/*
* Driver for the Diolan u2c-12 USB-I2C adapter
*
* Copyright (c) 2010-2011 Ericsson AB
*
* Derived from:
* i2c-tiny-usb.c
* Copyright (C) 2006-2007 Till Harbaum ([email protected])
*
* 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 Free Software Foundation, version 2.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#define DRIVER_NAME "i2c-diolan-u2c"
#define USB_VENDOR_ID_DIOLAN 0x0abf
#define USB_DEVICE_ID_DIOLAN_U2C 0x3370
/* commands via USB, must match command ids in the firmware */
#define CMD_I2C_READ 0x01
#define CMD_I2C_WRITE 0x02
#define CMD_I2C_SCAN 0x03 /* Returns list of detected devices */
#define CMD_I2C_RELEASE_SDA 0x04
#define CMD_I2C_RELEASE_SCL 0x05
#define CMD_I2C_DROP_SDA 0x06
#define CMD_I2C_DROP_SCL 0x07
#define CMD_I2C_READ_SDA 0x08
#define CMD_I2C_READ_SCL 0x09
#define CMD_GET_FW_VERSION 0x0a
#define CMD_GET_SERIAL 0x0b
#define CMD_I2C_START 0x0c
#define CMD_I2C_STOP 0x0d
#define CMD_I2C_REPEATED_START 0x0e
#define CMD_I2C_PUT_BYTE 0x0f
#define CMD_I2C_GET_BYTE 0x10
#define CMD_I2C_PUT_ACK 0x11
#define CMD_I2C_GET_ACK 0x12
#define CMD_I2C_PUT_BYTE_ACK 0x13
#define CMD_I2C_GET_BYTE_ACK 0x14
#define CMD_I2C_SET_SPEED 0x1b
#define CMD_I2C_GET_SPEED 0x1c
#define CMD_I2C_SET_CLK_SYNC 0x24
#define CMD_I2C_GET_CLK_SYNC 0x25
#define CMD_I2C_SET_CLK_SYNC_TO 0x26
#define CMD_I2C_GET_CLK_SYNC_TO 0x27
#define RESP_OK 0x00
#define RESP_FAILED 0x01
#define RESP_BAD_MEMADDR 0x04
#define RESP_DATA_ERR 0x05
#define RESP_NOT_IMPLEMENTED 0x06
#define RESP_NACK 0x07
#define RESP_TIMEOUT 0x09
#define U2C_I2C_SPEED_FAST 0 /* 400 kHz */
#define U2C_I2C_SPEED_STD 1 /* 100 kHz */
#define U2C_I2C_SPEED_2KHZ 242 /* 2 kHz, minimum speed */
#define U2C_I2C_SPEED(f) ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
#define U2C_I2C_FREQ_FAST 400000
#define U2C_I2C_FREQ_STD 100000
#define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))
#define DIOLAN_USB_TIMEOUT 100 /* in ms */
#define DIOLAN_SYNC_TIMEOUT 20 /* in ms */
#define DIOLAN_OUTBUF_LEN 128
#define DIOLAN_FLUSH_LEN (DIOLAN_OUTBUF_LEN - 4)
#define DIOLAN_INBUF_LEN 256 /* Maximum supported receive length */
/* Structure to hold all of our device specific stuff */
struct i2c_diolan_u2c {
u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */
u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */
int ep_in, ep_out; /* Endpoints */
struct usb_device *usb_dev; /* the usb device for this device */
struct usb_interface *interface;/* the interface for this device */
struct i2c_adapter adapter; /* i2c related things */
int olen; /* Output buffer length */
int ocount; /* Number of enqueued messages */
};
static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
module_param(frequency, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
/* usb layer */
/* Send command to device, and get response. */
static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
{
int ret = 0;
int actual;
int i;
if (!dev->olen || !dev->ocount)
return -EINVAL;
ret = usb_bulk_msg(dev->usb_dev,
usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
dev->obuffer, dev->olen, &actual,
DIOLAN_USB_TIMEOUT);
if (!ret) {
for (i = 0; i < dev->ocount; i++) {
int tmpret;
tmpret = usb_bulk_msg(dev->usb_dev,
usb_rcvbulkpipe(dev->usb_dev,
dev->ep_in),
dev->ibuffer,
sizeof(dev->ibuffer), &actual,
DIOLAN_USB_TIMEOUT);
/*
* Stop command processing if a previous command
* returned an error.
* Note that we still need to retrieve all messages.
*/
if (ret < 0)
continue;
ret = tmpret;
if (ret == 0 && actual > 0) {
switch (dev->ibuffer[actual - 1]) {
case RESP_NACK:
/*
* Return ENXIO if NACK was received as
* response to the address phase,
* EIO otherwise
*/
ret = i == 1 ? -ENXIO : -EIO;
break;
case RESP_TIMEOUT:
ret = -ETIMEDOUT;
break;
case RESP_OK:
/* strip off return code */
ret = actual - 1;
break;
default:
ret = -EIO;
break;
}
}
}
}
dev->olen = 0;
dev->ocount = 0;
return ret;
}
static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
{
if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
return diolan_usb_transfer(dev);
return 0;
}
/* Send command (no data) */
static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
{
dev->obuffer[dev->olen++] = command;
dev->ocount++;
return diolan_write_cmd(dev, flush);
}
/* Send command with one byte of data */
static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
bool flush)
{
dev->obuffer[dev->olen++] = command;
dev->obuffer[dev->olen++] = data;
dev->ocount++;
return diolan_write_cmd(dev, flush);
}
/* Send command with two bytes of data */
static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
u8 d2, bool flush)
{
dev->obuffer[dev->olen++] = command;
dev->obuffer[dev->olen++] = d1;
dev->obuffer[dev->olen++] = d2;
dev->ocount++;
return diolan_write_cmd(dev, flush);
}
/*
* Flush input queue.
* If we don't do this at startup and the controller has queued up
* messages which were not retrieved, it will stop responding
* at some point.
*/
static void diolan_flush_input(struct i2c_diolan_u2c *dev)
{
int i;
for (i = 0; i < 10; i++) {
int actual = 0;
int ret;
ret = usb_bulk_msg(dev->usb_dev,
usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
dev->ibuffer, sizeof(dev->ibuffer), &actual,
DIOLAN_USB_TIMEOUT);
if (ret < 0 || actual == 0)
break;
}
if (i == 10)
dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
}
static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
{
return diolan_usb_cmd(dev, CMD_I2C_START, false);
}
static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
{
return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
}
static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
{
return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
}
static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
u8 *byte)
{
int ret;
ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
if (ret > 0)
*byte = dev->ibuffer[0];
else if (ret == 0)
ret = -EIO;
return ret;
}
static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
{
return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
}
static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
{
return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
}
/* Enable or disable clock synchronization (stretching) */
static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
{
return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
}
/* Set clock synchronization timeout in ms */
static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
{
int to_val = ms * 10;
return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
to_val & 0xff, (to_val >> 8) & 0xff, true);
}
static void diolan_fw_version(struct i2c_diolan_u2c *dev)
{
int ret;
ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
if (ret >= 2)
dev_info(&dev->interface->dev,
"Diolan U2C firmware version %u.%u\n",
(unsigned int)dev->ibuffer[0],
(unsigned int)dev->ibuffer[1]);
}
static void diolan_get_serial(struct i2c_diolan_u2c *dev)
{
int ret;
u32 serial;
ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
if (ret >= 4) {
serial = le32_to_cpu(*(u32 *)dev->ibuffer);
dev_info(&dev->interface->dev,
"Diolan U2C serial number %u\n", serial);
}
}
static int diolan_init(struct i2c_diolan_u2c *dev)
{
int speed, ret;
if (frequency >= 200000) {
speed
