[PATCH/RFC] serial: sh-sci: Add device tree support for r8a7779

[Simon Horman]

On Fri, Apr 25, 2014 at 01:33:29AM +0200, Laurent Pinchart wrote:
> Hi Simon,
> 
> Thank you for the patch.
> 
> On Thursday 24 April 2014 15:54:44 Simon Horman wrote:
> > According to the platform data for the legacy-C initialisation of sh-sci
> > for the r8a7779 SoC and my own testing the SCIx_SH4_SCIF_REGTYPE bit of
> > scscr needs to be set.
> > 
> > Signed-off-by: Simon Horman <horms+renesas at verge.net.au>
> > 
> > ---
> > 
> > With the approach taken by this patch sh-sci may be initialised using the
> > "renesas,scif-r8a7779" compat string but not the generic "renesas,scif"
> > compat string.  An alternate approach would be to add a binding to allow
> > setting of this bit to be controlled directly from DT.
> 
> Handling the SCSCR bits properly with DT has been on my to-do list for some 
> time. Thank you for volunteering to implement that :-D
> 
> The CKE bits control both the behaviour of the SCK pin and the SCIF input 
> clock selection. The SCIF can use various internal and external clocks, with 
> up to two baud rate generators (programmable dividers) chained. Whether the 
> SoC is provided with an external clock for its serial ports is a board 
> property, not an SoC property. I would thus like to implement support for this 
> feature properly and avoid hardcoding the CKE bits like done below.
> 
> The Marzen board has an external clock generator connected to the SCIF_SCK pin 
> that can be used as a clock source, but I don't really see a reason why we 
> couldn't use the internal P clock instead. I don't want to delay integration 
> of SCIF DT support until we have a proper solution to handle clock 
> configuration, but couldn't we use the internal P clock on the Marzen board in 
> the meantime ?

I think that approach sounds reasonable and I seem to have it working
without any driver changes. Could you confirm that the following
DT snippet is what you have in mind? (I intend to update it as per any
relevant changes you make when reposting your DT sci patch for the
r8a7791.)


diff --git a/arch/arm/boot/dts/r8a7779.dtsi b/arch/arm/boot/dts/r8a7779.dtsi
index e924f96..3e9cca4 100644
--- a/arch/arm/boot/dts/r8a7779.dtsi
+++ b/arch/arm/boot/dts/r8a7779.dtsi
@@ -203,6 +203,66 @@
 		status = "disabled";
 	};
 
+	scif0: serial at ffe40000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe40000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 88 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
+	scif1: serial at ffe41000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe41000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 89 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
+	scif2: serial at ffe42000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe42000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 90 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
+	scif3: serial at ffe43000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe43000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 91 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
+	scif4: serial at ffe44000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe44000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 92 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
+	scif5: serial at ffe45000 {
+		compatible = "renesas,scif", "renesas,scif-r8a7779";
+		reg = <0xffe45000 265>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 93 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg_clocks R8A7779_CLK_P>;
+		clock-names = "sci_ick";
+		status = "disabled";
+	};
+
 	pfc: pfc at fffc0000 {
 		compatible = "renesas,pfc-r8a7779";
 		reg = <0xfffc0000 0x23c>;