[U-Boot] [PATCH v2 3/9] arm: exynos: Detect revision later, when all resources are ready

[Krzysztof Kozlowski <krzk@kernel.org>]

Detection of board revision is done early - before power setup.  In case of
Odroid XU3/XU4/HC1 family, the detection is done using ADC which
is supplied by LDO4/VDD_ADC regulator.  This regulator could be turned
off (e.g. by kernel before reboot).  If ADC is used early, the
regulators are not yet available and the detection won't work.

Split the revision detection out of set_board_type() into separate
function called later - either when displaying board info or during
misc_init_r (whatever succeeds first).  The idea is that
set_board_type() will be called early so its method of detection are
limited to flattened device tree (exynos5-dt-types.c for Exynos5) or
GPIO (odroid.c for Exynos4412).  The newly added set_board_revision()
can be called only later, when resources like regulator are available.

This is necessary to fix the detection of Odroid HC1 after reboot, if
kernel turned off the LDO4 regulator.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
---
 board/samsung/common/board.c            | 13 ++++++++++++-
 board/samsung/common/exynos5-dt-types.c | 20 +++++++++++++++++---
 board/samsung/odroid/odroid.c           |  8 ++++++++
 include/samsung/misc.h                  |  1 +
 4 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
index 96228a86a117..52a2764a1919 100644
--- a/board/samsung/common/board.c
+++ b/board/samsung/common/board.c
@@ -253,7 +253,12 @@ int board_eth_init(bd_t *bis)
 int checkboard(void)
 {
 	if (IS_ENABLED(CONFIG_BOARD_TYPES)) {
-		const char *board_info = get_board_type();
+		const char *board_info;
+
+		/* Printing type requires having revision */
+		set_board_revision();
+
+		board_info = get_board_type();
 
 		if (board_info)
 			printf("Type:  %s\n", board_info);
@@ -287,6 +292,12 @@ int board_late_init(void)
 #ifdef CONFIG_MISC_INIT_R
 int misc_init_r(void)
 {
+	/*
+	 * At this point regulators should be available so do full
+	 * revision detection
+	 */
+	set_board_revision();
+
 #ifdef CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG
 	set_board_info();
 #endif
diff --git a/board/samsung/common/exynos5-dt-types.c b/board/samsung/common/exynos5-dt-types.c
index 7a86e9187768..af711e727a78 100644
--- a/board/samsung/common/exynos5-dt-types.c
+++ b/board/samsung/common/exynos5-dt-types.c
@@ -192,8 +192,11 @@ const char *get_board_type(void)
 
 /**
  * set_board_type() - set board type in gd->board_type.
- * As default type set EXYNOS5_BOARD_GENERIC, if detect Odroid,
- * then set its proper type.
+ * As default type set EXYNOS5_BOARD_GENERIC. If Odroid is detected,
+ * set its proper type based on device tree.
+ *
+ * This might be called early when some more specific ways to detect revision
+ * are not yet available.
  */
 void set_board_type(void)
 {
@@ -211,8 +214,19 @@ void set_board_type(void)
 		gd->board_type = of_match->data;
 		break;
 	}
+}
+
+/**
+ * set_board_revision() - set detailed board type in gd->board_type.
+ * Should be called when resources (e.g. regulators) are available
+ * so ADC can be used to detect the specific revision of a board.
+ */
+void set_board_revision(void)
+{
+	/* Do not detect revision twice */
+	if (gd->board_type == EXYNOS5_BOARD_GENERIC)
+		return;
 
-	/* If Odroid, then check its revision */
 	if (board_is_odroidxu3())
 		gd->board_type = odroid_get_board_type();
 }
diff --git a/board/samsung/odroid/odroid.c b/board/samsung/odroid/odroid.c
index 552333fe869d..4be8cc9826c3 100644
--- a/board/samsung/odroid/odroid.c
+++ b/board/samsung/odroid/odroid.c
@@ -54,6 +54,14 @@ void set_board_type(void)
 		gd->board_type = ODROID_TYPE_U3;
 }
 
+void set_board_revision(void)
+{
+	/*
+	 * Revision already set by set_board_type() because it can be
+	 * executed early.
+	 */
+}
+
 const char *get_board_type(void)
 {
 	const char *board_type[] = {"u3", "x2"};
diff --git a/include/samsung/misc.h b/include/samsung/misc.h
index 017560c25662..4ff28a1df0e8 100644
--- a/include/samsung/misc.h
+++ b/include/samsung/misc.h
@@ -33,6 +33,7 @@ char *get_dfu_alt_system(char *interface, char *devstr);
 char *get_dfu_alt_boot(char *interface, char *devstr);
 #endif
 void set_board_type(void);
+void set_board_revision(void);
 const char *get_board_type(void);
 
 #endif /* __SAMSUNG_MISC_COMMON_H__ */
-- 
2.17.1