Re: [PATCH v2 2/2] arm64: dts: mt8173: Add I2C device node

From: Matthias Brugger <matthias.bgg@gmail.com>
To: Eddie Huang <eddie.huang@mediatek.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"moderated list:ARM/Mediatek SoC..." 
	<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH v2 2/2] arm64: dts: mt8173: Add I2C device node
Date: Mon, 8 Jun 2015 14:31:07 +0200	[thread overview]
Message-ID: <CABuKBeLSt9UA9os_GE140dfdpMeyWwF3cB-YNdyOP09ysuqohQ@mail.gmail.com> (raw)
In-Reply-To: <1433761837.31929.3.camel@mtksdaap41>

2015-06-08 13:10 GMT+02:00 Eddie Huang <eddie.huang@mediatek.com>:
> Hi Sascha,
>
> On Mon, 2015-06-08 at 09:27 +0200, Sascha Hauer wrote:
>> Hi Eddie,
>>
>> On Mon, Jun 01, 2015 at 09:08:27PM +0800, Eddie Huang wrote:
>> > Add MT8173 I2C device nodes, include I2C controllers and pins.
>> > MT8173 has six I2C controllers, from i2c0 to i2c6, exclude i2c5.
>> > The 6th I2C controller register base doesn't next to 5th I2C,
>> > and there is a hardware between 5th and 6th I2C controller. So
>> > SoC designer name 6th controller as "i2c6", not "i2c5".
>> >
>> > Signed-off-by: Eddie Huang <eddie.huang@mediatek.com>
>> > ---
>> >  arch/arm64/boot/dts/mediatek/mt8173.dtsi | 119 +++++++++++++++++++++++++++++++
>> >  1 file changed, 119 insertions(+)
>> >
>> > diff --git a/arch/arm64/boot/dts/mediatek/mt8173.dtsi b/arch/arm64/boot/dts/mediatek/mt8173.dtsi
>> > index b52ec43..7003ed2 100644
>> > --- a/arch/arm64/boot/dts/mediatek/mt8173.dtsi
>> > +++ b/arch/arm64/boot/dts/mediatek/mt8173.dtsi
>> > @@ -158,6 +158,53 @@
>> >                     interrupts = <GIC_SPI 145 IRQ_TYPE_LEVEL_HIGH>,
>> >                                             <GIC_SPI 146 IRQ_TYPE_LEVEL_HIGH>,
>> >                                             <GIC_SPI 147 IRQ_TYPE_LEVEL_HIGH>;
>> > +                   i2c0_pins_a: i2c0@0 {
>> > +                           pins1 {
>> > +                                   pinmux = <MT8173_PIN_45_SDA0__FUNC_SDA0>,
>> > +                                            <MT8173_PIN_46_SCL0__FUNC_SCL0>;
>> > +                                   bias-disable;
>> > +                           };
>> > +                   };
>>
>> The pinmux nodes should be in the board dts, not in the SoC dtsi.
>>
>
> These pins are fixed, and all boards using MT8173 SoC I2C controller
> should use these pins. To reduce spread these to many board dts files,
> so I put i2c pins in SoC dtsi.

There might be boards with MT8173 which don't use the I2C controller,
right? So this should not go into the SoC dtsi.
For now, we just have one board dts file for MT8173, so I think we can
put it in there.
If in the future more boards get added, we can evaluate if it makes
sense to share the I2C controller pins config between them.

Thanks,
Matthias

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