Re: [PATCH 1/3] doc: dt: add documentation for Mediatek spi-nor controller
From: Brian Norris <hidden>
Date: 2015-09-11 21:47:10
Also in:
linux-arm-kernel, linux-mediatek, lkml
On Tue, Sep 08, 2015 at 05:49:54PM +0800, Bayi Cheng wrote:
quoted hunk ↗ jump to hunk
Add device tree binding documentation for serial flash with Mediatek serial flash controller Signed-off-by: Bayi Cheng <bayi.cheng-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org> --- Documentation/devicetree/bindings/mtd/mtk_nor.txt | 25 +++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/devicetree/bindings/mtd/mtk_nor.txtdiff --git a/Documentation/devicetree/bindings/mtd/mtk_nor.txt b/Documentation/devicetree/bindings/mtd/mtk_nor.txt new file mode 100644 index 0000000..0eca0cd --- /dev/null +++ b/Documentation/devicetree/bindings/mtd/mtk_nor.txt@@ -0,0 +1,25 @@ +* MTD SPI nor driver for MTK MT81xx (and similar) serial flash controller + +MTK MT81xx serial flash controller is designed for serial Flash device. +It supports one Flash device with signal mode, dual mode and quad mode. + +Required properties: +- compatible: should be "mediatek,mt8173-nor"; +- reg: physical base address and length of the controller's register +- clocks: spi nor source clock +- clock-names: "spi_clk", "axi_clk", "mux_clk", "sf_clk" + +See Documentation/devicetree/bindings/clock/clock-bindings.txt +and Documentation/mtd/spi-nor.txt for details. + +Example: +nor_flash: nor@1100d000 { + compatible = "mediatek,mt8173-nor"; + reg = <0 0x1100d000 0 0xe0>; + clocks = <&pericfg CLK_PERI_SPI>, + <&topckgen CLK_TOP_AXI_SEL>, + <&topckgen CLK_TOP_UNIVPLL2_D8>, + <&topckgen CLK_TOP_SPINFI_IFR_SEL>; + clock-names = "spi_clk", "axi_clk", "mux_clk", "sf_clk"; +};
I understand that for now, you only support a single flash, and you
don't need any extra flash-specific DT properties, but in the interest
of being more generic and more in-line with other drivers, can you
include:
* #addres-cells (= <1>) and #size-cells (= <0>) properties
* sub-node(s) representing the flash; reference [1], and there's a
good example in a recent submission [2]
So I'd expect something like:
nor_flash: nor@1100d000 {
compatible = "mediatek,mt8173-nor";
...
#address-cells = <1>;
#size-cells = <0>;
flash@0 {
compatible = "jedec,spi-nor";
reg = <0>;
...
};
};
This patch is also relevant [3] (hopefully I'll get to merge that one
soon); you'll want to use the sub-node (not the main node) when
initializing the flash device.
I think maybe we'll want to codify some of this in a "SPI NOR
controller" document, so we can make sure more developers follow this
when designing their binding.
Brian
[1] https://www.kernel.org/doc/Documentation/devicetree/bindings/mtd/jedec,spi-nor.txt
[2] http://lists.infradead.org/pipermail/linux-mtd/2015-August/061439.html
[3] http://lists.infradead.org/pipermail/linux-mtd/2015-September/061637.html
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