board: asus: transformer: implement multi-DTB support

Use board revision detection mechanism to choose correct DTB.
Adjust documentation and build setup accordingly.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
diff --git a/board/asus/transformer-t30/board-info.c b/board/asus/transformer-t30/board-info.c
new file mode 100644
index 0000000..a2b540c
--- /dev/null
+++ b/board/asus/transformer-t30/board-info.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  (C) Copyright 2024
+ *  Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <env.h>
+#include <spl_gpio.h>
+
+#include <asm/gpio.h>
+#include <asm/arch/pinmux.h>
+
+/*
+ *	PCB_ID[1] is kb_row5_pr5
+ *	PCB_ID[3] is kb_col7_pq7
+ *	PCB_ID[4] is kb_row2_pr2
+ *	PCB_ID[5] is kb_col5_pq5
+ *
+ *			  Project ID
+ *	=====================================================
+ *	PCB_ID[1] PCB_ID[5] PCB_ID[4] PCB_ID[3]	Project
+ *	0	  0	    0	      0		TF201
+ *	0	  0	    0	      1		P1801
+ *	0	  0	    1	      0		TF300T
+ *	0	  0	    1	      1		TF300TG
+ *	0	  1	    0	      0		TF700T
+ *	0	  1	    0	      1		TF300TL
+ *	0	  1	    1	      0		Extension
+ *	0	  1	    1	      1		TF500T
+ *	1	  0	    0	      0		TF502T/TF600T
+ *	=====================================================
+ */
+enum project_rev {
+	TF201, P1801, TF300T, TF300TG, TF700T,
+	TF300TL, EXT, TF500T, TF600T
+};
+
+static const char * const project_id_to_fdt[] = {
+	[TF201] = "tegra30-asus-tf201",
+	[P1801] = "tegra30-asus-p1801-t",
+	[TF300T] = "tegra30-asus-tf300t",
+	[TF300TG] = "tegra30-asus-tf300tg",
+	[TF700T] = "tegra30-asus-tf700t",
+	[TF300TL] = "tegra30-asus-tf300tl",
+	[TF600T] = "tegra30-asus-tf600t",
+};
+
+static int id_gpio_get_value(u32 pingrp, u32 pin)
+{
+	/* Configure pinmux */
+	pinmux_set_func(pingrp, PMUX_FUNC_KBC);
+	pinmux_set_pullupdown(pingrp, PMUX_PULL_DOWN);
+	pinmux_tristate_enable(pingrp);
+	pinmux_set_io(pingrp, PMUX_PIN_INPUT);
+
+	/*
+	 * Since this function may be called
+	 * during DM reload we should use SPL
+	 * GPIO functions which do not depend
+	 * on DM.
+	 */
+	spl_gpio_input(NULL, pin);
+	return spl_gpio_get_value(NULL, pin);
+}
+
+static int get_project_id(void)
+{
+	u32 pcb_id1, pcb_id3, pcb_id4, pcb_id5;
+
+	pcb_id1 = id_gpio_get_value(PMUX_PINGRP_KB_ROW5_PR5,
+				    TEGRA_GPIO(R, 5));
+	pcb_id3 = id_gpio_get_value(PMUX_PINGRP_KB_COL7_PQ7,
+				    TEGRA_GPIO(Q, 7));
+	pcb_id4 = id_gpio_get_value(PMUX_PINGRP_KB_ROW2_PR2,
+				    TEGRA_GPIO(R, 2));
+	pcb_id5 = id_gpio_get_value(PMUX_PINGRP_KB_COL5_PQ5,
+				    TEGRA_GPIO(Q, 5));
+
+	/* Construct board ID */
+	int proj_id = pcb_id1 << 3 | pcb_id5 << 2 |
+		      pcb_id4 << 1 | pcb_id3;
+
+	log_debug("[TRANSFORMER]: project id %d (%s)\n", proj_id,
+		  project_id_to_fdt[proj_id]);
+
+	/* Mark tablet with SPI flash */
+	if (proj_id == TF600T)
+		env_set_hex("spiflash", true);
+	else
+		env_set_hex("spiflash", false);
+
+	return proj_id & 0xf;
+}
+
+int board_fit_config_name_match(const char *name)
+{
+	if (!strcmp(name, project_id_to_fdt[get_project_id()]))
+		return 0;
+
+	return -1;
+}
+
+void nvidia_board_late_init(void)
+{
+	char dt_path[64] = { 0 };
+
+	snprintf(dt_path, sizeof(dt_path), "%s.dtb",
+		 project_id_to_fdt[get_project_id()]);
+	env_set("fdtfile", dt_path);
+}