[U-Boot] [PATCH 02/19] dm: timer: uclass: add timer init to add timer device

[Mugunthan V N]

Adding timer_init function to create and initialize the timer
device on platforms where u-boot,dm-pre-reloc is not used. Since
there will be multiple timer devices in the system, adding a
tick-timer node in chosen node to know which timer device to be
used as tick timer in u-boot.

Signed-off-by: Mugunthan V N <mugunthanvnm at ti.com>
---
 doc/device-tree-bindings/chosen.txt | 43 +++++++++++++++++++++++++++++++++++++
 drivers/timer/timer-uclass.c        | 34 +++++++++++++++++++++++++++++
 lib/time.c                          |  5 +++++
 3 files changed, 82 insertions(+)
 create mode 100644 doc/device-tree-bindings/chosen.txt

diff --git a/doc/device-tree-bindings/chosen.txt b/doc/device-tree-bindings/chosen.txt
new file mode 100644
index 0000000..58f29f9
--- /dev/null
+++ b/doc/device-tree-bindings/chosen.txt
@@ -0,0 +1,43 @@
+The chosen node
+---------------
+The chosen node does not represent a real device, but serves as a place
+for passing data like which serial device to used to print the logs etc
+
+
+stdout-path property
+--------------------
+Device trees may specify the device to be used for boot console output
+with a stdout-path property under /chosen.
+
+Example
+-------
+/ {
+	chosen {
+		stdout-path = "/serial at f00:115200";
+	};
+
+	serial at f00 {
+		compatible = "vendor,some-uart";
+		reg = <0xf00 0x10>;
+	};
+};
+
+tick-timer property
+-------------------
+In a system there are multiple timers, specify which timer to be used
+as the tick-timer. Earlier it was hardcoded in the timer driver now
+since device tree has all the timer nodes. Specify which timer to be
+used as tick timer.
+
+Example
+-------
+/ {
+	chosen {
+		tick-timer = &timer2;
+	};
+
+	timer2 at f00 {
+		compatible = "vendor,some-uart";
+		reg = <0xf00 0x10>;
+	};
+};
diff --git a/drivers/timer/timer-uclass.c b/drivers/timer/timer-uclass.c
index 12aee5b..78ec989 100644
--- a/drivers/timer/timer-uclass.c
+++ b/drivers/timer/timer-uclass.c
@@ -6,9 +6,13 @@
 
 #include <common.h>
 #include <dm.h>
+#include <dm/lists.h>
+#include <dm/device-internal.h>
 #include <errno.h>
 #include <timer.h>
 
+DECLARE_GLOBAL_DATA_PTR;
+
 /*
  * Implement a Timer uclass to work with lib/time.c. The timer is usually
  * a 32 bits free-running up counter. The get_rate() method is used to get
@@ -35,6 +39,36 @@ unsigned long timer_get_rate(struct udevice *dev)
 	return uc_priv->clock_rate;
 }
 
+int timer_init(void)
+{
+	const void *blob = gd->fdt_blob;
+	struct udevice *dev;
+	int node;
+
+	if (CONFIG_IS_ENABLED(OF_CONTROL) && blob) {
+		/* Check for a chosen timer to be used for tick */
+		node = fdtdec_get_chosen_node(blob, "tick-timer");
+		if (node < 0)
+			return -ENODEV;
+
+		if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) {
+			/*
+			 * If the timer is not marked to be bound before
+			 * relocation, bind it anyway.
+			 */
+			if (node > 0 &&
+			    !lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
+				int ret = device_probe(dev);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	gd->timer = dev;
+	return 0;
+}
+
 UCLASS_DRIVER(timer) = {
 	.id		= UCLASS_TIMER,
 	.name		= "timer",
diff --git a/lib/time.c b/lib/time.c
index b001745..22f7d23 100644
--- a/lib/time.c
+++ b/lib/time.c
@@ -47,6 +47,11 @@ static int notrace dm_timer_init(void)
 	int ret;
 
 	if (!gd->timer) {
+		/* Check if we have a chosen timer */
+		timer_init();
+		if (gd->timer)
+			return 0;
+
 		ret = uclass_first_device(UCLASS_TIMER, &dev);
 		if (ret)
 			return ret;
-- 
2.6.3.368.gf34be46