[PATCH 3/3] clk: add clock lookup from devicetree
Sascha Hauer
s.hauer at pengutronix.de
Wed Jun 5 02:47:33 EDT 2013
On Tue, Jun 04, 2013 at 09:29:11AM +0200, Lucas Stach wrote:
> Taken from the Linuxkernel with some small adjustments for barebox.
>
> Signed-off-by: Lucas Stach <dev at lynxeye.de>
> ---
> drivers/clk/clk.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/clk/clkdev.c | 74 +++++++++++++++++++++++++++++++++++++++
> include/linux/clk.h | 33 ++++++++++++++++++
> 3 files changed, 204 insertions(+)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 690a0c6..bad3386 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -16,6 +16,7 @@
> */
> #include <common.h>
> #include <errno.h>
> +#include <malloc.h>
> #include <linux/clk.h>
> #include <linux/err.h>
>
> @@ -253,6 +254,102 @@ int clk_is_enabled_always(struct clk *clk)
> return 1;
> }
>
> +#ifdef CONFIG_OFTREE
> +/**
> + * struct of_clk_provider - Clock provider registration structure
> + * @link: Entry in global list of clock providers
> + * @node: Pointer to device tree node of clock provider
> + * @get: Get clock callback. Returns NULL or a struct clk for the
> + * given clock specifier
> + * @data: context pointer to be passed into @get callback
> + */
> +struct of_clk_provider {
> + struct list_head link;
> +
> + struct device_node *node;
> + struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
> + void *data;
> +};
> +
> +static LIST_HEAD(of_clk_providers);
> +
> +struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
> +{
> + struct clk_onecell_data *clk_data = data;
> + unsigned int idx = clkspec->args[0];
> +
> + if (idx >= clk_data->clk_num) {
> + pr_err("%s: invalid clock index %d\n", __func__, idx);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + return clk_data->clks[idx];
> +}
> +EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
> +
> +/**
> + * of_clk_add_provider() - Register a clock provider for a node
> + * @np: Device node pointer associated with clock provider
> + * @clk_src_get: callback for decoding clock
> + * @data: context pointer for @clk_src_get callback.
> + */
> +int of_clk_add_provider(struct device_node *np,
> + struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
> + void *data),
> + void *data)
> +{
> + struct of_clk_provider *cp;
> +
> + cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
> + if (!cp)
> + return -ENOMEM;
> +
> + cp->node = np;
> + cp->data = data;
> + cp->get = clk_src_get;
> +
> + list_add(&cp->link, &of_clk_providers);
> + pr_debug("Added clock from %s\n", np->full_name);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(of_clk_add_provider);
> +
> +/**
> + * of_clk_del_provider() - Remove a previously registered clock provider
> + * @np: Device node pointer associated with clock provider
> + */
> +void of_clk_del_provider(struct device_node *np)
> +{
> + struct of_clk_provider *cp;
> +
> + list_for_each_entry(cp, &of_clk_providers, link) {
> + if (cp->node == np) {
> + list_del(&cp->link);
> + kfree(cp);
> + break;
> + }
> + }
> +}
> +EXPORT_SYMBOL_GPL(of_clk_del_provider);
> +
> +struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
> +{
> + struct of_clk_provider *provider;
> + struct clk *clk = ERR_PTR(-ENOENT);
> +
> + /* Check if we have such a provider in our array */
> + list_for_each_entry(provider, &of_clk_providers, link) {
> + if (provider->node == clkspec->np)
> + clk = provider->get(clkspec, provider->data);
> + if (!IS_ERR(clk))
> + break;
> + }
> +
> + return clk;
> +}
> +#endif
> +
> static void dump_one(struct clk *clk, int verbose, int indent)
> {
> struct clk *c;
> diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
> index 256927e..0b91af0 100644
> --- a/drivers/clk/clkdev.c
> +++ b/drivers/clk/clkdev.c
> @@ -19,10 +19,80 @@
> #include <linux/clkdev.h>
> #include <init.h>
> #include <malloc.h>
> +#include <of.h>
> #include <stdio.h>
>
> static LIST_HEAD(clocks);
>
> +#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK)
> +struct clk *of_clk_get(struct device_node *np, int index)
> +{
> + struct of_phandle_args clkspec;
> + struct clk *clk;
> + int rc;
> +
> + if (index < 0)
> + return ERR_PTR(-EINVAL);
> +
> + rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
> + &clkspec);
> + if (rc)
> + return ERR_PTR(rc);
> +
> + clk = of_clk_get_from_provider(&clkspec);
> + return clk;
> +}
> +EXPORT_SYMBOL(of_clk_get);
> +
> +/**
> + * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
> + * @np: pointer to clock consumer node
> + * @name: name of consumer's clock input, or NULL for the first clock reference
> + *
> + * This function parses the clocks and clock-names properties,
> + * and uses them to look up the struct clk from the registered list of clock
> + * providers.
> + */
> +struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
> +{
> + struct clk *clk = ERR_PTR(-ENOENT);
> +
> + /* Walk up the tree of devices looking for a clock that matches */
> + while (np) {
> + int index = 0;
> +
> + /*
> + * For named clocks, first look up the name in the
> + * "clock-names" property. If it cannot be found, then
> + * index will be an error code, and of_clk_get() will fail.
> + */
> + if (name)
> + index = of_property_match_string(np, "clock-names",
> + name);
> + clk = of_clk_get(np, index);
> + if (!IS_ERR(clk))
> + break;
> + else if (name && index >= 0) {
> + pr_err("ERROR: could not get clock %s:%s(%i)\n",
> + np->full_name, name ? name : "", index);
> + return clk;
> + }
> +
> + /*
> + * No matching clock found on this node. If the parent node
> + * has a "clock-ranges" property, then we can try one of its
> + * clocks.
> + */
> + np = np->parent;
> + if (np && !of_get_property(np, "clock-ranges", NULL))
> + break;
> + }
> +
> + return clk;
> +}
> +EXPORT_SYMBOL(of_clk_get_by_name);
> +#endif
> +
> /*
> * Find the correct struct clk for the device and connection ID.
> * We do slightly fuzzy matching here:
> @@ -109,6 +179,10 @@ struct clk *clk_get(struct device_d *dev, const char *con_id)
> if (!IS_ERR(clk))
> return clk;
>
> + clk = of_clk_get_by_name(dev->device_node, con_id);
> + if (!IS_ERR(clk))
> + return clk;
> +
> return clk_get_sys(dev_id, con_id);
> }
> EXPORT_SYMBOL(clk_get);
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 37a4813..0f7158a 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -11,6 +11,8 @@
> #ifndef __LINUX_CLK_H
> #define __LINUX_CLK_H
>
> +#include <linux/err.h>
> +
> struct device_d;
>
> /*
> @@ -210,4 +212,35 @@ void clk_dump(int verbose);
>
> #endif
>
> +struct device_node;
> +struct of_phandle_args;
> +
> +#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK)
> +int of_clk_add_provider(struct device_node *np,
> + struct clk *(*clk_src_get)(struct of_phandle_args *args,
> + void *data),
> + void *data);
> +void of_clk_del_provider(struct device_node *np);
> +
> +struct clk_onecell_data {
> + struct clk **clks;
> + unsigned int clk_num;
> +};
> +struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data);
> +
> +struct clk *of_clk_get(struct device_node *np, int index);
> +struct clk *of_clk_get_by_name(struct device_node *np, const char *name);
> +struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
Can we have a CLK_HAVE_OF_PROVIDER Kconfig symbol and a static inline
version of of_clk_get_from_provider if this is not set? On architectures
which do not call of_clk_add_provider this only adds to the binary space
otherwise.
Sascha
--
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