serial: sh-sci: Add more Serial Port Control/Data Register documentation

Improve documentation for the SCIFA/SCIFB Serial Port Control and Data
Registers:
  - State clearly that the RTS and CTS lines are active-low,
  - Document the bits related to the serial port's SCK, RXD, and TXD
    pins.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index 85a2b81..e7d2bc6 100644 (file)
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -121,12 +121,18 @@ enum {
 #define HSCIF_SRE      BIT(15) /* Sampling Rate Register Enable */
 
 /* SCPCR (Serial Port Control Register), SCIFA/SCIFB only */
-#define SCPCR_RTSC     BIT(4)  /* Serial Port RTS Pin / Output Pin */
-#define SCPCR_CTSC     BIT(3)  /* Serial Port CTS Pin / Input Pin */
+#define SCPCR_RTSC     BIT(4)  /* Serial Port RTS# Pin / Output Pin */
+#define SCPCR_CTSC     BIT(3)  /* Serial Port CTS# Pin / Input Pin */
+#define SCPCR_SCKC     BIT(2)  /* Serial Port SCK Pin / Output Pin */
+#define SCPCR_RXDC     BIT(1)  /* Serial Port RXD Pin / Input Pin */
+#define SCPCR_TXDC     BIT(0)  /* Serial Port TXD Pin / Output Pin */
 
 /* SCPDR (Serial Port Data Register), SCIFA/SCIFB only */
-#define SCPDR_RTSD     BIT(4)  /* Serial Port RTS Output Pin Data */
-#define SCPDR_CTSD     BIT(3)  /* Serial Port CTS Input Pin Data */
+#define SCPDR_RTSD     BIT(4)  /* Serial Port RTS# Output Pin Data */
+#define SCPDR_CTSD     BIT(3)  /* Serial Port CTS# Input Pin Data */
+#define SCPDR_SCKD     BIT(2)  /* Serial Port SCK Output Pin Data */
+#define SCPDR_RXDD     BIT(1)  /* Serial Port RXD Input Pin Data */
+#define SCPDR_TXDD     BIT(0)  /* Serial Port TXD Output Pin Data */
 
 /*
  * BRG Clock Select Register (Some SCIF and HSCIF)