1/*
2 * Copyright (C) 2012-2013, Analog Devices Inc.
3 * Author: Lars-Peter Clausen <lars@metafoo.de>
4 *
5 * Licensed under the GPL-2.
6 */
7
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/slab.h>
13#include <linux/of.h>
14#include <linux/clk.h>
15#include <linux/regmap.h>
16
17#include <sound/core.h>
18#include <sound/pcm.h>
19#include <sound/pcm_params.h>
20#include <sound/soc.h>
21#include <sound/initval.h>
22#include <sound/dmaengine_pcm.h>
23
24#define AXI_SPDIF_REG_CTRL	0x0
25#define AXI_SPDIF_REG_STAT	0x4
26#define AXI_SPDIF_REG_TX_FIFO	0xc
27
28#define AXI_SPDIF_CTRL_TXDATA BIT(1)
29#define AXI_SPDIF_CTRL_TXEN BIT(0)
30#define AXI_SPDIF_CTRL_CLKDIV_OFFSET 8
31#define AXI_SPDIF_CTRL_CLKDIV_MASK (0xff << 8)
32
33#define AXI_SPDIF_FREQ_44100	(0x0 << 6)
34#define AXI_SPDIF_FREQ_48000	(0x1 << 6)
35#define AXI_SPDIF_FREQ_32000	(0x2 << 6)
36#define AXI_SPDIF_FREQ_NA	(0x3 << 6)
37
38struct axi_spdif {
39	struct regmap *regmap;
40	struct clk *clk;
41	struct clk *clk_ref;
42
43	struct snd_dmaengine_dai_dma_data dma_data;
44
45	struct snd_ratnum ratnum;
46	struct snd_pcm_hw_constraint_ratnums rate_constraints;
47};
48
49static int axi_spdif_trigger(struct snd_pcm_substream *substream, int cmd,
50	struct snd_soc_dai *dai)
51{
52	struct axi_spdif *spdif = snd_soc_dai_get_drvdata(dai);
53	unsigned int val;
54
55	switch (cmd) {
56	case SNDRV_PCM_TRIGGER_START:
57	case SNDRV_PCM_TRIGGER_RESUME:
58	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
59		val = AXI_SPDIF_CTRL_TXDATA;
60		break;
61	case SNDRV_PCM_TRIGGER_STOP:
62	case SNDRV_PCM_TRIGGER_SUSPEND:
63	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
64		val = 0;
65		break;
66	default:
67		return -EINVAL;
68	}
69
70	regmap_update_bits(spdif->regmap, AXI_SPDIF_REG_CTRL,
71		AXI_SPDIF_CTRL_TXDATA, val);
72
73	return 0;
74}
75
76static int axi_spdif_hw_params(struct snd_pcm_substream *substream,
77	struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
78{
79	struct axi_spdif *spdif = snd_soc_dai_get_drvdata(dai);
80	unsigned int rate = params_rate(params);
81	unsigned int clkdiv, stat;
82
83	switch (params_rate(params)) {
84	case 32000:
85		stat = AXI_SPDIF_FREQ_32000;
86		break;
87	case 44100:
88		stat = AXI_SPDIF_FREQ_44100;
89		break;
90	case 48000:
91		stat = AXI_SPDIF_FREQ_48000;
92		break;
93	default:
94		stat = AXI_SPDIF_FREQ_NA;
95		break;
96	}
97
98	clkdiv = DIV_ROUND_CLOSEST(clk_get_rate(spdif->clk_ref),
99			rate * 64 * 2) - 1;
100	clkdiv <<= AXI_SPDIF_CTRL_CLKDIV_OFFSET;
101
102	regmap_write(spdif->regmap, AXI_SPDIF_REG_STAT, stat);
103	regmap_update_bits(spdif->regmap, AXI_SPDIF_REG_CTRL,
104		AXI_SPDIF_CTRL_CLKDIV_MASK, clkdiv);
105
106	return 0;
107}
108
109static int axi_spdif_dai_probe(struct snd_soc_dai *dai)
110{
111	struct axi_spdif *spdif = snd_soc_dai_get_drvdata(dai);
112
113	snd_soc_dai_init_dma_data(dai, &spdif->dma_data, NULL);
114
115	return 0;
116}
117
118static int axi_spdif_startup(struct snd_pcm_substream *substream,
119	struct snd_soc_dai *dai)
120{
121	struct axi_spdif *spdif = snd_soc_dai_get_drvdata(dai);
122	int ret;
123
124	ret = snd_pcm_hw_constraint_ratnums(substream->runtime, 0,
125			   SNDRV_PCM_HW_PARAM_RATE,
126			   &spdif->rate_constraints);
127	if (ret)
128		return ret;
129
130	ret = clk_prepare_enable(spdif->clk_ref);
131	if (ret)
132		return ret;
133
134	regmap_update_bits(spdif->regmap, AXI_SPDIF_REG_CTRL,
135		AXI_SPDIF_CTRL_TXEN, AXI_SPDIF_CTRL_TXEN);
136
137	return 0;
138}
139
140static void axi_spdif_shutdown(struct snd_pcm_substream *substream,
141	struct snd_soc_dai *dai)
142{
143	struct axi_spdif *spdif = snd_soc_dai_get_drvdata(dai);
144
145	regmap_update_bits(spdif->regmap, AXI_SPDIF_REG_CTRL,
146		AXI_SPDIF_CTRL_TXEN, 0);
147
148	clk_disable_unprepare(spdif->clk_ref);
149}
150
151static const struct snd_soc_dai_ops axi_spdif_dai_ops = {
152	.startup = axi_spdif_startup,
153	.shutdown = axi_spdif_shutdown,
154	.trigger = axi_spdif_trigger,
155	.hw_params = axi_spdif_hw_params,
156};
157
158static struct snd_soc_dai_driver axi_spdif_dai = {
159	.probe = axi_spdif_dai_probe,
160	.playback = {
161		.channels_min = 2,
162		.channels_max = 2,
163		.rates = SNDRV_PCM_RATE_KNOT,
164		.formats = SNDRV_PCM_FMTBIT_S16_LE,
165	},
166	.ops = &axi_spdif_dai_ops,
167};
168
169static const struct snd_soc_component_driver axi_spdif_component = {
170	.name = "axi-spdif",
171};
172
173static const struct regmap_config axi_spdif_regmap_config = {
174	.reg_bits = 32,
175	.reg_stride = 4,
176	.val_bits = 32,
177	.max_register = AXI_SPDIF_REG_STAT,
178};
179
180static int axi_spdif_probe(struct platform_device *pdev)
181{
182	struct axi_spdif *spdif;
183	struct resource *res;
184	void __iomem *base;
185	int ret;
186
187	spdif = devm_kzalloc(&pdev->dev, sizeof(*spdif), GFP_KERNEL);
188	if (!spdif)
189		return -ENOMEM;
190
191	platform_set_drvdata(pdev, spdif);
192
193	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194	base = devm_ioremap_resource(&pdev->dev, res);
195	if (IS_ERR(base))
196		return PTR_ERR(base);
197
198	spdif->regmap = devm_regmap_init_mmio(&pdev->dev, base,
199					    &axi_spdif_regmap_config);
200	if (IS_ERR(spdif->regmap))
201		return PTR_ERR(spdif->regmap);
202
203	spdif->clk = devm_clk_get(&pdev->dev, "axi");
204	if (IS_ERR(spdif->clk))
205		return PTR_ERR(spdif->clk);
206
207	spdif->clk_ref = devm_clk_get(&pdev->dev, "ref");
208	if (IS_ERR(spdif->clk_ref))
209		return PTR_ERR(spdif->clk_ref);
210
211	ret = clk_prepare_enable(spdif->clk);
212	if (ret)
213		return ret;
214
215	spdif->dma_data.addr = res->start + AXI_SPDIF_REG_TX_FIFO;
216	spdif->dma_data.addr_width = 4;
217	spdif->dma_data.maxburst = 1;
218
219	spdif->ratnum.num = clk_get_rate(spdif->clk_ref) / 128;
220	spdif->ratnum.den_step = 1;
221	spdif->ratnum.den_min = 1;
222	spdif->ratnum.den_max = 64;
223
224	spdif->rate_constraints.rats = &spdif->ratnum;
225	spdif->rate_constraints.nrats = 1;
226
227	ret = devm_snd_soc_register_component(&pdev->dev, &axi_spdif_component,
228					 &axi_spdif_dai, 1);
229	if (ret)
230		goto err_clk_disable;
231
232	ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
233	if (ret)
234		goto err_clk_disable;
235
236	return 0;
237
238err_clk_disable:
239	clk_disable_unprepare(spdif->clk);
240	return ret;
241}
242
243static int axi_spdif_dev_remove(struct platform_device *pdev)
244{
245	struct axi_spdif *spdif = platform_get_drvdata(pdev);
246
247	clk_disable_unprepare(spdif->clk);
248
249	return 0;
250}
251
252static const struct of_device_id axi_spdif_of_match[] = {
253	{ .compatible = "adi,axi-spdif-tx-1.00.a", },
254	{},
255};
256MODULE_DEVICE_TABLE(of, axi_spdif_of_match);
257
258static struct platform_driver axi_spdif_driver = {
259	.driver = {
260		.name = "axi-spdif",
261		.of_match_table = axi_spdif_of_match,
262	},
263	.probe = axi_spdif_probe,
264	.remove = axi_spdif_dev_remove,
265};
266module_platform_driver(axi_spdif_driver);
267
268MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
269MODULE_DESCRIPTION("AXI SPDIF driver");
270MODULE_LICENSE("GPL");
271