1/**
2 * Freescale ALSA SoC Machine driver utility
3 *
4 * Author: Timur Tabi <timur@freescale.com>
5 *
6 * Copyright 2010 Freescale Semiconductor, Inc.
7 *
8 * This file is licensed under the terms of the GNU General Public License
9 * version 2.  This program is licensed "as is" without any warranty of any
10 * kind, whether express or implied.
11 */
12
13#include <linux/module.h>
14#include <linux/of_address.h>
15#include <sound/soc.h>
16
17#include "fsl_utils.h"
18
19/**
20 * fsl_asoc_get_dma_channel - determine the dma channel for a SSI node
21 *
22 * @ssi_np: pointer to the SSI device tree node
23 * @name: name of the phandle pointing to the dma channel
24 * @dai: ASoC DAI link pointer to be filled with platform_name
25 * @dma_channel_id: dma channel id to be returned
26 * @dma_id: dma id to be returned
27 *
28 * This function determines the dma and channel id for given SSI node.  It
29 * also discovers the platform_name for the ASoC DAI link.
30 */
31int fsl_asoc_get_dma_channel(struct device_node *ssi_np,
32			     const char *name,
33			     struct snd_soc_dai_link *dai,
34			     unsigned int *dma_channel_id,
35			     unsigned int *dma_id)
36{
37	struct resource res;
38	struct device_node *dma_channel_np, *dma_np;
39	const u32 *iprop;
40	int ret;
41
42	dma_channel_np = of_parse_phandle(ssi_np, name, 0);
43	if (!dma_channel_np)
44		return -EINVAL;
45
46	if (!of_device_is_compatible(dma_channel_np, "fsl,ssi-dma-channel")) {
47		of_node_put(dma_channel_np);
48		return -EINVAL;
49	}
50
51	/* Determine the dev_name for the device_node.  This code mimics the
52	 * behavior of of_device_make_bus_id(). We need this because ASoC uses
53	 * the dev_name() of the device to match the platform (DMA) device with
54	 * the CPU (SSI) device.  It's all ugly and hackish, but it works (for
55	 * now).
56	 *
57	 * dai->platform name should already point to an allocated buffer.
58	 */
59	ret = of_address_to_resource(dma_channel_np, 0, &res);
60	if (ret) {
61		of_node_put(dma_channel_np);
62		return ret;
63	}
64	snprintf((char *)dai->platform_name, DAI_NAME_SIZE, "%llx.%s",
65		 (unsigned long long) res.start, dma_channel_np->name);
66
67	iprop = of_get_property(dma_channel_np, "cell-index", NULL);
68	if (!iprop) {
69		of_node_put(dma_channel_np);
70		return -EINVAL;
71	}
72	*dma_channel_id = be32_to_cpup(iprop);
73
74	dma_np = of_get_parent(dma_channel_np);
75	iprop = of_get_property(dma_np, "cell-index", NULL);
76	if (!iprop) {
77		of_node_put(dma_np);
78		return -EINVAL;
79	}
80	*dma_id = be32_to_cpup(iprop);
81
82	of_node_put(dma_np);
83	of_node_put(dma_channel_np);
84
85	return 0;
86}
87EXPORT_SYMBOL(fsl_asoc_get_dma_channel);
88
89MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
90MODULE_DESCRIPTION("Freescale ASoC utility code");
91MODULE_LICENSE("GPL v2");
92