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Message-ID: <20150724150735.GH3436@x1>
Date: Fri, 24 Jul 2015 16:07:35 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Nicolas Ferre <nicolas.ferre@...el.com>
Cc: Boris Brezillon <boris.brezillon@...e-electrons.com>,
Cyrille Pitchen <cyrille.pitchen@...el.com>,
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
On Fri, 24 Jul 2015, Lee Jones wrote:
> On Fri, 24 Jul 2015, Nicolas Ferre wrote:
>
> > 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>
>
> Please see my reply to v6 for the usual way to achieve this.
Ah, actually scrap that. Looks like I was thinking you were doing
something different. Well I don't know enough about the advanced use
of the ranges property to comment on this. I need to call for some
assistance from the DT chaps.
> > >> + 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>;
> > >> + };
> > >> + };
> > >> +};
> > >
> > >
> > >
> >
> >
>
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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