drivers/dma/sh/shdma-of.c

   1 /*
   2  * SHDMA Device Tree glue
   3  *
   4  * Copyright (C) 2013 Renesas Electronics Inc.
   5  * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   6  *
   7  * This is free software; you can redistribute it and/or modify
   8  * it under the terms of version 2 of the GNU General Public License as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/dmaengine.h>
  13 #include <linux/module.h>
  14 #include <linux/of.h>
  15 #include <linux/of_dma.h>
  16 #include <linux/of_platform.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/shdma-base.h>
  19
  20 #define to_shdma_chan(c) container_of(c, struct shdma_chan, dma_chan)
  21
  22 static struct dma_chan *shdma_of_xlate(struct of_phandle_args *dma_spec,
  23                                        struct of_dma *ofdma)
  24 {
  25         u32 id = dma_spec->args[0];
  26         dma_cap_mask_t mask;
  27         struct dma_chan *chan;
  28
  29         if (dma_spec->args_count != 1)
  30                 return NULL;
  31
  32         dma_cap_zero(mask);
  33         /* Only slave DMA channels can be allocated via DT */
  34         dma_cap_set(DMA_SLAVE, mask);
  35
  36         chan = dma_request_channel(mask, shdma_chan_filter, (void *)id);
  37         if (chan)
  38                 to_shdma_chan(chan)->hw_req = id;
  39
  40         return chan;
  41 }
  42
  43 static int shdma_of_probe(struct platform_device *pdev)
  44 {
  45         const struct of_dev_auxdata *lookup = pdev->dev.platform_data;
  46         int ret;
  47
  48         if (!lookup)
  49                 return -EINVAL;
  50
  51         ret = of_dma_controller_register(pdev->dev.of_node,
  52                                          shdma_of_xlate, pdev);
  53         if (ret < 0)
  54                 return ret;
  55
  56         ret = of_platform_populate(pdev->dev.of_node, NULL, lookup, &pdev->dev);
  57         if (ret < 0)
  58                 of_dma_controller_free(pdev->dev.of_node);
  59
  60         return ret;
  61 }
  62
  63 static const struct of_device_id shdma_of_match[] = {
  64         { .compatible = "renesas,shdma-mux", },
  65         { }
  66 };
  67 MODULE_DEVICE_TABLE(of, sh_dmae_of_match);
  68
  69 static struct platform_driver shdma_of = {
  70         .driver         = {
  71                 .owner  = THIS_MODULE,
  72                 .name   = "shdma-of",
  73                 .of_match_table = shdma_of_match,
  74         },
  75         .probe          = shdma_of_probe,
  76 };
  77
  78 module_platform_driver(shdma_of);
  79
  80 MODULE_LICENSE("GPL v2");
  81 MODULE_DESCRIPTION("SH-DMA driver DT glue");
  82 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");