[PATCH 5.4 10/90] PM / devfreq: Add new name attribute for sysfs

Greg Kroah-Hartman
2020-02-03T16:34:10Z

From: Chanwoo Choi <cw00.choi@samsung.com>

commit 2fee1a7cc6b1ce6634bb0f025be2c94a58dfa34d upstream.

The commit 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for
sysfs") changed the node name to devfreq(x). After this commit, it is not
possible to get the device name through /sys/class/devfreq/devfreq(X)/*.

Add new name attribute in order to get device name.

Cc: stable@vger.kernel.org
Fixes: 4585fbcb5331 ("PM / devfreq: Modify the device name as devfreq(X) for sysfs")
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
Documentation/ABI/testing/sysfs-class-devfreq | 7 +++++++
drivers/devfreq/devfreq.c | 9 +++++++++
2 files changed, 16 insertions(+)

--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -7,6 +7,13 @@ Description:
The name of devfreq object denoted as ... is same as the
name of device using devfreq.

+What: /sys/class/devfreq/.../name
+Date: November 2019
+Contact: Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+ The /sys/class/devfreq/.../name shows the name of device
+ of the corresponding devfreq object.
+
What: /sys/class/devfreq/.../governor
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1112,6 +1112,14 @@ err_out:
}
EXPORT_SYMBOL(devfreq_remove_governor);

+static ssize_t name_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *devfreq = to_devfreq(dev);
+ return sprintf(buf, "%s\n", dev_name(devfreq->dev.parent));
+}
+static DEVICE_ATTR_RO(name);
+
static ssize_t governor_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1440,6 +1448,7 @@ static ssize_t trans_stat_show(struct de
static DEVICE_ATTR_RO(trans_stat);

static struct attribute *devfreq_attrs[] = {
+ &dev_attr_name.attr,
&dev_attr_governor.attr,
&dev_attr_available_governors.attr,
&dev_attr_cur_freq.attr,