1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com
6 * Jyri Sarha <jsarha@ti.com>
7 * Sergej Sawazki <ce3a@gmx.de>
9 * Gpio controlled clock implementation
12 #include <linux/clk-provider.h>
13 #include <linux/export.h>
14 #include <linux/slab.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/err.h>
17 #include <linux/device.h>
18 #include <linux/platform_device.h>
19 #include <linux/of_device.h>
22 * DOC: basic gpio gated clock which can be enabled and disabled
24 * Traits of this clock:
25 * prepare - clk_(un)prepare only ensures parent is (un)prepared
26 * enable - clk_enable and clk_disable are functional & control gpio
27 * rate - inherits rate from parent. No clk_set_rate support
28 * parent - fixed parent. No clk_set_parent support
31 static int clk_gpio_gate_enable(struct clk_hw *hw)
33 struct clk_gpio *clk = to_clk_gpio(hw);
35 gpiod_set_value(clk->gpiod, 1);
40 static void clk_gpio_gate_disable(struct clk_hw *hw)
42 struct clk_gpio *clk = to_clk_gpio(hw);
44 gpiod_set_value(clk->gpiod, 0);
47 static int clk_gpio_gate_is_enabled(struct clk_hw *hw)
49 struct clk_gpio *clk = to_clk_gpio(hw);
51 return gpiod_get_value(clk->gpiod);
54 const struct clk_ops clk_gpio_gate_ops = {
55 .enable = clk_gpio_gate_enable,
56 .disable = clk_gpio_gate_disable,
57 .is_enabled = clk_gpio_gate_is_enabled,
59 EXPORT_SYMBOL_GPL(clk_gpio_gate_ops);
62 * DOC: basic clock multiplexer which can be controlled with a gpio output
63 * Traits of this clock:
64 * prepare - clk_prepare only ensures that parents are prepared
65 * rate - rate is only affected by parent switching. No clk_set_rate support
66 * parent - parent is adjustable through clk_set_parent
69 static u8 clk_gpio_mux_get_parent(struct clk_hw *hw)
71 struct clk_gpio *clk = to_clk_gpio(hw);
73 return gpiod_get_value_cansleep(clk->gpiod);
76 static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index)
78 struct clk_gpio *clk = to_clk_gpio(hw);
80 gpiod_set_value_cansleep(clk->gpiod, index);
85 const struct clk_ops clk_gpio_mux_ops = {
86 .get_parent = clk_gpio_mux_get_parent,
87 .set_parent = clk_gpio_mux_set_parent,
88 .determine_rate = __clk_mux_determine_rate,
90 EXPORT_SYMBOL_GPL(clk_gpio_mux_ops);
92 static struct clk_hw *clk_register_gpio(struct device *dev, const char *name,
93 const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
94 unsigned long flags, const struct clk_ops *clk_gpio_ops)
96 struct clk_gpio *clk_gpio;
98 struct clk_init_data init = {};
102 clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL);
104 clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL);
107 return ERR_PTR(-ENOMEM);
110 init.ops = clk_gpio_ops;
111 init.flags = flags | CLK_IS_BASIC;
112 init.parent_names = parent_names;
113 init.num_parents = num_parents;
115 clk_gpio->gpiod = gpiod;
116 clk_gpio->hw.init = &init;
120 err = devm_clk_hw_register(dev, hw);
122 err = clk_hw_register(NULL, hw);
135 * clk_hw_register_gpio_gate - register a gpio clock gate with the clock
137 * @dev: device that is registering this clock
138 * @name: name of this clock
139 * @parent_name: name of this clock's parent
140 * @gpiod: gpio descriptor to gate this clock
141 * @flags: clock flags
143 struct clk_hw *clk_hw_register_gpio_gate(struct device *dev, const char *name,
144 const char *parent_name, struct gpio_desc *gpiod,
147 return clk_register_gpio(dev, name,
148 (parent_name ? &parent_name : NULL),
149 (parent_name ? 1 : 0), gpiod, flags,
152 EXPORT_SYMBOL_GPL(clk_hw_register_gpio_gate);
154 struct clk *clk_register_gpio_gate(struct device *dev, const char *name,
155 const char *parent_name, struct gpio_desc *gpiod,
160 hw = clk_hw_register_gpio_gate(dev, name, parent_name, gpiod, flags);
165 EXPORT_SYMBOL_GPL(clk_register_gpio_gate);
168 * clk_hw_register_gpio_mux - register a gpio clock mux with the clock framework
169 * @dev: device that is registering this clock
170 * @name: name of this clock
171 * @parent_names: names of this clock's parents
172 * @num_parents: number of parents listed in @parent_names
173 * @gpiod: gpio descriptor to gate this clock
174 * @flags: clock flags
176 struct clk_hw *clk_hw_register_gpio_mux(struct device *dev, const char *name,
177 const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
180 if (num_parents != 2) {
181 pr_err("mux-clock %s must have 2 parents\n", name);
182 return ERR_PTR(-EINVAL);
185 return clk_register_gpio(dev, name, parent_names, num_parents,
186 gpiod, flags, &clk_gpio_mux_ops);
188 EXPORT_SYMBOL_GPL(clk_hw_register_gpio_mux);
190 struct clk *clk_register_gpio_mux(struct device *dev, const char *name,
191 const char * const *parent_names, u8 num_parents, struct gpio_desc *gpiod,
196 hw = clk_hw_register_gpio_mux(dev, name, parent_names, num_parents,
202 EXPORT_SYMBOL_GPL(clk_register_gpio_mux);
204 static int gpio_clk_driver_probe(struct platform_device *pdev)
206 struct device_node *node = pdev->dev.of_node;
207 const char **parent_names, *gpio_name;
208 unsigned int num_parents;
209 struct gpio_desc *gpiod;
214 num_parents = of_clk_get_parent_count(node);
216 parent_names = devm_kcalloc(&pdev->dev, num_parents,
217 sizeof(char *), GFP_KERNEL);
221 of_clk_parent_fill(node, parent_names, num_parents);
226 is_mux = of_device_is_compatible(node, "gpio-mux-clock");
228 gpio_name = is_mux ? "select" : "enable";
229 gpiod = devm_gpiod_get(&pdev->dev, gpio_name, GPIOD_OUT_LOW);
231 ret = PTR_ERR(gpiod);
232 if (ret == -EPROBE_DEFER)
233 pr_debug("%pOFn: %s: GPIOs not yet available, retry later\n",
236 pr_err("%pOFn: %s: Can't get '%s' named GPIO property\n",
243 clk = clk_register_gpio_mux(&pdev->dev, node->name,
244 parent_names, num_parents, gpiod, 0);
246 clk = clk_register_gpio_gate(&pdev->dev, node->name,
247 parent_names ? parent_names[0] : NULL, gpiod,
252 return of_clk_add_provider(node, of_clk_src_simple_get, clk);
255 static const struct of_device_id gpio_clk_match_table[] = {
256 { .compatible = "gpio-mux-clock" },
257 { .compatible = "gpio-gate-clock" },
261 static struct platform_driver gpio_clk_driver = {
262 .probe = gpio_clk_driver_probe,
265 .of_match_table = gpio_clk_match_table,
268 builtin_platform_driver(gpio_clk_driver);