[U-Boot] [PATCH v4 3/9] arm: exynos: Detect revision later, when all resources are ready

[Krzysztof Kozlowski]

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 (in late mode)
or during misc_init_r.  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 at kernel.org>
Reviewed-by: Lukasz Majewski <lukma at denx.de>
Tested-by: Anand Moon <linux.amoon at gmail.com>
---
 board/samsung/common/board.c            | 22 +++++++++++++++++++++-
 board/samsung/common/exynos5-dt-types.c | 16 +++++++++++++---
 board/samsung/odroid/odroid.c           |  8 ++++++++
 include/samsung/misc.h                  |  1 +
 4 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
index 96228a86a117..ef2204742e1d 100644
--- a/board/samsung/common/board.c
+++ b/board/samsung/common/board.c
@@ -253,7 +253,18 @@ 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;
+
+		if (IS_ENABLED(CONFIG_DISPLAY_BOARDINFO_LATE)) {
+			/*
+			 * Printing type requires having revision, although
+			 * this will succeed only if done late.
+			 * Otherwise revision will be set in misc_init_r().
+			 */
+			set_board_revision();
+		}
+
+		board_info = get_board_type();
 
 		if (board_info)
 			printf("Type:  %s\n", board_info);
@@ -287,6 +298,15 @@ int board_late_init(void)
 #ifdef CONFIG_MISC_INIT_R
 int misc_init_r(void)
 {
+	if (!IS_ENABLED(CONFIG_DISPLAY_BOARDINFO_LATE)) {
+		/*
+		 * If revision was not set by late display boardinfo,
+		 * set it here. At this point regulators should be already
+		 * available.
+		 */
+		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..7c1271d6547a 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 +214,15 @@ void set_board_type(void)
 		gd->board_type = of_match->data;
 		break;
 	}
+}
 
-	/* If Odroid, then check its revision */
+/**
+ * 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)
+{
 	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