drivers/acpi/acpi_amba.c

   1
   2 /*
   3  * ACPI support for platform bus type.
   4  *
   5  * Copyright (C) 2015, Linaro Ltd
   6  * Author: Graeme Gregory <graeme.gregory@linaro.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/acpi.h>
  14 #include <linux/amba/bus.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/device.h>
  18 #include <linux/err.h>
  19 #include <linux/ioport.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22
  23 #include "internal.h"
  24
  25 static const struct acpi_device_id amba_id_list[] = {
  26         {"ARMH0061", 0}, /* PL061 GPIO Device */
  27         {"", 0},
  28 };
  29
  30 static void amba_register_dummy_clk(void)
  31 {
  32         static struct clk *amba_dummy_clk;
  33
  34         /* If clock already registered */
  35         if (amba_dummy_clk)
  36                 return;
  37
  38         amba_dummy_clk = clk_register_fixed_rate(NULL, "apb_pclk", NULL,
  39                                                 CLK_IS_ROOT, 0);
  40         clk_register_clkdev(amba_dummy_clk, "apb_pclk", NULL);
  41 }
  42
  43 static int amba_handler_attach(struct acpi_device *adev,
  44                                 const struct acpi_device_id *id)
  45 {
  46         struct amba_device *dev;
  47         struct resource_entry *rentry;
  48         struct list_head resource_list;
  49         bool address_found = false;
  50         int irq_no = 0;
  51         int ret;
  52
  53         /* If the ACPI node already has a physical device attached, skip it. */
  54         if (adev->physical_node_count)
  55                 return 0;
  56
  57         dev = amba_device_alloc(dev_name(&adev->dev), 0, 0);
  58         if (!dev) {
  59                 dev_err(&adev->dev, "%s(): amba_device_alloc() failed\n",
  60                         __func__);
  61                 return -ENOMEM;
  62         }
  63
  64         INIT_LIST_HEAD(&resource_list);
  65         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
  66         if (ret < 0)
  67                 goto err_free;
  68
  69         list_for_each_entry(rentry, &resource_list, node) {
  70                 switch (resource_type(rentry->res)) {
  71                 case IORESOURCE_MEM:
  72                         if (!address_found) {
  73                                 dev->res = *rentry->res;
  74                                 address_found = true;
  75                         }
  76                         break;
  77                 case IORESOURCE_IRQ:
  78                         if (irq_no < AMBA_NR_IRQS)
  79                                 dev->irq[irq_no++] = rentry->res->start;
  80                         break;
  81                 default:
  82                         dev_warn(&adev->dev, "Invalid resource\n");
  83                         break;
  84                 }
  85         }
  86
  87         acpi_dev_free_resource_list(&resource_list);
  88
  89         /*
  90          * If the ACPI node has a parent and that parent has a physical device
  91          * attached to it, that physical device should be the parent of
  92          * the amba device we are about to create.
  93          */
  94         if (adev->parent)
  95                 dev->dev.parent = acpi_get_first_physical_node(adev->parent);
  96
  97         ACPI_COMPANION_SET(&dev->dev, adev);
  98
  99         ret = amba_device_add(dev, &iomem_resource);
 100         if (ret) {
 101                 dev_err(&adev->dev, "%s(): amba_device_add() failed (%d)\n",
 102                        __func__, ret);
 103                 goto err_free;
 104         }
 105
 106         return 1;
 107
 108 err_free:
 109         amba_device_put(dev);
 110         return ret;
 111 }
 112
 113 static struct acpi_scan_handler amba_handler = {
 114         .ids = amba_id_list,
 115         .attach = amba_handler_attach,
 116 };
 117
 118 void __init acpi_amba_init(void)
 119 {
 120         amba_register_dummy_clk();
 121         acpi_scan_add_handler(&amba_handler);
 122 }