diff mbox series

[net-next,28/47] can: peak_usb: export PCAN CAN channel ID as sysfs device attribute

Message ID 20230206131620.2758724-29-mkl@pengutronix.de (mailing list archive)
State Accepted
Commit 6d02f6daeb44c0099ace2e3597d56420eecfaeb2
Delegated to: Netdev Maintainers
Headers show
Series [net-next,01/47] can: gw: give feedback on missing CGW_FLAGS_CAN_IIF_TX_OK flag | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Pull request is its own cover letter
netdev/patch_count warning Series longer than 15 patches
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 4 maintainers not CCed: wg@grandegger.com edumazet@google.com mailhol.vincent@wanadoo.fr pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 96 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Marc Kleine-Budde Feb. 6, 2023, 1:16 p.m. UTC 
From: Lukas Magel <lukas.magel@posteo.net>

This patch exports the CAN channel ID as a sysfs attribute. The CAN
channel ID is a user-configurable u8/u32 identifier that can be set
individually for each CAN interface of a PEAK USB device.

Exporting the channel ID as a sysfs attribute allows users to easily read
the ID and to write udev rules that can match against the ID. This is
especially useful for PEAK USB devices that do not export a serial
number at SUB level.

Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Lukas Magel <lukas.magel@posteo.net>
Link: https://lore.kernel.org/all/20230116200932.157769-7-lukas.magel@posteo.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 .../ABI/testing/sysfs-class-net-peak_usb      | 19 ++++++++++++++
 drivers/net/can/usb/peak_usb/pcan_usb_core.c  | 25 +++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-net-peak_usb
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-class-net-peak_usb b/Documentation/ABI/testing/sysfs-class-net-peak_usb
new file mode 100644
index 000000000000..9e3d0bf4d4b2
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-net-peak_usb
@@ -0,0 +1,19 @@ 
+
+What:		/sys/class/net/<iface>/peak_usb/can_channel_id
+Date:		November 2022
+KernelVersion:	6.2
+Contact:	Stephane Grosjean <s.grosjean@peak-system.com>
+Description:
+		PEAK PCAN-USB devices support user-configurable CAN channel
+		identifiers. Contrary to a USB serial number, these identifiers
+		are writable and can be set per CAN interface. This means that
+		if a USB device exports multiple CAN interfaces, each of them
+		can be assigned a unique channel ID.
+		This attribute provides read-only access to the currently
+		configured value of the channel identifier. Depending on the
+		device type, the identifier has a length of 8 or 32 bit. The
+		value read from this attribute is always an 8 digit 32 bit
+		hexadecimal value in big endian format. If the device only
+		supports an 8 bit identifier, the upper 24 bit of the value are
+		set to zero.
+
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index 3bfd27742ae4..676923bd4213 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -15,6 +15,8 @@ 
 #include <linux/netdevice.h>
 #include <linux/usb.h>
 #include <linux/ethtool.h>
+#include <linux/sysfs.h>
+#include <linux/device.h>
 
 #include <linux/can.h>
 #include <linux/can/dev.h>
@@ -53,6 +55,26 @@  static const struct usb_device_id peak_usb_table[] = {
 
 MODULE_DEVICE_TABLE(usb, peak_usb_table);
 
+static ssize_t can_channel_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	struct peak_usb_device *peak_dev = netdev_priv(netdev);
+
+	return sysfs_emit(buf, "%08X\n", peak_dev->can_channel_id);
+}
+static DEVICE_ATTR_RO(can_channel_id);
+
+/* mutable to avoid cast in attribute_group */
+static struct attribute *peak_usb_sysfs_attrs[] = {
+	&dev_attr_can_channel_id.attr,
+	NULL,
+};
+
+static const struct attribute_group peak_usb_sysfs_group = {
+	.name	= "peak_usb",
+	.attrs	= peak_usb_sysfs_attrs,
+};
+
 /*
  * dump memory
  */
@@ -961,6 +983,9 @@  static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
 	/* add ethtool support */
 	netdev->ethtool_ops = peak_usb_adapter->ethtool_ops;
 
+	/* register peak_usb sysfs files */
+	netdev->sysfs_groups[0] = &peak_usb_sysfs_group;
+
 	init_usb_anchor(&dev->rx_submitted);
 
 	init_usb_anchor(&dev->tx_submitted);