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From 4a84eacedc55e78c8f64a5a4f9ade6e285844b85 Mon Sep 17 00:00:00 2001
From: Ioana Ciornei <ioana.ciornei@nxp.com>
Date: Mon, 25 Jun 2018 13:19:53 +0300
Subject: [PATCH] drivers/base: add sysfs entries for suppliers and consumers
Instead of scraping dmesg for messages such as 'Linked as a consumer to'
or 'Dropping the link to' export two new sysfs entries in the device
folder that list the consumer and supplier devices.
Signed-off-by: Ioana Ciornei <ioana.ciornei@nxp.com>
---
Documentation/ABI/testing/sysfs-devices-links | 13 +++++++++
drivers/base/core.c | 42 +++++++++++++++++++++++++++
2 files changed, 55 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-devices-links
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-links
@@ -0,0 +1,13 @@
+What: /sys/devices/.../consumers
+Date: October 2018
+Contact: Ioana Ciornei <ioana.ciornei@nxp.com>
+Description:
+ Read-only attribute that lists the current "consumers" of
+ a specific device.
+
+What: /sys/devices/.../suppliers
+Date: October 2018
+Contact: Ioana Ciornei <ioana.ciornei@nxp.com>
+Description:
+ Read-only attribute that lists the current "suppliers" of
+ a specific device.
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1333,6 +1333,34 @@ static ssize_t online_store(struct devic
}
static DEVICE_ATTR_RW(online);
+static ssize_t suppliers_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct device_link *link;
+ size_t count = 0;
+
+ list_for_each_entry(link, &dev->links.suppliers, c_node)
+ count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n",
+ dev_name(link->supplier));
+
+ return count;
+}
+static DEVICE_ATTR_RO(suppliers);
+
+static ssize_t consumers_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct device_link *link;
+ size_t count = 0;
+
+ list_for_each_entry(link, &dev->links.consumers, s_node)
+ count += scnprintf(buf + count, PAGE_SIZE - count, "%s\n",
+ dev_name(link->consumer));
+
+ return count;
+}
+static DEVICE_ATTR_RO(consumers);
+
int device_add_groups(struct device *dev, const struct attribute_group **groups)
{
return sysfs_create_groups(&dev->kobj, groups);
@@ -1504,8 +1532,20 @@ static int device_add_attrs(struct devic
goto err_remove_dev_groups;
}
+ error = device_create_file(dev, &dev_attr_suppliers);
+ if (error)
+ goto err_remove_online;
+
+ error = device_create_file(dev, &dev_attr_consumers);
+ if (error)
+ goto err_remove_suppliers;
+
return 0;
+ err_remove_suppliers:
+ device_remove_file(dev, &dev_attr_suppliers);
+ err_remove_online:
+ device_remove_file(dev, &dev_attr_online);
err_remove_dev_groups:
device_remove_groups(dev, dev->groups);
err_remove_type_groups:
@@ -1523,6 +1563,8 @@ static void device_remove_attrs(struct d
struct class *class = dev->class;
const struct device_type *type = dev->type;
+ device_remove_file(dev, &dev_attr_consumers);
+ device_remove_file(dev, &dev_attr_suppliers);
device_remove_file(dev, &dev_attr_online);
device_remove_groups(dev, dev->groups);
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