[PATCH V2 4/5] dt-bindings: pinctrl: add imx7ulp pinctrl binding doc

-----Original Message-----
From: Linus Walleij [mailto:linus.walleij at linaro.org]
Sent: Monday, May 22, 2017 5:27 PM
To: A.S. Dong; Jacopo Mondi; Geert Uytterhoeven; Chris Brandt; Andy
Shevchenko
Cc: linux-gpio at vger.kernel.org; linux-arm-kernel at lists.infradead.org;
Shawn Guo; Stefan Agner; Jacky Bai; Andy Duan; Sascha Hauer; Rob Herring;
Mark Rutland; devicetree at vger.kernel.org
Subject: Re: [PATCH V2 4/5] dt-bindings: pinctrl: add imx7ulp pinctrl
binding doc

On Fri, May 19, 2017 at 9:05 AM, Dong Aisheng [off-list ref] wrote:

quoted

i.MX 7ULP has three IOMUXC instances: IOMUXC0 for M4 ports,
IOMUXC1 for A7 ports and IOMUXC DDR for DDR interface.

This patch adds the IOMUXC1 support for A7.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree at vger.kernel.org
Cc: Linus Walleij <redacted>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>

(...)

quoted

+=== Pin Configuration Node ===
+- pins: One integers array, represents a group of pins mux setting.
+       The format is fsl,pins = <PIN_FUNC_ID>, PIN_FUNC_ID is a pin

working on

quoted

+       a specific function.
+
+       NOTE: i.MX7ULP PIN_FUNC_ID consists of 4 integers as it shares

one mux

quoted

+       and config register as follows:
+       <mux_conf_reg input_reg mux_mode input_val>
+
+       Refer to imx7ulp-pinfunc.h in in device tree source folder for

all

quoted

+       available imx7ulp PIN_FUNC_ID.
+
+Optional Properties:
+- nxp,output-buffer-enable:    Bool. Output buffer enabled
+- nxp,input-buffer-enable:     Bool. Input buffer enabled
+- drive-strength               Integer. Controls Drive Strength
+                                       0: Standard
+                                       1: Hi Driver

(...)

WELL LOOK AT THAT

Custom input/output buffer enable properties eh?

We had this really really long discussion with the Renesas people about
whether they make this a custom property or a generic one or whether
anyone else would ever have the same need.

This would be a vote for adding output-buffer-enable and input-buffer-
enable as generic properies hm?

Yes, that would be good if they're made generic properties.

UNLESS the existing device tree properties already cover the usecases.

Andy has made some good points there.

Can you please read up on the discussion thread for subject "[PATCH v5
01/10] pinctrl: generic: Add bi-directional and output-enable"
and contribute to this discussion?

Sure, will find time to read it.

Thanks for the reminder.

Regards
Dong Aisheng