target/linux/layerscape/patches-5.4/303-core-0002-drivers-base-add-sysfs-entries-for-suppliers-and-con.patch

   1 From 4a84eacedc55e78c8f64a5a4f9ade6e285844b85 Mon Sep 17 00:00:00 2001
   2 From: Ioana Ciornei <ioana.ciornei@nxp.com>
   3 Date: Mon, 25 Jun 2018 13:19:53 +0300
   4 Subject: [PATCH] drivers/base: add sysfs entries for suppliers and consumers
   5
   6 Instead of scraping dmesg for messages such as 'Linked as a consumer to'
   7 or 'Dropping the link to' export two new sysfs entries in the device
   8 folder that list the consumer and supplier devices.
   9
  10 Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
  11 ---
  12  Documentation/ABI/testing/sysfs-devices-links | 13 +++++++++
  13  drivers/base/core.c                           | 42 +++++++++++++++++++++++++++
  14  2 files changed, 55 insertions(+)
  15  create mode 100644 Documentation/ABI/testing/sysfs-devices-links
  16
  17 --- /dev/null
  18 +++ b/Documentation/ABI/testing/sysfs-devices-links
  19 @@ -0,0 +1,13 @@
  20 +What:          /sys/devices/.../consumers
  21 +Date:          October 2018
  22 +Contact:       Ioana Ciornei <ioana.ciornei@nxp.com>
  23 +Description:
  24 +               Read-only attribute that lists the current "consumers" of
  25 +               a specific device.
  26 +
  27 +What:          /sys/devices/.../suppliers
  28 +Date:          October 2018
  29 +Contact:       Ioana Ciornei <ioana.ciornei@nxp.com>
  30 +Description:
  31 +               Read-only attribute that lists the current "suppliers" of
  32 +               a specific device.
  33 --- a/drivers/base/core.c
  34 +++ b/drivers/base/core.c
  35 @@ -1333,6 +1333,34 @@ static ssize_t online_store(struct devic
  36  }
  37  static DEVICE_ATTR_RW(online);
  38
  39 +static ssize_t suppliers_show(struct device *dev, struct device_attribute *attr,
  40 +                             char *buf)
  41 +{
  42 +       struct device_link *link;
  43 +       size_t count = 0;
  44 +
  45 +       list_for_each_entry(link, &dev->links.suppliers, c_node)
  46 +               count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n",
  47 +                                  dev_name(link->supplier));
  48 +
  49 +       return count;
  50 +}
  51 +static DEVICE_ATTR_RO(suppliers);
  52 +
  53 +static ssize_t consumers_show(struct device *dev, struct device_attribute *attr,
  54 +                             char *buf)
  55 +{
  56 +       struct device_link *link;
  57 +       size_t count = 0;
  58 +
  59 +       list_for_each_entry(link, &dev->links.consumers, s_node)
  60 +               count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n",
  61 +                                  dev_name(link->consumer));
  62 +
  63 +       return count;
  64 +}
  65 +static DEVICE_ATTR_RO(consumers);
  66 +
  67  int device_add_groups(struct device *dev, const struct attribute_group **groups)
  68  {
  69         return sysfs_create_groups(&dev->kobj, groups);
  70 @@ -1504,8 +1532,20 @@ static int device_add_attrs(struct devic
  71                         goto err_remove_dev_groups;
  72         }
  73
  74 +       error = device_create_file(dev, &dev_attr_suppliers);
  75 +       if (error)
  76 +               goto err_remove_online;
  77 +
  78 +       error = device_create_file(dev, &dev_attr_consumers);
  79 +       if (error)
  80 +               goto err_remove_suppliers;
  81 +
  82         return 0;
  83
  84 + err_remove_suppliers:
  85 +       device_remove_file(dev, &dev_attr_suppliers);
  86 + err_remove_online:
  87 +       device_remove_file(dev, &dev_attr_online);
  88   err_remove_dev_groups:
  89         device_remove_groups(dev, dev->groups);
  90   err_remove_type_groups:
  91 @@ -1523,6 +1563,8 @@ static void device_remove_attrs(struct d
  92         struct class *class = dev->class;
  93         const struct device_type *type = dev->type;
  94
  95 +       device_remove_file(dev, &dev_attr_consumers);
  96 +       device_remove_file(dev, &dev_attr_suppliers);
  97         device_remove_file(dev, &dev_attr_online);
  98         device_remove_groups(dev, dev->groups);
  99