ARM: EXYNOS: Bind devices to power domains using DT

This patch adds a way to specify bindings between devices and power
domains using device tree.

A device can be bound to particular power domain by adding a
power-domain property containing a phandle to the domain. The device
will be bound to the domain before binding a driver to it and unbound
after unbinding a driver from it.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

2 files changed, 94 insertions, 1 deletions

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 843b54622313..5216b419016a 100644
--- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
+++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
@@ -4,14 +4,25 @@ Exynos processors include support for multiple power domains which are used
 to gate power to one or more peripherals on the processor.
 
 Required Properties:
-- compatiable: should be one of the following.
+- compatible: should be one of the following.
     * samsung,exynos4210-pd - for exynos4210 type power domain.
 - reg: physical base address of the controller and length of memory mapped
     region.
 
+Node of a device using power domains must have a samsung,power-domain property
+defined with a phandle to respective power domain.
+
 Example:
 
         lcd0: power-domain-lcd0 {
                 compatible = "samsung,exynos4210-pd";
                 reg = <0x10023C00 0x10>;
         };
+
+Example of the node using power domain:
+
+        node {
+                /* ... */
+                samsung,power-domain = <&lcd0>;
+                /* ... */
+        };
diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
index 5b7ce7ea6c61..9f1351de52f7 100644
--- a/arch/arm/mach-exynos/pm_domains.c
+++ b/arch/arm/mach-exynos/pm_domains.c
@@ -19,6 +19,8 @@
 #include <linux/pm_domain.h>
 #include <linux/delay.h>
 #include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/sched.h>
 
 #include <mach/regs-pmu.h>
 #include <plat/devs.h>
@@ -83,14 +85,89 @@ static struct exynos_pm_domain PD = {			\
 }
 
 #ifdef CONFIG_OF
+static void exynos_add_device_to_domain(struct exynos_pm_domain *pd,
+                                         struct device *dev)
+{
+        int ret;
+
+        dev_dbg(dev, "adding to power domain %s\n", pd->pd.name);
+
+        while (1) {
+                ret = pm_genpd_add_device(&pd->pd, dev);
+                if (ret != -EAGAIN)
+                        break;
+                cond_resched();
+        }
+
+        pm_genpd_dev_need_restore(dev, true);
+}
+
+static void exynos_remove_device_from_domain(struct device *dev)
+{
+        struct generic_pm_domain *genpd = dev_to_genpd(dev);
+        int ret;
+
+        dev_dbg(dev, "removing from power domain %s\n", genpd->name);
+
+        while (1) {
+                ret = pm_genpd_remove_device(genpd, dev);
+                if (ret != -EAGAIN)
+                        break;
+                cond_resched();
+        }
+}
+
+static void exynos_read_domain_from_dt(struct device *dev)
+{
+        struct platform_device *pd_pdev;
+        struct exynos_pm_domain *pd;
+        struct device_node *node;
+
+        node = of_parse_phandle(dev->of_node, "samsung,power-domain", 0);
+        if (!node)
+                return;
+        pd_pdev = of_find_device_by_node(node);
+        if (!pd_pdev)
+                return;
+        pd = platform_get_drvdata(pd_pdev);
+        exynos_add_device_to_domain(pd, dev);
+}
+
+static int exynos_pm_notifier_call(struct notifier_block *nb,
+                                    unsigned long event, void *data)
+{
+        struct device *dev = data;
+
+        switch (event) {
+        case BUS_NOTIFY_BIND_DRIVER:
+                if (dev->of_node)
+                        exynos_read_domain_from_dt(dev);
+
+                break;
+
+        case BUS_NOTIFY_UNBOUND_DRIVER:
+                exynos_remove_device_from_domain(dev);
+
+                break;
+        }
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block platform_nb = {
+        .notifier_call = exynos_pm_notifier_call,
+};
+
 static __init int exynos_pm_dt_parse_domains(void)
 {
+        struct platform_device *pdev;
         struct device_node *np;
 
         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
                 struct exynos_pm_domain *pd;
                 int on;
 
+                pdev = of_find_device_by_node(np);
+
                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
                 if (!pd) {
                         pr_err("%s: failed to allocate memory for domain\n",
@@ -105,10 +182,15 @@ static __init int exynos_pm_dt_parse_domains(void)
                 pd->pd.power_on = exynos_pd_power_on;
                 pd->pd.of_node = np;
 
+                platform_set_drvdata(pdev, pd);
+
                 on = __raw_readl(pd->base + 0x4) & S5P_INT_LOCAL_PWR_EN;
 
                 pm_genpd_init(&pd->pd, NULL, !on);
         }
+
+        bus_register_notifier(&platform_bus_type, &platform_nb);
+
         return 0;
 }
 #else