WIP: ARM: tegra: Add device-tree for EFI booting Surface RT

Signed-off-by: Anton Bambura <[email protected]>
Signed-off-by: Jonas Schwöbel <[email protected]>

arch/arm/boot/dts/Makefile

@@ -1353,6 +1353,7 @@ dtb-$(CONFIG_ARCH_TEGRA_3x_SOC) += \
 	tegra30-colibri-eval-v3.dtb \
 	tegra30-lenovo-ideatab-a2109a.dtb \
 	tegra30-microsoft-surface-rt.dtb \
+	tegra30-microsoft-surface-rt-efi.dtb \
 	tegra30-ouya.dtb \
 	tegra30-pegatron-chagall.dtb
 dtb-$(CONFIG_ARCH_TEGRA_114_SOC) += \

arch/arm/boot/dts/tegra30-microsoft-surface-rt-efi.dts

@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "tegra30-microsoft-surface-rt.dts"
+
+/*
+ * Temporary Microsoft Surface RT device-tree for EFI booting.
+ * Replacing PMIC with fixed regulators.
+ */
+
+/ {
+	compatible = "microsoft,surface-rt-efi", "microsoft,surface-rt", "nvidia,tegra30";
+
+	/* L2 cache does not work yet */
+	/delete-node/ cache-controller@50043000;
+
+	pmc@7000e400 {
+		/* CPU Idle does not work yet, disabling LP2 */
+		/delete-property/ nvidia,suspend-mode;
+
+		/* Core regulator cannot work with UEFI, use fallback stub */
+		core-supply = <&vdd_pd_core_stub>;
+	};
+
+	ldo5_reg: tps65911-ldo5 {
+		compatible = "regulator-fixed";
+		regulator-name = "vddio_sdmmc";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-always-on;
+	};
+
+	/* Core regulator cannot work with UEFI, delete it */
+	i2c@7000d000 {
+		/delete-node/ core-regulator@60;
+	};
+
+	/* DVFS cannot work with UEFI, delete it */
+	cpus {
+		cpu@0 {
+			/delete-property/ cpu-supply;
+			/delete-property/ operating-points-v2;
+		};
+
+		cpu@1 {
+			/delete-property/ cpu-supply;
+			/delete-property/ operating-points-v2;
+		};
+
+		cpu@2 {
+			/delete-property/ cpu-supply;
+			/delete-property/ operating-points-v2;
+		};
+
+		cpu@3 {
+			/delete-property/ cpu-supply;
+			/delete-property/ operating-points-v2;
+		};
+	};
+};
+
+&pmic {
+	/delete-node/ regulators;
+};

drivers/i2c/i2c-core-base.c

@@ -727,6 +727,12 @@ static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
  * are purposely not enforced, except for the general call address. */
 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 {
+	// Fix for Surface RT tCover support.
+	// tCover uses address 0x00 which is reserved for general call
+	if (addr == 0x00 && of_machine_is_compatible("microsoft,surface-rt")) {
+		return 0;
+	}
+
 	if (flags & I2C_CLIENT_TEN) {
 		/* 10-bit address, all values are valid */
 		if (addr > 0x3ff)
@@ -755,6 +761,12 @@ int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 	 *  0x78-0x7b  10-bit slave addressing
 	 *  0x7c-0x7f  Reserved for future purposes
 	 */
+	// Fix for Surface RT tCover support.
+	// tCover uses address 0x00 which is reserved for general call
+	if (addr == 0x00 && of_machine_is_compatible("microsoft,surface-rt")) {
+		return 0;
+	}
+
 	if (addr < 0x08 || addr > 0x77)
 		return -EINVAL;
 	return 0;