diff options
| -rw-r--r-- | Documentation/devicetree/bindings/clock/clock-bindings.txt | 117 | ||||
| -rw-r--r-- | Documentation/devicetree/bindings/clock/fixed-clock.txt | 21 | ||||
| -rw-r--r-- | drivers/clk/clk.c | 140 | ||||
| -rw-r--r-- | drivers/clk/clkdev.c | 77 | ||||
| -rw-r--r-- | include/linux/clk-provider.h | 14 | ||||
| -rw-r--r-- | include/linux/clk.h | 19 |
6 files changed, 388 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt new file mode 100644 index 00000000000..eb65d417f8c --- /dev/null +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt @@ -0,0 +1,117 @@ +This binding is a work-in-progress, and are based on some experimental +work by benh[1]. + +Sources of clock signal can be represented by any node in the device +tree. Those nodes are designated as clock providers. Clock consumer +nodes use a phandle and clock specifier pair to connect clock provider +outputs to clock inputs. Similar to the gpio specifiers, a clock +specifier is an array of one more more cells identifying the clock +output on a device. The length of a clock specifier is defined by the +value of a #clock-cells property in the clock provider node. + +[1] http://patchwork.ozlabs.org/patch/31551/ + +==Clock providers== + +Required properties: +#clock-cells: Number of cells in a clock specifier; Typically 0 for nodes + with a single clock output and 1 for nodes with multiple + clock outputs. + +Optional properties: +clock-output-names: Recommended to be a list of strings of clock output signal + names indexed by the first cell in the clock specifier. + However, the meaning of clock-output-names is domain + specific to the clock provider, and is only provided to + encourage using the same meaning for the majority of clock + providers. This format may not work for clock providers + using a complex clock specifier format. In those cases it + is recommended to omit this property and create a binding + specific names property. + + Clock consumer nodes must never directly reference + the provider's clock-output-names property. + +For example: + + oscillator { + #clock-cells = <1>; + clock-output-names = "ckil", "ckih"; + }; + +- this node defines a device with two clock outputs, the first named + "ckil" and the second named "ckih". Consumer nodes always reference + clocks by index. The names should reflect the clock output signal + names for the device. + +==Clock consumers== + +Required properties: +clocks: List of phandle and clock specifier pairs, one pair + for each clock input to the device. Note: if the + clock provider specifies '0' for #clock-cells, then + only the phandle portion of the pair will appear. + +Optional properties: +clock-names: List of clock input name strings sorted in the same + order as the clocks property. Consumers drivers + will use clock-names to match clock input names + with clocks specifiers. +clock-ranges: Empty property indicating that child nodes can inherit named + clocks from this node. Useful for bus nodes to provide a + clock to their children. + +For example: + + device { + clocks = <&osc 1>, <&ref 0>; + clock-names = "baud", "register"; + }; + + +This represents a device with two clock inputs, named "baud" and "register". +The baud clock is connected to output 1 of the &osc device, and the register +clock is connected to output 0 of the &ref. + +==Example== + + /* external oscillator */ + osc: oscillator { + compatible = "fixed-clock"; + #clock-cells = <1>; + clock-frequency = <32678>; + clock-output-names = "osc"; + }; + + /* phase-locked-loop device, generates a higher frequency clock + * from the external oscillator reference */ + pll: pll@4c000 { + compatible = "vendor,some-pll-interface" + #clock-cells = <1>; + clocks = <&osc 0>; + clock-names = "ref"; + reg = <0x4c000 0x1000>; + clock-output-names = "pll", "pll-switched"; + }; + + /* UART, using the low frequency oscillator for the baud clock, + * and the high frequency switched PLL output for register + * clocking */ + uart@a000 { + compatible = "fsl,imx-uart"; + reg = <0xa000 0x1000>; + interrupts = <33>; + clocks = <&osc 0>, <&pll 1>; + clock-names = "baud", "register"; + }; + +This DT fragment defines three devices: an external oscillator to provide a +low-frequency reference clock, a PLL device to generate a higher frequency +clock signal, and a UART. + +* The oscillator is fixed-frequency, and provides one clock output, named "osc". +* The PLL is both a clock provider and a clock consumer. It uses the clock + signal generated by the external oscillator, and provides two output signals + ("pll" and "pll-switched"). +* The UART has its baud clock connected the external oscillator and its + register clock connected to the PLL clock (the "pll-switched" signal) diff --git a/Documentation/devicetree/bindings/clock/fixed-clock.txt b/Documentation/devicetree/bindings/clock/fixed-clock.txt new file mode 100644 index 00000000000..0b1fe782409 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/fixed-clock.txt @@ -0,0 +1,21 @@ +Binding for simple fixed-rate clock sources. + +This binding uses the common clock binding[1]. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt + +Required properties: +- compatible : shall be "fixed-clock". +- #clock-cells : from common clock binding; shall be set to 0. +- clock-frequency : frequency of clock in Hz. Should be a single cell. + +Optional properties: +- gpios : From common gpio binding; gpio connection to clock enable pin. +- clock-output-names : From common clock binding. + +Example: + clock { + compatible = "fixed-clock"; + #clock-cells = <0>; + clock-frequency = <1000000000>; + }; diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 46317cbc088..c87fdd71056 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -16,6 +16,7 @@ #include <linux/err.h> #include <linux/list.h> #include <linux/slab.h> +#include <linux/of.h> static DEFINE_SPINLOCK(enable_lock); static DEFINE_MUTEX(prepare_lock); @@ -1550,3 +1551,142 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb) return ret; } EXPORT_SYMBOL_GPL(clk_notifier_unregister); + +#ifdef CONFIG_OF +/** + * 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); +static DEFINE_MUTEX(of_clk_lock); + +struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec, + void *data) +{ + return data; +} +EXPORT_SYMBOL_GPL(of_clk_src_simple_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 = of_node_get(np); + cp->data = data; + cp->get = clk_src_get; + + mutex_lock(&of_clk_lock); + list_add(&cp->link, &of_clk_providers); + mutex_unlock(&of_clk_lock); + 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; + + mutex_lock(&of_clk_lock); + list_for_each_entry(cp, &of_clk_providers, link) { + if (cp->node == np) { + list_del(&cp->link); + of_node_put(cp->node); + kfree(cp); + break; + } + } + mutex_unlock(&of_clk_lock); +} +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 */ + mutex_lock(&of_clk_lock); + 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; + } + mutex_unlock(&of_clk_lock); + + return clk; +} + +const char *of_clk_get_parent_name(struct device_node *np, int index) +{ + struct of_phandle_args clkspec; + const char *clk_name; + int rc; + + if (index < 0) + return NULL; + + rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, + &clkspec); + if (rc) + return NULL; + + if (of_property_read_string_index(clkspec.np, "clock-output-names", + clkspec.args_count ? clkspec.args[0] : 0, + &clk_name) < 0) + clk_name = clkspec.np->name; + + of_node_put(clkspec.np); + return clk_name; +} +EXPORT_SYMBOL_GPL(of_clk_get_parent_name); + +/** + * of_clk_init() - Scan and init clock providers from the DT + * @matches: array of compatible values and init functions for providers. + * + * This function scans the device tree for matching clock providers and + * calls their initialization functions + */ +void __init of_clk_init(const struct of_device_id *matches) +{ + struct device_node *np; + + for_each_matching_node(np, matches) { + const struct of_device_id *match = of_match_node(matches, np); + of_clk_init_cb_t clk_init_cb = match->data; + clk_init_cb(np); + } +} +#endif diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index c535cf8c577..20649b3c88f 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -19,10 +19,80 @@ #include <linux/mutex.h> #include <linux/clk.h> #include <linux/clkdev.h> +#include <linux/of.h> static LIST_HEAD(clocks); static DEFINE_MUTEX(clocks_mutex); +#ifdef CONFIG_OF +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); + of_node_put(clkspec.np); + 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: @@ -83,6 +153,13 @@ EXPORT_SYMBOL(clk_get_sys); struct clk *clk_get(struct device *dev, const char *con_id) { const char *dev_id = dev ? dev_name(dev) : NULL; + struct clk *clk; + + if (dev) { + clk = of_clk_get_by_name(dev->of_node, con_id); + if (clk && __clk_get(clk)) + return clk; + } return clk_get_sys(dev_id, con_id); } diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 06ad617664a..7c9c691102b 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -347,5 +347,19 @@ void __clk_unprepare(struct clk *clk); void __clk_reparent(struct clk *clk, struct clk *new_parent); unsigned long __clk_round_rate(struct clk *clk, unsigned long rate); +struct of_device_id; + +typedef void (*of_clk_init_cb_t)(struct device_node *); + +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 *of_clk_src_simple_get(struct of_phandle_args *clkspec, + void *data); +const char *of_clk_get_parent_name(struct device_node *np, int index); +void of_clk_init(const struct of_device_id *matches); + #endif /* CONFIG_COMMON_CLK */ #endif /* CLK_PROVIDER_H */ diff --git a/include/linux/clk.h b/include/linux/clk.h index ad5c43e8ae8..8b70342e7e0 100644 --- a/include/linux/clk.h +++ b/include/linux/clk.h @@ -310,4 +310,23 @@ struct clk *clk_get_sys(const char *dev_id, const char *con_id); int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, struct device *dev); +struct device_node; +struct of_phandle_args; + +#ifdef CONFIG_OF +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); +#else +static inline struct clk *of_clk_get(struct device_node *np, int index) +{ + return NULL; +} +static inline struct clk *of_clk_get_by_name(struct device_node *np, + const char *name) +{ + return NULL; +} +#endif + #endif |