- 根目录:
- drivers
- i2c
- busses
- i2c-viperboard.c
/*
* Nano River Technologies viperboard i2c master driver
*
* (C) 2012 by Lemonage GmbH
* Author: Lars Poeschel <poeschel@lemonage.de>
* All rights reserved.
*
* 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; either version 2 of the License, or (at your
* option) any later version.
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include <linux/mfd/viperboard.h>
struct vprbrd_i2c {
struct i2c_adapter i2c;
u8 bus_freq_param;
};
/* i2c bus frequency module parameter */
static u8 i2c_bus_param;
static unsigned int i2c_bus_freq = 100;
module_param(i2c_bus_freq, int, 0);
MODULE_PARM_DESC(i2c_bus_freq,
"i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");
static int vprbrd_i2c_status(struct i2c_adapter *i2c,
struct vprbrd_i2c_status *status, bool prev_error)
{
u16 bytes_xfer;
int ret;
struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
/* check for protocol error */
bytes_xfer = sizeof(struct vprbrd_i2c_status);
ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,
status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);
if (ret != bytes_xfer)
prev_error = true;
if (prev_error) {
dev_err(&i2c->dev, "failure in usb communication\n");
return -EREMOTEIO;
}
dev_dbg(&i2c->dev, " status = %d\n", status->status);
if (status->status != 0x00) {
dev_err(&i2c->dev, "failure: i2c protocol error\n");
return -EPROTO;
}
return 0;
}
static int vprbrd_i2c_receive(struct usb_device *usb_dev,
struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)
{
int ret, bytes_actual;
int error = 0;
/* send the read request */
ret = usb_bulk_msg(usb_dev,
usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,
sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,
VPRBRD_USB_TIMEOUT_MS);
if ((ret < 0)
|| (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {
dev_err(&usb_dev->dev, "failure transmitting usb\n");
error = -EREMOTEIO;
}
/* read the actual data */
ret = usb_bulk_msg(usb_dev,
usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,
bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
if ((ret < 0) || (bytes_xfer != bytes_actual)) {
dev_err(&usb_dev->dev, "failure receiving usb\n");
error = -EREMOTEIO;
}
return error;
}
static int vprbrd_i2c_addr(struct usb_device *usb_dev,
struct vprbrd_i2c_addr_msg *amsg)
{
int ret, bytes_actual;
ret = usb_bulk_msg(usb_dev,
usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,
sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,
VPRBRD_USB_TIMEOUT_MS);
if ((ret < 0) ||
(sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {
dev_err(&usb_dev->dev, "failure transmitting usb\n");
return -EREMOTEIO;
}
return 0;
}
static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
{
int ret;
u16 remain_len, len1, len2, start = 0x0000;
struct vprbrd_i2c_read_msg *rmsg =
(struct vprbrd_i2c_read_msg *)vb->buf;
remain_len = msg->len;
rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
while (remain_len > 0) {
rmsg->header.addr = cpu_to_le16(start + 0x4000);
if (remain_len <= 255) {
len1 = remain_len;
len2 = 0x00;
rmsg->header.len0 = remain_len;
rmsg->header.len1 = 0x00;
rmsg->header.len2 = 0x00;
rmsg->header.len3 = 0x00;
rmsg->header.len4 = 0x00;
rmsg->header.len5 = 0x00;
remain_len = 0;
} else if (remain_len <= 510) {
len1 = remain_len;
len2 = 0x00;
rmsg->header.len0 = remain_len - 255;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0x00;
rmsg->header.len3 = 0x00;
rmsg->header.len4 = 0x00;
rmsg->header.len5 = 0x00;
remain_len = 0;
} else if (remain_len <= 512) {
len1 = remain_len;
len2 = 0x00;
rmsg->header.len0 = remain_len - 510;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0xff;
rmsg->header.len3 = 0x00;
rmsg->header.len4 = 0x00;
rmsg->header.len5 = 0x00;
remain_len = 0;
} else if (remain_len <= 767) {
len1 = 512;
len2 = remain_len - 512;
rmsg->header.len0 = 0x02;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0xff;
rmsg->header.len3 = remain_len - 512;
rmsg->header.len4 = 0x00;
rmsg->header.len5 = 0x00;
remain_len = 0;
} else if (remain_len <= 1022) {
len1 = 512;
len2 = remain_len - 512;
rmsg->header.len0 = 0x02;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0xff;
rmsg->header.len3 = remain_len - 767;
rmsg->header.len4 = 0xff;
rmsg->header.len5 = 0x00;
remain_len = 0;
} else if (remain_len <= 1024) {
len1 = 512;
len2 = remain_len - 512;
rmsg->header.len0 = 0x02;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0xff;
rmsg->header.len3 = remain_len - 1022;
rmsg->header.len4 = 0xff;
rmsg->header.len5 = 0xff;
remain_len = 0;
} else {
len1 = 512;
len2 = 512;
rmsg->header.len0 = 0x02;
rmsg->header.len1 = 0xff;
rmsg->header.len2 = 0xff;
rmsg->header.len3 = 0x02;
rmsg->header.len4 = 0xff;
rmsg->header.len5 = 0xff;
remain_len -= 1024;
start += 1024;
}
rmsg->header.tf1 = cpu_to_le16(len1);
rmsg->header.tf2 = cpu_to_le16(len2);
/* first read transfer */
ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
if (ret < 0)
return ret;
/* copy the received data */
memcpy(msg->buf + start, rmsg, len1);
/* second read transfer if neccessary */
if (len2 > 0) {
ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
if (ret < 0)
return ret;
/* copy the received data */
memcpy(msg->buf + start + 512, rmsg, len2);
}
}
return 0;
}
static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)
{
int ret, bytes_actual;
u16 remain_len, bytes_xfer,
start = 0x0000;
struct vprbrd_i2c_write_msg *wmsg =
(struct vprbrd_i2c_write_msg *)vb->buf;
remain_len = msg->len;
wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;
wmsg->header.last = 0x00;
wmsg->header.chan = 0x00;
wmsg->header.spi = 0x0000;
while (remain_len > 0) {
wmsg->header.addr = cpu_to_le16(start + 0x4000);
if (remain_len > 503) {
wmsg->header.len1 = 0xff;
wmsg->header.len2 = 0xf8;
remain_len -= 503;
bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);
start += 503;
} else if (remain_len > 255) {
wmsg->header.len1 = 0xff;
wmsg->header.len2 = (remain_len - 255);
bytes_xfer = remain_len +
sizeof(struct vprbrd_i2c_write_hdr);
remain_len = 0;
} else {
wmsg->header.len1 = remain_len;
wmsg->header.len2 = 0x00;
bytes_xfer = remain_len +
sizeof(struct vprbrd_i2c_write_hdr);
remain_len = 0;
}
memcpy(wmsg->data, msg->buf + start,
bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));
ret = usb_bulk_msg(vb->usb_dev,
usb_sndbulkpipe(vb->usb_dev,
VPRBRD_EP_OUT), wmsg,
bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
if ((ret < 0) || (bytes_xfer != bytes_actual))
return -EREMOTEIO;
}
return 0;
}
static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
int num)
{
struct i2c_msg *pmsg;
int i, ret,
error = 0;
struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
struct vprbrd_i2c_addr_msg *amsg =
(struct vprbrd_i2c_addr_msg *)vb->buf;
struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;
dev_dbg(&i2c->dev, "master xfer %d messages:\n", num);
for (i = 0 ; i < num ; i++) {
pmsg = &msgs[i];
dev_dbg(&i2c->dev,
" %d: %s (flags %d) %d bytes to 0x%02x\n",
i, pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->flags, pmsg->len, pmsg->addr);
mutex_lock(&vb->lock);
/* directly send the message */
if (pmsg->flags & I2C_M_RD) {
/* read data */
amsg->cmd = VPRBRD_I2C_CMD_ADDR;
amsg->unknown2 = 0x00;
amsg->unknown3 = 0x00;
amsg->addr = pmsg->addr;
amsg->unknown1 = 0x01;
amsg->len = cpu_to_le16(pmsg->len);
/* send the addr and len, we're interested to board */
ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
if (ret < 0)
error = ret;
ret = vprbrd_i2c_read(vb, pmsg);
if (ret < 0)
error = ret;
ret = vprbrd_i2c_status(i2c, smsg, error);
if (ret < 0)
error = ret;
/* in case of protocol error, return the error */
if (error < 0)
goto error;
} else {
/* write data */
ret = vprbrd_i2c_write(vb, pmsg);
amsg->cmd = VPRBRD_I2C_CMD_ADDR;
amsg->unknown2 = 0x00;
amsg->unknown3 = 0x00;
amsg->addr = pmsg->addr;
amsg->unknown1 = 0x00;
amsg->len = cpu_to_le16(pmsg->len);
/* send the addr, the data goes to to board */
ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
if (ret < 0)
error = ret;
ret = vprbrd_i2c_status(i2c, smsg, error);
if (ret < 0)
error = ret;
if (error < 0)
goto error;
}
mutex_unlock(&vb->lock);
}
return 0;
error:
mutex_unlock(&vb->lock);
return error;
}
static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
/* This is the actual algorithm we define */
static const struct i2c_algorithm vprbrd_algorithm = {
.master_xfer = vprbrd_i2c_xfer,
.functionality = vprbrd_i2c_func,
};
static struct i2c_adapter_quirks vprbrd_quirks = {
.max_read_len = 2048,
.max_write_len = 2048,
};
static int vprbrd_i2c_probe(struct platform_device *pdev)
{
struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
struct vprbrd_i2c *vb_i2c;
int ret;
int pipe;
vb_i2c = devm_kzalloc(&pdev->dev, sizeof(*vb_i2c), GFP_KERNEL);
if (vb_i2c == NULL)
return -ENOMEM;
/* setup i2c adapter description */
vb_i2c->i2c.owner = THIS_MODULE;
vb_i2c->i2c.class = I2C_CLASS_HWMON;
vb_i2c->i2c.algo = &vprbrd_algorithm;
vb_i2c->i2c.quirks = &vprbrd_quirks;
vb_i2c->i2c.algo_data = vb;
/* save the param in usb capabable memory */
vb_i2c->bus_freq_param = i2c_bus_param;
snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),
"viperboard at bus %03d device %03d",
vb->usb_dev->bus->busnum, vb->usb_dev->devnum);
/* setting the bus frequency */
if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)
&& (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {
pipe = usb_sndctrlpipe(vb->usb_dev, 0);
ret = usb_control_msg(vb->usb_dev, pipe,
VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,
0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,
VPRBRD_USB_TIMEOUT_MS);
if (ret != 1) {
dev_err(&pdev->dev,
"failure setting i2c_bus_freq to %d\n", i2c_bus_freq);
return -EIO;
}
} else {
dev_err(&pdev->dev,
"invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);
return -EIO;
}
vb_i2c->i2c.dev.parent = &pdev->dev;
/* attach to i2c layer */
i2c_add_adapter(&vb_i2c->i2c);
platform_set_drvdata(pdev, vb_i2c);
return 0;
}
static int vprbrd_i2c_remove(struct platform_device *pdev)
{
struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);
i2c_del_adapter(&vb_i2c->i2c);
return 0;
}
static struct platform_driver vprbrd_i2c_driver = {
.driver.name = "viperboard-i2c",
.driver.owner = THIS_MODULE,
.probe = vprbrd_i2c_probe,
.remove = vprbrd_i2c_remove,
};
static int __init vprbrd_i2c_init(void)
{
switch (i2c_bus_freq) {
case 6000:
i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;
break;
case 3000:
i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;
break;
case 1000:
i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;
break;
case 400:
i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;
break;
case 200:
i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;
break;
case 100:
i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
break;
case 10:
i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;
break;
default:
pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);
i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
}
return platform_driver_register(&vprbrd_i2c_driver);
}
subsys_initcall(vprbrd_i2c_init);
static void __exit vprbrd_i2c_exit(void)
{
platform_driver_unregister(&vprbrd_i2c_driver);
}
module_exit(vprbrd_i2c_exit);
MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
MODULE_DESCRIPTION("I2C master driver for Nano River Techs Viperboard");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:viperboard-i2c");