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Re: [PATCH 2/3] dt-bindings: add binding for at91-usart in spi mode




On 13/04/2018 at 18:23, Alexandre Belloni wrote:
On 13/04/2018 19:11:16+0300, Radu Pirea wrote:
These are bindings for at91-usart IP in spi spi mode. There is no support for
internal chip select. Only kind of chip selects available are gpio chip
selects.

Signed-off-by: Radu Pirea <radu.pirea@xxxxxxxxxxxxx>
---
  .../bindings/spi/microchip,at91-usart-spi.txt | 24 +++++++++++++++++++
  1 file changed, 24 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt

diff --git a/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt b/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
new file mode 100644
index 000000000000..92d33ccdffae
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/microchip,at91-usart-spi.txt
@@ -0,0 +1,24 @@
+* Universal Synchronous Asynchronous Receiver/Transmitter (USART) in SPI mode
+
+Required properties:
+- #size-cells      : Must be <0>
+- #address-cells   : Must be <1>
+- compatible: Should be "microchip,at91sam9g45-usart-spi" or "microchip,sama5d2-usart-spi"
+- reg: Should contain registers location and length
+- interrupts: Should contain interrupt
+- clocks: phandles to input clocks.
+- clock-names: tuple listing input clock names.
+	Required elements: "usart"
+- cs-gpios: chipselects (internal cs not supported)
+
+Example:
+	spi0: spi@f001c000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "microchip,sama5d2-usart-spi", "microchip,at91sam9g45-usart-spi";

I'm pretty sure this will be considered configuration rather than
hardware description. Why don't you do something like the flexcom mode
selection?

Because we are not in the same situation as having a glue layer that would select one of the already existing peripherals with associated drivers above. This layout of the hardware is completely different from the USART one and it seems to makes sense to address it with a different hardware description and so a different compatible string.

Regards,
  Nicolas

+		reg = <0xf001c000 0x100>;
+		interrupts = <12 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&usart0_clk>;
+		clock-names = "usart";
+		cs-gpios = <&pioB 3 0>;
+	};
--
2.17.0




--
Nicolas Ferre