Enable the Mali GPU in the Turing RK1.

This patch also sets the external GPU voltage regulator in the RK806-1
to "always-on" because it is necessary for this regulator to be active
when enabling the GPU power domain or the kernel will fail with:

rockchip-pm-domain fd8d8000.power-management:power-controller: \
    failed to set domain 'gpu', val=0
rockchip-pm-domain fd8d8000.power-management:power-controller: \
    failed to get ack on domain 'gpu', val=0x1bffff

...followed by a panic when it attempts to access unavailable QoS
registers.

Since there is currently no `domain-supply` or similar to express this
dependency, the only way to ensure that the regulator is never off when
the GPU power domain is brought up is to ensure that the regulator is
never off.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>

---

Hi list,

This particular patch will probably need to be revisited once something
like [1] lands. I'm completely unable to get the GPU up and running
without some kind of solution to the power dependency issue, but it's
possible that this is because I'm just particularly unlucky in the
timing department.

Cheers,
Sam

[1]: https://lore.kernel.org/lkml/20240910180530.47194-7-sebastian.reichel@collabora.com/T/
---
 .../boot/dts/rockchip/rk3588-turing-rk1.dtsi     | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
index 6036c4fe6727..dedfb9ede4a3 100644
--- a/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3588-turing-rk1.dtsi
@@ -116,6 +116,11 @@ &gmac1_rgmii_clk
 	status = "okay";
 };
 
+&gpu {
+	mali-supply = <&vdd_gpu_s0>;
+	status = "okay";
+};
+
 &i2c0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&i2c0m2_xfer>;
@@ -386,6 +391,17 @@ rk806_dvs3_null: dvs3-null-pins {
 
 		regulators {
 			vdd_gpu_s0: vdd_gpu_mem_s0: dcdc-reg1 {
+				/*
+				 * RK3588's GPU power domain cannot be enabled
+				 * without this regulator active, but it
+				 * doesn't have to be on when the GPU PD is
+				 * disabled.  Because the PD binding does not
+				 * currently allow us to express this
+				 * relationship, we have no choice but to do
+				 * this instead:
+				 */
+				regulator-always-on;
+
 				regulator-boot-on;
 				regulator-min-microvolt = <550000>;
 				regulator-max-microvolt = <950000>;
-- 
2.44.2