rockchip: rk3399-puma: add boot-on regulator to override BIOS_DISABLE

The (Qseven) BIOS_DISABLE signal on the RK3399-Q7 (Puma) keeps the
eMMC and SPI in reset initially and we need to write a GPIO to turn
them on before continuing the boot-up.

This adds the DTS entries for the additional regulator and makes
pinctrl and gpio3 available during SPL.  It also adds a hook to the
spl_board_init() to ensure that the regulator gets probed and enabled.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/dts/rk3399-puma.dtsi

@@ -101,6 +101,24 @@
 		regulator-max-microvolt = <3300000>;
 	};
 
+	/*
+	 * The Qseven BIOS_DISABLE signal on the RK3399-Q7 keeps the on-module
+	 * eMMC and SPI flash powered-down initially (in fact it keeps the
+	 * reset signal asserted).  Even though it is an enable signal, we
+	 * model this as a regulator.
+	 */
+	bios_enable: bios_enable {
+		compatible = "regulator-fixed";
+		u-boot,dm-pre-reloc;
+		regulator-name = "bios_enable";
+		enable-active-low;
+		gpio = <&gpio3 29 GPIO_ACTIVE_HIGH>;
+		regulator-always-on;
+		regulator-boot-on;
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
+
 	vccadc_ref: vccadc-ref {
 		compatible = "regulator-fixed";
 		regulator-name = "vcc1v8_sys";
@@ -459,7 +477,7 @@
 };
 
 &pcie_phy {
-	        status = "okay";
+		status = "okay";
 };
 
 &pmu_io_domains {
@@ -486,7 +504,7 @@
 };
 
 &sdmmc {
-        u-boot,dm-pre-reloc;
+	u-boot,dm-pre-reloc;
 	clock-frequency = <150000000>;
 	clock-freq-min-max = <100000 150000000>;
 	supports-sd;
@@ -533,10 +551,15 @@
 	status = "okay";
 };
 
+&gpio3 {
+	u-boot,dm-pre-reloc;
+};
+
 &pinctrl {
 	/* Pins that are not explicitely used by any devices */
 	pinctrl-names = "default";
 	pinctrl-0 = <&puma_pin_hog>;
+
 	hog {
 		puma_pin_hog: puma_pin_hog {
 			rockchip,pins =
@@ -576,7 +599,7 @@
 	i2c8 {
 		i2c8_xfer_a: i2c8-xfer {
 			rockchip,pins = <1 21 RK_FUNC_1 &pcfg_pull_up>,
-			                <1 20 RK_FUNC_1 &pcfg_pull_up>;
+					<1 20 RK_FUNC_1 &pcfg_pull_up>;
 		};
 	};
 };
@@ -652,4 +675,3 @@
 &spi5 {
 	status = "okay";
 };
-

board/theobroma-systems/puma_rk3399/puma-rk3399.c

@@ -34,6 +34,16 @@ int board_init(void)
 
 void spl_board_init(void)
 {
+	int  ret;
+
+	/*
+	 * Turning the eMMC and SPI back on (if disabled via the Qseven
+	 * BIOS_ENABLE) signal is done through a always-on regulator).
+	 */
+	ret = regulators_enable_boot_on(false);
+	if (ret)
+		debug("%s: Cannot enable boot on regulator\n", __func__);
+
 	preloader_console_init();
 }