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 contain a list of the consumer and supplier devices.
Also, lower the log level of the prints since the same information is available in the sysfs entries. Signed-off-by: Ioana Ciornei <ioana.cior...@nxp.com> --- Changes in v3: - lower the log level of prints Changes in v2: - add documentation entries for the new sysfs files Documentation/ABI/testing/sysfs-devices-links | 13 +++++++ drivers/base/core.c | 52 ++++++++++++++++++++++++--- 2 files changed, 60 insertions(+), 5 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-devices-links diff --git a/Documentation/ABI/testing/sysfs-devices-links b/Documentation/ABI/testing/sysfs-devices-links new file mode 100644 index 0000000..d3951c5 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-links @@ -0,0 +1,13 @@ +What: /sys/devices/.../consumers +Date: December 2018 +Contact: Ioana Ciornei <ioana.cior...@nxp.com> +Description: + Read-only attribute that lists the current "consumers" of + a specific device. + +What: /sys/devices/.../suppliers +Date: December 2018 +Contact: Ioana Ciornei <ioana.cior...@nxp.com> +Description: + Read-only attribute that lists the current "suppliers" of + a specific device. diff --git a/drivers/base/core.c b/drivers/base/core.c index a4ced33..5339bcf 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -301,7 +301,7 @@ struct device_link *device_link_add(struct device *consumer, list_add_tail_rcu(&link->s_node, &supplier->links.consumers); list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); - dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); + dev_dbg(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); out: device_pm_unlock(); @@ -327,8 +327,8 @@ static void __device_link_del(struct kref *kref) { struct device_link *link = container_of(kref, struct device_link, kref); - dev_info(link->consumer, "Dropping the link to %s\n", - dev_name(link->supplier)); + dev_dbg(link->consumer, "Dropping the link to %s\n", + dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); @@ -342,8 +342,8 @@ static void __device_link_del(struct kref *kref) { struct device_link *link = container_of(kref, struct device_link, kref); - dev_info(link->consumer, "Dropping the link to %s\n", - dev_name(link->supplier)); + dev_dbg(link->consumer, "Dropping the link to %s\n", + dev_name(link->supplier)); if (link->flags & DL_FLAG_PM_RUNTIME) pm_runtime_drop_link(link->consumer); @@ -1117,6 +1117,34 @@ 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); @@ -1288,8 +1316,20 @@ 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: @@ -1307,6 +1347,8 @@ 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); -- 1.9.1