[PATCH 2/2] spi: spidev: document SPI_IOC_WR_DEFAULT_MAX_SPEED_HZ

From: Seraphime Kirkovski
Date: Tue May 09 2017 - 08:24:34 EST


This adds documentation of the new spidev ioctl.

Signed-off-by: Seraphime Kirkovski (Haapie) <kirkseraph@xxxxxxxxx>
---
Documentation/spi/spidev | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/Documentation/spi/spidev b/Documentation/spi/spidev
index 3d14035b1766..c67a00594dce 100644
--- a/Documentation/spi/spidev
+++ b/Documentation/spi/spidev
@@ -108,6 +108,13 @@ settings for data transfer parameters:
speed, in Hz. The controller can't necessarily assign that specific
clock speed.

+ SPI_IOC_WR_DEFAULT_MAX_SPEED_HZ ... pass a pointer to a u32 which will
+ assign the maximum speed in Hz directly to the underlying device.
+ The controller can't necessarily assign that clock speed.
+ Any subsequent open() to the same /dev/spidevB.D will be configured
+ by default to use the maximum speed assigned by the last successful
+ call to SPI_IOC_WR_DEFAULT_MAX_SPEED_HZ.
+
NOTES:

- At this time there is no async I/O support; everything is purely
--
2.13.0.rc1