drivers/clk/clk-gpio.c - kernel/bruno - Git at Google

 /*
  * Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com
  *
  * Authors:
  *    Jyri Sarha <jsarha@ti.com>
  *    Sergej Sawazki <ce3a@gmx.de>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Gpio controlled clock implementation
  */

 #include <linux/clk-provider.h>
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/of_gpio.h>
 #include <linux/err.h>
 #include <linux/device.h>

 /**
  * DOC: basic gpio gated clock which can be enabled and disabled
  *      with gpio output
  * Traits of this clock:
  * prepare - clk_(un)prepare only ensures parent is (un)prepared
  * enable - clk_enable and clk_disable are functional & control gpio
  * rate - inherits rate from parent.  No clk_set_rate support
  * parent - fixed parent.  No clk_set_parent support
  */

 #define to_clk_gpio(_hw) container_of(_hw, struct clk_gpio, hw)

 static int clk_gpio_gate_enable(struct clk_hw *hw)
 {
 	struct clk_gpio *clk = to_clk_gpio(hw);

 	gpiod_set_value(clk->gpiod, 1);

 	return 0;
 }

 static void clk_gpio_gate_disable(struct clk_hw *hw)
 {
 	struct clk_gpio *clk = to_clk_gpio(hw);

 	gpiod_set_value(clk->gpiod, 0);
 }

 static int clk_gpio_gate_is_enabled(struct clk_hw *hw)
 {
 	struct clk_gpio *clk = to_clk_gpio(hw);

 	return gpiod_get_value(clk->gpiod);
 }

 const struct clk_ops clk_gpio_gate_ops = {
 	.enable = clk_gpio_gate_enable,
 	.disable = clk_gpio_gate_disable,
 	.is_enabled = clk_gpio_gate_is_enabled,
 };
 EXPORT_SYMBOL_GPL(clk_gpio_gate_ops);

 /**
  * DOC: basic clock multiplexer which can be controlled with a gpio output
  * Traits of this clock:
  * prepare - clk_prepare only ensures that parents are prepared
  * rate - rate is only affected by parent switching.  No clk_set_rate support
  * parent - parent is adjustable through clk_set_parent
  */

 static u8 clk_gpio_mux_get_parent(struct clk_hw *hw)
 {
 	struct clk_gpio *clk = to_clk_gpio(hw);

 	return gpiod_get_value(clk->gpiod);
 }

 static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index)
 {
 	struct clk_gpio *clk = to_clk_gpio(hw);

 	gpiod_set_value(clk->gpiod, index);

 	return 0;
 }

 const struct clk_ops clk_gpio_mux_ops = {
 	.get_parent = clk_gpio_mux_get_parent,
 	.set_parent = clk_gpio_mux_set_parent,
 	.determine_rate = __clk_mux_determine_rate,
 };
 EXPORT_SYMBOL_GPL(clk_gpio_mux_ops);

 static struct clk *clk_register_gpio(struct device *dev, const char *name,
 		const char * const *parent_names, u8 num_parents, unsigned gpio,
 		bool active_low, unsigned long flags,
 		const struct clk_ops *clk_gpio_ops)
 {
 	struct clk_gpio *clk_gpio;
 	struct clk *clk;
 	struct clk_init_data init = {};
 	unsigned long gpio_flags;
 	int err;

 	if (dev)
 		clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio),	GFP_KERNEL);
 	else
 		clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL);

 	if (!clk_gpio)
 		return ERR_PTR(-ENOMEM);

 	if (active_low)
 		gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_HIGH;
 	else
 		gpio_flags = GPIOF_OUT_INIT_LOW;

 	if (dev)
 		err = devm_gpio_request_one(dev, gpio, gpio_flags, name);
 	else
 		err = gpio_request_one(gpio, gpio_flags, name);
 	if (err) {
 		if (err != -EPROBE_DEFER)
 			pr_err("%s: %s: Error requesting clock control gpio %u\n",
 					__func__, name, gpio);
 		if (!dev)
 			kfree(clk_gpio);

 		return ERR_PTR(err);
 	}

 	init.name = name;
 	init.ops = clk_gpio_ops;
 	init.flags = flags | CLK_IS_BASIC;
 	init.parent_names = parent_names;
 	init.num_parents = num_parents;

 	clk_gpio->gpiod = gpio_to_desc(gpio);
 	clk_gpio->hw.init = &init;

 	if (dev)
 		clk = devm_clk_register(dev, &clk_gpio->hw);
 	else
 		clk = clk_register(NULL, &clk_gpio->hw);

 	if (!IS_ERR(clk))
 		return clk;

 	if (!dev) {
 		gpiod_put(clk_gpio->gpiod);
 		kfree(clk_gpio);
 	}

 	return clk;
 }

 /**
  * clk_register_gpio_gate - register a gpio clock gate with the clock framework
  * @dev: device that is registering this clock
  * @name: name of this clock
  * @parent_name: name of this clock's parent
  * @gpio: gpio number to gate this clock
  * @active_low: true if gpio should be set to 0 to enable clock
  * @flags: clock flags
  */
 struct clk *clk_register_gpio_gate(struct device *dev, const char *name,
 		const char *parent_name, unsigned gpio, bool active_low,
 		unsigned long flags)
 {
 	return clk_register_gpio(dev, name,
 			(parent_name ? &parent_name : NULL),
 			(parent_name ? 1 : 0), gpio, active_low, flags,
 			&clk_gpio_gate_ops);
 }
 EXPORT_SYMBOL_GPL(clk_register_gpio_gate);

 /**
  * clk_register_gpio_mux - register a gpio clock mux with the clock framework
  * @dev: device that is registering this clock
  * @name: name of this clock
  * @parent_names: names of this clock's parents
  * @num_parents: number of parents listed in @parent_names
  * @gpio: gpio number to gate this clock
  * @active_low: true if gpio should be set to 0 to enable clock
  * @flags: clock flags
  */
 struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
 		const char * const *parent_names, u8 num_parents, unsigned gpio,
 		bool active_low, unsigned long flags)
 {
 	if (num_parents != 2) {
 		pr_err("mux-clock %s must have 2 parents\n", name);
 		return ERR_PTR(-EINVAL);
 	}

 	return clk_register_gpio(dev, name, parent_names, num_parents,
 			gpio, active_low, flags, &clk_gpio_mux_ops);
 }
 EXPORT_SYMBOL_GPL(clk_register_gpio_mux);

 #ifdef CONFIG_OF
 /**
  * clk_register_get() has to be delayed, because -EPROBE_DEFER
  * can not be handled properly at of_clk_init() call time.
  */

 struct clk_gpio_delayed_register_data {
 	const char *gpio_name;
 	int num_parents;
 	const char **parent_names;
 	struct device_node *node;
 	struct mutex lock;
 	struct clk *clk;
 	struct clk *(*clk_register_get)(const char *name,
 			const char * const *parent_names, u8 num_parents,
 			unsigned gpio, bool active_low);
 };

 static struct clk *of_clk_gpio_delayed_register_get(
 		struct of_phandle_args *clkspec, void *_data)
 {
 	struct clk_gpio_delayed_register_data *data = _data;
 	struct clk *clk;
 	int gpio;
 	enum of_gpio_flags of_flags;

 	mutex_lock(&data->lock);

 	if (data->clk) {
 		mutex_unlock(&data->lock);
 		return data->clk;
 	}

 	gpio = of_get_named_gpio_flags(data->node, data->gpio_name, 0,
 			&of_flags);
 	if (gpio < 0) {
 		mutex_unlock(&data->lock);
 		if (gpio == -EPROBE_DEFER)
 			pr_debug("%s: %s: GPIOs not yet available, retry later\n",
 					data->node->name, __func__);
 		else
 			pr_err("%s: %s: Can't get '%s' DT property\n",
 					data->node->name, __func__,
 					data->gpio_name);
 		return ERR_PTR(gpio);
 	}

 	clk = data->clk_register_get(data->node->name, data->parent_names,
 			data->num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
 	if (IS_ERR(clk))
 		goto out;

 	data->clk = clk;
 out:
 	mutex_unlock(&data->lock);

 	return clk;
 }

 static struct clk *of_clk_gpio_gate_delayed_register_get(const char *name,
 		const char * const *parent_names, u8 num_parents,
 		unsigned gpio, bool active_low)
 {
 	return clk_register_gpio_gate(NULL, name, parent_names[0],
 			gpio, active_low, 0);
 }

 static struct clk *of_clk_gpio_mux_delayed_register_get(const char *name,
 		const char * const *parent_names, u8 num_parents, unsigned gpio,
 		bool active_low)
 {
 	return clk_register_gpio_mux(NULL, name, parent_names, num_parents,
 			gpio, active_low, 0);
 }

 static void __init of_gpio_clk_setup(struct device_node *node,
 		const char *gpio_name,
 		struct clk *(*clk_register_get)(const char *name,
 				const char * const *parent_names,
 				u8 num_parents,
 				unsigned gpio, bool active_low))
 {
 	struct clk_gpio_delayed_register_data *data;
 	const char **parent_names;
 	int i, num_parents;

 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return;

 	num_parents = of_clk_get_parent_count(node);

 	parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
 	if (!parent_names)
 		return;

 	for (i = 0; i < num_parents; i++)
 		parent_names[i] = of_clk_get_parent_name(node, i);

 	data->num_parents = num_parents;
 	data->parent_names = parent_names;
 	data->node = node;
 	data->gpio_name = gpio_name;
 	data->clk_register_get = clk_register_get;
 	mutex_init(&data->lock);

 	of_clk_add_provider(node, of_clk_gpio_delayed_register_get, data);
 }

 static void __init of_gpio_gate_clk_setup(struct device_node *node)
 {
 	of_gpio_clk_setup(node, "enable-gpios",
 		of_clk_gpio_gate_delayed_register_get);
 }
 CLK_OF_DECLARE(gpio_gate_clk, "gpio-gate-clock", of_gpio_gate_clk_setup);

 void __init of_gpio_mux_clk_setup(struct device_node *node)
 {
 	of_gpio_clk_setup(node, "select-gpios",
 		of_clk_gpio_mux_delayed_register_get);
 }
 CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup);
 #endif
	/*
	* Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com
	*
	* Authors:
	* Jyri Sarha <jsarha@ti.com>
	* Sergej Sawazki <ce3a@gmx.de>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Gpio controlled clock implementation
	*/

	#include <linux/clk-provider.h>
	#include <linux/export.h>
	#include <linux/slab.h>
	#include <linux/gpio.h>
	#include <linux/gpio/consumer.h>
	#include <linux/of_gpio.h>
	#include <linux/err.h>
	#include <linux/device.h>

	/**
	* DOC: basic gpio gated clock which can be enabled and disabled
	* with gpio output
	* Traits of this clock:
	* prepare - clk_(un)prepare only ensures parent is (un)prepared
	* enable - clk_enable and clk_disable are functional & control gpio
	* rate - inherits rate from parent. No clk_set_rate support
	* parent - fixed parent. No clk_set_parent support
	*/

	#define to_clk_gpio(_hw) container_of(_hw, struct clk_gpio, hw)

	static int clk_gpio_gate_enable(struct clk_hw *hw)
	{
	struct clk_gpio *clk = to_clk_gpio(hw);

	gpiod_set_value(clk->gpiod, 1);

	return 0;
	}

	static void clk_gpio_gate_disable(struct clk_hw *hw)
	{
	struct clk_gpio *clk = to_clk_gpio(hw);

	gpiod_set_value(clk->gpiod, 0);
	}

	static int clk_gpio_gate_is_enabled(struct clk_hw *hw)
	{
	struct clk_gpio *clk = to_clk_gpio(hw);

	return gpiod_get_value(clk->gpiod);
	}

	const struct clk_ops clk_gpio_gate_ops = {
	.enable = clk_gpio_gate_enable,
	.disable = clk_gpio_gate_disable,
	.is_enabled = clk_gpio_gate_is_enabled,
	};
	EXPORT_SYMBOL_GPL(clk_gpio_gate_ops);

	/**
	* DOC: basic clock multiplexer which can be controlled with a gpio output
	* Traits of this clock:
	* prepare - clk_prepare only ensures that parents are prepared
	* rate - rate is only affected by parent switching. No clk_set_rate support
	* parent - parent is adjustable through clk_set_parent
	*/

	static u8 clk_gpio_mux_get_parent(struct clk_hw *hw)
	{
	struct clk_gpio *clk = to_clk_gpio(hw);

	return gpiod_get_value(clk->gpiod);
	}

	static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index)
	{
	struct clk_gpio *clk = to_clk_gpio(hw);

	gpiod_set_value(clk->gpiod, index);

	return 0;
	}

	const struct clk_ops clk_gpio_mux_ops = {
	.get_parent = clk_gpio_mux_get_parent,
	.set_parent = clk_gpio_mux_set_parent,
	.determine_rate = __clk_mux_determine_rate,
	};
	EXPORT_SYMBOL_GPL(clk_gpio_mux_ops);

	static struct clk clk_register_gpio(struct device dev, const char *name,
	const char * const *parent_names, u8 num_parents, unsigned gpio,
	bool active_low, unsigned long flags,
	const struct clk_ops *clk_gpio_ops)
	{
	struct clk_gpio *clk_gpio;
	struct clk *clk;
	struct clk_init_data init = {};
	unsigned long gpio_flags;
	int err;

	if (dev)
	clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL);
	else
	clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL);

	if (!clk_gpio)
	return ERR_PTR(-ENOMEM);

	if (active_low)
	gpio_flags = GPIOF_ACTIVE_LOW \| GPIOF_OUT_INIT_HIGH;
	else
	gpio_flags = GPIOF_OUT_INIT_LOW;

	if (dev)
	err = devm_gpio_request_one(dev, gpio, gpio_flags, name);
	else
	err = gpio_request_one(gpio, gpio_flags, name);
	if (err) {
	if (err != -EPROBE_DEFER)
	pr_err("%s: %s: Error requesting clock control gpio %u\n",
	__func__, name, gpio);
	if (!dev)
	kfree(clk_gpio);

	return ERR_PTR(err);
	}

	init.name = name;
	init.ops = clk_gpio_ops;
	init.flags = flags \| CLK_IS_BASIC;
	init.parent_names = parent_names;
	init.num_parents = num_parents;

	clk_gpio->gpiod = gpio_to_desc(gpio);
	clk_gpio->hw.init = &init;

	if (dev)
	clk = devm_clk_register(dev, &clk_gpio->hw);
	else
	clk = clk_register(NULL, &clk_gpio->hw);

	if (!IS_ERR(clk))
	return clk;

	if (!dev) {
	gpiod_put(clk_gpio->gpiod);
	kfree(clk_gpio);
	}

	return clk;
	}

	/**
	* clk_register_gpio_gate - register a gpio clock gate with the clock framework
	* @dev: device that is registering this clock
	* @name: name of this clock
	* @parent_name: name of this clock's parent
	* @gpio: gpio number to gate this clock
	* @active_low: true if gpio should be set to 0 to enable clock
	* @flags: clock flags
	*/
	struct clk clk_register_gpio_gate(struct device dev, const char *name,
	const char *parent_name, unsigned gpio, bool active_low,
	unsigned long flags)
	{
	return clk_register_gpio(dev, name,
	(parent_name ? &parent_name : NULL),
	(parent_name ? 1 : 0), gpio, active_low, flags,
	&clk_gpio_gate_ops);
	}
	EXPORT_SYMBOL_GPL(clk_register_gpio_gate);

	/**
	* clk_register_gpio_mux - register a gpio clock mux with the clock framework
	* @dev: device that is registering this clock
	* @name: name of this clock
	* @parent_names: names of this clock's parents
	* @num_parents: number of parents listed in @parent_names
	* @gpio: gpio number to gate this clock
	* @active_low: true if gpio should be set to 0 to enable clock
	* @flags: clock flags
	*/
	struct clk clk_register_gpio_mux(struct device dev, const char *name,
	const char * const *parent_names, u8 num_parents, unsigned gpio,
	bool active_low, unsigned long flags)
	{
	if (num_parents != 2) {
	pr_err("mux-clock %s must have 2 parents\n", name);
	return ERR_PTR(-EINVAL);
	}

	return clk_register_gpio(dev, name, parent_names, num_parents,
	gpio, active_low, flags, &clk_gpio_mux_ops);
	}
	EXPORT_SYMBOL_GPL(clk_register_gpio_mux);

	#ifdef CONFIG_OF
	/**
	* clk_register_get() has to be delayed, because -EPROBE_DEFER
	* can not be handled properly at of_clk_init() call time.
	*/

	struct clk_gpio_delayed_register_data {
	const char *gpio_name;
	int num_parents;
	const char **parent_names;
	struct device_node *node;
	struct mutex lock;
	struct clk *clk;
	struct clk (clk_register_get)(const char *name,
	const char * const *parent_names, u8 num_parents,
	unsigned gpio, bool active_low);
	};

	static struct clk *of_clk_gpio_delayed_register_get(
	struct of_phandle_args clkspec, void _data)
	{
	struct clk_gpio_delayed_register_data *data = _data;
	struct clk *clk;
	int gpio;
	enum of_gpio_flags of_flags;

	mutex_lock(&data->lock);

	if (data->clk) {
	mutex_unlock(&data->lock);
	return data->clk;
	}

	gpio = of_get_named_gpio_flags(data->node, data->gpio_name, 0,
	&of_flags);
	if (gpio < 0) {
	mutex_unlock(&data->lock);
	if (gpio == -EPROBE_DEFER)
	pr_debug("%s: %s: GPIOs not yet available, retry later\n",
	data->node->name, __func__);
	else
	pr_err("%s: %s: Can't get '%s' DT property\n",
	data->node->name, __func__,
	data->gpio_name);
	return ERR_PTR(gpio);
	}

	clk = data->clk_register_get(data->node->name, data->parent_names,
	data->num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
	if (IS_ERR(clk))
	goto out;

	data->clk = clk;
	out:
	mutex_unlock(&data->lock);

	return clk;
	}

	static struct clk of_clk_gpio_gate_delayed_register_get(const char name,
	const char * const *parent_names, u8 num_parents,
	unsigned gpio, bool active_low)
	{
	return clk_register_gpio_gate(NULL, name, parent_names[0],
	gpio, active_low, 0);
	}

	static struct clk of_clk_gpio_mux_delayed_register_get(const char name,
	const char * const *parent_names, u8 num_parents, unsigned gpio,
	bool active_low)
	{
	return clk_register_gpio_mux(NULL, name, parent_names, num_parents,
	gpio, active_low, 0);
	}

	static void __init of_gpio_clk_setup(struct device_node *node,
	const char *gpio_name,
	struct clk (clk_register_get)(const char *name,
	const char * const *parent_names,
	u8 num_parents,
	unsigned gpio, bool active_low))
	{
	struct clk_gpio_delayed_register_data *data;
	const char **parent_names;
	int i, num_parents;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
	return;

	num_parents = of_clk_get_parent_count(node);

	parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
	if (!parent_names)
	return;

	for (i = 0; i < num_parents; i++)
	parent_names[i] = of_clk_get_parent_name(node, i);

	data->num_parents = num_parents;
	data->parent_names = parent_names;
	data->node = node;
	data->gpio_name = gpio_name;
	data->clk_register_get = clk_register_get;
	mutex_init(&data->lock);

	of_clk_add_provider(node, of_clk_gpio_delayed_register_get, data);
	}

	static void __init of_gpio_gate_clk_setup(struct device_node *node)
	{
	of_gpio_clk_setup(node, "enable-gpios",
	of_clk_gpio_gate_delayed_register_get);
	}
	CLK_OF_DECLARE(gpio_gate_clk, "gpio-gate-clock", of_gpio_gate_clk_setup);

	void __init of_gpio_mux_clk_setup(struct device_node *node)
	{
	of_gpio_clk_setup(node, "select-gpios",
	of_clk_gpio_mux_delayed_register_get);
	}
	CLK_OF_DECLARE(gpio_mux_clk, "gpio-mux-clock", of_gpio_mux_clk_setup);
	#endif