ARM: davinci: add runtime PM support for clock management

Add runtime PM core support to davinci by using the pm_clk
infrastructure of the PM core.

When runtime PM is enabled, the davinci runtime PM implementation will
use the pm_clk layer to enable/disable clocks on demand.  When runtime
PM is disabled, the pm_clk core will automatically enable clocks when
the driver is bound and disable clocks when the driver is unbound.

Cc: Mark A. Greer <mgreer@animalcreek.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
[nsekhar@ti.com: pruned list of header file includes and removed some
debug code]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>

arch/arm/mach-davinci/Makefile

@@ -39,3 +39,4 @@ obj-$(CONFIG_MACH_OMAPL138_HAWKBOARD)	+= board-omapl138-hawk.o
 obj-$(CONFIG_CPU_FREQ)			+= cpufreq.o
 obj-$(CONFIG_CPU_IDLE)			+= cpuidle.o
 obj-$(CONFIG_SUSPEND)			+= pm.o sleep.o
+obj-$(CONFIG_HAVE_CLK)			+= pm_domain.o

arch/arm/mach-davinci/pm_domain.c

@@ -0,0 +1,64 @@
+/*
+ * Runtime PM support code for DaVinci
+ *
+ * Author: Kevin Hilman
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/init.h>
+#include <linux/pm_runtime.h>
+#include <linux/pm_clock.h>
+#include <linux/platform_device.h>
+
+#ifdef CONFIG_PM_RUNTIME
+static int davinci_pm_runtime_suspend(struct device *dev)
+{
+	int ret;
+
+	dev_dbg(dev, "%s\n", __func__);
+
+	ret = pm_generic_runtime_suspend(dev);
+	if (ret)
+		return ret;
+
+	ret = pm_clk_suspend(dev);
+	if (ret) {
+		pm_generic_runtime_resume(dev);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int davinci_pm_runtime_resume(struct device *dev)
+{
+	dev_dbg(dev, "%s\n", __func__);
+
+	pm_clk_resume(dev);
+	return pm_generic_runtime_resume(dev);
+}
+#endif
+
+static struct dev_pm_domain davinci_pm_domain = {
+	.ops = {
+		SET_RUNTIME_PM_OPS(davinci_pm_runtime_suspend,
+				   davinci_pm_runtime_resume, NULL)
+		USE_PLATFORM_PM_SLEEP_OPS
+	},
+};
+
+static struct pm_clk_notifier_block platform_bus_notifier = {
+	.pm_domain = &davinci_pm_domain,
+};
+
+static int __init davinci_pm_runtime_init(void)
+{
+	pm_clk_add_notifier(&platform_bus_type, &platform_bus_notifier);
+
+	return 0;
+}
+core_initcall(davinci_pm_runtime_init);