1// SPDX-License-Identifier: (GPL-2.0 OR MIT)
2//
3// Copyright (c) 2018 BayLibre, SAS.
4// Author: Jerome Brunet <jbrunet@baylibre.com>
5
6#include <linux/clk.h>
7#include <linux/module.h>
8#include <linux/of_platform.h>
9#include <linux/regmap.h>
10#include <linux/reset.h>
11#include <sound/soc.h>
12
13#include "axg-tdm-formatter.h"
14
15struct axg_tdm_formatter {
16	struct list_head list;
17	struct axg_tdm_stream *stream;
18	const struct axg_tdm_formatter_driver *drv;
19	struct clk *pclk;
20	struct clk *sclk;
21	struct clk *lrclk;
22	struct clk *sclk_sel;
23	struct clk *lrclk_sel;
24	struct reset_control *reset;
25	bool enabled;
26	struct regmap *map;
27};
28
29int axg_tdm_formatter_set_channel_masks(struct regmap *map,
30					struct axg_tdm_stream *ts,
31					unsigned int offset)
32{
33	unsigned int ch = ts->channels;
34	u32 val[AXG_TDM_NUM_LANES];
35	int i, j, k;
36
37	/*
38	 * We need to mimick the slot distribution used by the HW to keep the
39	 * channel placement consistent regardless of the number of channel
40	 * in the stream. This is why the odd algorithm below is used.
41	 */
42	memset(val, 0, sizeof(*val) * AXG_TDM_NUM_LANES);
43
44	/*
45	 * Distribute the channels of the stream over the available slots
46	 * of each TDM lane. We need to go over the 32 slots ...
47	 */
48	for (i = 0; (i < 32) && ch; i += 2) {
49		/* ... of all the lanes ... */
50		for (j = 0; j < AXG_TDM_NUM_LANES; j++) {
51			/* ... then distribute the channels in pairs */
52			for (k = 0; k < 2; k++) {
53				if ((BIT(i + k) & ts->mask[j]) && ch) {
54					val[j] |= BIT(i + k);
55					ch -= 1;
56				}
57			}
58		}
59	}
60
61	/*
62	 * If we still have channel left at the end of the process, it means
63	 * the stream has more channels than we can accommodate and we should
64	 * have caught this earlier.
65	 */
66	if (WARN_ON(ch != 0)) {
67		pr_err("channel mask error\n");
68		return -EINVAL;
69	}
70
71	for (i = 0; i < AXG_TDM_NUM_LANES; i++) {
72		regmap_write(map, offset, val[i]);
73		offset += regmap_get_reg_stride(map);
74	}
75
76	return 0;
77}
78EXPORT_SYMBOL_GPL(axg_tdm_formatter_set_channel_masks);
79
80static int axg_tdm_formatter_enable(struct axg_tdm_formatter *formatter)
81{
82	struct axg_tdm_stream *ts = formatter->stream;
83	bool invert;
84	int ret;
85
86	/* Do nothing if the formatter is already enabled */
87	if (formatter->enabled)
88		return 0;
89
90	/*
91	 * On the g12a (and possibly other SoCs), when a stream using
92	 * multiple lanes is restarted, it will sometimes not start
93	 * from the first lane, but randomly from another used one.
94	 * The result is an unexpected and random channel shift.
95	 *
96	 * The hypothesis is that an HW counter is not properly reset
97	 * and the formatter simply starts on the lane it stopped
98	 * before. Unfortunately, there does not seems to be a way to
99	 * reset this through the registers of the block.
100	 *
101	 * However, the g12a has indenpendent reset lines for each audio
102	 * devices. Using this reset before each start solves the issue.
103	 */
104	ret = reset_control_reset(formatter->reset);
105	if (ret)
106		return ret;
107
108	/*
109	 * If sclk is inverted, it means the bit should latched on the
110	 * rising edge which is what our HW expects. If not, we need to
111	 * invert it before the formatter.
112	 */
113	invert = axg_tdm_sclk_invert(ts->iface->fmt);
114	ret = clk_set_phase(formatter->sclk, invert ? 0 : 180);
115	if (ret)
116		return ret;
117
118	/* Setup the stream parameter in the formatter */
119	ret = formatter->drv->ops->prepare(formatter->map,
120					   formatter->drv->quirks,
121					   formatter->stream);
122	if (ret)
123		return ret;
124
125	/* Enable the signal clocks feeding the formatter */
126	ret = clk_prepare_enable(formatter->sclk);
127	if (ret)
128		return ret;
129
130	ret = clk_prepare_enable(formatter->lrclk);
131	if (ret) {
132		clk_disable_unprepare(formatter->sclk);
133		return ret;
134	}
135
136	/* Finally, actually enable the formatter */
137	formatter->drv->ops->enable(formatter->map);
138	formatter->enabled = true;
139
140	return 0;
141}
142
143static void axg_tdm_formatter_disable(struct axg_tdm_formatter *formatter)
144{
145	/* Do nothing if the formatter is already disabled */
146	if (!formatter->enabled)
147		return;
148
149	formatter->drv->ops->disable(formatter->map);
150	clk_disable_unprepare(formatter->lrclk);
151	clk_disable_unprepare(formatter->sclk);
152	formatter->enabled = false;
153}
154
155static int axg_tdm_formatter_attach(struct axg_tdm_formatter *formatter)
156{
157	struct axg_tdm_stream *ts = formatter->stream;
158	int ret = 0;
159
160	mutex_lock(&ts->lock);
161
162	/* Catch up if the stream is already running when we attach */
163	if (ts->ready) {
164		ret = axg_tdm_formatter_enable(formatter);
165		if (ret) {
166			pr_err("failed to enable formatter\n");
167			goto out;
168		}
169	}
170
171	list_add_tail(&formatter->list, &ts->formatter_list);
172out:
173	mutex_unlock(&ts->lock);
174	return ret;
175}
176
177static void axg_tdm_formatter_dettach(struct axg_tdm_formatter *formatter)
178{
179	struct axg_tdm_stream *ts = formatter->stream;
180
181	mutex_lock(&ts->lock);
182	list_del(&formatter->list);
183	mutex_unlock(&ts->lock);
184
185	axg_tdm_formatter_disable(formatter);
186}
187
188static int axg_tdm_formatter_power_up(struct axg_tdm_formatter *formatter,
189				      struct snd_soc_dapm_widget *w)
190{
191	struct axg_tdm_stream *ts = formatter->drv->ops->get_stream(w);
192	int ret;
193
194	/*
195	 * If we don't get a stream at this stage, it would mean that the
196	 * widget is powering up but is not attached to any backend DAI.
197	 * It should not happen, ever !
198	 */
199	if (WARN_ON(!ts))
200		return -ENODEV;
201
202	/* Clock our device */
203	ret = clk_prepare_enable(formatter->pclk);
204	if (ret)
205		return ret;
206
207	/* Reparent the bit clock to the TDM interface */
208	ret = clk_set_parent(formatter->sclk_sel, ts->iface->sclk);
209	if (ret)
210		goto disable_pclk;
211
212	/* Reparent the sample clock to the TDM interface */
213	ret = clk_set_parent(formatter->lrclk_sel, ts->iface->lrclk);
214	if (ret)
215		goto disable_pclk;
216
217	formatter->stream = ts;
218	ret = axg_tdm_formatter_attach(formatter);
219	if (ret)
220		goto disable_pclk;
221
222	return 0;
223
224disable_pclk:
225	clk_disable_unprepare(formatter->pclk);
226	return ret;
227}
228
229static void axg_tdm_formatter_power_down(struct axg_tdm_formatter *formatter)
230{
231	axg_tdm_formatter_dettach(formatter);
232	clk_disable_unprepare(formatter->pclk);
233	formatter->stream = NULL;
234}
235
236int axg_tdm_formatter_event(struct snd_soc_dapm_widget *w,
237			    struct snd_kcontrol *control,
238			    int event)
239{
240	struct snd_soc_component *c = snd_soc_dapm_to_component(w->dapm);
241	struct axg_tdm_formatter *formatter = snd_soc_component_get_drvdata(c);
242	int ret = 0;
243
244	switch (event) {
245	case SND_SOC_DAPM_PRE_PMU:
246		ret = axg_tdm_formatter_power_up(formatter, w);
247		break;
248
249	case SND_SOC_DAPM_PRE_PMD:
250		axg_tdm_formatter_power_down(formatter);
251		break;
252
253	default:
254		dev_err(c->dev, "Unexpected event %d\n", event);
255		return -EINVAL;
256	}
257
258	return ret;
259}
260EXPORT_SYMBOL_GPL(axg_tdm_formatter_event);
261
262int axg_tdm_formatter_probe(struct platform_device *pdev)
263{
264	struct device *dev = &pdev->dev;
265	const struct axg_tdm_formatter_driver *drv;
266	struct axg_tdm_formatter *formatter;
267	void __iomem *regs;
268
269	drv = of_device_get_match_data(dev);
270	if (!drv) {
271		dev_err(dev, "failed to match device\n");
272		return -ENODEV;
273	}
274
275	formatter = devm_kzalloc(dev, sizeof(*formatter), GFP_KERNEL);
276	if (!formatter)
277		return -ENOMEM;
278	platform_set_drvdata(pdev, formatter);
279	formatter->drv = drv;
280
281	regs = devm_platform_ioremap_resource(pdev, 0);
282	if (IS_ERR(regs))
283		return PTR_ERR(regs);
284
285	formatter->map = devm_regmap_init_mmio(dev, regs, drv->regmap_cfg);
286	if (IS_ERR(formatter->map)) {
287		dev_err(dev, "failed to init regmap: %ld\n",
288			PTR_ERR(formatter->map));
289		return PTR_ERR(formatter->map);
290	}
291
292	/* Peripharal clock */
293	formatter->pclk = devm_clk_get(dev, "pclk");
294	if (IS_ERR(formatter->pclk))
295		return dev_err_probe(dev, PTR_ERR(formatter->pclk), "failed to get pclk\n");
296
297	/* Formatter bit clock */
298	formatter->sclk = devm_clk_get(dev, "sclk");
299	if (IS_ERR(formatter->sclk))
300		return dev_err_probe(dev, PTR_ERR(formatter->sclk), "failed to get sclk\n");
301
302	/* Formatter sample clock */
303	formatter->lrclk = devm_clk_get(dev, "lrclk");
304	if (IS_ERR(formatter->lrclk))
305		return dev_err_probe(dev, PTR_ERR(formatter->lrclk), "failed to get lrclk\n");
306
307	/* Formatter bit clock input multiplexer */
308	formatter->sclk_sel = devm_clk_get(dev, "sclk_sel");
309	if (IS_ERR(formatter->sclk_sel))
310		return dev_err_probe(dev, PTR_ERR(formatter->sclk_sel), "failed to get sclk_sel\n");
311
312	/* Formatter sample clock input multiplexer */
313	formatter->lrclk_sel = devm_clk_get(dev, "lrclk_sel");
314	if (IS_ERR(formatter->lrclk_sel))
315		return dev_err_probe(dev, PTR_ERR(formatter->lrclk_sel),
316				     "failed to get lrclk_sel\n");
317
318	/* Formatter dedicated reset line */
319	formatter->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
320	if (IS_ERR(formatter->reset))
321		return dev_err_probe(dev, PTR_ERR(formatter->reset), "failed to get reset\n");
322
323	return devm_snd_soc_register_component(dev, drv->component_drv,
324					       NULL, 0);
325}
326EXPORT_SYMBOL_GPL(axg_tdm_formatter_probe);
327
328int axg_tdm_stream_start(struct axg_tdm_stream *ts)
329{
330	struct axg_tdm_formatter *formatter;
331	int ret = 0;
332
333	mutex_lock(&ts->lock);
334	ts->ready = true;
335
336	/* Start all the formatters attached to the stream */
337	list_for_each_entry(formatter, &ts->formatter_list, list) {
338		ret = axg_tdm_formatter_enable(formatter);
339		if (ret) {
340			pr_err("failed to start tdm stream\n");
341			goto out;
342		}
343	}
344
345out:
346	mutex_unlock(&ts->lock);
347	return ret;
348}
349EXPORT_SYMBOL_GPL(axg_tdm_stream_start);
350
351void axg_tdm_stream_stop(struct axg_tdm_stream *ts)
352{
353	struct axg_tdm_formatter *formatter;
354
355	mutex_lock(&ts->lock);
356	ts->ready = false;
357
358	/* Stop all the formatters attached to the stream */
359	list_for_each_entry(formatter, &ts->formatter_list, list) {
360		axg_tdm_formatter_disable(formatter);
361	}
362
363	mutex_unlock(&ts->lock);
364}
365EXPORT_SYMBOL_GPL(axg_tdm_stream_stop);
366
367struct axg_tdm_stream *axg_tdm_stream_alloc(struct axg_tdm_iface *iface)
368{
369	struct axg_tdm_stream *ts;
370
371	ts = kzalloc(sizeof(*ts), GFP_KERNEL);
372	if (ts) {
373		INIT_LIST_HEAD(&ts->formatter_list);
374		mutex_init(&ts->lock);
375		ts->iface = iface;
376	}
377
378	return ts;
379}
380EXPORT_SYMBOL_GPL(axg_tdm_stream_alloc);
381
382void axg_tdm_stream_free(struct axg_tdm_stream *ts)
383{
384	/*
385	 * If the list is not empty, it would mean that one of the formatter
386	 * widget is still powered and attached to the interface while we
387	 * are removing the TDM DAI. It should not be possible
388	 */
389	WARN_ON(!list_empty(&ts->formatter_list));
390	mutex_destroy(&ts->lock);
391	kfree(ts);
392}
393EXPORT_SYMBOL_GPL(axg_tdm_stream_free);
394
395MODULE_DESCRIPTION("Amlogic AXG TDM formatter driver");
396MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
397MODULE_LICENSE("GPL v2");
398