1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/clk/clk-gpio.c b/drivers/clk/clk-gpio.c
new file mode 100644
index 000000000..38755a241
--- /dev/null
+++ b/drivers/clk/clk-gpio.c
@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2013 - 2014 Texas Instruments Incorporated - https://www.ti.com
+ *
+ * Authors:
+ *    Jyri Sarha <jsarha@ti.com>
+ *    Sergej Sawazki <ce3a@gmx.de>
+ *
+ * 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
+ */
+
+/**
+ * struct clk_gpio - gpio gated clock
+ *
+ * @hw:		handle between common and hardware-specific interfaces
+ * @gpiod:	gpio descriptor
+ *
+ * Clock with a gpio control for enabling and disabling the parent clock
+ * or switching between two parents by asserting or deasserting the gpio.
+ *
+ * Implements .enable, .disable and .is_enabled or
+ * .get_parent, .set_parent and .determine_rate depending on which clk_ops
+ * is used.
+ */
+struct clk_gpio {
+	struct clk_hw	hw;
+	struct gpio_desc *gpiod;
+};
+
+#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);
+}
+
+static 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,
+};
+
+static int clk_sleeping_gpio_gate_prepare(struct clk_hw *hw)
+{
+	struct clk_gpio *clk = to_clk_gpio(hw);
+
+	gpiod_set_value_cansleep(clk->gpiod, 1);
+
+	return 0;
+}
+
+static void clk_sleeping_gpio_gate_unprepare(struct clk_hw *hw)
+{
+	struct clk_gpio *clk = to_clk_gpio(hw);
+
+	gpiod_set_value_cansleep(clk->gpiod, 0);
+}
+
+static int clk_sleeping_gpio_gate_is_prepared(struct clk_hw *hw)
+{
+	struct clk_gpio *clk = to_clk_gpio(hw);
+
+	return gpiod_get_value_cansleep(clk->gpiod);
+}
+
+static const struct clk_ops clk_sleeping_gpio_gate_ops = {
+	.prepare = clk_sleeping_gpio_gate_prepare,
+	.unprepare = clk_sleeping_gpio_gate_unprepare,
+	.is_prepared = clk_sleeping_gpio_gate_is_prepared,
+};
+
+/**
+ * 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;
+}
+
+static 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,
+};
+
+static struct clk_hw *clk_register_gpio(struct device *dev, u8 num_parents,
+					struct gpio_desc *gpiod,
+					const struct clk_ops *clk_gpio_ops)
+{
+	struct clk_gpio *clk_gpio;
+	struct clk_hw *hw;
+	struct clk_init_data init = {};
+	int err;
+	const struct clk_parent_data gpio_parent_data[] = {
+		{ .index = 0 },
+		{ .index = 1 },
+	};
+
+	clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio),	GFP_KERNEL);
+	if (!clk_gpio)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = dev->of_node->name;
+	init.ops = clk_gpio_ops;
+	init.parent_data = gpio_parent_data;
+	init.num_parents = num_parents;
+	init.flags = CLK_SET_RATE_PARENT;
+
+	clk_gpio->gpiod = gpiod;
+	clk_gpio->hw.init = &init;
+
+	hw = &clk_gpio->hw;
+	err = devm_clk_hw_register(dev, hw);
+	if (err)
+		return ERR_PTR(err);
+
+	return hw;
+}
+
+static struct clk_hw *clk_hw_register_gpio_gate(struct device *dev,
+						int num_parents,
+						struct gpio_desc *gpiod)
+{
+	const struct clk_ops *ops;
+
+	if (gpiod_cansleep(gpiod))
+		ops = &clk_sleeping_gpio_gate_ops;
+	else
+		ops = &clk_gpio_gate_ops;
+
+	return clk_register_gpio(dev, num_parents, gpiod, ops);
+}
+
+static struct clk_hw *clk_hw_register_gpio_mux(struct device *dev,
+					       struct gpio_desc *gpiod)
+{
+	return clk_register_gpio(dev, 2, gpiod, &clk_gpio_mux_ops);
+}
+
+static int gpio_clk_driver_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	const char *gpio_name;
+	unsigned int num_parents;
+	struct gpio_desc *gpiod;
+	struct clk_hw *hw;
+	bool is_mux;
+	int ret;
+
+	is_mux = of_device_is_compatible(node, "gpio-mux-clock");
+
+	num_parents = of_clk_get_parent_count(node);
+	if (is_mux && num_parents != 2) {
+		dev_err(dev, "mux-clock must have 2 parents\n");
+		return -EINVAL;
+	}
+
+	gpio_name = is_mux ? "select" : "enable";
+	gpiod = devm_gpiod_get(dev, gpio_name, GPIOD_OUT_LOW);
+	if (IS_ERR(gpiod)) {
+		ret = PTR_ERR(gpiod);
+		if (ret == -EPROBE_DEFER)
+			pr_debug("%pOFn: %s: GPIOs not yet available, retry later\n",
+					node, __func__);
+		else
+			pr_err("%pOFn: %s: Can't get '%s' named GPIO property\n",
+					node, __func__,
+					gpio_name);
+		return ret;
+	}
+
+	if (is_mux)
+		hw = clk_hw_register_gpio_mux(dev, gpiod);
+	else
+		hw = clk_hw_register_gpio_gate(dev, num_parents, gpiod);
+	if (IS_ERR(hw))
+		return PTR_ERR(hw);
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, hw);
+}
+
+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);