1 files changed, 325 insertions, 0 deletions
diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
new file mode 100644
index 000000000000..10819e248414
--- /dev/null
+++ b/drivers/clk/clk-gpio.c
@@ -0,0 +1,325 @@
+/*
+ * 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;
+	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;
+	const char **parent_names;
+	int i, num_parents;
+	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);
+	}
+
+	num_parents = of_clk_get_parent_count(data->node);
+
+	parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
+	if (!parent_names) {
+		clk = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	for (i = 0; i < num_parents; i++)
+		parent_names[i] = of_clk_get_parent_name(data->node, i);
+
+	clk = data->clk_register_get(data->node->name, parent_names,
+			num_parents, gpio, of_flags & OF_GPIO_ACTIVE_LOW);
+	if (IS_ERR(clk))
+		goto out;
+
+	data->clk = clk;
+out:
+	mutex_unlock(&data->lock);
+	kfree(parent_names);
+
+	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;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return;
+
+	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