| Message ID | 1435583070-9600-3-git-send-email-leilk.liu@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 29, 2015 at 9:04 PM, Leilk Liu <leilk.liu@mediatek.com> wrote: > Signed-off-by: Leilk Liu <leilk.liu@mediatek.com> > --- > .../devicetree/bindings/spi/spi-mt65xx.txt | 32 ++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > create mode 100644 Documentation/devicetree/bindings/spi/spi-mt65xx.txt > > diff --git a/Documentation/devicetree/bindings/spi/spi-mt65xx.txt b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt > new file mode 100644 > index 0000000..04c28fd > --- /dev/null > +++ b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt > @@ -0,0 +1,32 @@ > +MTK SPI device > + > +Required properties: > +- compatible: should be one of the following. > + - mediatek,mt8173-spi: for mt8173 platforms > + - mediatek,mt8135-spi: for mt8135 platforms > + - mediatek,mt6589-spi: for mt6589 platforms > + > +- reg: Address and length of the register set for the device > + > +- interrupts: Should contain spi interrupt > + > +- clock-names: tuple listing input clock names. > + Required elements: "main" > + > +- clocks: phandles to input clocks. > + > +- pad-select: should specify spi pad used, only required for MT8173. > + This value should be 0~3. > + > +Example: > + > +- SoC Specific Portion: > +spi: spi@1100a000 { > + compatible = "mediatek,mt8173-spi"; > + reg = <0 0x1100a000 0 0x1000>; > + interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_LOW>; > + clocks = <&pericfg PERI_SPI0>; CLK_PERI_SPI0 > + clock-names = "main"; > + pad-select = <1>; According to [0], a SPI bus should also specify address-cells/size-cells to allow SPI bus devices to specify a chip select. [0] Documentation/devicetree/bindings/spi/spi-bus.txt - #address-cells - number of cells required to define a chip select address on the SPI bus. - #size-cells - should be zero. The spi-bus document even describes how to mix "native" and gpio CS lines. I am still not sure what to do with the "pad-select" feature. Does "pad-select" just select one of 4 dedicated chip select lines? Or, does it also change which CK/MOSI/MISO lines are used? Ideally, the same CK/MOSI/MISO signals are sent on all CK/MOSI/MISO lines enabled by pinctrl, and "pad-select" just chooses which CS_N line to use. In this case, we can use the SPI slave device reg value to select which CS_N to use for any given device. Furthermore, we can also support using additional cs-gpios. However, if the pad-select also specifies which CK/MOSI/MISO pins are used for a given transaction, then supporting cs-gpios becomes a bit trickier, since the spi slave device would need to specify both which gpio-cs to use, as well as which SPI pad it is connected to. -Dan > + status = "disabled"; > +}; > -- > 1.8.1.1.dirty > > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-mediatek
> > + > > +- pad-select: should specify spi pad used, only required for MT8173. > > + This value should be 0~3. > > + > > +Example: > > + > > +- SoC Specific Portion: > > +spi: spi@1100a000 { > > + compatible = "mediatek,mt8173-spi"; > > + reg = <0 0x1100a000 0 0x1000>; > > + interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_LOW>; > > + clocks = <&pericfg PERI_SPI0>; > > CLK_PERI_SPI0 yes,it will be fixed. > > > + clock-names = "main"; > > + pad-select = <1>; > > According to [0], a SPI bus should also specify > address-cells/size-cells to allow SPI bus devices to specify a chip > select. > [0] Documentation/devicetree/bindings/spi/spi-bus.txt > > - #address-cells - number of cells required to define a chip select > address on the SPI bus. > - #size-cells - should be zero. > > The spi-bus document even describes how to mix "native" and gpio CS lines. > Got it, it will be added in mt8173.dtsi. > > I am still not sure what to do with the "pad-select" feature. > Does "pad-select" just select one of 4 dedicated chip select lines? > Or, does it also change which CK/MOSI/MISO lines are used? > > Ideally, the same CK/MOSI/MISO signals are sent on all CK/MOSI/MISO > lines enabled by pinctrl, and "pad-select" just chooses which CS_N > line to use. > In this case, we can use the SPI slave device reg value to select > which CS_N to use for any given device. > Furthermore, we can also support using additional cs-gpios. > > However, if the pad-select also specifies which CK/MOSI/MISO pins are > used for a given transaction, then supporting cs-gpios becomes a bit > trickier, since the spi slave device would need to specify both which > gpio-cs to use, as well as which SPI pad it is connected to. > > -Dan The pad-select changes CS/CK/MO/MI lines. Mt8173 spi has 4 group pins, and it can select which group pins will be used. Leilk. > > + status = "disabled"; > > +}; > > -- > > 1.8.1.1.dirty > > > > > > _______________________________________________ > > Linux-mediatek mailing list > > Linux-mediatek@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/linux-mediatek
On Monday, June 29, 2015 09:04:28 PM Leilk Liu wrote: > Signed-off-by: Leilk Liu <leilk.liu@mediatek.com> > --- Please add a proper patch description. Cheers, Matthias
Hi, On Mon, Jun 29, 2015 at 3:04 PM, Leilk Liu <leilk.liu@mediatek.com> wrote: > Signed-off-by: Leilk Liu <leilk.liu@mediatek.com> > --- > .../devicetree/bindings/spi/spi-mt65xx.txt | 32 ++++++++++++++++++++++ > 1 file changed, 32 insertions(+) > create mode 100644 Documentation/devicetree/bindings/spi/spi-mt65xx.txt > > diff --git a/Documentation/devicetree/bindings/spi/spi-mt65xx.txt b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt > new file mode 100644 > index 0000000..04c28fd > --- /dev/null > +++ b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt > @@ -0,0 +1,32 @@ > +MTK SPI device "SPI device" lets me think "SPI slave device", not "SPI master controller", so maybe call it "MTK SPI Controller"? > + > +Required properties: > +- compatible: should be one of the following. > + - mediatek,mt8173-spi: for mt8173 platforms > + - mediatek,mt8135-spi: for mt8135 platforms > + - mediatek,mt6589-spi: for mt6589 platforms > + > +- reg: Address and length of the register set for the device > + > +- interrupts: Should contain spi interrupt > + > +- clock-names: tuple listing input clock names. > + Required elements: "main" > + > +- clocks: phandles to input clocks. > + > +- pad-select: should specify spi pad used, only required for MT8173. > + This value should be 0~3. AFAIK device-specific non-generic properties should be vendor-prefixed, i.e. it should be "mediatek,pad-select", not just "pad-select". Regards Jonas
diff --git a/Documentation/devicetree/bindings/spi/spi-mt65xx.txt b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt new file mode 100644 index 0000000..04c28fd --- /dev/null +++ b/Documentation/devicetree/bindings/spi/spi-mt65xx.txt @@ -0,0 +1,32 @@ +MTK SPI device + +Required properties: +- compatible: should be one of the following. + - mediatek,mt8173-spi: for mt8173 platforms + - mediatek,mt8135-spi: for mt8135 platforms + - mediatek,mt6589-spi: for mt6589 platforms + +- reg: Address and length of the register set for the device + +- interrupts: Should contain spi interrupt + +- clock-names: tuple listing input clock names. + Required elements: "main" + +- clocks: phandles to input clocks. + +- pad-select: should specify spi pad used, only required for MT8173. + This value should be 0~3. + +Example: + +- SoC Specific Portion: +spi: spi@1100a000 { + compatible = "mediatek,mt8173-spi"; + reg = <0 0x1100a000 0 0x1000>; + interrupts = <GIC_SPI 110 IRQ_TYPE_LEVEL_LOW>; + clocks = <&pericfg PERI_SPI0>; + clock-names = "main"; + pad-select = <1>; + status = "disabled"; +};
Signed-off-by: Leilk Liu <leilk.liu@mediatek.com> --- .../devicetree/bindings/spi/spi-mt65xx.txt | 32 ++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 Documentation/devicetree/bindings/spi/spi-mt65xx.txt