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>

diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
index 843b54622313670984d6d7cbd62fe05ae8ef27ed..5216b419016aa7065e618285047b44ab0b033e1e 100644 (file)
--- 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 5b7ce7ea6c6182e9fdb3e91c9133771a814f0f9c..9f1351de52f7533a731f6d2d2d26bb644c639c09 100644 (file)
--- 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