/* * 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 ? parent_names[0] : NULL, 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; num_parents = of_clk_get_parent_count(node); if (num_parents < 0) return; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return; if (num_parents) { parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL); if (!parent_names) { kfree(data); return; } for (i = 0; i < num_parents; i++) parent_names[i] = of_clk_get_parent_name(node, i); } else { parent_names = NULL; } 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