mmc: document 'Reliable Write' bit in uapi header

If we use it this way, people should know about it. Also, replace
true/false with nonzero/zero because the flag is not strictly a bool
anymore.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/include/uapi/linux/mmc/ioctl.h b/include/uapi/linux/mmc/ioctl.h
index 45f369d..00c0812 100644 (file)
--- a/include/uapi/linux/mmc/ioctl.h
+++ b/include/uapi/linux/mmc/ioctl.h
@@ -5,7 +5,10 @@
 #include <linux/types.h>
 
 struct mmc_ioc_cmd {
-       /* Implies direction of data.  true = write, false = read */
+       /*
+        * Direction of data: nonzero = write, zero = read.
+        * Bit 31 selects 'Reliable Write' for RPMB.
+        */
        int write_flag;
 
        /* Application-specific command.  true = precede with CMD55 */