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- /*
- * 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
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