Hi Ulf, Tomasz,
On Thu, Aug 28, 2014 at 10:38 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> From: Tomasz Figa <t.figa@xxxxxxxxxxx>
>
> This patch introduces generic code to perform power domain look-up using
Should "power domain" be replaced by "PM domain" here (and everywhere else
in this patch), too, cfr. Rafael's earlier comment?
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -0,0 +1,51 @@
> +* Generic power domains
> +
> +System on chip designs are often divided into multiple power domains that
> +can be used for power gating of selected IP blocks for power saving by
> +reduced leakage current.
> +
> +This device tree binding can be used to bind power domain consumer devices
> +with their power domains provided by power domain providers. A power domain
> +provider can be represented by any node in the device tree and can provide
> +one or more power domains. A consumer node can refer to the provider by
> +a phandle and a set of phandle arguments (so called power domain specifier)
specifiers
> +of length specified by #power-domain-cells property in the power domain
the #power-domain-cells property
> +provider node.
> +
> +==Power domain providers==
> +
> +Required properties:
> + - #power-domain-cells : Number of cells in a power domain specifier;
> + Typically 0 for nodes representing a single power domain and 1 for nodes
> + providing multiple power domains (e.g. power controllers), but can be
> + any value as specified by device tree binding documentation of particular
> + provider.
> +
> +Example:
> +
> + power: power-controller@12340000 {
> + compatible = "foo,power-controller";
> + reg = <0x12340000 0x1000>;
> + #power-domain-cells = <1>;
> + };
> +
> +The node above defines a power controller that is a power domain provider
> +and expects one cell as its phandle argument.
> +
> +==Power domain consumers==
> +
> +Required properties:
> + - power-domains : A phandle and power domain specifier as defined by bindings
> + of power controller specified by phandle.
the power controller
> +
> +Example:
> +
> + leaky-device@12350000 {
> + compatible = "foo,i-leak-current";
> + reg = <0x12350000 0x1000>;
> + power-domains = <&power 0>;
> + };
> +
> +The node above defines a typical power domain consumer device, which is located
> +inside power domain with index 0 of power controller represented by node with
the power domain ... the power controller ... the node
> +label "power".
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> +#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> +/*
> + * Device Tree based power domain providers.
> + *
> + * The code below implements generic device tree based power domain providers
> + * that bind device tree nodes with generic power domains registered in the
> + * system.
> + *
> + * Any driver that registers generic power domains and need to support binding
needs
> + * of devices to these domains is supposed to register a power domain provider,
> + * which maps a power domain specifier retrieved from device tree to a power
the device tree
> +/**
> + * of_genpd_xlate_onecell() - Xlate function for providers using single index.
a single index
> + * @genpdspec: OF phandle args to map into a power domain
> + * @data: xlate function private data - pointer to struct genpd_onecell_data
> + *
> + * This is a generic xlate function that can be used to model simple power
> + * domain controllers that have one device tree node and provide multiple
> + * power domains. A single cell is used as an index to an array of power
an index into
> + * domains specified in genpd_onecell_data struct when registering the
the genpd_onecell_data struct
> + * provider.
> + */
> +struct generic_pm_domain *of_genpd_xlate_onecell(
> + struct of_phandle_args *genpdspec,
> + void *data)
> +{
> + struct genpd_onecell_data *genpd_data = data;
> + unsigned int idx = genpdspec->args[0];
> +
> + if (genpdspec->args_count != 1)
> + return ERR_PTR(-EINVAL);
> +
> + if (idx >= genpd_data->domain_num) {
> + pr_err("%s: invalid domain index %d\n", __func__, idx);
%u for unsigned int idx
> + return ERR_PTR(-EINVAL);
> + }
> +
> + return genpd_data->domains[idx];
This assumes ->domains[] is a contiguous array.
I'd add a NULL check here, to translate NULL to ERR_PTR(-Esomething),
so it can support sparse power domain spaces.
E.g. indexed by the "bit_shift" value of struct rmobile_pm_domain, which
is the actual bit number to use to power up/down an R-Mobile domain.
Different members of the R-Mobile family have different numbers of
domains, and use more or less bits in the same power up/down registers.
This would be similar to the sparse clock-indices handling in
renesas,cpg-mstp-clocks.
> +}
> +EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell);
> +
> +/**
> + * of_genpd_add_provider() - Register a domain provider for a node
> + * @np: Device node pointer associated with domain provider.
the domain provider
> +/**
> + * of_genpd_del_provider() - Remove a previously registered domain provider
> + * @np: Device node pointer associated with domain provider
the domain provider
> +/**
> + * of_genpd_get_from_provider() - Look-up power domain
> + * @genpdspec: OF phandle args to use for look-up
> + *
> + * Looks for domain provider under node specified by @genpdspec and if found
a domain provider ... under the node
> + * uses xlate function of the provider to map phandle args to a power domain.
> +/**
> + * genpd_dev_pm_attach - Attach a device to it's power domain using DT.
its
> + * @dev: Device to attach.
> +/**
> + * genpd_dev_pm_detach - Detach a device from it's power domain.
its
> + * @dev: Device to attach.
> + *
> + * Try to locate a corresponding generic power domain, which the device
> + * then previously were attached to. If found the device is detached from
"was attached to previously"?
> + * the power domain.
> diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> index 7c1d252..5989758 100644
> --- a/include/linux/pm_domain.h
> +++ b/include/linux/pm_domain.h
> @@ -310,4 +310,50 @@ static inline void pm_genpd_syscore_poweron(struct device *dev)
> pm_genpd_syscore_switch(dev, false);
> }
>
> +/* OF power domain providers */
> +struct of_device_id;
> +
> +struct genpd_onecell_data {
> + struct generic_pm_domain **domains;
> + unsigned int domain_num;
This is the number of domains: "num_domains"?
> +};
> +
> +typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
> + void *data);
> +
> +#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
> +int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
> + void *data);
> +void of_genpd_del_provider(struct device_node *np);
> +
> +struct generic_pm_domain *of_genpd_xlate_simple(
> + struct of_phandle_args *genpdspec,
> + void *data);
> +struct generic_pm_domain *of_genpd_xlate_onecell(
> + struct of_phandle_args *genpdspec,
> + void *data);
> +
> +int genpd_dev_pm_attach(struct device *dev);
> +int genpd_dev_pm_detach(struct device *dev);
> +#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
> +static inline int of_genpd_add_provider(struct device_node *np,
> + genpd_xlate_t xlate, void *data)
> +{
> + return 0;
> +}
> +static inline void of_genpd_del_provider(struct device_node *np) {}
> +
> +#define of_genpd_xlate_simple NULL
> +#define of_genpd_xlate_onecell NULL
> +
> +static inline int genpd_dev_pm_attach(struct device *dev)
> +{
> + return -ENODEV;
> +}
> +static inline int genpd_dev_pm_detach(struct device *dev)
> +{
> + return -ENODEV;
> +}
> +#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
As of_genpd_add_provider() provides no compile-time type-checking for
"void *data", I propose to prepend a double underscore to
of_genpd_add_provider(), and to the xlate helpers of_genpd_xlate_simple()
and of_genpd_xlate_onecell(), and provide type-checking wrappers:
static inline int of_genpd_add_provider_simple(struct device_node *np,
struct generic_pm_domain *genpd)
{
return __of_genpd_add_provider(np, __of_genpd_xlate_simple, genpd);
}
static inline int of_genpd_add_provider_onecell(struct device_node *np,
struct genpd_onecell_data *data)
{
return __of_genpd_add_provider(np, __of_genpd_xlate_onecell, data);
}
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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