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Shawn Guo60aae8d2012-03-16 16:56:40 +08001/**
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>
Shawn Guo60aae8d2012-03-16 16:56:40 +080015#include <sound/soc.h>
16
17#include "fsl_utils.h"
18
19/**
Shawn Guo60aae8d2012-03-16 16:56:40 +080020 * 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");