1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
new file mode 100644
index 000000000..af9cc00d2
--- /dev/null
+++ b/drivers/clk/clk-gpio.c
@@ -0,0 +1,271 @@
+/*
+ * 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/consumer.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/of_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
+ */
+
+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_cansleep(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_cansleep(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_hw *clk_register_gpio(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
+		unsigned long flags, const struct clk_ops *clk_gpio_ops)
+{
+	struct clk_gpio *clk_gpio;
+	struct clk_hw *hw;
+	struct clk_init_data init = {};
+	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);
+
+	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 = gpiod;
+	clk_gpio->hw.init = &init;
+
+	hw = &clk_gpio->hw;
+	if (dev)
+		err = devm_clk_hw_register(dev, hw);
+	else
+		err = clk_hw_register(NULL, hw);
+
+	if (!err)
+		return hw;
+
+	if (!dev) {
+		kfree(clk_gpio);
+	}
+
+	return ERR_PTR(err);
+}
+
+/**
+ * clk_hw_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
+ * @gpiod: gpio descriptor to gate this clock
+ * @flags: clock flags
+ */
+struct clk_hw *clk_hw_register_gpio_gate(struct device *dev, const char *name,
+		const char *parent_name, struct gpio_desc *gpiod,
+		unsigned long flags)
+{
+	return clk_register_gpio(dev, name,
+			(parent_name ? &parent_name : NULL),
+			(parent_name ? 1 : 0), gpiod, flags,
+			&clk_gpio_gate_ops);
+}
+EXPORT_SYMBOL_GPL(clk_hw_register_gpio_gate);
+
+struct clk *clk_register_gpio_gate(struct device *dev, const char *name,
+		const char *parent_name, struct gpio_desc *gpiod,
+		unsigned long flags)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_gpio_gate(dev, name, parent_name, gpiod, flags);
+	if (IS_ERR(hw))
+		return ERR_CAST(hw);
+	return hw->clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_gpio_gate);
+
+/**
+ * clk_hw_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
+ * @gpiod: gpio descriptor to gate this clock
+ * @flags: clock flags
+ */
+struct clk_hw *clk_hw_register_gpio_mux(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
+		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,
+			gpiod, flags, &clk_gpio_mux_ops);
+}
+EXPORT_SYMBOL_GPL(clk_hw_register_gpio_mux);
+
+struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
+		const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
+		unsigned long flags)
+{
+	struct clk_hw *hw;
+
+	hw = clk_hw_register_gpio_mux(dev, name, parent_names, num_parents,
+			gpiod, flags);
+	if (IS_ERR(hw))
+		return ERR_CAST(hw);
+	return hw->clk;
+}
+EXPORT_SYMBOL_GPL(clk_register_gpio_mux);
+
+static int gpio_clk_driver_probe(struct platform_device *pdev)
+{
+	struct device_node *node = pdev->dev.of_node;
+	const char **parent_names, *gpio_name;
+	unsigned int num_parents;
+	struct gpio_desc *gpiod;
+	struct clk *clk;
+	bool is_mux;
+	int ret;
+
+	num_parents = of_clk_get_parent_count(node);
+	if (num_parents) {
+		parent_names = devm_kcalloc(&pdev->dev, num_parents,
+					    sizeof(char *), GFP_KERNEL);
+		if (!parent_names)
+			return -ENOMEM;
+
+		of_clk_parent_fill(node, parent_names, num_parents);
+	} else {
+		parent_names = NULL;
+	}
+
+	is_mux = of_device_is_compatible(node, "gpio-mux-clock");
+
+	gpio_name = is_mux ? "select" : "enable";
+	gpiod = devm_gpiod_get(&pdev->dev, gpio_name, GPIOD_OUT_LOW);
+	if (IS_ERR(gpiod)) {
+		ret = PTR_ERR(gpiod);
+		if (ret == -EPROBE_DEFER)
+			pr_debug("%s: %s: GPIOs not yet available, retry later\n",
+					node->name, __func__);
+		else
+			pr_err("%s: %s: Can't get '%s' named GPIO property\n",
+					node->name, __func__,
+					gpio_name);
+		return ret;
+	}
+
+	if (is_mux)
+		clk = clk_register_gpio_mux(&pdev->dev, node->name,
+				parent_names, num_parents, gpiod, 0);
+	else
+		clk = clk_register_gpio_gate(&pdev->dev, node->name,
+				parent_names ?  parent_names[0] : NULL, gpiod,
+				CLK_SET_RATE_PARENT);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	return of_clk_add_provider(node, of_clk_src_simple_get, clk);
+}
+
+static const struct of_device_id gpio_clk_match_table[] = {
+	{ .compatible = "gpio-mux-clock" },
+	{ .compatible = "gpio-gate-clock" },
+	{ }
+};
+
+static struct platform_driver gpio_clk_driver = {
+	.probe		= gpio_clk_driver_probe,
+	.driver		= {
+		.name	= "gpio-clk",
+		.of_match_table = gpio_clk_match_table,
+	},
+};
+builtin_platform_driver(gpio_clk_driver);