samsung: board: support eMMC reset using DT
Some exynos boards require special handling of nRESET_OUT line for eMMC
memory to perform complete reboot e.g. Odroid X2/U3/XU3 boards.
This will support eMMC reset using DT from reset_misc of samsung common
board file.
Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/board/samsung/common/board.c b/board/samsung/common/board.c
index 8b4c8e9..da2245f 100644
--- a/board/samsung/common/board.c
+++ b/board/samsung/common/board.c
@@ -355,3 +355,31 @@
return 0;
}
#endif
+
+void reset_misc(void)
+{
+ struct gpio_desc gpio = {};
+ int node;
+
+ node = fdt_node_offset_by_compatible(gd->fdt_blob, 0,
+ "samsung,emmc-reset");
+ if (node < 0)
+ return;
+
+ gpio_request_by_name_nodev(gd->fdt_blob, node, "reset-gpio", 0, &gpio,
+ GPIOD_IS_OUT);
+
+ if (dm_gpio_is_valid(&gpio)) {
+ /*
+ * Reset eMMC
+ *
+ * FIXME: Need to optimize delay time. Minimum 1usec pulse is
+ * required by 'JEDEC Standard No.84-A441' (eMMC)
+ * document but real delay time is expected to greater
+ * than 1usec.
+ */
+ dm_gpio_set_value(&gpio, 0);
+ mdelay(10);
+ dm_gpio_set_value(&gpio, 1);
+ }
+}