linux-kernel - Re: [PATCH v7 1/2] mfd: devicetree: add bindings for Atmel Flexcom

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Message-ID: <55B1F9B7.2080206@atmel.com>
Date:	Fri, 24 Jul 2015 10:39:19 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Boris Brezillon <boris.brezillon@...e-electrons.com>,
	Cyrille Pitchen <cyrille.pitchen@...el.com>,
	<lee.jones@...aro.org>
CC:	<alexandre.belloni@...e-electrons.com>, <sameo@...ux.intel.com>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <robh+dt@...nel.org>,
	<pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>,
	<devicetree@...r.kernel.org>
Subject: Re: [PATCH v7 1/2] mfd: devicetree: add bindings for Atmel Flexcom

Le 23/07/2015 21:48, Boris Brezillon a écrit :
> On Thu, 23 Jul 2015 18:42:55 +0200
> Cyrille Pitchen <cyrille.pitchen@...el.com> wrote:
> 
>> This patch documents the DT bindings for the Atmel Flexcom which will be
>> introduced by sama5d2x SoCs. These bindings will be used by the actual
>> Flexcom driver to be sent in another patch.
>>
>> Signed-off-by: Cyrille Pitchen <cyrille.pitchen@...el.com>
>> ---
>>  .../devicetree/bindings/mfd/atmel-flexcom.txt      | 68 ++++++++++++++++++++++
>>  1 file changed, 68 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
>> new file mode 100644
>> index 000000000000..a63226b7a9cb
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/atmel-flexcom.txt
>> @@ -0,0 +1,68 @@
>> +* Device tree bindings for Atmel Flexcom (Flexible Serial Communication Unit)
>> +
>> +The Atmel Flexcom is just a wrapper which embeds a SPI controller, an I2C
>> +controller and an USART. Only one function can be used at a time and is chosen
>> +at boot time according to the device tree.
>> +
>> +Required properties:
>> +- compatible:		Should be "atmel,sama5d2-flexcom"
>> +- reg:			Should be the pair (offset, size) for the Flexcom
>> +			dedicated I/O registers (without USART, TWI or SPI
>> +			registers).
>> +- clocks:		Should be the Flexcom peripheral clock from PMC.
>> +- #address-cells:	Should be <2>
>> +- #size-cells:		Should be <1>
>> +- ranges:		Should be a list of ranges.
>> +			One range per peripheral wrapped by the Flexcom. So each
>> +			range is a triplet (child_addr, parent_addr, size). The
>> +			first u32 of "child_addr" is the value to be set in the
>> +			Operating Mode bitfield of the Flexcom Mode Register.
>> +			Then "parent_addr" stores the base address of the
>> +			corresponding peripheral in the system memory. Finally,
>> +			"size" if the size of the memory region of this
>> +			peripheral.
>> +
>> +Required child:
>> +A single available child for the serial controller to enable.
>> +
>> +Required properties of this child:
>> +- reg:			Should be a pair (child_addr, size) with child_addr
>> +			matching one of the parent ranges.
>> +- clocks:		Should be the very same phandle as for the parent's one.
>> +
>> +Other properties remain unchanged. See documentation of the respective device:
>> +- ../serial/atmel-usart.txt
>> +- ../spi/spi_atmel.txt
>> +- ../i2c/i2c-at91.txt
>> +
>> +Example:
>> +
>> +flexcom@...34000 {
>> +	compatible = "atmel,sama5d2-flexcom";
>> +	reg = <0xf8034000 0x200>;
>> +	clocks = <&flx0_clk>;
>> +	#address-cells = <2>;
>> +	#size-cells = <1>;
>> +	ranges = <1 0 0xf8034200 0x200		/* opmode 1: USART */
>> +		  2 0 0xf8034400 0x200		/* opmode 2: SPI */
>> +		  3 0 0xf8034600 0x200>;	/* opmode 3: I2C */

Yes, the opmode(s) are exactly the values described in the product
datasheet.

>> +
>> +	spi@...34400 {
> 
> Should be:
> 
> 	spi@2,0 {

Yep!

I was silently following the discussion in the background and I admit
that this approach is pretty elegant.

So, if this approach is validated you can also add my:
Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>


>> +		compatible = "atmel,at91rm9200-spi";
>> +		reg = <2 0 0x200>;
>> +		interrupts = <19 IRQ_TYPE_LEVEL_HIGH 7>;
>> +		pinctrl-names = "default";
>> +		pinctrl-0 = <&pinctrl_flx0_default>;
>> +		#address-cells = <1>;
>> +		#size-cells = <0>;
>> +		clocks = <&flx0_clk>;
>> +		clock-names = "spi_clk";
>> +		atmel,fifo-size = <32>;
>> +
>> +		mtd_dataflash@0 {
>> +			compatible = "atmel,at25f512b";
>> +			reg = <0>;
>> +			spi-max-frequency = <20000000>;
>> +		};
>> +	};
>> +};
> 
> 
> 


-- 
Nicolas Ferre
--
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