On 6 September 2012 15:08, Tomasz Figa <t.figa@xxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
> .../bindings/arm/exynos/power_domain.txt | 13 +++-
> arch/arm/mach-exynos/pm_domains.c | 82 ++++++++++++++++++++++
> 2 files changed, 94 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt
> index 843b546..8ed914f 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 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 {
> + /* ... */
> + power-domain = <&lcd0>;
> + /* ... */
> + };
Since the value of power-domain property is mostly samsung specific,
should this be "samsung,power-domain" ?
> diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c
> index 5b7ce7e..7b3b8a3 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, "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);
> +}
The function "exynos_read_domain_from_dt" does more than reading the
domain from dt. It associates a device with a power domain. So should
it be renamed accordingly?
> +
> +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,
> +};
All the functions above are so generic (or can be made generic with
minor modifications) that it can be placed outside of mach-exynos. Or
better still, reusable for all platforms.
> +
> 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
> --
> 1.7.12
>
This patch looks so nice. I learned a thing or two from this patch.
Reviewed-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx>
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