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Commit 97a87393 authored by Deepak Katragadda's avatar Deepak Katragadda Committed by David Dai
Browse files

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



Add a dummy clock provider that registers a simple callback that
in turn always returns the dummy clock for any clk_get call.

In addition, consumers of the dummy clock provider would require
support for dummy resets, which would make a dummy assert/deassert
of the reset signals.

Change-Id: I08fcb174fd0e0c49f8069e106b48597bcdfe847d
Signed-off-by: default avatarTaniya Das <tdas@codeaurora.org>
Signed-off-by: default avatarDeepak Katragadda <dkatraga@codeaurora.org>
Signed-off-by: default avatarDavid Dai <daidavid1@codeaurora.org>
parent fd04f068

drivers/clk/qcom/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ clk-qcom-y += clk-regmap-mux-div.o 
clk-qcom-$(CONFIG_KRAIT_CLOCKS) += clk-krait.o

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

clk-qcom-y += reset.o

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

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



# Keep alphabetically sorted by config

drivers/clk/qcom/clk-dummy.c

0 → 100644
+138 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2018-2019, The Linux Foundation. All rights reserved.

 */



#include <linux/clk-provider.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/slab.h>



#include "common.h"



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



#define RESET_MAX	100



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("%s: rate %lu\n", __func__, 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("%s: returning a clock rate of %lu\n",

				__func__, dummy->rrate);



	return dummy->rrate;

}



const 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(clk_dummy_ops);



static int dummy_reset_assert(struct reset_controller_dev *rcdev,

				unsigned long id)

{

	return 0;

}



static int dummy_reset_deassert(struct reset_controller_dev *rcdev,

				unsigned long id)

{

	return 0;

}



static struct reset_control_ops dummy_reset_ops = {

	.assert         = dummy_reset_assert,

	.deassert       = dummy_reset_deassert,

};



/**

 * 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

 * @node: device node

 */

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

		unsigned long flags, struct device_node *node)

{

	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;

	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;

	}



	dummy->reset.of_node = node;

	dummy->reset.ops = &dummy_reset_ops;

	dummy->reset.nr_resets = RESET_MAX;



	if (reset_controller_register(&dummy->reset))

		pr_err("Failed to register reset controller for %s\n", name);

	else

		pr_info("Successfully registered dummy reset controller for %s\n",

								name);



	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, node);

	if (!IS_ERR(clk)) {

		of_clk_add_provider(node, of_clk_src_simple_get, clk);

	} else {

		pr_err("Failed to register dummy clock controller for %s\n",

								clk_name);

		return;

	}



	pr_info("Successfully registered dummy clock controller for %s\n",

								clk_name);

}

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

drivers/clk/qcom/common.h

+11 −3
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

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

/* SPDX-License-Identifier: GPL-2.0-only */

/* Copyright (c) 2014, 2018, The Linux Foundation. All rights reserved. */



#ifndef __QCOM_CLK_COMMON_H__

#define __QCOM_CLK_COMMON_H__



#include <linux/reset-controller.h>



struct platform_device;

struct regmap_config;

struct clk_regmap;
@@ -41,6 +43,12 @@ struct parent_map { 
	u8 cfg;

};



struct clk_dummy {

	struct clk_hw hw;

	struct reset_controller_dev reset;

	unsigned long rrate;

};



extern const struct freq_tbl *qcom_find_freq(const struct freq_tbl *f,

					     unsigned long rate);

extern const struct freq_tbl *qcom_find_freq_floor(const struct freq_tbl *f,
@@ -61,5 +69,5 @@ extern int qcom_cc_really_probe(struct platform_device *pdev, 
				struct regmap *regmap);

extern int qcom_cc_probe(struct platform_device *pdev,

			 const struct qcom_cc_desc *desc);



extern const struct clk_ops clk_dummy_ops;

#endif