warren [this message]
2015-03-04 9:10 ` Sebastian Hesselbarth
2015-03-09 12:21 ` [PATCH v3 " Sebastian Hesselbarth
2015-03-10 16:28 ` Stephen Warren
2015-03-16 20:15 ` Sebastian Hesselbarth
2015-03-18 12:30 ` Wolfram Sang
2015-03-18 13:23 ` Sebastian Hesselbarth
2015-03-18 14:00 ` Wolfram Sang
2015-03-18 23:10 ` Sebastian Hesselbarth
2015-03-19 10:09 ` Wolfram Sang
2015-03-19 10:48 ` Wolfram Sang
2015-03-19 15:47 ` Stephen Warren
2015-03-19 16:02 ` Wolfram Sang
2015-03-19 16:49 ` Stephen Warren
2015-03-19 20:52 ` Sebastian Hesselbarth
2015-03-20 10:19 ` Wolfram Sang
2015-03-21 21:00 ` Wolfram Sang
2015-03-22 13:03 ` Sebastian Hesselbarth
2015-03-23 18:32 ` Wolfram Sang
2015-03-27 21:08 ` Sebastian Hesselbarth
2015-04-03 18:17 ` Wolfram Sang
2015-02-27 12:24 ` [PATCH v2 2/4] devicetree: vendor-prefixes: Add CompuLab to known vendors Sebastian Hesselbarth
2015-02-27 12:24 ` [PATCH v2 3/4] ARM: dts: dove: Add internal i2c multiplexer node Sebastian Hesselbarth
2015-02-27 12:24 ` [PATCH v2 4/4] ARM: dts: dove: Add proper support for Compulab CM-A510/SBC-A510 Sebastian Hesselbarth
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