u-boot/doc/device-tree-bindings/spi/spi-mcf-dspi.txt
Vladimir Oltean e7005b3e80 fsl_dspi: Introduce DT bindings for CS-SCK and SCK-CS delays
Communication with some SPI slaves just won't cut it if these delays
(before the beginning, and after the end of a transfer) are not added to
the Chip Select signal.

These are a straight copy from Linux:
Documentation/devicetree/bindings/spi/spi-fsl-dspi.txt
drivers/spi/spi-fsl-dspi.c

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
[Rebased]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>
2020-07-27 14:16:26 +05:30

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Text

Freescale ColdFire DSPI controller
Required properties:
- compatible : "fsl,mcf-dspi"
- #address-cells: <1>, as required by generic SPI binding
- #size-cells: <0>, also as required by generic SPI binding
- reg : offset and length of the register set for the device
Optional properties:
- spi-max-frequency : max supported spi frequency
- num-cs : the number of the chipselect signals
- spi-mode: spi motorola mode, 0 to 3
- ctar-params: CTAR0 to 7 register configuration, as an array
of 8 integer fields for each register, where each register
is defined as: <fmsz, pcssck, pasc, pdt, cssck, asc, dt, br>.
- fsl,spi-cs-sck-delay: a delay in nanoseconds between activating chip
select and the start of clock signal, at the start of a transfer.
- fsl,spi-sck-cs-delay: a delay in nanoseconds between stopping the clock
signal and deactivating chip select, at the end of a transfer.
Example:
dspi0: dspi@fc05c000 {
compatible = "fsl,mcf-dspi";
#address-cells = <1>;
#size-cells = <0>;
reg = <0xfc05c000 0x100>;
spi-max-frequency = <50000000>;
num-cs = <4>;
spi-mode = <0>;
ctar-fields = <7, 0, 0, 0, 0, 0, 1, 6>,
<7, 0, 0, 0, 0, 0, 1, 6>,
<7, 0, 0, 0, 0, 0, 1, 6>;
};