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c873d14d JS |
1 | /* |
2 | * Copyright (C) 2013 - 2014 Texas Instruments Incorporated - http://www.ti.com | |
80eeb1f0 SS |
3 | * |
4 | * Authors: | |
5 | * Jyri Sarha <jsarha@ti.com> | |
6 | * Sergej Sawazki <ce3a@gmx.de> | |
c873d14d JS |
7 | * |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
80eeb1f0 | 12 | * Gpio controlled clock implementation |
c873d14d JS |
13 | */ |
14 | ||
15 | #include <linux/clk-provider.h> | |
e21b08e2 | 16 | #include <linux/export.h> |
c873d14d JS |
17 | #include <linux/slab.h> |
18 | #include <linux/gpio.h> | |
44b4aa97 | 19 | #include <linux/gpio/consumer.h> |
c873d14d JS |
20 | #include <linux/of_gpio.h> |
21 | #include <linux/err.h> | |
22 | #include <linux/device.h> | |
14b04f28 SB |
23 | #include <linux/platform_device.h> |
24 | #include <linux/of_device.h> | |
c873d14d JS |
25 | |
26 | /** | |
27 | * DOC: basic gpio gated clock which can be enabled and disabled | |
28 | * with gpio output | |
29 | * Traits of this clock: | |
30 | * prepare - clk_(un)prepare only ensures parent is (un)prepared | |
31 | * enable - clk_enable and clk_disable are functional & control gpio | |
32 | * rate - inherits rate from parent. No clk_set_rate support | |
33 | * parent - fixed parent. No clk_set_parent support | |
34 | */ | |
35 | ||
c873d14d JS |
36 | static int clk_gpio_gate_enable(struct clk_hw *hw) |
37 | { | |
38 | struct clk_gpio *clk = to_clk_gpio(hw); | |
39 | ||
40 | gpiod_set_value(clk->gpiod, 1); | |
41 | ||
42 | return 0; | |
43 | } | |
44 | ||
45 | static void clk_gpio_gate_disable(struct clk_hw *hw) | |
46 | { | |
47 | struct clk_gpio *clk = to_clk_gpio(hw); | |
48 | ||
49 | gpiod_set_value(clk->gpiod, 0); | |
50 | } | |
51 | ||
52 | static int clk_gpio_gate_is_enabled(struct clk_hw *hw) | |
53 | { | |
54 | struct clk_gpio *clk = to_clk_gpio(hw); | |
55 | ||
56 | return gpiod_get_value(clk->gpiod); | |
57 | } | |
58 | ||
59 | const struct clk_ops clk_gpio_gate_ops = { | |
60 | .enable = clk_gpio_gate_enable, | |
61 | .disable = clk_gpio_gate_disable, | |
62 | .is_enabled = clk_gpio_gate_is_enabled, | |
63 | }; | |
64 | EXPORT_SYMBOL_GPL(clk_gpio_gate_ops); | |
65 | ||
66 | /** | |
80eeb1f0 SS |
67 | * DOC: basic clock multiplexer which can be controlled with a gpio output |
68 | * Traits of this clock: | |
69 | * prepare - clk_prepare only ensures that parents are prepared | |
70 | * rate - rate is only affected by parent switching. No clk_set_rate support | |
71 | * parent - parent is adjustable through clk_set_parent | |
c873d14d | 72 | */ |
80eeb1f0 SS |
73 | |
74 | static u8 clk_gpio_mux_get_parent(struct clk_hw *hw) | |
c873d14d | 75 | { |
80eeb1f0 SS |
76 | struct clk_gpio *clk = to_clk_gpio(hw); |
77 | ||
78 | return gpiod_get_value(clk->gpiod); | |
79 | } | |
80 | ||
81 | static int clk_gpio_mux_set_parent(struct clk_hw *hw, u8 index) | |
82 | { | |
83 | struct clk_gpio *clk = to_clk_gpio(hw); | |
84 | ||
85 | gpiod_set_value(clk->gpiod, index); | |
86 | ||
87 | return 0; | |
88 | } | |
89 | ||
90 | const struct clk_ops clk_gpio_mux_ops = { | |
91 | .get_parent = clk_gpio_mux_get_parent, | |
92 | .set_parent = clk_gpio_mux_set_parent, | |
93 | .determine_rate = __clk_mux_determine_rate, | |
94 | }; | |
95 | EXPORT_SYMBOL_GPL(clk_gpio_mux_ops); | |
96 | ||
97 | static struct clk *clk_register_gpio(struct device *dev, const char *name, | |
37bff2c1 | 98 | const char * const *parent_names, u8 num_parents, unsigned gpio, |
80eeb1f0 SS |
99 | bool active_low, unsigned long flags, |
100 | const struct clk_ops *clk_gpio_ops) | |
101 | { | |
102 | struct clk_gpio *clk_gpio; | |
103 | struct clk *clk; | |
104 | struct clk_init_data init = {}; | |
c873d14d JS |
105 | unsigned long gpio_flags; |
106 | int err; | |
107 | ||
80eeb1f0 SS |
108 | if (dev) |
109 | clk_gpio = devm_kzalloc(dev, sizeof(*clk_gpio), GFP_KERNEL); | |
110 | else | |
111 | clk_gpio = kzalloc(sizeof(*clk_gpio), GFP_KERNEL); | |
112 | ||
113 | if (!clk_gpio) | |
114 | return ERR_PTR(-ENOMEM); | |
115 | ||
820ad975 MF |
116 | if (active_low) |
117 | gpio_flags = GPIOF_ACTIVE_LOW | GPIOF_OUT_INIT_HIGH; | |
c873d14d JS |
118 | else |
119 | gpio_flags = GPIOF_OUT_INIT_LOW; | |
120 | ||
121 | if (dev) | |
820ad975 | 122 | err = devm_gpio_request_one(dev, gpio, gpio_flags, name); |
c873d14d | 123 | else |
820ad975 | 124 | err = gpio_request_one(gpio, gpio_flags, name); |
c873d14d | 125 | if (err) { |
281cbb00 SS |
126 | if (err != -EPROBE_DEFER) |
127 | pr_err("%s: %s: Error requesting clock control gpio %u\n", | |
128 | __func__, name, gpio); | |
80eeb1f0 SS |
129 | if (!dev) |
130 | kfree(clk_gpio); | |
c873d14d | 131 | |
80eeb1f0 | 132 | return ERR_PTR(err); |
c873d14d JS |
133 | } |
134 | ||
135 | init.name = name; | |
80eeb1f0 | 136 | init.ops = clk_gpio_ops; |
c873d14d | 137 | init.flags = flags | CLK_IS_BASIC; |
80eeb1f0 SS |
138 | init.parent_names = parent_names; |
139 | init.num_parents = num_parents; | |
c873d14d | 140 | |
820ad975 | 141 | clk_gpio->gpiod = gpio_to_desc(gpio); |
c873d14d JS |
142 | clk_gpio->hw.init = &init; |
143 | ||
80eeb1f0 SS |
144 | if (dev) |
145 | clk = devm_clk_register(dev, &clk_gpio->hw); | |
146 | else | |
147 | clk = clk_register(NULL, &clk_gpio->hw); | |
c873d14d JS |
148 | |
149 | if (!IS_ERR(clk)) | |
150 | return clk; | |
151 | ||
80eeb1f0 SS |
152 | if (!dev) { |
153 | gpiod_put(clk_gpio->gpiod); | |
c873d14d | 154 | kfree(clk_gpio); |
80eeb1f0 | 155 | } |
c873d14d JS |
156 | |
157 | return clk; | |
158 | } | |
80eeb1f0 SS |
159 | |
160 | /** | |
161 | * clk_register_gpio_gate - register a gpio clock gate with the clock framework | |
162 | * @dev: device that is registering this clock | |
163 | * @name: name of this clock | |
164 | * @parent_name: name of this clock's parent | |
165 | * @gpio: gpio number to gate this clock | |
166 | * @active_low: true if gpio should be set to 0 to enable clock | |
167 | * @flags: clock flags | |
168 | */ | |
169 | struct clk *clk_register_gpio_gate(struct device *dev, const char *name, | |
170 | const char *parent_name, unsigned gpio, bool active_low, | |
171 | unsigned long flags) | |
172 | { | |
173 | return clk_register_gpio(dev, name, | |
174 | (parent_name ? &parent_name : NULL), | |
175 | (parent_name ? 1 : 0), gpio, active_low, flags, | |
176 | &clk_gpio_gate_ops); | |
177 | } | |
c873d14d JS |
178 | EXPORT_SYMBOL_GPL(clk_register_gpio_gate); |
179 | ||
80eeb1f0 SS |
180 | /** |
181 | * clk_register_gpio_mux - register a gpio clock mux with the clock framework | |
182 | * @dev: device that is registering this clock | |
183 | * @name: name of this clock | |
184 | * @parent_names: names of this clock's parents | |
185 | * @num_parents: number of parents listed in @parent_names | |
186 | * @gpio: gpio number to gate this clock | |
187 | * @active_low: true if gpio should be set to 0 to enable clock | |
188 | * @flags: clock flags | |
189 | */ | |
190 | struct clk *clk_register_gpio_mux(struct device *dev, const char *name, | |
37bff2c1 | 191 | const char * const *parent_names, u8 num_parents, unsigned gpio, |
80eeb1f0 SS |
192 | bool active_low, unsigned long flags) |
193 | { | |
194 | if (num_parents != 2) { | |
195 | pr_err("mux-clock %s must have 2 parents\n", name); | |
196 | return ERR_PTR(-EINVAL); | |
197 | } | |
198 | ||
199 | return clk_register_gpio(dev, name, parent_names, num_parents, | |
200 | gpio, active_low, flags, &clk_gpio_mux_ops); | |
201 | } | |
202 | EXPORT_SYMBOL_GPL(clk_register_gpio_mux); | |
203 | ||
14b04f28 | 204 | static int gpio_clk_driver_probe(struct platform_device *pdev) |
c873d14d | 205 | { |
14b04f28 SB |
206 | struct device_node *node = pdev->dev.of_node; |
207 | const char **parent_names, *gpio_name; | |
208 | int num_parents, gpio; | |
820ad975 | 209 | enum of_gpio_flags of_flags; |
14b04f28 SB |
210 | struct clk *clk; |
211 | bool active_low, is_mux; | |
212 | ||
213 | num_parents = of_clk_get_parent_count(node); | |
214 | if (num_parents < 0) | |
6a05d862 | 215 | num_parents = 0; |
c873d14d | 216 | |
14b04f28 SB |
217 | if (num_parents) { |
218 | parent_names = devm_kcalloc(&pdev->dev, num_parents, | |
219 | sizeof(char *), GFP_KERNEL); | |
220 | if (!parent_names) | |
221 | return -ENOMEM; | |
c873d14d | 222 | |
14b04f28 SB |
223 | of_clk_parent_fill(node, parent_names, num_parents); |
224 | } else { | |
225 | parent_names = NULL; | |
c873d14d JS |
226 | } |
227 | ||
14b04f28 SB |
228 | is_mux = of_device_is_compatible(node, "gpio-mux-clock"); |
229 | ||
230 | gpio_name = is_mux ? "select-gpios" : "enable-gpios"; | |
231 | gpio = of_get_named_gpio_flags(node, gpio_name, 0, &of_flags); | |
c873d14d | 232 | if (gpio < 0) { |
80eeb1f0 SS |
233 | if (gpio == -EPROBE_DEFER) |
234 | pr_debug("%s: %s: GPIOs not yet available, retry later\n", | |
14b04f28 | 235 | node->name, __func__); |
80eeb1f0 SS |
236 | else |
237 | pr_err("%s: %s: Can't get '%s' DT property\n", | |
14b04f28 SB |
238 | node->name, __func__, |
239 | gpio_name); | |
240 | return gpio; | |
c873d14d | 241 | } |
c873d14d | 242 | |
14b04f28 | 243 | active_low = of_flags & OF_GPIO_ACTIVE_LOW; |
c873d14d | 244 | |
14b04f28 SB |
245 | if (is_mux) |
246 | clk = clk_register_gpio_mux(&pdev->dev, node->name, | |
247 | parent_names, num_parents, gpio, active_low, 0); | |
248 | else | |
249 | clk = clk_register_gpio_gate(&pdev->dev, node->name, | |
250 | parent_names ? parent_names[0] : NULL, gpio, | |
251 | active_low, 0); | |
252 | if (IS_ERR(clk)) | |
253 | return PTR_ERR(clk); | |
c873d14d | 254 | |
14b04f28 | 255 | return of_clk_add_provider(node, of_clk_src_simple_get, clk); |
80eeb1f0 SS |
256 | } |
257 | ||
14b04f28 SB |
258 | static const struct of_device_id gpio_clk_match_table[] = { |
259 | { .compatible = "gpio-mux-clock" }, | |
260 | { .compatible = "gpio-gate-clock" }, | |
261 | { } | |
262 | }; | |
80eeb1f0 | 263 | |
14b04f28 SB |
264 | static struct platform_driver gpio_clk_driver = { |
265 | .probe = gpio_clk_driver_probe, | |
266 | .driver = { | |
267 | .name = "gpio-clk", | |
268 | .of_match_table = gpio_clk_match_table, | |
269 | }, | |
270 | }; | |
271 | builtin_platform_driver(gpio_clk_driver); |