[PATCH 1/3] clkdev: add devm_get_clk_from_child()
From: kuninori.morimoto.gx@renesas.com (Kuninori Morimoto)
Date: 2016-12-05 05:23:59
Also in:
alsa-devel, linux-clk, linux-devicetree, lkml
Subsystem:
clk api, common clk framework, the rest · Maintainers:
Russell King, Michael Turquette, Stephen Boyd, Linus Torvalds
From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Some driver is using this type of DT bindings for clock (more detail,
see ${LINUX}/Documentation/devicetree/bindings/sound/simple-card.txt).
sound_soc {
...
cpu {
clocks = <&xxx>;
...
};
codec {
clocks = <&xxx>;
...
};
};
Current driver in this case uses of_clk_get() for each node, but there
is no devm_of_clk_get() today.
OTOH, the problem of having devm_of_clk_get() is that it encourages the
use of of_clk_get() when clk_get() is more desirable.
Thus, this patch adds new devm_get_clk_from_chile() which explicitly
reads as get a clock from a child node of this device.
By this function, we can also use this type of DT bindings
sound_soc {
clocks = <&xxx>, <&xxx>;
clock-names = "cpu", "codec";
...
cpu {
...
};
codec {
...
};
};
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
drivers/clk/clk-devres.c | 21 +++++++++++++++++++++
include/linux/clk.h | 29 +++++++++++++++++++++++++----
2 files changed, 46 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index 8f57154..3a218c3 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c@@ -53,3 +53,24 @@ void devm_clk_put(struct device *dev, struct clk *clk) WARN_ON(ret); } EXPORT_SYMBOL(devm_clk_put); + +struct clk *devm_get_clk_from_child(struct device *dev, + struct device_node *np, const char *con_id) +{ + struct clk **ptr, *clk; + + ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + clk = of_clk_get_by_name(np, con_id); + if (!IS_ERR(clk)) { + *ptr = clk; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return clk; +} +EXPORT_SYMBOL(devm_get_clk_from_child);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 123c027..e9d36b3 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h@@ -17,8 +17,9 @@ #include <linux/notifier.h> struct device; - struct clk; +struct device_node; +struct of_phandle_args; /** * DOC: clk notifier callback types
@@ -249,6 +250,23 @@ static inline void clk_unprepare(struct clk *clk) struct clk *devm_clk_get(struct device *dev, const char *id); /** + * devm_get_clk_from_child - lookup and obtain a managed reference to a + * clock producer from child node. + * @dev: device for clock "consumer" + * @np: pointer to clock consumer node + * @con_id: clock consumer ID + * + * This function parses the clocks, and uses them to look up the + * struct clk from the registered list of clock providers by using + * @np and @con_id + * + * The clock will automatically be freed when the device is unbound + * from the bus. + */ +struct clk *devm_get_clk_from_child(struct device *dev, + struct device_node *np, const char *con_id); + +/** * clk_enable - inform the system when the clock source should be running. * @clk: clock source *
@@ -432,6 +450,12 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id) return NULL; } +static inline struct clk *devm_get_clk_from_child(struct device *dev, + struct device_node *np, const char *con_id) +{ + return NULL; +} + static inline void clk_put(struct clk *clk) {} static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
@@ -501,9 +525,6 @@ static inline void clk_disable_unprepare(struct clk *clk) clk_unprepare(clk); } -struct device_node; -struct of_phandle_args; - #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) 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);
--
1.9.1