can: peak_usb: add callback to read CAN channel ID of PEAK CAN-FD devices

This patch adds a new function that allows to read the CAN channel ID
from the non volatile memory of the USB CAN-FD PEAK devices. The CAN
channel ID is a user-configurable u8/u32 identifier value that can be set
individually for each PEAK CAN interface.
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/20230116200932.157769-3-lukas.magel@posteo.netSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/peak_usb/pcan_usb_core.c

@@ -922,8 +922,7 @@ static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
 	}
 
 	/* get CAN channel id early */
-	if (dev->adapter->dev_get_can_channel_id)
-		dev->adapter->dev_get_can_channel_id(dev, &dev->can_channel_id);
+	dev->adapter->dev_get_can_channel_id(dev, &dev->can_channel_id);
 
 	netdev_info(netdev, "attached to %s channel %u (device %u)\n",
 			peak_usb_adapter->name, ctrl_idx, dev->can_channel_id);

drivers/net/can/usb/peak_usb/pcan_usb_fd.c

@@ -234,6 +234,15 @@ static int pcan_usb_fd_send_cmd(struct peak_usb_device *dev, void *cmd_tail)
 	return err;
 }
 
+static int pcan_usb_fd_read_fwinfo(struct peak_usb_device *dev,
+				   struct pcan_ufd_fw_info *fw_info)
+{
+	return pcan_usb_pro_send_req(dev, PCAN_USBPRO_REQ_INFO,
+				     PCAN_USBPRO_INFO_FW,
+				     fw_info,
+				     sizeof(*fw_info));
+}
+
 /* build the commands list in the given buffer, to enter operational mode */
 static int pcan_usb_fd_build_restart_cmd(struct peak_usb_device *dev, u8 *buf)
 {
@@ -434,6 +443,21 @@ static int pcan_usb_fd_set_bittiming_fast(struct peak_usb_device *dev,
 	return pcan_usb_fd_send_cmd(dev, ++cmd);
 }
 
+/* read user CAN channel id from device */
+static int pcan_usb_fd_get_can_channel_id(struct peak_usb_device *dev,
+					  u32 *can_ch_id)
+{
+	int err;
+	struct pcan_usb_fd_if *usb_if = pcan_usb_fd_dev_if(dev);
+
+	err = pcan_usb_fd_read_fwinfo(dev, &usb_if->fw_info);
+	if (err)
+		return err;
+
+	*can_ch_id = le32_to_cpu(usb_if->fw_info.dev_id[dev->ctrl_idx]);
+	return err;
+}
+
 /* handle restart but in asynchronously way
  * (uses PCAN-USB Pro code to complete asynchronous request)
  */
@@ -907,10 +931,7 @@ static int pcan_usb_fd_init(struct peak_usb_device *dev)
 
 		fw_info = &pdev->usb_if->fw_info;
 
-		err = pcan_usb_pro_send_req(dev, PCAN_USBPRO_REQ_INFO,
-					    PCAN_USBPRO_INFO_FW,
-					    fw_info,
-					    sizeof(*fw_info));
+		err = pcan_usb_fd_read_fwinfo(dev, fw_info);
 		if (err) {
 			dev_err(dev->netdev->dev.parent,
 				"unable to read %s firmware info (err %d)\n",
@@ -1148,6 +1169,7 @@ const struct peak_usb_adapter pcan_usb_fd = {
 	.dev_set_bus = pcan_usb_fd_set_bus,
 	.dev_set_bittiming = pcan_usb_fd_set_bittiming_slow,
 	.dev_set_data_bittiming = pcan_usb_fd_set_bittiming_fast,
+	.dev_get_can_channel_id = pcan_usb_fd_get_can_channel_id,
 	.dev_decode_buf = pcan_usb_fd_decode_buf,
 	.dev_start = pcan_usb_fd_start,
 	.dev_stop = pcan_usb_fd_stop,
@@ -1222,6 +1244,7 @@ const struct peak_usb_adapter pcan_usb_chip = {
 	.dev_set_bus = pcan_usb_fd_set_bus,
 	.dev_set_bittiming = pcan_usb_fd_set_bittiming_slow,
 	.dev_set_data_bittiming = pcan_usb_fd_set_bittiming_fast,
+	.dev_get_can_channel_id = pcan_usb_fd_get_can_channel_id,
 	.dev_decode_buf = pcan_usb_fd_decode_buf,
 	.dev_start = pcan_usb_fd_start,
 	.dev_stop = pcan_usb_fd_stop,
@@ -1296,6 +1319,7 @@ const struct peak_usb_adapter pcan_usb_pro_fd = {
 	.dev_set_bus = pcan_usb_fd_set_bus,
 	.dev_set_bittiming = pcan_usb_fd_set_bittiming_slow,
 	.dev_set_data_bittiming = pcan_usb_fd_set_bittiming_fast,
+	.dev_get_can_channel_id = pcan_usb_fd_get_can_channel_id,
 	.dev_decode_buf = pcan_usb_fd_decode_buf,
 	.dev_start = pcan_usb_fd_start,
 	.dev_stop = pcan_usb_fd_stop,
@@ -1370,6 +1394,7 @@ const struct peak_usb_adapter pcan_usb_x6 = {
 	.dev_set_bus = pcan_usb_fd_set_bus,
 	.dev_set_bittiming = pcan_usb_fd_set_bittiming_slow,
 	.dev_set_data_bittiming = pcan_usb_fd_set_bittiming_fast,
+	.dev_get_can_channel_id = pcan_usb_fd_get_can_channel_id,
 	.dev_decode_buf = pcan_usb_fd_decode_buf,
 	.dev_start = pcan_usb_fd_start,
 	.dev_stop = pcan_usb_fd_stop,