[PATCH v3 17/27] serial: sh-sci: Add BRG register definitions

[Geert Uytterhoeven <geert+renesas@glider.be>]

Add register definitions for the Baud Rate Generator for External Clock
(BRG), as found in some SCIF and in HSCIF, including a new regtype for
the "SH-4(A)"-derived SCIF variant with BRG.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
v3:
  - Add Acked-by,
  - Add comment clarifying frequency divided SC_CLK vs. undivided
    (H)SCK.
---
 drivers/tty/serial/sh-sci.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
 drivers/tty/serial/sh-sci.h | 10 ++++++++++
 include/linux/serial_sci.h  |  1 +
 3 files changed, 57 insertions(+)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 5b120757c02a555a..fb5eac2e3182304d 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -161,6 +161,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -183,6 +185,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -204,6 +208,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= { 0x30, 16 },
 		[SCPDR]		= { 0x34, 16 },
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -225,6 +231,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= { 0x30, 16 },
 		[SCPDR]		= { 0x34, 16 },
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -247,6 +255,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -268,6 +278,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -289,6 +301,32 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
+	},
+
+	/*
+	 * Common SCIF definitions for ports with a Baud Rate Generator for
+	 * External Clock (BRG).
+	 */
+	[SCIx_SH4_SCIF_BRG_REGTYPE] = {
+		[SCSMR]		= { 0x00, 16 },
+		[SCBRR]		= { 0x04,  8 },
+		[SCSCR]		= { 0x08, 16 },
+		[SCxTDR]	= { 0x0c,  8 },
+		[SCxSR]		= { 0x10, 16 },
+		[SCxRDR]	= { 0x14,  8 },
+		[SCFCR]		= { 0x18, 16 },
+		[SCFDR]		= { 0x1c, 16 },
+		[SCTFDR]	= sci_reg_invalid,
+		[SCRFDR]	= sci_reg_invalid,
+		[SCSPTR]	= { 0x20, 16 },
+		[SCLSR]		= { 0x24, 16 },
+		[HSSRR]		= sci_reg_invalid,
+		[SCPCR]		= sci_reg_invalid,
+		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= { 0x30, 16 },
+		[SCCKS]		= { 0x34, 16 },
 	},
 
 	/*
@@ -310,6 +348,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= { 0x40, 16 },
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= { 0x30, 16 },
+		[SCCKS]		= { 0x34, 16 },
 	},
 
 	/*
@@ -332,6 +372,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -354,6 +396,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 
 	/*
@@ -376,6 +420,8 @@ static const struct plat_sci_reg sci_regmap[SCIx_NR_REGTYPES][SCIx_NR_REGS] = {
 		[HSSRR]		= sci_reg_invalid,
 		[SCPCR]		= sci_reg_invalid,
 		[SCPDR]		= sci_reg_invalid,
+		[SCDL]		= sci_reg_invalid,
+		[SCCKS]		= sci_reg_invalid,
 	},
 };
 
diff --git a/drivers/tty/serial/sh-sci.h b/drivers/tty/serial/sh-sci.h
index bf69bbdcc1f9aa39..fb176025042185c4 100644
--- a/drivers/tty/serial/sh-sci.h
+++ b/drivers/tty/serial/sh-sci.h
@@ -27,6 +27,8 @@ enum {
 	HSSRR,				/* Sampling Rate Register */
 	SCPCR,				/* Serial Port Control Register */
 	SCPDR,				/* Serial Port Data Register */
+	SCDL,				/* BRG Frequency Division Register */
+	SCCKS,				/* BRG Clock Select Register */
 
 	SCIx_NR_REGS,
 };
@@ -109,6 +111,14 @@ enum {
 #define SCPDR_RTSD	BIT(4)	/* Serial Port RTS Output Pin Data */
 #define SCPDR_CTSD	BIT(3)	/* Serial Port CTS Input Pin Data */
 
+/*
+ * BRG Clock Select Register (Some SCIF and HSCIF)
+ * The Baud Rate Generator for external clock can provide a clock source for
+ * the sampling clock. It outputs either its frequency divided clock, or the
+ * (undivided) (H)SCK external clock.
+ */
+#define SCCKS_CKS	BIT(15)	/* Select (H)SCK (1) or divided SC_CLK (0) */
+#define SCCKS_XIN	BIT(14)	/* SC_CLK uses bus clock (1) or SCIF_CLK (0) */
 
 #define SCxSR_TEND(port)	(((port)->type = PORT_SCI) ? SCI_TEND   : SCIF_TEND)
 #define SCxSR_RDxF(port)	(((port)->type = PORT_SCI) ? SCI_RDRF   : SCIF_RDF)
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index 7c536ac5be05d3aa..9f2bfd0557429ac3 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -32,6 +32,7 @@ enum {
 	SCIx_SH2_SCIF_FIFODATA_REGTYPE,
 	SCIx_SH3_SCIF_REGTYPE,
 	SCIx_SH4_SCIF_REGTYPE,
+	SCIx_SH4_SCIF_BRG_REGTYPE,
 	SCIx_SH4_SCIF_NO_SCSPTR_REGTYPE,
 	SCIx_SH4_SCIF_FIFODATA_REGTYPE,
 	SCIx_SH7705_SCIF_REGTYPE,
-- 
1.9.1