On 10/27/2020 3:43 AM, carl.yin@xxxxxxxxxxx wrote:
From: "carl.yin" <carl.yin@xxxxxxxxxxx>
User space software like ModemManager can identify the function
of the mhi chan device by ul_chan_id.
Signed-off-by: carl.yin <carl.yin@xxxxxxxxxxx>
---
Documentation/ABI/stable/sysfs-bus-mhi | 10 ++++++++++
drivers/bus/mhi/core/init.c | 15 +++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/Documentation/ABI/stable/sysfs-bus-mhi b/Documentation/ABI/stable/sysfs-bus-mhi
index ecfe766..6d52768 100644
--- a/Documentation/ABI/stable/sysfs-bus-mhi
+++ b/Documentation/ABI/stable/sysfs-bus-mhi
@@ -19,3 +19,13 @@ Description: The file holds the OEM PK Hash value of the endpoint device
read without having the device power on at least once, the file
will read all 0's.
Users: Any userspace application or clients interested in device info.
+
+What: /sys/bus/mhi/devices/.../ul_chan_id
+Date: November 2020
+KernelVersion: 5.10
+Contact: Carl Yin <carl.yin@xxxxxxxxxxx>
+Description: The file holds the uplink chan id of the mhi chan device.
+ User space software like ModemManager can identify the function of
+ the mhi chan device. If the mhi device is not a chan device,
+ eg mhi controller device, the file read -1.
+Users: Any userspace application or clients interested in device info.
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index c6b43e9..ac4aa5c 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -105,9 +105,24 @@ static ssize_t oem_pk_hash_show(struct device *dev,
}
static DEVICE_ATTR_RO(oem_pk_hash);
+static ssize_t ul_chan_id_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct mhi_device *mhi_dev = to_mhi_device(dev);
+ int ul_chan_id = -1;
+
+ if (mhi_dev->ul_chan)
+ ul_chan_id = mhi_dev->ul_chan_id;
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", ul_chan_id);
+}
+static DEVICE_ATTR_RO(ul_chan_id);
+
static struct attribute *mhi_dev_attrs[] = {
&dev_attr_serial_number.attr,
&dev_attr_oem_pk_hash.attr,
+ &dev_attr_ul_chan_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(mhi_dev);
NACK
Channel ID is a device specific detail. Userspace should be basing
decisions on the channel name.
--
Jeffrey Hugo
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
