1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * wm8978.c -- WM8978 ALSA SoC Audio Codec driver
4 *
5 * Copyright (C) 2009-2010 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
6 * Copyright (C) 2007 Carlos Munoz <carlos@kenati.com>
7 * Copyright 2006-2009 Wolfson Microelectronics PLC.
8 * Based on wm8974 and wm8990 by Liam Girdwood <lrg@slimlogic.co.uk>
9 */
10
11#include <linux/module.h>
12#include <linux/moduleparam.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/delay.h>
16#include <linux/pm.h>
17#include <linux/i2c.h>
18#include <linux/regmap.h>
19#include <linux/slab.h>
20#include <sound/core.h>
21#include <sound/pcm.h>
22#include <sound/pcm_params.h>
23#include <sound/soc.h>
24#include <sound/initval.h>
25#include <sound/tlv.h>
26#include <asm/div64.h>
27
28#include "wm8978.h"
29
30static const struct reg_default wm8978_reg_defaults[] = {
31 { 1, 0x0000 },
32 { 2, 0x0000 },
33 { 3, 0x0000 },
34 { 4, 0x0050 },
35 { 5, 0x0000 },
36 { 6, 0x0140 },
37 { 7, 0x0000 },
38 { 8, 0x0000 },
39 { 9, 0x0000 },
40 { 10, 0x0000 },
41 { 11, 0x00ff },
42 { 12, 0x00ff },
43 { 13, 0x0000 },
44 { 14, 0x0100 },
45 { 15, 0x00ff },
46 { 16, 0x00ff },
47 { 17, 0x0000 },
48 { 18, 0x012c },
49 { 19, 0x002c },
50 { 20, 0x002c },
51 { 21, 0x002c },
52 { 22, 0x002c },
53 { 23, 0x0000 },
54 { 24, 0x0032 },
55 { 25, 0x0000 },
56 { 26, 0x0000 },
57 { 27, 0x0000 },
58 { 28, 0x0000 },
59 { 29, 0x0000 },
60 { 30, 0x0000 },
61 { 31, 0x0000 },
62 { 32, 0x0038 },
63 { 33, 0x000b },
64 { 34, 0x0032 },
65 { 35, 0x0000 },
66 { 36, 0x0008 },
67 { 37, 0x000c },
68 { 38, 0x0093 },
69 { 39, 0x00e9 },
70 { 40, 0x0000 },
71 { 41, 0x0000 },
72 { 42, 0x0000 },
73 { 43, 0x0000 },
74 { 44, 0x0033 },
75 { 45, 0x0010 },
76 { 46, 0x0010 },
77 { 47, 0x0100 },
78 { 48, 0x0100 },
79 { 49, 0x0002 },
80 { 50, 0x0001 },
81 { 51, 0x0001 },
82 { 52, 0x0039 },
83 { 53, 0x0039 },
84 { 54, 0x0039 },
85 { 55, 0x0039 },
86 { 56, 0x0001 },
87 { 57, 0x0001 },
88};
89
90static bool wm8978_volatile(struct device *dev, unsigned int reg)
91{
92 return reg == WM8978_RESET;
93}
94
95/* codec private data */
96struct wm8978_priv {
97 struct regmap *regmap;
98 unsigned int f_pllout;
99 unsigned int f_mclk;
100 unsigned int f_256fs;
101 unsigned int f_opclk;
102 int mclk_idx;
103 enum wm8978_sysclk_src sysclk;
104};
105
106static const char *wm8978_companding[] = {"Off", "NC", "u-law", "A-law"};
107static const char *wm8978_eqmode[] = {"Capture", "Playback"};
108static const char *wm8978_bw[] = {"Narrow", "Wide"};
109static const char *wm8978_eq1[] = {"80Hz", "105Hz", "135Hz", "175Hz"};
110static const char *wm8978_eq2[] = {"230Hz", "300Hz", "385Hz", "500Hz"};
111static const char *wm8978_eq3[] = {"650Hz", "850Hz", "1.1kHz", "1.4kHz"};
112static const char *wm8978_eq4[] = {"1.8kHz", "2.4kHz", "3.2kHz", "4.1kHz"};
113static const char *wm8978_eq5[] = {"5.3kHz", "6.9kHz", "9kHz", "11.7kHz"};
114static const char *wm8978_alc3[] = {"ALC", "Limiter"};
115static const char *wm8978_alc1[] = {"Off", "Right", "Left", "Both"};
116
117static SOC_ENUM_SINGLE_DECL(adc_compand, WM8978_COMPANDING_CONTROL, 1,
118 wm8978_companding);
119static SOC_ENUM_SINGLE_DECL(dac_compand, WM8978_COMPANDING_CONTROL, 3,
120 wm8978_companding);
121static SOC_ENUM_SINGLE_DECL(eqmode, WM8978_EQ1, 8, wm8978_eqmode);
122static SOC_ENUM_SINGLE_DECL(eq1, WM8978_EQ1, 5, wm8978_eq1);
123static SOC_ENUM_SINGLE_DECL(eq2bw, WM8978_EQ2, 8, wm8978_bw);
124static SOC_ENUM_SINGLE_DECL(eq2, WM8978_EQ2, 5, wm8978_eq2);
125static SOC_ENUM_SINGLE_DECL(eq3bw, WM8978_EQ3, 8, wm8978_bw);
126static SOC_ENUM_SINGLE_DECL(eq3, WM8978_EQ3, 5, wm8978_eq3);
127static SOC_ENUM_SINGLE_DECL(eq4bw, WM8978_EQ4, 8, wm8978_bw);
128static SOC_ENUM_SINGLE_DECL(eq4, WM8978_EQ4, 5, wm8978_eq4);
129static SOC_ENUM_SINGLE_DECL(eq5, WM8978_EQ5, 5, wm8978_eq5);
130static SOC_ENUM_SINGLE_DECL(alc3, WM8978_ALC_CONTROL_3, 8, wm8978_alc3);
131static SOC_ENUM_SINGLE_DECL(alc1, WM8978_ALC_CONTROL_1, 7, wm8978_alc1);
132
133static const DECLARE_TLV_DB_SCALE(digital_tlv, -12750, 50, 1);
134static const DECLARE_TLV_DB_SCALE(eq_tlv, -1200, 100, 0);
135static const DECLARE_TLV_DB_SCALE(inpga_tlv, -1200, 75, 0);
136static const DECLARE_TLV_DB_SCALE(spk_tlv, -5700, 100, 0);
137static const DECLARE_TLV_DB_SCALE(boost_tlv, -1500, 300, 1);
138static const DECLARE_TLV_DB_SCALE(limiter_tlv, 0, 100, 0);
139
140static const struct snd_kcontrol_new wm8978_snd_controls[] = {
141
142 SOC_SINGLE("Digital Loopback Switch",
143 WM8978_COMPANDING_CONTROL, 0, 1, 0),
144
145 SOC_ENUM("ADC Companding", adc_compand),
146 SOC_ENUM("DAC Companding", dac_compand),
147
148 SOC_DOUBLE("DAC Inversion Switch", WM8978_DAC_CONTROL, 0, 1, 1, 0),
149
150 SOC_DOUBLE_R_TLV("PCM Volume",
151 WM8978_LEFT_DAC_DIGITAL_VOLUME, WM8978_RIGHT_DAC_DIGITAL_VOLUME,
152 0, 255, 0, digital_tlv),
153
154 SOC_SINGLE("High Pass Filter Switch", WM8978_ADC_CONTROL, 8, 1, 0),
155 SOC_SINGLE("High Pass Cut Off", WM8978_ADC_CONTROL, 4, 7, 0),
156 SOC_DOUBLE("ADC Inversion Switch", WM8978_ADC_CONTROL, 0, 1, 1, 0),
157
158 SOC_DOUBLE_R_TLV("ADC Volume",
159 WM8978_LEFT_ADC_DIGITAL_VOLUME, WM8978_RIGHT_ADC_DIGITAL_VOLUME,
160 0, 255, 0, digital_tlv),
161
162 SOC_ENUM("Equaliser Function", eqmode),
163 SOC_ENUM("EQ1 Cut Off", eq1),
164 SOC_SINGLE_TLV("EQ1 Volume", WM8978_EQ1, 0, 24, 1, eq_tlv),
165
166 SOC_ENUM("Equaliser EQ2 Bandwidth", eq2bw),
167 SOC_ENUM("EQ2 Cut Off", eq2),
168 SOC_SINGLE_TLV("EQ2 Volume", WM8978_EQ2, 0, 24, 1, eq_tlv),
169
170 SOC_ENUM("Equaliser EQ3 Bandwidth", eq3bw),
171 SOC_ENUM("EQ3 Cut Off", eq3),
172 SOC_SINGLE_TLV("EQ3 Volume", WM8978_EQ3, 0, 24, 1, eq_tlv),
173
174 SOC_ENUM("Equaliser EQ4 Bandwidth", eq4bw),
175 SOC_ENUM("EQ4 Cut Off", eq4),
176 SOC_SINGLE_TLV("EQ4 Volume", WM8978_EQ4, 0, 24, 1, eq_tlv),
177
178 SOC_ENUM("EQ5 Cut Off", eq5),
179 SOC_SINGLE_TLV("EQ5 Volume", WM8978_EQ5, 0, 24, 1, eq_tlv),
180
181 SOC_SINGLE("DAC Playback Limiter Switch",
182 WM8978_DAC_LIMITER_1, 8, 1, 0),
183 SOC_SINGLE("DAC Playback Limiter Decay",
184 WM8978_DAC_LIMITER_1, 4, 15, 0),
185 SOC_SINGLE("DAC Playback Limiter Attack",
186 WM8978_DAC_LIMITER_1, 0, 15, 0),
187
188 SOC_SINGLE("DAC Playback Limiter Threshold",
189 WM8978_DAC_LIMITER_2, 4, 7, 0),
190 SOC_SINGLE_TLV("DAC Playback Limiter Volume",
191 WM8978_DAC_LIMITER_2, 0, 12, 0, limiter_tlv),
192
193 SOC_ENUM("ALC Enable Switch", alc1),
194 SOC_SINGLE("ALC Capture Min Gain", WM8978_ALC_CONTROL_1, 0, 7, 0),
195 SOC_SINGLE("ALC Capture Max Gain", WM8978_ALC_CONTROL_1, 3, 7, 0),
196
197 SOC_SINGLE("ALC Capture Hold", WM8978_ALC_CONTROL_2, 4, 10, 0),
198 SOC_SINGLE("ALC Capture Target", WM8978_ALC_CONTROL_2, 0, 15, 0),
199
200 SOC_ENUM("ALC Capture Mode", alc3),
201 SOC_SINGLE("ALC Capture Decay", WM8978_ALC_CONTROL_3, 4, 10, 0),
202 SOC_SINGLE("ALC Capture Attack", WM8978_ALC_CONTROL_3, 0, 10, 0),
203
204 SOC_SINGLE("ALC Capture Noise Gate Switch", WM8978_NOISE_GATE, 3, 1, 0),
205 SOC_SINGLE("ALC Capture Noise Gate Threshold",
206 WM8978_NOISE_GATE, 0, 7, 0),
207
208 SOC_DOUBLE_R("Capture PGA ZC Switch",
209 WM8978_LEFT_INP_PGA_CONTROL, WM8978_RIGHT_INP_PGA_CONTROL,
210 7, 1, 0),
211
212 /* OUT1 - Headphones */
213 SOC_DOUBLE_R("Headphone Playback ZC Switch",
214 WM8978_LOUT1_HP_CONTROL, WM8978_ROUT1_HP_CONTROL, 7, 1, 0),
215
216 SOC_DOUBLE_R_TLV("Headphone Playback Volume",
217 WM8978_LOUT1_HP_CONTROL, WM8978_ROUT1_HP_CONTROL,
218 0, 63, 0, spk_tlv),
219
220 /* OUT2 - Speakers */
221 SOC_DOUBLE_R("Speaker Playback ZC Switch",
222 WM8978_LOUT2_SPK_CONTROL, WM8978_ROUT2_SPK_CONTROL, 7, 1, 0),
223
224 SOC_DOUBLE_R_TLV("Speaker Playback Volume",
225 WM8978_LOUT2_SPK_CONTROL, WM8978_ROUT2_SPK_CONTROL,
226 0, 63, 0, spk_tlv),
227
228 /* OUT3/4 - Line Output */
229 SOC_DOUBLE_R("Line Playback Switch",
230 WM8978_OUT3_MIXER_CONTROL, WM8978_OUT4_MIXER_CONTROL, 6, 1, 1),
231
232 /* Mixer #3: Boost (Input) mixer */
233 SOC_DOUBLE_R("PGA Boost (+20dB)",
234 WM8978_LEFT_ADC_BOOST_CONTROL, WM8978_RIGHT_ADC_BOOST_CONTROL,
235 8, 1, 0),
236 SOC_DOUBLE_R_TLV("L2/R2 Boost Volume",
237 WM8978_LEFT_ADC_BOOST_CONTROL, WM8978_RIGHT_ADC_BOOST_CONTROL,
238 4, 7, 0, boost_tlv),
239 SOC_DOUBLE_R_TLV("Aux Boost Volume",
240 WM8978_LEFT_ADC_BOOST_CONTROL, WM8978_RIGHT_ADC_BOOST_CONTROL,
241 0, 7, 0, boost_tlv),
242
243 /* Input PGA volume */
244 SOC_DOUBLE_R_TLV("Input PGA Volume",
245 WM8978_LEFT_INP_PGA_CONTROL, WM8978_RIGHT_INP_PGA_CONTROL,
246 0, 63, 0, inpga_tlv),
247
248 /* Headphone */
249 SOC_DOUBLE_R("Headphone Switch",
250 WM8978_LOUT1_HP_CONTROL, WM8978_ROUT1_HP_CONTROL, 6, 1, 1),
251
252 /* Speaker */
253 SOC_DOUBLE_R("Speaker Switch",
254 WM8978_LOUT2_SPK_CONTROL, WM8978_ROUT2_SPK_CONTROL, 6, 1, 1),
255
256 /* DAC / ADC oversampling */
257 SOC_SINGLE("DAC 128x Oversampling Switch", WM8978_DAC_CONTROL,
258 5, 1, 0),
259 SOC_SINGLE("ADC 128x Oversampling Switch", WM8978_ADC_CONTROL,
260 5, 1, 0),
261};
262
263/* Mixer #1: Output (OUT1, OUT2) Mixer: mix AUX, Input mixer output and DAC */
264static const struct snd_kcontrol_new wm8978_left_out_mixer[] = {
265 SOC_DAPM_SINGLE("Line Bypass Switch", WM8978_LEFT_MIXER_CONTROL, 1, 1, 0),
266 SOC_DAPM_SINGLE("Aux Playback Switch", WM8978_LEFT_MIXER_CONTROL, 5, 1, 0),
267 SOC_DAPM_SINGLE("PCM Playback Switch", WM8978_LEFT_MIXER_CONTROL, 0, 1, 0),
268};
269
270static const struct snd_kcontrol_new wm8978_right_out_mixer[] = {
271 SOC_DAPM_SINGLE("Line Bypass Switch", WM8978_RIGHT_MIXER_CONTROL, 1, 1, 0),
272 SOC_DAPM_SINGLE("Aux Playback Switch", WM8978_RIGHT_MIXER_CONTROL, 5, 1, 0),
273 SOC_DAPM_SINGLE("PCM Playback Switch", WM8978_RIGHT_MIXER_CONTROL, 0, 1, 0),
274};
275
276/* OUT3/OUT4 Mixer not implemented */
277
278/* Mixer #2: Input PGA Mute */
279static const struct snd_kcontrol_new wm8978_left_input_mixer[] = {
280 SOC_DAPM_SINGLE("L2 Switch", WM8978_INPUT_CONTROL, 2, 1, 0),
281 SOC_DAPM_SINGLE("MicN Switch", WM8978_INPUT_CONTROL, 1, 1, 0),
282 SOC_DAPM_SINGLE("MicP Switch", WM8978_INPUT_CONTROL, 0, 1, 0),
283};
284static const struct snd_kcontrol_new wm8978_right_input_mixer[] = {
285 SOC_DAPM_SINGLE("R2 Switch", WM8978_INPUT_CONTROL, 6, 1, 0),
286 SOC_DAPM_SINGLE("MicN Switch", WM8978_INPUT_CONTROL, 5, 1, 0),
287 SOC_DAPM_SINGLE("MicP Switch", WM8978_INPUT_CONTROL, 4, 1, 0),
288};
289
290static const struct snd_soc_dapm_widget wm8978_dapm_widgets[] = {
291 SND_SOC_DAPM_DAC("Left DAC", "Left HiFi Playback",
292 WM8978_POWER_MANAGEMENT_3, 0, 0),
293 SND_SOC_DAPM_DAC("Right DAC", "Right HiFi Playback",
294 WM8978_POWER_MANAGEMENT_3, 1, 0),
295 SND_SOC_DAPM_ADC("Left ADC", "Left HiFi Capture",
296 WM8978_POWER_MANAGEMENT_2, 0, 0),
297 SND_SOC_DAPM_ADC("Right ADC", "Right HiFi Capture",
298 WM8978_POWER_MANAGEMENT_2, 1, 0),
299
300 /* Mixer #1: OUT1,2 */
301 SOC_MIXER_ARRAY("Left Output Mixer", WM8978_POWER_MANAGEMENT_3,
302 2, 0, wm8978_left_out_mixer),
303 SOC_MIXER_ARRAY("Right Output Mixer", WM8978_POWER_MANAGEMENT_3,
304 3, 0, wm8978_right_out_mixer),
305
306 SOC_MIXER_ARRAY("Left Input Mixer", WM8978_POWER_MANAGEMENT_2,
307 2, 0, wm8978_left_input_mixer),
308 SOC_MIXER_ARRAY("Right Input Mixer", WM8978_POWER_MANAGEMENT_2,
309 3, 0, wm8978_right_input_mixer),
310
311 SND_SOC_DAPM_PGA("Left Boost Mixer", WM8978_POWER_MANAGEMENT_2,
312 4, 0, NULL, 0),
313 SND_SOC_DAPM_PGA("Right Boost Mixer", WM8978_POWER_MANAGEMENT_2,
314 5, 0, NULL, 0),
315
316 SND_SOC_DAPM_PGA("Left Capture PGA", WM8978_LEFT_INP_PGA_CONTROL,
317 6, 1, NULL, 0),
318 SND_SOC_DAPM_PGA("Right Capture PGA", WM8978_RIGHT_INP_PGA_CONTROL,
319 6, 1, NULL, 0),
320
321 SND_SOC_DAPM_PGA("Left Headphone Out", WM8978_POWER_MANAGEMENT_2,
322 7, 0, NULL, 0),
323 SND_SOC_DAPM_PGA("Right Headphone Out", WM8978_POWER_MANAGEMENT_2,
324 8, 0, NULL, 0),
325
326 SND_SOC_DAPM_PGA("Left Speaker Out", WM8978_POWER_MANAGEMENT_3,
327 6, 0, NULL, 0),
328 SND_SOC_DAPM_PGA("Right Speaker Out", WM8978_POWER_MANAGEMENT_3,
329 5, 0, NULL, 0),
330
331 SND_SOC_DAPM_MIXER("OUT4 VMID", WM8978_POWER_MANAGEMENT_3,
332 8, 0, NULL, 0),
333
334 SND_SOC_DAPM_MICBIAS("Mic Bias", WM8978_POWER_MANAGEMENT_1, 4, 0),
335
336 SND_SOC_DAPM_INPUT("LMICN"),
337 SND_SOC_DAPM_INPUT("LMICP"),
338 SND_SOC_DAPM_INPUT("RMICN"),
339 SND_SOC_DAPM_INPUT("RMICP"),
340 SND_SOC_DAPM_INPUT("LAUX"),
341 SND_SOC_DAPM_INPUT("RAUX"),
342 SND_SOC_DAPM_INPUT("L2"),
343 SND_SOC_DAPM_INPUT("R2"),
344 SND_SOC_DAPM_OUTPUT("LHP"),
345 SND_SOC_DAPM_OUTPUT("RHP"),
346 SND_SOC_DAPM_OUTPUT("LSPK"),
347 SND_SOC_DAPM_OUTPUT("RSPK"),
348};
349
350static const struct snd_soc_dapm_route wm8978_dapm_routes[] = {
351 /* Output mixer */
352 {"Right Output Mixer", "PCM Playback Switch", "Right DAC"},
353 {"Right Output Mixer", "Aux Playback Switch", "RAUX"},
354 {"Right Output Mixer", "Line Bypass Switch", "Right Boost Mixer"},
355
356 {"Left Output Mixer", "PCM Playback Switch", "Left DAC"},
357 {"Left Output Mixer", "Aux Playback Switch", "LAUX"},
358 {"Left Output Mixer", "Line Bypass Switch", "Left Boost Mixer"},
359
360 /* Outputs */
361 {"Right Headphone Out", NULL, "Right Output Mixer"},
362 {"RHP", NULL, "Right Headphone Out"},
363
364 {"Left Headphone Out", NULL, "Left Output Mixer"},
365 {"LHP", NULL, "Left Headphone Out"},
366
367 {"Right Speaker Out", NULL, "Right Output Mixer"},
368 {"RSPK", NULL, "Right Speaker Out"},
369
370 {"Left Speaker Out", NULL, "Left Output Mixer"},
371 {"LSPK", NULL, "Left Speaker Out"},
372
373 /* Boost Mixer */
374 {"Right ADC", NULL, "Right Boost Mixer"},
375
376 {"Right Boost Mixer", NULL, "RAUX"},
377 {"Right Boost Mixer", NULL, "Right Capture PGA"},
378 {"Right Boost Mixer", NULL, "R2"},
379
380 {"Left ADC", NULL, "Left Boost Mixer"},
381
382 {"Left Boost Mixer", NULL, "LAUX"},
383 {"Left Boost Mixer", NULL, "Left Capture PGA"},
384 {"Left Boost Mixer", NULL, "L2"},
385
386 /* Input PGA */
387 {"Right Capture PGA", NULL, "Right Input Mixer"},
388 {"Left Capture PGA", NULL, "Left Input Mixer"},
389
390 {"Right Input Mixer", "R2 Switch", "R2"},
391 {"Right Input Mixer", "MicN Switch", "RMICN"},
392 {"Right Input Mixer", "MicP Switch", "RMICP"},
393
394 {"Left Input Mixer", "L2 Switch", "L2"},
395 {"Left Input Mixer", "MicN Switch", "LMICN"},
396 {"Left Input Mixer", "MicP Switch", "LMICP"},
397};
398
399/* PLL divisors */
400struct wm8978_pll_div {
401 u32 k;
402 u8 n;
403 u8 div2;
404};
405
406#define FIXED_PLL_SIZE (1 << 24)
407
408static void pll_factors(struct snd_soc_component *component,
409 struct wm8978_pll_div *pll_div, unsigned int target, unsigned int source)
410{
411 u64 k_part;
412 unsigned int k, n_div, n_mod;
413
414 n_div = target / source;
415 if (n_div < 6) {
416 source >>= 1;
417 pll_div->div2 = 1;
418 n_div = target / source;
419 } else {
420 pll_div->div2 = 0;
421 }
422
423 if (n_div < 6 || n_div > 12)
424 dev_warn(component->dev,
425 "WM8978 N value exceeds recommended range! N = %u\n",
426 n_div);
427
428 pll_div->n = n_div;
429 n_mod = target - source * n_div;
430 k_part = FIXED_PLL_SIZE * (long long)n_mod + source / 2;
431
432 do_div(k_part, source);
433
434 k = k_part & 0xFFFFFFFF;
435
436 pll_div->k = k;
437}
438
439/* MCLK dividers */
440static const int mclk_numerator[] = {1, 3, 2, 3, 4, 6, 8, 12};
441static const int mclk_denominator[] = {1, 2, 1, 1, 1, 1, 1, 1};
442
443/*
444 * find index >= idx, such that, for a given f_out,
445 * 3 * f_mclk / 4 <= f_PLLOUT < 13 * f_mclk / 4
446 * f_out can be f_256fs or f_opclk, currently only used for f_256fs. Can be
447 * generalised for f_opclk with suitable coefficient arrays, but currently
448 * the OPCLK divisor is calculated directly, not iteratively.
449 */
450static int wm8978_enum_mclk(unsigned int f_out, unsigned int f_mclk,
451 unsigned int *f_pllout)
452{
453 int i;
454
455 for (i = 0; i < ARRAY_SIZE(mclk_numerator); i++) {
456 unsigned int f_pllout_x4 = 4 * f_out * mclk_numerator[i] /
457 mclk_denominator[i];
458 if (3 * f_mclk <= f_pllout_x4 && f_pllout_x4 < 13 * f_mclk) {
459 *f_pllout = f_pllout_x4 / 4;
460 return i;
461 }
462 }
463
464 return -EINVAL;
465}
466
467/*
468 * Calculate internal frequencies and dividers, according to Figure 40
469 * "PLL and Clock Select Circuit" in WM8978 datasheet Rev. 2.6
470 */
471static int wm8978_configure_pll(struct snd_soc_component *component)
472{
473 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
474 struct wm8978_pll_div pll_div;
475 unsigned int f_opclk = wm8978->f_opclk, f_mclk = wm8978->f_mclk,
476 f_256fs = wm8978->f_256fs;
477 unsigned int f2;
478
479 if (!f_mclk)
480 return -EINVAL;
481
482 if (f_opclk) {
483 unsigned int opclk_div;
484 /* Cannot set up MCLK divider now, do later */
485 wm8978->mclk_idx = -1;
486
487 /*
488 * The user needs OPCLK. Choose OPCLKDIV to put
489 * 6 <= R = f2 / f1 < 13, 1 <= OPCLKDIV <= 4.
490 * f_opclk = f_mclk * prescale * R / 4 / OPCLKDIV, where
491 * prescale = 1, or prescale = 2. Prescale is calculated inside
492 * pll_factors(). We have to select f_PLLOUT, such that
493 * f_mclk * 3 / 4 <= f_PLLOUT < f_mclk * 13 / 4. Must be
494 * f_mclk * 3 / 16 <= f_opclk < f_mclk * 13 / 4.
495 */
496 if (16 * f_opclk < 3 * f_mclk || 4 * f_opclk >= 13 * f_mclk)
497 return -EINVAL;
498
499 if (4 * f_opclk < 3 * f_mclk)
500 /* Have to use OPCLKDIV */
501 opclk_div = DIV_ROUND_UP(3 * f_mclk / 4, f_opclk);
502 else
503 opclk_div = 1;
504
505 dev_dbg(component->dev, "%s: OPCLKDIV=%d\n", __func__, opclk_div);
506
507 snd_soc_component_update_bits(component, WM8978_GPIO_CONTROL, mask: 0x30,
508 val: (opclk_div - 1) << 4);
509
510 wm8978->f_pllout = f_opclk * opclk_div;
511 } else if (f_256fs) {
512 /*
513 * Not using OPCLK, but PLL is used for the codec, choose R:
514 * 6 <= R = f2 / f1 < 13, to put 1 <= MCLKDIV <= 12.
515 * f_256fs = f_mclk * prescale * R / 4 / MCLKDIV, where
516 * prescale = 1, or prescale = 2. Prescale is calculated inside
517 * pll_factors(). We have to select f_PLLOUT, such that
518 * f_mclk * 3 / 4 <= f_PLLOUT < f_mclk * 13 / 4. Must be
519 * f_mclk * 3 / 48 <= f_256fs < f_mclk * 13 / 4. This means MCLK
520 * must be 3.781MHz <= f_MCLK <= 32.768MHz
521 */
522 int idx = wm8978_enum_mclk(f_out: f_256fs, f_mclk, f_pllout: &wm8978->f_pllout);
523 if (idx < 0)
524 return idx;
525
526 wm8978->mclk_idx = idx;
527 } else {
528 return -EINVAL;
529 }
530
531 f2 = wm8978->f_pllout * 4;
532
533 dev_dbg(component->dev, "%s: f_MCLK=%uHz, f_PLLOUT=%uHz\n", __func__,
534 wm8978->f_mclk, wm8978->f_pllout);
535
536 pll_factors(component, pll_div: &pll_div, target: f2, source: wm8978->f_mclk);
537
538 dev_dbg(component->dev, "%s: calculated PLL N=0x%x, K=0x%x, div2=%d\n",
539 __func__, pll_div.n, pll_div.k, pll_div.div2);
540
541 /* Turn PLL off for configuration... */
542 snd_soc_component_update_bits(component, WM8978_POWER_MANAGEMENT_1, mask: 0x20, val: 0);
543
544 snd_soc_component_write(component, WM8978_PLL_N, val: (pll_div.div2 << 4) | pll_div.n);
545 snd_soc_component_write(component, WM8978_PLL_K1, val: pll_div.k >> 18);
546 snd_soc_component_write(component, WM8978_PLL_K2, val: (pll_div.k >> 9) & 0x1ff);
547 snd_soc_component_write(component, WM8978_PLL_K3, val: pll_div.k & 0x1ff);
548
549 /* ...and on again */
550 snd_soc_component_update_bits(component, WM8978_POWER_MANAGEMENT_1, mask: 0x20, val: 0x20);
551
552 if (f_opclk)
553 /* Output PLL (OPCLK) to GPIO1 */
554 snd_soc_component_update_bits(component, WM8978_GPIO_CONTROL, mask: 7, val: 4);
555
556 return 0;
557}
558
559/*
560 * Configure WM8978 clock dividers.
561 */
562static int wm8978_set_dai_clkdiv(struct snd_soc_dai *codec_dai,
563 int div_id, int div)
564{
565 struct snd_soc_component *component = codec_dai->component;
566 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
567 int ret = 0;
568
569 switch (div_id) {
570 case WM8978_OPCLKRATE:
571 wm8978->f_opclk = div;
572
573 if (wm8978->f_mclk)
574 /*
575 * We know the MCLK frequency, the user has requested
576 * OPCLK, configure the PLL based on that and start it
577 * and OPCLK immediately. We will configure PLL to match
578 * user-requested OPCLK frquency as good as possible.
579 * In fact, it is likely, that matching the sampling
580 * rate, when it becomes known, is more important, and
581 * we will not be reconfiguring PLL then, because we
582 * must not interrupt OPCLK. But it should be fine,
583 * because typically the user will request OPCLK to run
584 * at 256fs or 512fs, and for these cases we will also
585 * find an exact MCLK divider configuration - it will
586 * be equal to or double the OPCLK divisor.
587 */
588 ret = wm8978_configure_pll(component);
589 break;
590 case WM8978_BCLKDIV:
591 if (div & ~0x1c)
592 return -EINVAL;
593 snd_soc_component_update_bits(component, WM8978_CLOCKING, mask: 0x1c, val: div);
594 break;
595 default:
596 return -EINVAL;
597 }
598
599 dev_dbg(component->dev, "%s: ID %d, value %u\n", __func__, div_id, div);
600
601 return ret;
602}
603
604/*
605 * @freq: when .set_pll() us not used, freq is codec MCLK input frequency
606 */
607static int wm8978_set_dai_sysclk(struct snd_soc_dai *codec_dai, int clk_id,
608 unsigned int freq, int dir)
609{
610 struct snd_soc_component *component = codec_dai->component;
611 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
612 int ret = 0;
613
614 dev_dbg(component->dev, "%s: ID %d, freq %u\n", __func__, clk_id, freq);
615
616 if (freq) {
617 wm8978->f_mclk = freq;
618
619 /* Even if MCLK is used for system clock, might have to drive OPCLK */
620 if (wm8978->f_opclk)
621 ret = wm8978_configure_pll(component);
622
623 /* Our sysclk is fixed to 256 * fs, will configure in .hw_params() */
624
625 if (!ret)
626 wm8978->sysclk = clk_id;
627 }
628
629 if (wm8978->sysclk == WM8978_PLL && (!freq || clk_id == WM8978_MCLK)) {
630 /* Clock CODEC directly from MCLK */
631 snd_soc_component_update_bits(component, WM8978_CLOCKING, mask: 0x100, val: 0);
632
633 /* GPIO1 into default mode as input - before configuring PLL */
634 snd_soc_component_update_bits(component, WM8978_GPIO_CONTROL, mask: 7, val: 0);
635
636 /* Turn off PLL */
637 snd_soc_component_update_bits(component, WM8978_POWER_MANAGEMENT_1, mask: 0x20, val: 0);
638 wm8978->sysclk = WM8978_MCLK;
639 wm8978->f_pllout = 0;
640 wm8978->f_opclk = 0;
641 }
642
643 return ret;
644}
645
646/*
647 * Set ADC and Voice DAC format.
648 */
649static int wm8978_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt)
650{
651 struct snd_soc_component *component = codec_dai->component;
652 /*
653 * BCLK polarity mask = 0x100, LRC clock polarity mask = 0x80,
654 * Data Format mask = 0x18: all will be calculated anew
655 */
656 u16 iface = snd_soc_component_read(component, WM8978_AUDIO_INTERFACE) & ~0x198;
657 u16 clk = snd_soc_component_read(component, WM8978_CLOCKING);
658
659 dev_dbg(component->dev, "%s\n", __func__);
660
661 /* set master/slave audio interface */
662 switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
663 case SND_SOC_DAIFMT_CBM_CFM:
664 clk |= 1;
665 break;
666 case SND_SOC_DAIFMT_CBS_CFS:
667 clk &= ~1;
668 break;
669 default:
670 return -EINVAL;
671 }
672
673 /* interface format */
674 switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
675 case SND_SOC_DAIFMT_I2S:
676 iface |= 0x10;
677 break;
678 case SND_SOC_DAIFMT_RIGHT_J:
679 break;
680 case SND_SOC_DAIFMT_LEFT_J:
681 iface |= 0x8;
682 break;
683 case SND_SOC_DAIFMT_DSP_A:
684 iface |= 0x18;
685 break;
686 default:
687 return -EINVAL;
688 }
689
690 /* clock inversion */
691 switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
692 case SND_SOC_DAIFMT_NB_NF:
693 break;
694 case SND_SOC_DAIFMT_IB_IF:
695 iface |= 0x180;
696 break;
697 case SND_SOC_DAIFMT_IB_NF:
698 iface |= 0x100;
699 break;
700 case SND_SOC_DAIFMT_NB_IF:
701 iface |= 0x80;
702 break;
703 default:
704 return -EINVAL;
705 }
706
707 snd_soc_component_write(component, WM8978_AUDIO_INTERFACE, val: iface);
708 snd_soc_component_write(component, WM8978_CLOCKING, val: clk);
709
710 return 0;
711}
712
713/*
714 * Set PCM DAI bit size and sample rate.
715 */
716static int wm8978_hw_params(struct snd_pcm_substream *substream,
717 struct snd_pcm_hw_params *params,
718 struct snd_soc_dai *dai)
719{
720 struct snd_soc_component *component = dai->component;
721 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
722 /* Word length mask = 0x60 */
723 u16 iface_ctl = snd_soc_component_read(component, WM8978_AUDIO_INTERFACE) & ~0x60;
724 /* Sampling rate mask = 0xe (for filters) */
725 u16 add_ctl = snd_soc_component_read(component, WM8978_ADDITIONAL_CONTROL) & ~0xe;
726 u16 clking = snd_soc_component_read(component, WM8978_CLOCKING);
727 enum wm8978_sysclk_src current_clk_id = (clking & 0x100) ?
728 WM8978_PLL : WM8978_MCLK;
729 unsigned int f_sel, diff, diff_best = INT_MAX;
730 int i, best = 0;
731
732 if (!wm8978->f_mclk)
733 return -EINVAL;
734
735 /* bit size */
736 switch (params_width(p: params)) {
737 case 16:
738 break;
739 case 20:
740 iface_ctl |= 0x20;
741 break;
742 case 24:
743 iface_ctl |= 0x40;
744 break;
745 case 32:
746 iface_ctl |= 0x60;
747 break;
748 }
749
750 /* filter coefficient */
751 switch (params_rate(p: params)) {
752 case 8000:
753 add_ctl |= 0x5 << 1;
754 break;
755 case 11025:
756 add_ctl |= 0x4 << 1;
757 break;
758 case 16000:
759 add_ctl |= 0x3 << 1;
760 break;
761 case 22050:
762 add_ctl |= 0x2 << 1;
763 break;
764 case 32000:
765 add_ctl |= 0x1 << 1;
766 break;
767 case 44100:
768 case 48000:
769 break;
770 }
771
772 /* Sampling rate is known now, can configure the MCLK divider */
773 wm8978->f_256fs = params_rate(p: params) * 256;
774
775 if (wm8978->sysclk == WM8978_MCLK) {
776 wm8978->mclk_idx = -1;
777 f_sel = wm8978->f_mclk;
778 } else {
779 if (!wm8978->f_opclk) {
780 /* We only enter here, if OPCLK is not used */
781 int ret = wm8978_configure_pll(component);
782 if (ret < 0)
783 return ret;
784 }
785 f_sel = wm8978->f_pllout;
786 }
787
788 if (wm8978->mclk_idx < 0) {
789 /* Either MCLK is used directly, or OPCLK is used */
790 if (f_sel < wm8978->f_256fs || f_sel > 12 * wm8978->f_256fs)
791 return -EINVAL;
792
793 for (i = 0; i < ARRAY_SIZE(mclk_numerator); i++) {
794 diff = abs(wm8978->f_256fs * 3 -
795 f_sel * 3 * mclk_denominator[i] / mclk_numerator[i]);
796
797 if (diff < diff_best) {
798 diff_best = diff;
799 best = i;
800 }
801
802 if (!diff)
803 break;
804 }
805 } else {
806 /* OPCLK not used, codec driven by PLL */
807 best = wm8978->mclk_idx;
808 diff = 0;
809 }
810
811 if (diff)
812 dev_warn(component->dev, "Imprecise sampling rate: %uHz%s\n",
813 f_sel * mclk_denominator[best] / mclk_numerator[best] / 256,
814 wm8978->sysclk == WM8978_MCLK ?
815 ", consider using PLL" : "");
816
817 dev_dbg(component->dev, "%s: width %d, rate %u, MCLK divisor #%d\n", __func__,
818 params_width(params), params_rate(params), best);
819
820 /* MCLK divisor mask = 0xe0 */
821 snd_soc_component_update_bits(component, WM8978_CLOCKING, mask: 0xe0, val: best << 5);
822
823 snd_soc_component_write(component, WM8978_AUDIO_INTERFACE, val: iface_ctl);
824 snd_soc_component_write(component, WM8978_ADDITIONAL_CONTROL, val: add_ctl);
825
826 if (wm8978->sysclk != current_clk_id) {
827 if (wm8978->sysclk == WM8978_PLL)
828 /* Run CODEC from PLL instead of MCLK */
829 snd_soc_component_update_bits(component, WM8978_CLOCKING,
830 mask: 0x100, val: 0x100);
831 else
832 /* Clock CODEC directly from MCLK */
833 snd_soc_component_update_bits(component, WM8978_CLOCKING, mask: 0x100, val: 0);
834 }
835
836 return 0;
837}
838
839static int wm8978_mute(struct snd_soc_dai *dai, int mute, int direction)
840{
841 struct snd_soc_component *component = dai->component;
842
843 dev_dbg(component->dev, "%s: %d\n", __func__, mute);
844
845 if (mute)
846 snd_soc_component_update_bits(component, WM8978_DAC_CONTROL, mask: 0x40, val: 0x40);
847 else
848 snd_soc_component_update_bits(component, WM8978_DAC_CONTROL, mask: 0x40, val: 0);
849
850 return 0;
851}
852
853static int wm8978_set_bias_level(struct snd_soc_component *component,
854 enum snd_soc_bias_level level)
855{
856 u16 power1 = snd_soc_component_read(component, WM8978_POWER_MANAGEMENT_1) & ~3;
857
858 switch (level) {
859 case SND_SOC_BIAS_ON:
860 case SND_SOC_BIAS_PREPARE:
861 power1 |= 1; /* VMID 75k */
862 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_1, val: power1);
863 break;
864 case SND_SOC_BIAS_STANDBY:
865 /* bit 3: enable bias, bit 2: enable I/O tie off buffer */
866 power1 |= 0xc;
867
868 if (snd_soc_component_get_bias_level(component) == SND_SOC_BIAS_OFF) {
869 /* Initial cap charge at VMID 5k */
870 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_1,
871 val: power1 | 0x3);
872 mdelay(100);
873 }
874
875 power1 |= 0x2; /* VMID 500k */
876 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_1, val: power1);
877 break;
878 case SND_SOC_BIAS_OFF:
879 /* Preserve PLL - OPCLK may be used by someone */
880 snd_soc_component_update_bits(component, WM8978_POWER_MANAGEMENT_1, mask: ~0x20, val: 0);
881 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_2, val: 0);
882 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_3, val: 0);
883 break;
884 }
885
886 dev_dbg(component->dev, "%s: %d, %x\n", __func__, level, power1);
887
888 return 0;
889}
890
891#define WM8978_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE | \
892 SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S32_LE)
893
894static const struct snd_soc_dai_ops wm8978_dai_ops = {
895 .hw_params = wm8978_hw_params,
896 .mute_stream = wm8978_mute,
897 .set_fmt = wm8978_set_dai_fmt,
898 .set_clkdiv = wm8978_set_dai_clkdiv,
899 .set_sysclk = wm8978_set_dai_sysclk,
900 .no_capture_mute = 1,
901};
902
903/* Also supports 12kHz */
904static struct snd_soc_dai_driver wm8978_dai = {
905 .name = "wm8978-hifi",
906 .playback = {
907 .stream_name = "Playback",
908 .channels_min = 1,
909 .channels_max = 2,
910 .rates = SNDRV_PCM_RATE_8000_48000,
911 .formats = WM8978_FORMATS,
912 },
913 .capture = {
914 .stream_name = "Capture",
915 .channels_min = 1,
916 .channels_max = 2,
917 .rates = SNDRV_PCM_RATE_8000_48000,
918 .formats = WM8978_FORMATS,
919 },
920 .ops = &wm8978_dai_ops,
921 .symmetric_rate = 1,
922};
923
924static int wm8978_suspend(struct snd_soc_component *component)
925{
926 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
927
928 snd_soc_component_force_bias_level(component, level: SND_SOC_BIAS_OFF);
929 /* Also switch PLL off */
930 snd_soc_component_write(component, WM8978_POWER_MANAGEMENT_1, val: 0);
931
932 regcache_mark_dirty(map: wm8978->regmap);
933
934 return 0;
935}
936
937static int wm8978_resume(struct snd_soc_component *component)
938{
939 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
940
941 /* Sync reg_cache with the hardware */
942 regcache_sync(map: wm8978->regmap);
943
944 snd_soc_component_force_bias_level(component, level: SND_SOC_BIAS_STANDBY);
945
946 if (wm8978->f_pllout)
947 /* Switch PLL on */
948 snd_soc_component_update_bits(component, WM8978_POWER_MANAGEMENT_1, mask: 0x20, val: 0x20);
949
950 return 0;
951}
952
953/*
954 * These registers contain an "update" bit - bit 8. This means, for example,
955 * that one can write new DAC digital volume for both channels, but only when
956 * the update bit is set, will also the volume be updated - simultaneously for
957 * both channels.
958 */
959static const int update_reg[] = {
960 WM8978_LEFT_DAC_DIGITAL_VOLUME,
961 WM8978_RIGHT_DAC_DIGITAL_VOLUME,
962 WM8978_LEFT_ADC_DIGITAL_VOLUME,
963 WM8978_RIGHT_ADC_DIGITAL_VOLUME,
964 WM8978_LEFT_INP_PGA_CONTROL,
965 WM8978_RIGHT_INP_PGA_CONTROL,
966 WM8978_LOUT1_HP_CONTROL,
967 WM8978_ROUT1_HP_CONTROL,
968 WM8978_LOUT2_SPK_CONTROL,
969 WM8978_ROUT2_SPK_CONTROL,
970};
971
972static int wm8978_probe(struct snd_soc_component *component)
973{
974 struct wm8978_priv *wm8978 = snd_soc_component_get_drvdata(c: component);
975 int i;
976
977 /*
978 * Set default system clock to PLL, it is more precise, this is also the
979 * default hardware setting
980 */
981 wm8978->sysclk = WM8978_PLL;
982
983 /*
984 * Set the update bit in all registers, that have one. This way all
985 * writes to those registers will also cause the update bit to be
986 * written.
987 */
988 for (i = 0; i < ARRAY_SIZE(update_reg); i++)
989 snd_soc_component_update_bits(component, reg: update_reg[i], mask: 0x100, val: 0x100);
990
991 return 0;
992}
993
994static const struct snd_soc_component_driver soc_component_dev_wm8978 = {
995 .probe = wm8978_probe,
996 .suspend = wm8978_suspend,
997 .resume = wm8978_resume,
998 .set_bias_level = wm8978_set_bias_level,
999 .controls = wm8978_snd_controls,
1000 .num_controls = ARRAY_SIZE(wm8978_snd_controls),
1001 .dapm_widgets = wm8978_dapm_widgets,
1002 .num_dapm_widgets = ARRAY_SIZE(wm8978_dapm_widgets),
1003 .dapm_routes = wm8978_dapm_routes,
1004 .num_dapm_routes = ARRAY_SIZE(wm8978_dapm_routes),
1005 .idle_bias_on = 1,
1006 .use_pmdown_time = 1,
1007 .endianness = 1,
1008};
1009
1010static const struct regmap_config wm8978_regmap_config = {
1011 .reg_bits = 7,
1012 .val_bits = 9,
1013
1014 .max_register = WM8978_MAX_REGISTER,
1015 .volatile_reg = wm8978_volatile,
1016
1017 .cache_type = REGCACHE_MAPLE,
1018 .reg_defaults = wm8978_reg_defaults,
1019 .num_reg_defaults = ARRAY_SIZE(wm8978_reg_defaults),
1020};
1021
1022static int wm8978_i2c_probe(struct i2c_client *i2c)
1023{
1024 struct wm8978_priv *wm8978;
1025 int ret;
1026
1027 wm8978 = devm_kzalloc(dev: &i2c->dev, size: sizeof(struct wm8978_priv),
1028 GFP_KERNEL);
1029 if (wm8978 == NULL)
1030 return -ENOMEM;
1031
1032 wm8978->regmap = devm_regmap_init_i2c(i2c, &wm8978_regmap_config);
1033 if (IS_ERR(ptr: wm8978->regmap)) {
1034 ret = PTR_ERR(ptr: wm8978->regmap);
1035 dev_err(&i2c->dev, "Failed to allocate regmap: %d\n", ret);
1036 return ret;
1037 }
1038
1039 i2c_set_clientdata(client: i2c, data: wm8978);
1040
1041 /* Reset the codec */
1042 ret = regmap_write(map: wm8978->regmap, WM8978_RESET, val: 0);
1043 if (ret != 0) {
1044 dev_err(&i2c->dev, "Failed to issue reset: %d\n", ret);
1045 return ret;
1046 }
1047
1048 ret = devm_snd_soc_register_component(dev: &i2c->dev,
1049 component_driver: &soc_component_dev_wm8978, dai_drv: &wm8978_dai, num_dai: 1);
1050 if (ret != 0) {
1051 dev_err(&i2c->dev, "Failed to register CODEC: %d\n", ret);
1052 return ret;
1053 }
1054
1055 return 0;
1056}
1057
1058static const struct i2c_device_id wm8978_i2c_id[] = {
1059 { "wm8978", 0 },
1060 { }
1061};
1062MODULE_DEVICE_TABLE(i2c, wm8978_i2c_id);
1063
1064static const struct of_device_id wm8978_of_match[] = {
1065 { .compatible = "wlf,wm8978", },
1066 { }
1067};
1068MODULE_DEVICE_TABLE(of, wm8978_of_match);
1069
1070static struct i2c_driver wm8978_i2c_driver = {
1071 .driver = {
1072 .name = "wm8978",
1073 .of_match_table = wm8978_of_match,
1074 },
1075 .probe = wm8978_i2c_probe,
1076 .id_table = wm8978_i2c_id,
1077};
1078
1079module_i2c_driver(wm8978_i2c_driver);
1080
1081MODULE_DESCRIPTION("ASoC WM8978 codec driver");
1082MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
1083MODULE_LICENSE("GPL");
1084

source code of linux/sound/soc/codecs/wm8978.c