[PATCH 1/3] pinctrl: pinctrl-imx: add imx pinctrl core driver

[Sascha Hauer]

On Sun, Apr 15, 2012 at 10:17:43PM +0800, Shawn Guo wrote:
> On Sun, Apr 15, 2012 at 11:49:04AM +0800, Dong Aisheng wrote:
> ...
> I'm thinking about documenting the definition we used to have in
> iomux-mx*.h in the binding document and assign id to each of them
> in order.
> 
> pinmux						id
> ------						--
> MX6Q_PAD_SD2_DAT1__USDHC2_DAT1			0
> MX6Q_PAD_SD2_DAT1__ECSPI5_SS0			1
> MX6Q_PAD_SD2_DAT1__WEIM_WEIM_CS_2		2
> ...
> 
> The ordering between the list and imx6q_pin_regs[] array need to match.
> 
> By looking at the binding document, we can just put pinmux-id into
> property "fsl,pins" (maybe rename it to "fsl,pinmux-ids") to get the
> desired pinmux settings.  With doing so, we can gain the following.
> 
> 1) The pinmux-id can be used as index to locate the entry in array
>    imx6q_pin_regs[], so that the slow string lookup can be avoid.
> 
> 2) Property "fsl,mux" can be dropped, as it's been encoded in
>    imx6q_pin_regs[] entry.
> 
> 3) Converting the existing board files to device tree will be much
>    easier.  We only need to find the pinmux-id of those existing
>    definitions and put them in "fsl, pinmux-ids".
> 
> 4) When DTC support macro, we can simply move the pinmux-id list from
>    binding document into dts file.  No driver change is needed at all.

How far are we away from getting macro support? Do we already agree that we
want to have such a feature? I remember I saw someone mentioning it,
maybe even by piping the devicetree though CPP, but I didn't follow the
further discussion.

Sascha

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