clk: add DT clock binding support
Based on work 1st by Ben Herrenschmidt and Jeremy Kerr, then by Grant Likely, this patch adds support to clk_get to allow drivers to retrieve clock data from the device tree. Platforms scan for clocks in DT with of_clk_init and a match table, and the register a provider through of_clk_add_provider. The provider's clk_src_get function will be called when a device references the provider's OF node for a clock reference. v6 (Rob Herring): - Return error values instead of NULL to match clock framework expectations v5 (Rob Herring): - Move from drivers/of into common clock subsystem - Squashed "dt/clock: add a simple provider get function" and "dt/clock: add function to get parent clock name" - Rebase to 3.4-rc1 - Drop CONFIG_OF_CLOCK and just use CONFIG_OF - Add missing EXPORT_SYMBOL to various functions - s/clock-output-name/clock-output-names/ - Define that fixed-clock binding is a single output v4 (Rob Herring): - Rework for common clk subsystem - Add of_clk_get_parent_name function v3: - Clarified documentation v2: - fixed errant ';' causing compile error - Editorial fixes from Shawn Guo - merged in adding lookup to clkdev - changed property names to match established convention. After working with the binding a bit it really made more sense to follow the lead of 'reg', 'gpios' and 'interrupts' by making the input simply 'clocks' & 'clock-names' instead of 'clock-input-*', and to only use clock-output* for the producer nodes. (Sorry Shawn, this will mean you need to change some code, but it should be trivial) - Add ability to inherit clocks from parent nodes by using an empty 'clock-ranges' property. Useful for busses. I could use some feedback on the new property name, 'clock-ranges' doesn't feel right to me. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Rob Herring <rob.herring@calxeda.com> Reviewed-by: Shawn Guo <shawn.guo@freescale.com> Cc: Sascha Hauer <kernel@pengutronix.de> Signed-off-by: Mike Turquette <mturquette@linaro.org>
This commit is contained in:
parent
a613163dff
commit
766e6a4ec6
117
Documentation/devicetree/bindings/clock/clock-bindings.txt
Normal file
117
Documentation/devicetree/bindings/clock/clock-bindings.txt
Normal file
|
@ -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)
|
21
Documentation/devicetree/bindings/clock/fixed-clock.txt
Normal file
21
Documentation/devicetree/bindings/clock/fixed-clock.txt
Normal file
|
@ -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>;
|
||||
};
|
|
@ -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
|
||||
|
|
|
@ -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);
|
||||
}
|
||||
|
|
|
@ -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 */
|
||||
|
|
|
@ -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
|
||||
|
|
Loading…
Reference in a new issue