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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>
5.4-rM2-2.2.x-imx-squashed
Ioana Ciornei 2018-06-25 13:19:53 +03:00 committed by Dong Aisheng
parent 21187fcd08
commit df3e8521e0
2 changed files with 55 additions and 0 deletions
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13
Documentation/ABI/testing/sysfs-devices-links 100644
View File

@ -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.

42
drivers/base/core.c
View File

@ -1320,6 +1320,34 @@ static ssize_t online_store(struct device *dev, struct device_attribute *attr,
}
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);
@ -1491,8 +1519,20 @@ static int device_add_attrs(struct device *dev)
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:
@ -1510,6 +1550,8 @@ static void device_remove_attrs(struct device *dev)
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);