From mboxrd@z Thu Jan  1 00:00:00 1970
From: ipaton0@gmail.com (Iain Paton)
Date: Fri, 09 May 2014 08:48:07 +0100
Subject: [PATCH v2] ARM: dts: imx6: add new board RIoTboard
In-Reply-To: <20140509030938.GK2794@dragon>
References: <53695C34.5000604@gmail.com> <20140508054106.GH2794@dragon>
 <536B4ACD.30001@gmail.com> <20140509030938.GK2794@dragon>
Message-ID: <536C8837.9090802@gmail.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 09/05/14 04:09, Shawn Guo wrote:
> On Thu, May 08, 2014 at 10:13:49AM +0100, Iain Paton wrote:

>> +&ecspi1 {
>> +	fsl,spi-num-chipselects = <1>;
>> +	cs-gpios = <&gpio5 17 0>;
>> +	pinctrl-names = "default";
>> +	pinctrl-0 = <&pinctrl_ecspi1>;
>> +	status = "okay";
>> +
>> +	spidev at 0 {
>> +		spi-max-frequency = <24000000>;
>> +		reg = <0>;
>> +		compatible = "spidev";
>> +	};
> 
> What's this?  Is this the common way we code spi devices in device tree?

I'd appreciate your guidance here, what would you prefer?

My reasons for adding spidev were as follows:

1. The SPI pins are not used on the board, they go to an expansion header.
2. Board is targeted at makers who are likely to want to attach 
   external devices.
3. Experience has been that if they don't find an easy and already 
   configured way to use something they reach for devmem2 or similar.
4. devicetree is often seen as being too hard by people who come to these
   boards from things like arduino

I've already had questions on how to find the physical address of /dev/i2c-0 
seemingly due to some of the above.

I'm happy to drop the spidev entries if that's what you'd prefer, but if I
do that I'm undecided if I should then just drop the ecspi sections as well 
and free up more gpio pins on the expansion header for other uses.

I'll tidy up all the other comments, and use your suggested method for the 
i2c4 changes.

Thanks,
Iain