can: usb: f81604: add Fintek F81604 support

This patch adds support for Fintek USB to 2CAN controller.

Changelog:
v7: https://lore.kernel.org/all/20230509073821.25289-1-peter_hong@fintek.com.tw
  1. Fix consistency of coding style for "break" in f81604_register_urbs().
  2. Remove goto statement in f81604_open().

v6: https://lore.kernel.org/all/20230505022317.22417-1-peter_hong@fintek.com.tw
  1. Remove non-used define and change constant mask to GENMASK().
  2. Move some variables declaration from function start to block start.
  3. Move some variables initization into declaration.
  4. Change variable "id" in f81604_start_xmit() only for CAN ID usage.

v5: https://lore.kernel.org/all/20230420024403.13830-1-peter_hong@fintek.com.tw
  1. Change all u8 *buff to struct f81604_int_data/f81604_can_frame.
  2. Change all netdev->dev_id to netdev->dev_port.
  3. Remove over design for f81604_process_rx_packet(). This device only
     report a frame at once, so the f81604_process_rx_packet() are reduced
     to process 1 frame.

v4: https://lore.kernel.org/all/20230413084253.1524-1-peter_hong@fintek.com.tw
  1. Remove f81604_prepare_urbs/f81604_remove_urbs() and alloc URB/buffer
     dynamically in f81604_register_urbs(), using "urbs_anchor" for manage
     all rx/int URBs.
  2. Add F81604 to MAINTAINERS list.
  3. Change handle_clear_reg_work/handle_clear_overrun_work to single
     clear_reg_work and using bitwise "clear_flags" to record it.
  4. Move __f81604_set_termination in front of f81604_probe() to avoid
     rarely racing condition.
  5. Add __aligned to struct f81604_int_data / f81604_sff / f81604_eff.
  6. Add aligned operations in f81604_start_xmit/f81604_process_rx_packet().
  7. Change lots of CANBUS functions first parameter from struct usb_device*
     to struct f81604_port_priv *priv. But remain f81604_write / f81604_read
     / f81604_update_bits() as struct usb_device* for
     __f81604_set_termination() in probe() stage.
  8. Simplify f81604_read_int_callback() and separate into
     f81604_handle_tx / f81604_handle_can_bus_errors() functions.

v3: https://lore.kernel.org/all/20230327051048.11589-1-peter_hong@fintek.com.tw
  1. Change CAN clock to using MEGA units.
  2. Remove USB set/get retry, only remain SJA1000 reset/operation retry.
  3. Fix all numberic constant to define.
  4. Add terminator control. (only 0 & 120 ohm)
  5. Using struct data to represent INT/TX/RX endpoints data instead byte
     arrays.
  6. Error message reports changed from %d to %pe for mnemotechnic values.
  7. Some bit operations are changed to FIELD_PREP().
  8. Separate TX functions from f81604_read_int_callback().
  9. cf->can_id |= CAN_ERR_CNT in f81604_read_int_callback to report valid
     TX/RX error counts.
  10. Move f81604_prepare_urbs/f81604_remove_urbs() from CAN open/close() to
      USB probe/disconnect().
  11. coding style refactoring.

v2: https://lore.kernel.org/all/20230321081152.26510-1-peter_hong@fintek.com.tw
  1. coding style refactoring.
  2. some const number are defined to describe itself.
  3. fix wrong usage for can_get_echo_skb() in f81604_write_bulk_callback().

v1: https://lore.kernel.org/all/20230317093352.3979-1-peter_hong@fintek.com.twSigned-off-by: Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/all/20230509073821.25289-1-peter_hong@fintek.com.tw
[mkl: add changelog, fix printf format]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

MAINTAINERS

@@ -7966,6 +7966,12 @@ S:	Maintained
 F:	drivers/hwmon/f75375s.c
 F:	include/linux/f75375s.h
 
+FINTEK F81604 USB to 2xCANBUS DEVICE DRIVER
+M:	Ji-Ze Hong (Peter Hong) <peter_hong@fintek.com.tw>
+L:	linux-can@vger.kernel.org
+S:	Maintained
+F:	drivers/net/can/usb/f81604.c
+
 FIREWIRE AUDIO DRIVERS and IEC 61883-1/6 PACKET STREAMING ENGINE
 M:	Clemens Ladisch <clemens@ladisch.de>
 M:	Takashi Sakamoto <o-takashi@sakamocchi.jp>

drivers/net/can/usb/Kconfig

@@ -38,6 +38,18 @@ config CAN_ETAS_ES58X
 	  To compile this driver as a module, choose M here: the module
 	  will be called etas_es58x.
 
+config CAN_F81604
+        tristate "Fintek F81604 USB to 2CAN interface"
+        help
+          This driver supports the Fintek F81604 USB to 2CAN interface.
+          The device can support CAN2.0A/B protocol and also support
+          2 output pins to control external terminator (optional).
+
+          To compile this driver as a module, choose M here: the module will
+          be called f81604.
+
+          (see also https://www.fintek.com.tw).
+
 config CAN_GS_USB
 	tristate "Geschwister Schneider UG and candleLight compatible interfaces"
 	help

drivers/net/can/usb/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_CAN_8DEV_USB) += usb_8dev.o
 obj-$(CONFIG_CAN_EMS_USB) += ems_usb.o
 obj-$(CONFIG_CAN_ESD_USB) += esd_usb.o
 obj-$(CONFIG_CAN_ETAS_ES58X) += etas_es58x/
+obj-$(CONFIG_CAN_F81604) += f81604.o
 obj-$(CONFIG_CAN_GS_USB) += gs_usb.o
 obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb/
 obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o