openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

spi: imx: Update device tree binding documentation 

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>
This commit is contained in:
Trent Piepho 2017-11-15 11:52:32 -08:00 committed by Mark Brown
parent abbdb5ce31
commit 8c059a4676
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
Documentation/devicetree/bindings/spi/fsl-imx-cspi.txt
View File

@ -12,24 +12,30 @@ Required properties:
- "fsl,imx53-ecspi" for SPI compatible with the one integrated on i.MX53 and later Soc
- reg : Offset and length of the register set for the device
- interrupts : Should contain CSPI/eCSPI interrupt
- cs-gpios : Specifies the gpio pins to be used for chipselects.
- clocks : Clock specifiers for both ipg and per clocks.
- clock-names : Clock names should include both "ipg" and "per"
See the clock consumer binding,
Documentation/devicetree/bindings/clock/clock-bindings.txt
- dmas: DMA specifiers for tx and rx dma. See the DMA client binding,
Documentation/devicetree/bindings/dma/dma.txt
- dma-names: DMA request names should include "tx" and "rx" if present.
Obsolete properties:
- fsl,spi-num-chipselects : Contains the number of the chipselect
Recommended properties:
- cs-gpios : GPIOs to use as chip selects, see spi-bus.txt. While the native chip
select lines can be used, they appear to always generate a pulse between each
word of a transfer. Most use cases will require GPIO based chip selects to
generate a valid transaction.
Optional properties:
- num-cs : Number of total chip selects, see spi-bus.txt.
- dmas: DMA specifiers for tx and rx dma. See the DMA client binding,
Documentation/devicetree/bindings/dma/dma.txt.
- dma-names: DMA request names, if present, should include "tx" and "rx".
- fsl,spi-rdy-drctl: Integer, representing the value of DRCTL, the register
controlling the SPI_READY handling. Note that to enable the DRCTL consideration,
the SPI_READY mode-flag needs to be set too.
Valid values are: 0 (disabled), 1 (edge-triggered burst) and 2 (level-triggered burst).
Obsolete properties:
- fsl,spi-num-chipselects : Contains the number of the chipselect
Example:
ecspi@70010000 {