sound/soc/fsl/fsl_utils.c

   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  */
  31 int 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 }
  87 EXPORT_SYMBOL(fsl_asoc_get_dma_channel);
  88
  89 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
  90 MODULE_DESCRIPTION("Freescale ASoC utility code");
  91 MODULE_LICENSE("GPL v2");