sound/soc/fsl/fsl_utils.c

   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  */
  27 int 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->platform_name, DAI_NAME_SIZE, "%llx.%s",
  61                  (unsigned long long) res.start, dma_channel_np->name);
  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                 return -EINVAL;
  75         }
  76         *dma_id = be32_to_cpup(iprop);
  77
  78         of_node_put(dma_np);
  79         of_node_put(dma_channel_np);
  80
  81         return 0;
  82 }
  83 EXPORT_SYMBOL(fsl_asoc_get_dma_channel);
  84
  85 MODULE_AUTHOR("Timur Tabi <timur@freescale.com>");
  86 MODULE_DESCRIPTION("Freescale ASoC utility code");
  87 MODULE_LICENSE("GPL v2");