Adding VExpress maintainers...

On Thu, Jan 8, 2015 at 1:44 PM, Linus Walleij [off-list ref] wrote:

On Tue, Dec 30, 2014 at 8:28 PM, Rob Herring [off-list ref] wrote:

quoted

From: Rob Herring <robh@kernel.org>

The Versatile boards have the same sysregs as other ARM Ltd boards. Add
the nodes in preparation to enable support for 24MHz counter as
sched_clock and MMC card detect and write protect support.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Russell King <redacted>
Cc: Linus Walleij <redacted>
---
 arch/arm/boot/dts/versatile-ab.dts | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/arm/boot/dts/versatile-ab.dts b/arch/arm/boot/dts/versatile-ab.dts
index 27d0d9c..62f04b0 100644
--- a/arch/arm/boot/dts/versatile-ab.dts
+++ b/arch/arm/boot/dts/versatile-ab.dts

@@ -252,6 +252,29 @@
                        #size-cells = <1>;
                        ranges = <0 0x10000000 0x10000>;

+                       sysreg at 0 {
+                               compatible = "arm,vexpress-sysreg";

vexpress? No...

Compatible with yes. Should perhaps be '"arm,versatile-sysreg",
"arm,vexpress-sysreg"' instead. Kind of backwards, as really the
versatile came first, but it would work. Or we just need another match
entry in the kernel.

I copied this whole chunk as is from VExpress and verified these sub
nodes are all the same hence why it is here.

compatible = "syscon";

maybe? VExpress is missing that then...

quoted

+                               reg = <0x00000 0x1000>;
+
+                               v2m_led_gpios: sys_led at 08 {
+                                       compatible = "arm,vexpress-sysreg,sys_led";
+                                       gpio-controller;
+                                       #gpio-cells = <2>;
+                               };

These are not GPIOs. These are LED registers really.

A register bit that controls an i/o signal sounds like a GPIO to me.

see how to use LEDs from drivers/leds/leds-syscon.c and bindings.
example in:
arch/arm/boot/dts/integrator.dtsi

Very straight-forward I think.

So we have 2 implementations and bindings for roughly the same hardware? Great!

quoted

+                               v2m_mmc_gpios: sys_mci at 48 {
+                                       compatible = "arm,vexpress-sysreg,sys_mci";
+                                       gpio-controller;
+                                       #gpio-cells = <2>;
+                               };
+
+                               v2m_flash_gpios: sys_flash at 4c {
+                                       compatible = "arm,vexpress-sysreg,sys_flash";
+                                       gpio-controller;
+                                       #gpio-cells = <2>;
+                               };

I don't have drivers for these "gpio controllers" and I don't think they are
GPIOs either, since they are not general purpose at all.

They are only general purpose until you connect the i/o lines to
something. But yes, if we went around making every misc internal
control line in SOCs a 1-bit GPIO controller that would be pretty
crazy.

Anyway, most of this is not actually used ATM on Versatile, but it is
present in VExpress. I added it only for sched_clock. We need to
resolve this with VExpress platforms, but it's already in use for MMC
and LEDs.

Rob

For the latter I have some code boiling for the Integrators:
https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-integrator.git/commit/?h=multiplatform&id=9c28e114ec957fadf1dade382d8e8b8aa43c8426
https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-integrator.git/commit/?h=multiplatform&id=a3d4512abb85de290cdca0586bcff9147833917f

Yours,
Linus Walleij