clk: qcom: clk-dummy: Add a dummy clock provider

Qualcomm Technologies Dummy Clock controller

Qualcomm Technologies Dummy Clock controller devices provide a dummy clock

for driver development during pre-silicon stage. The driver will always

return a dummy clock that has no effect on hardware.

Required properties:

- compatible:		Must be "qcom,dummycc"

- #clock_cells:		Must be <1>. This will allow the common clock device

			tree framework to recognize _this_ device node as a

			clock provider.

Optional properties:

- clock-output-names:	Name of the clock or the clock type.

Example:

	clock_gcc: qcom,gcc {

		compatible = "qcom,dummycc";

		clock-output-names = "gcc_clocks";

		#clock-cells = <1>;

	};

clk-qcom-y += clk-regmap-divider.o

clk-qcom-y += clk-regmap-mux.o

clk-qcom-y += reset.o

clk-qcom-y += clk-dummy.o

clk-qcom-$(CONFIG_QCOM_GDSC) += gdsc.o

obj-$(CONFIG_APQ_GCC_8084) += gcc-apq8084.o

/*

 * Copyright (c) 2016, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

#include <linux/clk-provider.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

struct clk_dummy {

	struct clk_hw hw;

	unsigned long rrate;

};

#define to_clk_dummy(_hw)	container_of(_hw, struct clk_dummy, hw)

static int dummy_clk_set_rate(struct clk_hw *hw, unsigned long rate,

					unsigned long parent_rate)

{

	struct clk_dummy *dummy = to_clk_dummy(hw);

	dummy->rrate = rate;

	pr_debug("set rate: %lu\n", rate);

	return 0;

}

static long dummy_clk_round_rate(struct clk_hw *hw, unsigned long rate,

					unsigned long *parent_rate)

{

	return rate;

}

static unsigned long dummy_clk_recalc_rate(struct clk_hw *hw,

		unsigned long parent_rate)

{

	struct clk_dummy *dummy = to_clk_dummy(hw);

	pr_debug("clock rate: %lu\n", dummy->rrate);

	return dummy->rrate;

}

struct clk_ops clk_dummy_ops = {

	.set_rate = dummy_clk_set_rate,

	.round_rate = dummy_clk_round_rate,

	.recalc_rate = dummy_clk_recalc_rate,

};

EXPORT_SYMBOL_GPL(clk_dummy_ops);

/**

 * clk_register_dummy - register dummy clock with the

 *				   clock framework

 * @dev: device that is registering this clock

 * @name: name of this clock

 * @flags: framework-specific flags

 */

static struct clk *clk_register_dummy(struct device *dev, const char *name,

		unsigned long flags)

{

	struct clk_dummy *dummy;

	struct clk *clk;

	struct clk_init_data init = {};

	/* allocate dummy clock */

	dummy = kzalloc(sizeof(*dummy), GFP_KERNEL);

	if (!dummy)

		return ERR_PTR(-ENOMEM);

	init.name = name;

	init.ops = &clk_dummy_ops;

	init.flags = flags | CLK_IS_BASIC;

	init.num_parents = 0;

	dummy->hw.init = &init;

	/* register the clock */

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

	if (IS_ERR(clk))

		kfree(dummy);

	return clk;

}

/**

 * of_dummy_clk_setup() - Setup function for simple fixed rate clock

 */

static void of_dummy_clk_setup(struct device_node *node)

{

	struct clk *clk;

	const char *clk_name = "dummy_clk";

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

	clk = clk_register_dummy(NULL, clk_name, 0);

	if (!IS_ERR(clk))

		of_clk_add_provider(node, of_clk_src_simple_get, clk);

	pr_info("%s: Dummy clock registered\n", clk_name);

}

CLK_OF_DECLARE(dummy_clk, "qcom,dummycc", of_dummy_clk_setup);

/*

 * Copyright (c) 2014, The Linux Foundation. All rights reserved.

 * Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

				struct regmap *regmap);

extern int qcom_cc_probe(struct platform_device *pdev,

			 const struct qcom_cc_desc *desc);

extern struct clk_ops clk_dummy_ops;

#endif