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-rw-r--r--Documentation/devicetree/bindings/spi/sh-msiof.txt10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/spi/sh-msiof.txt b/Documentation/devicetree/bindings/spi/sh-msiof.txt
index bc8c16a6cfc8..80710f0f0448 100644
--- a/Documentation/devicetree/bindings/spi/sh-msiof.txt
+++ b/Documentation/devicetree/bindings/spi/sh-msiof.txt
@@ -41,6 +41,16 @@ Optional properties:
0: MSIOF_SYNC
1: MSIOF_SS1
2: MSIOF_SS2
+ Hardware limitations related to chip selects:
+ - Native chip selects are always deasserted in
+ between transfers that are part of the same
+ message. Use cs-gpios to work around this.
+ - All slaves using native chip selects must use the
+ same spi-cs-high configuration. Use cs-gpios to
+ work around this.
+ - When using GPIO chip selects, at least one native
+ chip select must be left unused, as it will be
+ driven anyway.
- dmas : Must contain a list of two references to DMA
specifiers, one for transmission, and one for
reception.