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author | Sascha Hauer <s.hauer@pengutronix.de> | 2021-01-05 12:56:25 +0100 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2021-01-07 11:41:05 +0100 |
commit | 6ea3de1b8ce7a0154233bd75e77e6e44a525d0ef (patch) | |
tree | 5d16ca525c12dddb21d9c4750dfd1a1e354eb731 /dts/Bindings/spi/spi-controller.yaml | |
parent | 93c4690b4921d3149db3fcf5b62a8aa5010a4ae7 (diff) | |
download | barebox-6ea3de1b8ce7a0154233bd75e77e6e44a525d0ef.tar.gz barebox-6ea3de1b8ce7a0154233bd75e77e6e44a525d0ef.tar.xz |
dts: update to v5.11-rc1
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'dts/Bindings/spi/spi-controller.yaml')
-rw-r--r-- | dts/Bindings/spi/spi-controller.yaml | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/dts/Bindings/spi/spi-controller.yaml b/dts/Bindings/spi/spi-controller.yaml index 1b56d5e40f..5f50581010 100644 --- a/dts/Bindings/spi/spi-controller.yaml +++ b/dts/Bindings/spi/spi-controller.yaml @@ -42,6 +42,33 @@ properties: cs2 : &gpio1 1 0 cs3 : &gpio1 2 0 + The second flag of a gpio descriptor can be GPIO_ACTIVE_HIGH (0) + or GPIO_ACTIVE_LOW(1). Legacy device trees often use 0. + + There is a special rule set for combining the second flag of an + cs-gpio with the optional spi-cs-high flag for SPI slaves. + + Each table entry defines how the CS pin is to be physically + driven (not considering potential gpio inversions by pinmux): + + device node | cs-gpio | CS pin state active | Note + ================+===============+=====================+===== + spi-cs-high | - | H | + - | - | L | + spi-cs-high | ACTIVE_HIGH | H | + - | ACTIVE_HIGH | L | 1 + spi-cs-high | ACTIVE_LOW | H | 2 + - | ACTIVE_LOW | L | + + Notes: + 1) Should print a warning about polarity inversion. + Here it would be wise to avoid and define the gpio as + ACTIVE_LOW. + 2) Should print a warning about polarity inversion + because ACTIVE_LOW is overridden by spi-cs-high. + Should be generally avoided and be replaced by + spi-cs-high + ACTIVE_HIGH. + num-cs: $ref: /schemas/types.yaml#/definitions/uint32 description: |