LXR linux/sound/soc/fsl/fsl

   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