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USB: ark3116: Setup some basic infrastructure for new ark3116 driver.
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Signed-off-by: Bart Hartgers <bart.hartgers@gmail.com>
Cc: Mike McCormack <mikem@ring3k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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bart.hartgers@gmail.com authored and Greg Kroah-Hartman committed Dec 11, 2009
1 parent a2582bd commit 149fc79
Showing 1 changed file with 182 additions and 6 deletions.
188 changes: 182 additions & 6 deletions drivers/usb/serial/ark3116.c
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Original file line number Diff line number Diff line change
@@ -1,15 +1,20 @@
/*
* Copyright (C) 2009 by Bart Hartgers (bart.hartgers+ark3116@gmail.com)
* Original version:
* Copyright (C) 2006
* Simon Schulz (ark3116_driver <at> auctionant.de)
*
* ark3116
* - 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
Expand All @@ -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) },
Expand All @@ -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)
Expand Down Expand Up @@ -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;
}
Expand All @@ -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
*/

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