1// SPDX-License-Identifier: GPL-2.0
2//
3// Freescale ALSA SoC Machine driver utility
4//
5// Author: Timur Tabi <timur@freescale.com>
6//
7// Copyright 2010 Freescale Semiconductor, Inc.
8
9#include <linux/module.h>
10#include <linux/of_address.h>
11#include <sound/soc.h>
12
13#include "fsl_utils.h"
14
15/**
16 * fsl_asoc_get_dma_channel - determine the dma channel for a SSI node
17 *
18 * @ssi_np: pointer to the SSI device tree node
19 * @name: name of the phandle pointing to the dma channel
20 * @dai: ASoC DAI link pointer to be filled with platform_name
21 * @dma_channel_id: dma channel id to be returned
22 * @dma_id: dma id to be returned
23 *
24 * This function determines the dma and channel id for given SSI node.  It
25 * also discovers the platform_name for the ASoC DAI link.
26 */
27int fsl_asoc_get_dma_channel(struct device_node *ssi_np,
28			     const char *name,
29			     struct snd_soc_dai_link *dai,
30			     unsigned int *dma_channel_id,
31			     unsigned int *dma_id)
32{
33	struct resource res;
34	struct device_node *dma_channel_np, *dma_np;
35	const __be32 *iprop;
36	int ret;
37
38	dma_channel_np = of_parse_phandle(ssi_np, name, 0);
39	if (!dma_channel_np)
40		return -EINVAL;
41
42	if (!of_device_is_compatible(dma_channel_np, "fsl,ssi-dma-channel")) {
43		of_node_put(dma_channel_np);
44		return -EINVAL;
45	}
46
47	/* Determine the dev_name for the device_node.  This code mimics the
48	 * behavior of of_device_make_bus_id(). We need this because ASoC uses
49	 * the dev_name() of the device to match the platform (DMA) device with
50	 * the CPU (SSI) device.  It's all ugly and hackish, but it works (for
51	 * now).
52	 *
53	 * dai->platform name should already point to an allocated buffer.
54	 */
55	ret = of_address_to_resource(dma_channel_np, 0, &res);
56	if (ret) {
57		of_node_put(dma_channel_np);
58		return ret;
59	}
60	snprintf((char *)dai->platforms->name, DAI_NAME_SIZE, "%llx.%pOFn",
61		 (unsigned long long) res.start, dma_channel_np);
62
63	iprop = of_get_property(dma_channel_np, "cell-index", NULL);
64	if (!iprop) {
65		of_node_put(dma_channel_np);
66		return -EINVAL;
67	}
68	*dma_channel_id = be32_to_cpup(iprop);
69
70	dma_np = of_get_parent(dma_channel_np);
71	iprop = of_get_property(dma_np, "cell-index", NULL);
72	if (!iprop) {
73		of_node_put(dma_np);
74		of_node_put(dma_channel_np);
75		return -EINVAL;
76	}
77	*dma_id = be32_to_cpup(iprop);
78
79	of_node_put(dma_np);
80	of_node_put(dma_channel_np);
81
82	return 0;
83}
84EXPORT_SYMBOL(fsl_asoc_get_dma_channel);
85
86MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
87MODULE_DESCRIPTION("Freescale ASoC utility code");
88MODULE_LICENSE("GPL v2");
89