USB: ark3116: Setup some basic infrastructure for new ark3116 driver. (149fc791) · Commits · e / devices / android_kernel_oneplus_sm8150

drivers/usb/serial/ark3116.c

+182 −6

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
		* Original version:
		* Copyright (C) 2006
		* Simon Schulz (ark3116_driver <at> auctionant.de)
		*
		@@ -6,10 +8,13 @@
		* - implements a driver for the arkmicro ark3116 chipset (vendor=0x6547,
		* productid=0x0232) (used in a datacable called KQ-U8A)
		*
		* - based on code by krisfx -> thanks !!
		* (see http://www.linuxquestions.org/questions/showthread.php?p=2184457#post2184457)
		* Supports full modem status lines, break, hardware flow control. Does not
		* support software flow control, since I do not know how to enable it in hw.
		*
		* - based on logs created by usbsnoopy
		* This driver is a essentially new implementation. I initially dug
		* into the old ark3116.c driver and suddenly realized the ark3116 is
		* a 16450 with a USB interface glued to it. See comments at the
		* bottom of this file.
		*
		* This program is free software; you can redistribute it and/or modify it
		* under the terms of the GNU General Public License as published by the
		@@ -19,15 +24,31 @@

		#include <linux/kernel.h>
		#include <linux/init.h>
		#include <linux/ioctl.h>
		#include <linux/tty.h>
		#include <linux/tty_flip.h>
		#include <linux/module.h>
		#include <linux/usb.h>
		#include <linux/usb/serial.h>
		#include <linux/serial.h>
		#include <linux/serial_reg.h>
		#include <linux/uaccess.h>

		#include <linux/mutex.h>
		#include <linux/spinlock.h>

		static int debug;
		/*
		* Version information
		*/

		#define DRIVER_VERSION "v0.5"
		#define DRIVER_AUTHOR "Bart Hartgers <bart.hartgers+ark3116@gmail.com>"
		#define DRIVER_DESC "USB ARK3116 serial/IrDA driver"
		#define DRIVER_DEV_DESC "ARK3116 RS232/IrDA"
		#define DRIVER_NAME "ark3116"

		/* usb timeout of 1 second */
		#define ARK_TIMEOUT (1*HZ)

		static struct usb_device_id id_table [] = {
		{ USB_DEVICE(0x6547, 0x0232) },
		@@ -45,6 +66,53 @@ static int is_irda(struct usb_serial *serial)
		return 0;
		}

		struct ark3116_private {
		wait_queue_head_t delta_msr_wait;
		struct async_icount icount;
		int irda; /* 1 for irda device */

		/* protects hw register updates */
		struct mutex hw_lock;

		int quot; /* baudrate divisor */
		__u32 lcr; /* line control register value */
		__u32 hcr; /* handshake control register (0x8)
		* value */
		__u32 mcr; /* modem contol register value */

		/* protects the status values below */
		spinlock_t status_lock;
		__u32 msr; /* modem status register value */
		__u32 lsr; /* line status register value */
		};

		static int ark3116_write_reg(struct usb_serial *serial,
		unsigned reg, __u8 val)
		{
		int result;
		/* 0xfe 0x40 are magic values taken from original driver */
		result = usb_control_msg(serial->dev,
		usb_sndctrlpipe(serial->dev, 0),
		0xfe, 0x40, val, reg,
		NULL, 0, ARK_TIMEOUT);
		return result;
		}

		static int ark3116_read_reg(struct usb_serial *serial,
		unsigned reg, unsigned char *buf)
		{
		int result;
		/* 0xfe 0xc0 are magic values taken from original driver */
		result = usb_control_msg(serial->dev,
		usb_rcvctrlpipe(serial->dev, 0),
		0xfe, 0xc0, 0, reg,
		buf, 1, ARK_TIMEOUT);
		if (result < 0)
		return result;
		else
		return buf[0];
		}

		static inline void ARK3116_SND(struct usb_serial *serial, int seq,
		__u8 request, __u8 requesttype,
		__u16 value, __u16 index)
		@@ -465,7 +533,12 @@ static int __init ark3116_init(void)
		if (retval)
		return retval;
		retval = usb_register(&ark3116_driver);
		if (retval)
		if (retval == 0) {
		printk(KERN_INFO "%s:"
		DRIVER_VERSION ":"
		DRIVER_DESC "\n",
		KBUILD_MODNAME);
		} else
		usb_serial_deregister(&ark3116_device);
		return retval;
		}
		@@ -480,6 +553,109 @@ module_init(ark3116_init);
		module_exit(ark3116_exit);
		MODULE_LICENSE("GPL");

		MODULE_AUTHOR(DRIVER_AUTHOR);
		MODULE_DESCRIPTION(DRIVER_DESC);

		module_param(debug, bool, S_IRUGO \| S_IWUSR);
		MODULE_PARM_DESC(debug, "Debug enabled or not");
		MODULE_PARM_DESC(debug, "Enable debug");

		/*
		* The following describes what I learned from studying the old
		* ark3116.c driver, disassembling the windows driver, and some lucky
		* guesses. Since I do not have any datasheet or other
		* documentation, inaccuracies are almost guaranteed.
		*
		* Some specs for the ARK3116 can be found here:
		* http://web.archive.org/web/20060318000438/
		* www.arkmicro.com/en/products/view.php?id=10
		* On that page, 2 GPIO pins are mentioned: I assume these are the
		* OUT1 and OUT2 pins of the UART, so I added support for those
		* through the MCR. Since the pins are not available on my hardware,
		* I could not verify this.
		* Also, it states there is "on-chip hardware flow control". I have
		* discovered how to enable that. Unfortunately, I do not know how to
		* enable XON/XOFF (software) flow control, which would need support
		* from the chip as well to work. Because of the wording on the web
		* page there is a real possibility the chip simply does not support
		* software flow control.
		*
		* I got my ark3116 as part of a mobile phone adapter cable. On the
		* PCB, the following numbered contacts are present:
		*
		* 1:- +5V
		* 2:o DTR
		* 3:i RX
		* 4:i DCD
		* 5:o RTS
		* 6:o TX
		* 7:i RI
		* 8:i DSR
		* 10:- 0V
		* 11:i CTS
		*
		* On my chip, all signals seem to be 3.3V, but 5V tolerant. But that
		* may be different for the one you have ;-).
		*
		* The windows driver limits the registers to 0-F, so I assume there
		* are actually 16 present on the device.
		*
		* On an UART interrupt, 4 bytes of data come in on the interrupt
		* endpoint. The bytes are 0xe8 IIR LSR MSR.
		*
		* The baudrate seems to be generated from the 12MHz crystal, using
		* 4-times subsampling. So quot=12e6/(4*baud). Also see description
		* of register E.
		*
		* Registers 0-7:
		* These seem to be the same as for a regular 16450. The FCR is set
		* to UART_FCR_DMA_SELECT (0x8), I guess to enable transfers between
		* the UART and the USB bridge/DMA engine.
		*
		* Register 8:
		* By trial and error, I found out that bit 0 enables hardware CTS,
		* stopping TX when CTS is +5V. Bit 1 does the same for RTS, making
		* RTS +5V when the 3116 cannot transfer the data to the USB bus
		* (verified by disabling the reading URB). Note that as far as I can
		* tell, the windows driver does NOT use this, so there might be some
		* hardware bug or something.
		*
		* According to a patch provided here
		* (http://lkml.org/lkml/2009/7/26/56), the ARK3116 can also be used
		* as an IrDA dongle. Since I do not have such a thing, I could not
		* investigate that aspect. However, I can speculate ;-).
		*
		* - IrDA encodes data differently than RS232. Most likely, one of
		* the bits in registers 9..E enables the IR ENDEC (encoder/decoder).
		* - Depending on the IR transceiver, the input and output need to be
		* inverted, so there are probably bits for that as well.
		* - IrDA is half-duplex, so there should be a bit for selecting that.
		*
		* This still leaves at least two registers unaccounted for. Perhaps
		* The chip can do XON/XOFF or CRC in HW?
		*
		* Register 9:
		* Set to 0x00 for IrDA, when the baudrate is initialised.
		*
		* Register A:
		* Set to 0x01 for IrDA, at init.
		*
		* Register B:
		* Set to 0x01 for IrDA, 0x00 for RS232, at init.
		*
		* Register C:
		* Set to 00 for IrDA, at init.
		*
		* Register D:
		* Set to 0x41 for IrDA, at init.
		*
		* Register E:
		* Somekind of baudrate override. The windows driver seems to set
		* this to 0x00 for normal baudrates, 0x01 for 460800, 0x02 for 921600.
		* Since 460800 and 921600 cannot be obtained by dividing 3MHz by an integer,
		* it could be somekind of subdivisor thingy.
		* However,it does not seem to do anything: selecting 921600 (divisor 3,
		* reg E=2), still gets 1 MHz. I also checked if registers 9, C or F would
		* work, but they don't.
		*
		* Register F: unknown
		*/