serial: vt8500: UART uses gated clock rather than 24Mhz reference

UART modules on Wondermedia SoCs are connected via a gated clock
source, rather than directly to the 24Mhz reference clock. While
uboot enables UART0 for debugging, other UART ports are unavailable
until the clock is enabled.

This patch checks that a valid clock is actually passed from devicetree,
enables the clock in probe. This change removes the fallback when a
clock was not specified as it doesn't apply any longer (and would only
work if the UART clock was already enabled).

DTSI files are updated for VT8500, WM8505 and WM8650.

Signed-off-by: Tony Prisk <linux@prisktech.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 108 insertions, 12 deletions

diff --git a/arch/arm/boot/dts/vt8500.dtsi b/arch/arm/boot/dts/vt8500.dtsi
index d8645e990b21..cf31ced46602 100644
--- a/arch/arm/boot/dts/vt8500.dtsi
+++ b/arch/arm/boot/dts/vt8500.dtsi
@@ -45,6 +45,38 @@
                                         compatible = "fixed-clock";
                                         clock-frequency = <24000000>;
                                 };
+
+                                clkuart0: uart0 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <1>;
+                                };
+
+                                clkuart1: uart1 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <2>;
+                                };
+
+                                clkuart2: uart2 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <3>;
+                                };
+
+                                clkuart3: uart3 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <4>;
+                                };
                         };
                 };
 
@@ -83,28 +115,28 @@
                         compatible = "via,vt8500-uart";
                         reg = <0xd8200000 0x1040>;
                         interrupts = <32>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart0>;
                 };
 
                 uart@d82b0000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd82b0000 0x1040>;
                         interrupts = <33>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart1>;
                 };
 
                 uart@d8210000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd8210000 0x1040>;
                         interrupts = <47>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart2>;
                 };
 
                 uart@d82c0000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd82c0000 0x1040>;
                         interrupts = <50>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart3>;
                 };
 
                 rtc@d8100000 {
diff --git a/arch/arm/boot/dts/wm8505.dtsi b/arch/arm/boot/dts/wm8505.dtsi
index 330f833ac3b0..e74a1c0fb9a2 100644
--- a/arch/arm/boot/dts/wm8505.dtsi
+++ b/arch/arm/boot/dts/wm8505.dtsi
@@ -59,6 +59,54 @@
                                         compatible = "fixed-clock";
                                         clock-frequency = <24000000>;
                                 };
+
+                                clkuart0: uart0 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <1>;
+                                };
+
+                                clkuart1: uart1 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <2>;
+                                };
+
+                                clkuart2: uart2 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <3>;
+                                };
+
+                                clkuart3: uart3 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <4>;
+                                };
+
+                                clkuart4: uart4 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <22>;
+                                };
+
+                                clkuart5: uart5 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <23>;
+                                };
                         };
                 };
 
@@ -96,42 +144,42 @@
                         compatible = "via,vt8500-uart";
                         reg = <0xd8200000 0x1040>;
                         interrupts = <32>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart0>;
                 };
 
                 uart@d82b0000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd82b0000 0x1040>;
                         interrupts = <33>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart1>;
                 };
 
                 uart@d8210000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd8210000 0x1040>;
                         interrupts = <47>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart2>;
                 };
 
                 uart@d82c0000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd82c0000 0x1040>;
                         interrupts = <50>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart3>;
                 };
 
                 uart@d8370000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd8370000 0x1040>;
                         interrupts = <31>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart4>;
                 };
 
                 uart@d8380000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd8380000 0x1040>;
                         interrupts = <30>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart5>;
                 };
 
                 rtc@d8100000 {
diff --git a/arch/arm/boot/dts/wm8650.dtsi b/arch/arm/boot/dts/wm8650.dtsi
index 83b9467559bb..db3c0a12e052 100644
--- a/arch/arm/boot/dts/wm8650.dtsi
+++ b/arch/arm/boot/dts/wm8650.dtsi
@@ -75,6 +75,22 @@
                                         reg = <0x204>;
                                 };
 
+                                clkuart0: uart0 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <1>;
+                                };
+
+                                clkuart1: uart1 {
+                                        #clock-cells = <0>;
+                                        compatible = "via,vt8500-device-clock";
+                                        clocks = <&ref24>;
+                                        enable-reg = <0x250>;
+                                        enable-bit = <2>;
+                                };
+
                                 arm: arm {
                                         #clock-cells = <0>;
                                         compatible = "via,vt8500-device-clock";
@@ -128,14 +144,14 @@
                         compatible = "via,vt8500-uart";
                         reg = <0xd8200000 0x1040>;
                         interrupts = <32>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart0>;
                 };
 
                 uart@d82b0000 {
                         compatible = "via,vt8500-uart";
                         reg = <0xd82b0000 0x1040>;
                         interrupts = <33>;
-                        clocks = <&ref24>;
+                        clocks = <&clkuart1>;
                 };
 
                 rtc@d8100000 {