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8c059a4676
Update documentation for gpio-cs and num-cs to reflect the standard SPI bindings. The dma properties are optional. Include a warning that native CS do not work in a commonly useful manner with this hardware/driver, and therefor most users probably should use GPIO based CS lines rather than native. CC: Mark Brown <broonie@kernel.org> CC: Shawn Guo <shawnguo@kernel.org> CC: Sascha Hauer <kernel@pengutronix.de> CC: Fabio Estevam <fabio.estevam@nxp.com> CC: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Trent Piepho <tpiepho@impinj.com> Signed-off-by: Mark Brown <broonie@kernel.org>
53 lines
2.2 KiB
Plaintext
53 lines
2.2 KiB
Plaintext
* Freescale (Enhanced) Configurable Serial Peripheral Interface
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(CSPI/eCSPI) for i.MX
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Required properties:
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- compatible :
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- "fsl,imx1-cspi" for SPI compatible with the one integrated on i.MX1
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- "fsl,imx21-cspi" for SPI compatible with the one integrated on i.MX21
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- "fsl,imx27-cspi" for SPI compatible with the one integrated on i.MX27
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- "fsl,imx31-cspi" for SPI compatible with the one integrated on i.MX31
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- "fsl,imx35-cspi" for SPI compatible with the one integrated on i.MX35
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- "fsl,imx51-ecspi" for SPI compatible with the one integrated on i.MX51
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- "fsl,imx53-ecspi" for SPI compatible with the one integrated on i.MX53 and later Soc
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- reg : Offset and length of the register set for the device
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- interrupts : Should contain CSPI/eCSPI interrupt
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- clocks : Clock specifiers for both ipg and per clocks.
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- clock-names : Clock names should include both "ipg" and "per"
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See the clock consumer binding,
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Documentation/devicetree/bindings/clock/clock-bindings.txt
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Recommended properties:
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- cs-gpios : GPIOs to use as chip selects, see spi-bus.txt. While the native chip
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select lines can be used, they appear to always generate a pulse between each
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word of a transfer. Most use cases will require GPIO based chip selects to
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generate a valid transaction.
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Optional properties:
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- num-cs : Number of total chip selects, see spi-bus.txt.
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- dmas: DMA specifiers for tx and rx dma. See the DMA client binding,
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Documentation/devicetree/bindings/dma/dma.txt.
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- dma-names: DMA request names, if present, should include "tx" and "rx".
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- fsl,spi-rdy-drctl: Integer, representing the value of DRCTL, the register
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controlling the SPI_READY handling. Note that to enable the DRCTL consideration,
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the SPI_READY mode-flag needs to be set too.
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Valid values are: 0 (disabled), 1 (edge-triggered burst) and 2 (level-triggered burst).
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Obsolete properties:
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- fsl,spi-num-chipselects : Contains the number of the chipselect
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Example:
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ecspi@70010000 {
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#address-cells = <1>;
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#size-cells = <0>;
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compatible = "fsl,imx51-ecspi";
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reg = <0x70010000 0x4000>;
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interrupts = <36>;
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cs-gpios = <&gpio3 24 0>, /* GPIO3_24 */
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<&gpio3 25 0>; /* GPIO3_25 */
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dmas = <&sdma 3 7 1>, <&sdma 4 7 2>;
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dma-names = "rx", "tx";
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fsl,spi-rdy-drctl = <1>;
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};
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