xref: /openbmc/linux/drivers/clk/clk-wm831x.c (revision fa2a1931)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * WM831x clock control
4  *
5  * Copyright 2011-2 Wolfson Microelectronics PLC.
6  *
7  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8  */
9 
10 #include <linux/clk-provider.h>
11 #include <linux/delay.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/platform_device.h>
15 #include <linux/mfd/wm831x/core.h>
16 
17 struct wm831x_clk {
18 	struct wm831x *wm831x;
19 	struct clk_hw xtal_hw;
20 	struct clk_hw fll_hw;
21 	struct clk_hw clkout_hw;
22 	bool xtal_ena;
23 };
24 
wm831x_xtal_is_prepared(struct clk_hw * hw)25 static int wm831x_xtal_is_prepared(struct clk_hw *hw)
26 {
27 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
28 						  xtal_hw);
29 
30 	return clkdata->xtal_ena;
31 }
32 
wm831x_xtal_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)33 static unsigned long wm831x_xtal_recalc_rate(struct clk_hw *hw,
34 					     unsigned long parent_rate)
35 {
36 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
37 						  xtal_hw);
38 
39 	if (clkdata->xtal_ena)
40 		return 32768;
41 	else
42 		return 0;
43 }
44 
45 static const struct clk_ops wm831x_xtal_ops = {
46 	.is_prepared = wm831x_xtal_is_prepared,
47 	.recalc_rate = wm831x_xtal_recalc_rate,
48 };
49 
50 static const struct clk_init_data wm831x_xtal_init = {
51 	.name = "xtal",
52 	.ops = &wm831x_xtal_ops,
53 };
54 
55 static const unsigned long wm831x_fll_auto_rates[] = {
56 	 2048000,
57 	11289600,
58 	12000000,
59 	12288000,
60 	19200000,
61 	22579600,
62 	24000000,
63 	24576000,
64 };
65 
wm831x_fll_is_prepared(struct clk_hw * hw)66 static int wm831x_fll_is_prepared(struct clk_hw *hw)
67 {
68 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
69 						  fll_hw);
70 	struct wm831x *wm831x = clkdata->wm831x;
71 	int ret;
72 
73 	ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_1);
74 	if (ret < 0) {
75 		dev_err(wm831x->dev, "Unable to read FLL_CONTROL_1: %d\n",
76 			ret);
77 		return true;
78 	}
79 
80 	return (ret & WM831X_FLL_ENA) != 0;
81 }
82 
wm831x_fll_prepare(struct clk_hw * hw)83 static int wm831x_fll_prepare(struct clk_hw *hw)
84 {
85 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
86 						  fll_hw);
87 	struct wm831x *wm831x = clkdata->wm831x;
88 	int ret;
89 
90 	ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_1,
91 			      WM831X_FLL_ENA, WM831X_FLL_ENA);
92 	if (ret != 0)
93 		dev_crit(wm831x->dev, "Failed to enable FLL: %d\n", ret);
94 
95 	/* wait 2-3 ms for new frequency taking effect */
96 	usleep_range(2000, 3000);
97 
98 	return ret;
99 }
100 
wm831x_fll_unprepare(struct clk_hw * hw)101 static void wm831x_fll_unprepare(struct clk_hw *hw)
102 {
103 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
104 						  fll_hw);
105 	struct wm831x *wm831x = clkdata->wm831x;
106 	int ret;
107 
108 	ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_1, WM831X_FLL_ENA, 0);
109 	if (ret != 0)
110 		dev_crit(wm831x->dev, "Failed to disable FLL: %d\n", ret);
111 }
112 
wm831x_fll_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)113 static unsigned long wm831x_fll_recalc_rate(struct clk_hw *hw,
114 					    unsigned long parent_rate)
115 {
116 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
117 						  fll_hw);
118 	struct wm831x *wm831x = clkdata->wm831x;
119 	int ret;
120 
121 	ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
122 	if (ret < 0) {
123 		dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
124 			ret);
125 		return 0;
126 	}
127 
128 	if (ret & WM831X_FLL_AUTO)
129 		return wm831x_fll_auto_rates[ret & WM831X_FLL_AUTO_FREQ_MASK];
130 
131 	dev_err(wm831x->dev, "FLL only supported in AUTO mode\n");
132 
133 	return 0;
134 }
135 
wm831x_fll_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * unused)136 static long wm831x_fll_round_rate(struct clk_hw *hw, unsigned long rate,
137 				  unsigned long *unused)
138 {
139 	int best = 0;
140 	int i;
141 
142 	for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
143 		if (abs(wm831x_fll_auto_rates[i] - rate) <
144 		    abs(wm831x_fll_auto_rates[best] - rate))
145 			best = i;
146 
147 	return wm831x_fll_auto_rates[best];
148 }
149 
wm831x_fll_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)150 static int wm831x_fll_set_rate(struct clk_hw *hw, unsigned long rate,
151 			       unsigned long parent_rate)
152 {
153 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
154 						  fll_hw);
155 	struct wm831x *wm831x = clkdata->wm831x;
156 	int i;
157 
158 	for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
159 		if (wm831x_fll_auto_rates[i] == rate)
160 			break;
161 	if (i == ARRAY_SIZE(wm831x_fll_auto_rates))
162 		return -EINVAL;
163 
164 	if (wm831x_fll_is_prepared(hw))
165 		return -EPERM;
166 
167 	return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_2,
168 			       WM831X_FLL_AUTO_FREQ_MASK, i);
169 }
170 
171 static const char *wm831x_fll_parents[] = {
172 	"xtal",
173 	"clkin",
174 };
175 
wm831x_fll_get_parent(struct clk_hw * hw)176 static u8 wm831x_fll_get_parent(struct clk_hw *hw)
177 {
178 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
179 						  fll_hw);
180 	struct wm831x *wm831x = clkdata->wm831x;
181 	int ret;
182 
183 	/* AUTO mode is always clocked from the crystal */
184 	ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
185 	if (ret < 0) {
186 		dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
187 			ret);
188 		return 0;
189 	}
190 
191 	if (ret & WM831X_FLL_AUTO)
192 		return 0;
193 
194 	ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_5);
195 	if (ret < 0) {
196 		dev_err(wm831x->dev, "Unable to read FLL_CONTROL_5: %d\n",
197 			ret);
198 		return 0;
199 	}
200 
201 	switch (ret & WM831X_FLL_CLK_SRC_MASK) {
202 	case 0:
203 		return 0;
204 	case 1:
205 		return 1;
206 	default:
207 		dev_err(wm831x->dev, "Unsupported FLL clock source %d\n",
208 			ret & WM831X_FLL_CLK_SRC_MASK);
209 		return 0;
210 	}
211 }
212 
213 static const struct clk_ops wm831x_fll_ops = {
214 	.is_prepared = wm831x_fll_is_prepared,
215 	.prepare = wm831x_fll_prepare,
216 	.unprepare = wm831x_fll_unprepare,
217 	.round_rate = wm831x_fll_round_rate,
218 	.recalc_rate = wm831x_fll_recalc_rate,
219 	.set_rate = wm831x_fll_set_rate,
220 	.get_parent = wm831x_fll_get_parent,
221 };
222 
223 static const struct clk_init_data wm831x_fll_init = {
224 	.name = "fll",
225 	.ops = &wm831x_fll_ops,
226 	.parent_names = wm831x_fll_parents,
227 	.num_parents = ARRAY_SIZE(wm831x_fll_parents),
228 	.flags = CLK_SET_RATE_GATE,
229 };
230 
wm831x_clkout_is_prepared(struct clk_hw * hw)231 static int wm831x_clkout_is_prepared(struct clk_hw *hw)
232 {
233 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
234 						  clkout_hw);
235 	struct wm831x *wm831x = clkdata->wm831x;
236 	int ret;
237 
238 	ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
239 	if (ret < 0) {
240 		dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
241 			ret);
242 		return false;
243 	}
244 
245 	return (ret & WM831X_CLKOUT_ENA) != 0;
246 }
247 
wm831x_clkout_prepare(struct clk_hw * hw)248 static int wm831x_clkout_prepare(struct clk_hw *hw)
249 {
250 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
251 						  clkout_hw);
252 	struct wm831x *wm831x = clkdata->wm831x;
253 	int ret;
254 
255 	ret = wm831x_reg_unlock(wm831x);
256 	if (ret != 0) {
257 		dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
258 		return ret;
259 	}
260 
261 	ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
262 			      WM831X_CLKOUT_ENA, WM831X_CLKOUT_ENA);
263 	if (ret != 0)
264 		dev_crit(wm831x->dev, "Failed to enable CLKOUT: %d\n", ret);
265 
266 	wm831x_reg_lock(wm831x);
267 
268 	return ret;
269 }
270 
wm831x_clkout_unprepare(struct clk_hw * hw)271 static void wm831x_clkout_unprepare(struct clk_hw *hw)
272 {
273 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
274 						  clkout_hw);
275 	struct wm831x *wm831x = clkdata->wm831x;
276 	int ret;
277 
278 	ret = wm831x_reg_unlock(wm831x);
279 	if (ret != 0) {
280 		dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
281 		return;
282 	}
283 
284 	ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
285 			      WM831X_CLKOUT_ENA, 0);
286 	if (ret != 0)
287 		dev_crit(wm831x->dev, "Failed to disable CLKOUT: %d\n", ret);
288 
289 	wm831x_reg_lock(wm831x);
290 }
291 
292 static const char *wm831x_clkout_parents[] = {
293 	"fll",
294 	"xtal",
295 };
296 
wm831x_clkout_get_parent(struct clk_hw * hw)297 static u8 wm831x_clkout_get_parent(struct clk_hw *hw)
298 {
299 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
300 						  clkout_hw);
301 	struct wm831x *wm831x = clkdata->wm831x;
302 	int ret;
303 
304 	ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
305 	if (ret < 0) {
306 		dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
307 			ret);
308 		return 0;
309 	}
310 
311 	if (ret & WM831X_CLKOUT_SRC)
312 		return 1;
313 	else
314 		return 0;
315 }
316 
wm831x_clkout_set_parent(struct clk_hw * hw,u8 parent)317 static int wm831x_clkout_set_parent(struct clk_hw *hw, u8 parent)
318 {
319 	struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
320 						  clkout_hw);
321 	struct wm831x *wm831x = clkdata->wm831x;
322 
323 	return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
324 			       WM831X_CLKOUT_SRC,
325 			       parent << WM831X_CLKOUT_SRC_SHIFT);
326 }
327 
328 static const struct clk_ops wm831x_clkout_ops = {
329 	.is_prepared = wm831x_clkout_is_prepared,
330 	.prepare = wm831x_clkout_prepare,
331 	.unprepare = wm831x_clkout_unprepare,
332 	.determine_rate = clk_hw_determine_rate_no_reparent,
333 	.get_parent = wm831x_clkout_get_parent,
334 	.set_parent = wm831x_clkout_set_parent,
335 };
336 
337 static const struct clk_init_data wm831x_clkout_init = {
338 	.name = "clkout",
339 	.ops = &wm831x_clkout_ops,
340 	.parent_names = wm831x_clkout_parents,
341 	.num_parents = ARRAY_SIZE(wm831x_clkout_parents),
342 	.flags = CLK_SET_RATE_PARENT,
343 };
344 
wm831x_clk_probe(struct platform_device * pdev)345 static int wm831x_clk_probe(struct platform_device *pdev)
346 {
347 	struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
348 	struct wm831x_clk *clkdata;
349 	int ret;
350 
351 	clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
352 	if (!clkdata)
353 		return -ENOMEM;
354 
355 	clkdata->wm831x = wm831x;
356 
357 	/* XTAL_ENA can only be set via OTP/InstantConfig so just read once */
358 	ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
359 	if (ret < 0) {
360 		dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
361 			ret);
362 		return ret;
363 	}
364 	clkdata->xtal_ena = ret & WM831X_XTAL_ENA;
365 
366 	clkdata->xtal_hw.init = &wm831x_xtal_init;
367 	ret = devm_clk_hw_register(&pdev->dev, &clkdata->xtal_hw);
368 	if (ret)
369 		return ret;
370 
371 	clkdata->fll_hw.init = &wm831x_fll_init;
372 	ret = devm_clk_hw_register(&pdev->dev, &clkdata->fll_hw);
373 	if (ret)
374 		return ret;
375 
376 	clkdata->clkout_hw.init = &wm831x_clkout_init;
377 	ret = devm_clk_hw_register(&pdev->dev, &clkdata->clkout_hw);
378 	if (ret)
379 		return ret;
380 
381 	platform_set_drvdata(pdev, clkdata);
382 
383 	return 0;
384 }
385 
386 static struct platform_driver wm831x_clk_driver = {
387 	.probe = wm831x_clk_probe,
388 	.driver		= {
389 		.name	= "wm831x-clk",
390 	},
391 };
392 
393 module_platform_driver(wm831x_clk_driver);
394 
395 /* Module information */
396 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
397 MODULE_DESCRIPTION("WM831x clock driver");
398 MODULE_LICENSE("GPL");
399 MODULE_ALIAS("platform:wm831x-clk");
400