E850-96 is a 96boards development board manufactured by WinLink. It
incorporates Samsung Exynos850 SoC, and is compatible with 96boards
mezzanine boards [1], as it follows 96boards standards.

This patch adds minimal support for E850-96 board. Next features are
enabled in board dts file and verified with minimal BusyBox rootfs:

 * User buttons
 * LEDs
 * Serial console
 * Watchdog timers
 * RTC
 * eMMC

[1] https://www.96boards.org/products/mezzanine/

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
Changes in v2:
  - Removed board_id and board_rev properties
  - Removed BOARD_ID and BOARD_REV constants
  - Put dtb in alphabetical order in Makefile
  - Added "color" and "function" properties to LED nodes
  - Sorted all phandle overrides by phandle name
  - Removed 'broken-cd' property in eMMC node
  - Added memory node

 arch/arm64/boot/dts/exynos/Makefile           |   1 +
 .../boot/dts/exynos/exynos850-e850-96.dts     | 175 ++++++++++++++++++
 2 files changed, 176 insertions(+)
 create mode 100644 arch/arm64/boot/dts/exynos/exynos850-e850-96.dts

diff --git a/arch/arm64/boot/dts/exynos/Makefile b/arch/arm64/boot/dts/exynos/Makefile
index b41e86df0a84..be9df8e85c59 100644
--- a/arch/arm64/boot/dts/exynos/Makefile
+++ b/arch/arm64/boot/dts/exynos/Makefile

@@ -3,4 +3,5 @@ dtb-$(CONFIG_ARCH_EXYNOS) += \
        exynos5433-tm2.dtb      \
        exynos5433-tm2e.dtb     \
        exynos7-espresso.dtb    \
+       exynos850-e850-96.dtb   \
        exynosautov9-sadk.dtb

diff --git a/arch/arm64/boot/dts/exynos/exynos850-e850-96.dts b/arch/arm64/boot/dts/exynos/exynos850-e850-96.dts
new file mode 100644
index 000000000000..952a47c417d4
--- /dev/null
+++ b/arch/arm64/boot/dts/exynos/exynos850-e850-96.dts

@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * WinLink E850-96 board device tree source
+ *
+ * Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ * Copyright (C) 2021 Linaro Ltd.
+ *
+ * Device tree source file for WinLink's E850-96 board which is based on
+ * Samsung Exynos850 SoC.
+ */
+
+/dts-v1/;
+
+#include "exynos850.dtsi"
+#include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/input/input.h>
+#include <dt-bindings/leds/common.h>
+
+/ {
+       model = "WinLink E850-96 board";
+       compatible = "winlink,e850-96", "samsung,exynos850";
+
+       chosen {
+               stdout-path = &serial_0;
+       };
+
+       /*
+        * 4 GiB eMCP:
+        *   - 2 GiB at 0x80000000
+        *   - 2 GiB at 0x880000000
+        *
+        * 0xbab00000..0xbfffffff: secure memory (85 MiB).
+        */
+       memory@80000000 {
+               device_type = "memory";
+               reg = <0x0 0x80000000 0x3ab00000>,
+                     <0x0 0xc0000000 0x40000000>,
+                     <0x8 0x80000000 0x80000000>;
+       };
+
+       gpio-keys {
+               compatible = "gpio-keys";
+               pinctrl-names = "default";
+               pinctrl-0 = <&key_voldown_pins &key_volup_pins>;
+
+               volume-down-key {
+                       label = "Volume Down";
+                       linux,code = <KEY_VOLUMEDOWN>;
+                       gpios = <&gpa1 0 GPIO_ACTIVE_LOW>;
+               };
+
+               volume-up-key {
+                       label = "Volume Up";
+                       linux,code = <KEY_VOLUMEUP>;
+                       gpios = <&gpa0 7 GPIO_ACTIVE_LOW>;
+               };
+       };
+
+       leds {
+               compatible = "gpio-leds";
+
+               /* HEART_BEAT_LED */
+               user_led1: led-1 {
+                       label = "yellow:user1";
+                       gpios = <&gpg2 2 GPIO_ACTIVE_HIGH>;
+                       color = <LED_COLOR_ID_YELLOW>;
+                       function = LED_FUNCTION_HEARTBEAT;
+                       linux,default-trigger = "heartbeat";
+               };
+
+               /* eMMC_LED */
+               user_led2: led-2 {
+                       label = "yellow:user2";
+                       gpios = <&gpg2 3 GPIO_ACTIVE_HIGH>;
+                       color = <LED_COLOR_ID_YELLOW>;
+                       linux,default-trigger = "mmc0";
+               };
+
+               /* SD_LED */
+               user_led3: led-3 {
+                       label = "white:user3";
+                       gpios = <&gpg2 4 GPIO_ACTIVE_HIGH>;
+                       color = <LED_COLOR_ID_WHITE>;
+                       function = LED_FUNCTION_SD;
+                       linux,default-trigger = "mmc2";
+               };
+
+               /* WIFI_LED */
+               wlan_active_led: led-4 {
+                       label = "yellow:wlan";
+                       gpios = <&gpg2 6 GPIO_ACTIVE_HIGH>;
+                       color = <LED_COLOR_ID_YELLOW>;
+                       function = LED_FUNCTION_WLAN;
+                       linux,default-trigger = "phy0tx";
+                       default-state = "off";
+               };
+
+               /* BLUETOOTH_LED */
+               bt_active_led: led-5 {
+                       label = "blue:bt";
+                       gpios = <&gpg2 7 GPIO_ACTIVE_HIGH>;
+                       color = <LED_COLOR_ID_BLUE>;
+                       function = LED_FUNCTION_BLUETOOTH;
+                       linux,default-trigger = "hci0rx";
+                       default-state = "off";
+               };
+       };
+};
+
+&mmc_0 {
+       status = "okay";
+       mmc-hs200-1_8v;
+       mmc-hs400-1_8v;
+       cap-mmc-highspeed;
+       non-removable;
+       mmc-hs400-enhanced-strobe;
+       card-detect-delay = <200>;
+       clock-frequency = <800000000>;
+       bus-width = <8>;
+       samsung,dw-mshc-ciu-div = <3>;
+       samsung,dw-mshc-sdr-timing = <0 4>;
+       samsung,dw-mshc-ddr-timing = <2 4>;
+       samsung,dw-mshc-hs400-timing = <0 2>;
+
+       pinctrl-names = "default";
+       pinctrl-0 = <&sd0_clk_pins &sd0_cmd_pins &sd0_rdqs_pins &sd0_nreset_pins
+                    &sd0_bus1_pins &sd0_bus4_pins &sd0_bus8_pins>;
+};
+
+&oscclk {
+       clock-frequency = <26000000>;
+};
+
+&rtc {
+       status = "okay";
+};
+
+&rtcclk {
+       clock-frequency = <32768>;
+};
+
+&serial_0 {
+       status = "okay";
+       pinctrl-names = "default";
+       pinctrl-0 = <&uart1_pins>;
+};
+
+&usi_uart {
+       samsung,clkreq-on; /* needed for UART mode */
+       status = "okay";
+};
+
+&watchdog_cl0 {
+       status = "okay";
+};
+
+&watchdog_cl1 {
+       status = "okay";
+};
+
+&pinctrl_alive {