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69b921acae
The MPC8309 has a dedicated signal, SPISEL_BOOT, usually used as chip select for the flash device from which the bootloader is loaded. It is not an ordinary gpio, but is simply controlled via the SPI_CS register in the system configuration. To allow accessing such a spi slave, we need to teach fsl_spi_cs_control() how to control the SPISEL_BOOT signal. To distinguish the gpio-controlled slaves, continue to have those use chip_select values of 0..ngpios-1, and use chip_select == ngpios for the boot flash. I'm not too happy with all the ifdeffery, but it seems to be necessary for guarding the sysdev/fsl_soc.h and use of get_immrbase() (spi-fsl-lib.c already contains similar ifdeffery). Googling suggests that the MPC8306 is similar, with the SPI_CS register at the same offset. Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Mark Brown <broonie@kernel.org>
63 lines
2.1 KiB
Plaintext
63 lines
2.1 KiB
Plaintext
* SPI (Serial Peripheral Interface)
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Required properties:
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- cell-index : QE SPI subblock index.
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0: QE subblock SPI1
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1: QE subblock SPI2
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- compatible : should be "fsl,spi" or "aeroflexgaisler,spictrl".
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- mode : the SPI operation mode, it can be "cpu" or "cpu-qe".
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- reg : Offset and length of the register set for the device
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- interrupts : <a b> where a is the interrupt number and b is a
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field that represents an encoding of the sense and level
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information for the interrupt. This should be encoded based on
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the information in section 2) depending on the type of interrupt
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controller you have.
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- clock-frequency : input clock frequency to non FSL_SOC cores
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Optional properties:
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- gpios : specifies the gpio pins to be used for chipselects.
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The gpios will be referred to as reg = <index> in the SPI child nodes.
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If unspecified, a single SPI device without a chip select can be used.
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- fsl,spisel_boot : for the MPC8306 and MPC8309, specifies that the
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SPISEL_BOOT signal is used as chip select for a slave device. Use
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reg = <number of gpios> in the corresponding child node, i.e. 0 if
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the gpios property is not present.
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Example:
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spi@4c0 {
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cell-index = <0>;
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compatible = "fsl,spi";
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reg = <4c0 40>;
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interrupts = <82 0>;
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interrupt-parent = <700>;
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mode = "cpu";
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gpios = <&gpio 18 1 // device reg=<0>
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&gpio 19 1>; // device reg=<1>
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};
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* eSPI (Enhanced Serial Peripheral Interface)
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Required properties:
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- compatible : should be "fsl,mpc8536-espi".
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- reg : Offset and length of the register set for the device.
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- interrupts : should contain eSPI interrupt, the device has one interrupt.
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- fsl,espi-num-chipselects : the number of the chipselect signals.
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Optional properties:
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- fsl,csbef: chip select assertion time in bits before frame starts
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- fsl,csaft: chip select negation time in bits after frame ends
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Example:
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spi@110000 {
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#address-cells = <1>;
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#size-cells = <0>;
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compatible = "fsl,mpc8536-espi";
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reg = <0x110000 0x1000>;
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interrupts = <53 0x2>;
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interrupt-parent = <&mpic>;
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fsl,espi-num-chipselects = <4>;
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fsl,csbef = <1>;
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fsl,csaft = <1>;
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};
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