Subject: [PATCH V4 01/11] dt-bindings: firmware: imx-scu: new binding to parse clocks from device tree

From: Dong Aisheng <[email-masked]>
Date: Tue, 20 Aug 2019 07:13:15 -0400

There's a few limitations on the original one cell clock binding
(#clock-cells = <1>) that we have to define some SW clock IDs for device
tree to reference. This may cause troubles if we want to use common
clock IDs for multi platforms support when the clock of those platforms
are mostly the same.
e.g. Current clock IDs name are defined with SS prefix.

However the device may reside in different SS across CPUs, that means the
SS prefix may not valid anymore for a new SoC. Furthermore, the device
availability of those clocks may also vary a bit.

For such situation, we want to eliminate the using of SW Clock IDs and
change to use a more close to HW one instead.
For SCU clocks usage, only two params required: Resource id + Clock Type.
Both parameters are platform independent. So we could use two cells binding
to pass those parameters,

Cc: Rob Herring <[email-masked]>
Cc: Stephen Boyd <[email-masked]>
Cc: Shawn Guo <[email-masked]>
Cc: Sascha Hauer <[email-masked]>
Cc: Michael Turquette <[email-masked]>
Cc: [email-masked]
Signed-off-by: Dong Aisheng <[email-masked]>
---
ChangeLog:
v3->v4:
 * add some comments for various clock types
v2->v3:
 * Changed to two cells binding and register all clocks in driver
   instead of parse from device tree.
v1->v2:
 * changed to one cell binding inspired by arm,scpi.txt
   Documentation/devicetree/bindings/arm/arm,scpi.txt
   Resource ID is encoded in 'reg' property.
   Clock type is encoded in generic clock-indices property.
   Then we don't have to search all the DT nodes to fetch
   those two value to construct clocks which is relatively
   low efficiency.
 * Add required power-domain property as well.
---
 .../devicetree/bindings/arm/freescale/fsl,scu.txt  | 12 ++++++-----
 include/dt-bindings/firmware/imx/rsrc.h            | 23 ++++++++++++++++++++++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
index a575e42..8cee5bf 100644
--- a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
+++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
@@ -89,7 +89,10 @@ Required properties:
 			  "fsl,imx8qm-clock"
 			  "fsl,imx8qxp-clock"
 			followed by "fsl,scu-clk"
-- #clock-cells:		Should be 1. Contains the Clock ID value.
+- #clock-cells:		Should be either
+			2: Contains the Resource and Clock ID value.
+			or
+			1: Contains the Clock ID value. (DEPRECATED)
 - clocks:		List of clock specifiers, must contain an entry for
 			each required entry in clock-names
 - clock-names:		Should include entries "xtal_32KHz", "xtal_24MHz"
@@ -184,7 +187,7 @@ firmware {
 
 		clk: clk {
 			compatible = "fsl,imx8qxp-clk", "fsl,scu-clk";
-			#clock-cells = <1>;
+			#clock-cells = <2>;
 		};
 
 		iomuxc {
@@ -229,8 +232,7 @@ serial@5a060000 {
 	...
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_lpuart0>;
-	clocks = <&clk IMX8QXP_UART0_CLK>,
-		 <&clk IMX8QXP_UART0_IPG_CLK>;
-	clock-names = "per", "ipg";
+	clocks = <&uart0_clk IMX_SC_R_UART_0 IMX_SC_PM_CLK_PER>;
+	clock-names = "ipg";
 	power-domains = <&pd IMX_SC_R_UART_0>;
 };
diff --git a/include/dt-bindings/firmware/imx/rsrc.h b/include/dt-bindings/firmware/imx/rsrc.h
index 4e61f64..24c153d 100644
--- a/include/dt-bindings/firmware/imx/rsrc.h
+++ b/include/dt-bindings/firmware/imx/rsrc.h
@@ -547,4 +547,27 @@
 #define IMX_SC_R_ATTESTATION		545
 #define IMX_SC_R_LAST			546
 
+/*
+ * Defines for SC PM CLK
+ */
+
+/* Normal device resource clock */
+#define IMX_SC_PM_CLK_SLV_BUS		0	/* Slave bus clock */
+#define IMX_SC_PM_CLK_MST_BUS		1	/* Master bus clock */
+#define IMX_SC_PM_CLK_PER		2	/* Peripheral clock */
+#define IMX_SC_PM_CLK_PHY		3	/* Phy clock */
+#define IMX_SC_PM_CLK_MISC		4	/* Misc clock */
+
+/* Special clock types which do not belong to above normal clock types */
+#define IMX_SC_PM_CLK_MISC0		0	/* Misc 0 clock */
+#define IMX_SC_PM_CLK_MISC1		1	/* Misc 1 clock */
+#define IMX_SC_PM_CLK_MISC2		2	/* Misc 2 clock */
+#define IMX_SC_PM_CLK_MISC3		3	/* Misc 3 clock */
+#define IMX_SC_PM_CLK_MISC4		4	/* Misc 4 clock */
+
+/* Special clock types for CPU/PLL/BYPASS only */
+#define IMX_SC_PM_CLK_CPU		2	/* CPU clock */
+#define IMX_SC_PM_CLK_PLL		4	/* PLL */
+#define IMX_SC_PM_CLK_BYPASS		4	/* Bypass clock */
+
 #endif /* __DT_BINDINGS_RSCRC_IMX_H */
-- 
2.7.4

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