LXR linux/sound/soc/fsl/fsl

   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