From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/8] i2c: mux-pinctrl: Rework to honor disabled child nodes
Date: Tue, 17 Feb 2015 13:46:31 -0700 [thread overview]
Message-ID: <54E3A8A7.8080703@wwwdotorg.org> (raw)
In-Reply-To: <1424199129-22099-2-git-send-email-sebastian.hesselbarth@gmail.com>
On 02/17/2015 11:52 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.
Can you be more explicit about the problem here? Why does anything need
to be re-written if a child node is disabled; presumably there's no need
for the child bus numbers to be contiguous. In other words, with the
example in the existing DT binding doc:
i2cmux {
compatible = "i2c-mux-pinctrl";
...
pinctrl-names = "ddc", "pta", "idle";
pinctrl-0 = <&state_i2cmux_ddc>;
pinctrl-1 = <&state_i2cmux_pta>;
pinctrl-2 = <&state_i2cmux_idle>;
i2c at 0 {
reg = <0>;
...
i2c at 1 {
reg = <1>;
...
That would generate child busses 0 and 1. If I was to disable the i2c at 0
node, then there would still be definitions for child busses 0 and 1 in
the DT, it's just that child bus 0 wouldn't actually exist at run-time.
I don't see what part of DT needs to be re-written to accomodate this?
> 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 child node that is not disabled by a status != "okay", an I2C
> +child bus will be created. I2C child bus numbers are assigned based on the
> +order of child nodes.
I would have assumed that disabled sub-nodes was a global concept within
DT, and so wouldn't be mentioned in the binding. It would just be a bug
in the driver if it didn't ignore disabled sub-nodes.
>
> -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:
> -
> - pinctrl-names = "ddc", "pta", "idle" -> ddc = bus 0, pta = bus 1
> - pinctrl-names = "ddc", "idle", "pta" -> Invalid ("idle" not last)
> - pinctrl-names = "idle", "ddc", "pta" -> Invalid ("idle" not last)
> +There must be a corresponding pinctrl-names entry for each enabled child
> +node at the position of the child node's "reg" property.
The addition there seems fine, but the existing text re: the idle state
seems clearer in the original text.
>
> Whenever an access is made to a device on a child bus, the relevant pinctrl
> state will be programmed into hardware.
>
> -If an idle state is defined, whenever an access is not being made to a device
> -on a child bus, the idle pinctrl state will be programmed into hardware.
> +Also, there can be an idle pinctrl state defined at the end of possible
> +pinctrl states. If an idle state is defined, whenever an access is not being
> +made to a device on a child bus, the idle pinctrl state will be programmed
> +into hardware.
next prev parent reply other threads:[~2015-02-17 20:46 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 [this message]
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
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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