Re: [PATCH] ARM: dts: imx23-olinuxino: Add i2c support

From: Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>
To: harald-95f8Dae0BrPYtjvyW6yDsg@public.gmane.org
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>,
	Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Fabio.Estevam-KZfg59tc24xl57MIdRCFDg@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH] ARM: dts: imx23-olinuxino: Add i2c support
Date: Thu, 09 Apr 2015 11:20:10 +0200	[thread overview]
Message-ID: <5526444A.3060805@i2se.com> (raw)
In-Reply-To: <3f0efa88b69ea2e8eb22909b6fbe6f91-VlVdRp1qTtWC18heOpxMWqxOck334EZe@public.gmane.org>

Hi Harald,

>>> This patch provides the necessary devicetree code.
>>> Tested with MOD-LCD1x9 from Olimex.
>>>
>>> This patch is based on work by Fadil Berisha with his permission.
> However
>>> all bugs are mine.
>>>
>>> Signed-off-by: Harald Geyer <harald-95f8Dae0BrPYtjvyW6yDsg@public.gmane.org>
>>> ---
>>> arch/arm/boot/dts/imx23-olinuxino.dts | 6 +++++
>>> arch/arm/boot/dts/imx23.dtsi | 40 ++++++++++++++++++++++++++++++++-
>>> 2 files changed, 45 insertions(+), 1 deletion(-)
>>>
>>> [...]
>>> --- a/arch/arm/boot/dts/imx23.dtsi
>>> +++ b/arch/arm/boot/dts/imx23.dtsi
>>> @@ -308,6 +308,39 @@
>>> fsl,voltage = <MXS_VOLTAGE_HIGH>;
>>> fsl,pull-up = <MXS_PULL_ENABLE>;
>>> };
>>> +
>>> + i2c_pins_a: i2c@0 {
>>> + reg = <0>;
>>> + fsl,pinmux-ids = <
>>> + MX23_PAD_I2C_SCL__I2C_SCL
>>> + MX23_PAD_I2C_SDA__I2C_SDA
>>> + >;
>>> + fsl,drive-strength = <MXS_DRIVE_8mA>;
>>> + fsl,voltage = <MXS_VOLTAGE_HIGH>;
>>> + fsl,pull-up = <MXS_PULL_ENABLE>;
>>> + };
>>> +
>>> + i2c_pins_b: i2c@1 {
>>> + reg = <1>;
>>> + fsl,pinmux-ids = <
>>> + MX23_PAD_LCD_ENABLE__I2C_SCL
>>> + MX23_PAD_LCD_HSYNC__I2C_SDA
>>> + >;
>>> + fsl,drive-strength = <MXS_DRIVE_8mA>;
>>> + fsl,voltage = <MXS_VOLTAGE_HIGH>;
>>> + fsl,pull-up = <MXS_PULL_ENABLE>;
>>> + };
>>> +
>>> + i2c_pins_c: i2c@2 {
>>> + reg = <2>;
>>> + fsl,pinmux-ids = <
>>> + MX23_PAD_SSP1_DATA1__I2C_SCL
>>> + MX23_PAD_SSP1_DATA2__I2C_SDA
>>> + >;
>>> + fsl,drive-strength = <MXS_DRIVE_8mA>;
>>> + fsl,voltage = <MXS_VOLTAGE_HIGH>;
>>> + fsl,pull-up = <MXS_PULL_ENABLE>;
>>> + };
>> Please add only i2c_pins_b because this pin muxing is the only used one.
> I disagree: Having all possible i2c pin groups documented in devicetree is
> a good thing. Also imx23.dtsi is more general then olinuxino - somebody
> might produce a imx23 based board where one of the other pin groups makes
> more sense to use. Well, even on olinuxino somebody might use i2c_pins_a
> if they don't need an UART, but use an LCD.

Sure. But this 2 additional muxes have nothing to do with adding i2c
support to olinuxino and should be a separate patch. In case of a revert
of this patch the other i.MX23 boards are also affected. So i think it
should be a separate patch.

Btw i read that Shawn only want used muxes [1].

[1] -
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-August/115779.html

> Thanks,
> Harald

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