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Commit 0903ea60 authored by Boris Brezillon's avatar Boris Brezillon Committed by Mike Turquette
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clk: add accuracy support for fixed clock 



This patch adds support for accuracy retrieval on fixed clocks.
It also adds a new dt property called 'clock-accuracy' to define the clock
accuracy.

This can be usefull for oscillator (RC, crystal, ...) definitions which are
always given an accuracy characteristic.

Signed-off-by: default avatarBoris BREZILLON <b.brezillon@overkiz.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
parent 5279fc40

Documentation/devicetree/bindings/clock/fixed-clock.txt

+3 −0
Original line number Diff line number Diff line
@@ -10,6 +10,8 @@ Required properties: 
- clock-frequency : frequency of clock in Hz. Should be a single cell.



Optional properties:

- clock-accuracy : accuracy of clock in ppb (parts per billion).

		   Should be a single cell.

- gpios : From common gpio binding; gpio connection to clock enable pin.

- clock-output-names : From common clock binding.
@@ -18,4 +20,5 @@ Example: 
		compatible = "fixed-clock";

		#clock-cells = <0>;

		clock-frequency = <1000000000>;

		clock-accuracy = <100>;

	};

drivers/clk/clk-fixed-rate.c

+37 −6
Original line number Diff line number Diff line
@@ -34,22 +34,31 @@ static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, 
	return to_clk_fixed_rate(hw)->fixed_rate;

}



static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw,

		unsigned long parent_accuracy)

{

	return to_clk_fixed_rate(hw)->fixed_accuracy;

}



const struct clk_ops clk_fixed_rate_ops = {

	.recalc_rate = clk_fixed_rate_recalc_rate,

	.recalc_accuracy = clk_fixed_rate_recalc_accuracy,

};

EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);



/**

 * clk_register_fixed_rate - register fixed-rate clock with the clock framework

 * clk_register_fixed_rate_with_accuracy - register fixed-rate clock with the

 *					   clock framework

 * @dev: device that is registering this clock

 * @name: name of this clock

 * @parent_name: name of clock's parent

 * @flags: framework-specific flags

 * @fixed_rate: non-adjustable clock rate

 * @fixed_accuracy: non-adjustable clock rate

 */

struct clk *clk_register_fixed_rate(struct device *dev, const char *name,

		const char *parent_name, unsigned long flags,

		unsigned long fixed_rate)

struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev,

		const char *name, const char *parent_name, unsigned long flags,

		unsigned long fixed_rate, unsigned long fixed_accuracy)

{

	struct clk_fixed_rate *fixed;

	struct clk *clk;
@@ -70,16 +79,33 @@ struct clk *clk_register_fixed_rate(struct device *dev, const char *name, 


	/* struct clk_fixed_rate assignments */

	fixed->fixed_rate = fixed_rate;

	fixed->fixed_accuracy = fixed_accuracy;

	fixed->hw.init = &init;



	/* register the clock */

	clk = clk_register(dev, &fixed->hw);



	if (IS_ERR(clk))

		kfree(fixed);



	return clk;

}

EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy);



/**

 * clk_register_fixed_rate - register fixed-rate clock with the clock framework

 * @dev: device that is registering this clock

 * @name: name of this clock

 * @parent_name: name of clock's parent

 * @flags: framework-specific flags

 * @fixed_rate: non-adjustable clock rate

 */

struct clk *clk_register_fixed_rate(struct device *dev, const char *name,

		const char *parent_name, unsigned long flags,

		unsigned long fixed_rate)

{

	return clk_register_fixed_rate_with_accuracy(dev, name, parent_name,

						     flags, fixed_rate, 0);

}

EXPORT_SYMBOL_GPL(clk_register_fixed_rate);



#ifdef CONFIG_OF
@@ -91,13 +117,18 @@ void of_fixed_clk_setup(struct device_node *node) 
	struct clk *clk;

	const char *clk_name = node->name;

	u32 rate;

	u32 accuracy = 0;



	if (of_property_read_u32(node, "clock-frequency", &rate))

		return;



	of_property_read_u32(node, "clock-accuracy", &accuracy);



	of_property_read_string(node, "clock-output-names", &clk_name);



	clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT, rate);

	clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,

						    CLK_IS_ROOT, rate,

						    accuracy);

	if (!IS_ERR(clk))

		of_clk_add_provider(node, of_clk_src_simple_get, clk);

}

include/linux/clk-provider.h

+4 −0
Original line number Diff line number Diff line
@@ -204,6 +204,7 @@ struct clk_hw { 
struct clk_fixed_rate {

	struct		clk_hw hw;

	unsigned long	fixed_rate;

	unsigned long	fixed_accuracy;

	u8		flags;

};
@@ -211,6 +212,9 @@ extern const struct clk_ops clk_fixed_rate_ops; 
struct clk *clk_register_fixed_rate(struct device *dev, const char *name,

		const char *parent_name, unsigned long flags,

		unsigned long fixed_rate);

struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev,

		const char *name, const char *parent_name, unsigned long flags,

		unsigned long fixed_rate, unsigned long fixed_accuracy);



void of_fixed_clk_setup(struct device_node *np);