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android_kernel_motorola_sm6225/drivers/i2c/busses/i2c-sis96x.c
Roel Kluin 4ccc28f725 i2c: Timeouts off by 1 
with while (timeout++ < MAX_TIMEOUT); timeout reaches MAX_TIMEOUT + 1
after the loop, so the tests below are off by one.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2009-05-05 08:39:24 +02:00

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/*
Copyright (c) 2003 Mark M. Hoffman <mhoffman@lightlink.com>
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.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
This module must be considered BETA unless and until
the chipset manufacturer releases a datasheet.
The register definitions are based on the SiS630.
This module relies on quirk_sis_96x_smbus (drivers/pci/quirks.c)
for just about every machine for which users have reported.
If this module isn't detecting your 96x south bridge, have a
look there.
We assume there can only be one SiS96x with one SMBus interface.
*/
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/stddef.h>
#include <linux/ioport.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <asm/io.h>
/* base address register in PCI config space */
#define SIS96x_BAR 0x04
/* SiS96x SMBus registers */
#define SMB_STS 0x00
#define SMB_EN 0x01
#define SMB_CNT 0x02
#define SMB_HOST_CNT 0x03
#define SMB_ADDR 0x04
#define SMB_CMD 0x05
#define SMB_PCOUNT 0x06
#define SMB_COUNT 0x07
#define SMB_BYTE 0x08
#define SMB_DEV_ADDR 0x10
#define SMB_DB0 0x11
#define SMB_DB1 0x12
#define SMB_SAA 0x13
/* register count for request_region */
#define SMB_IOSIZE 0x20
/* Other settings */
#define MAX_TIMEOUT 500
/* SiS96x SMBus constants */
#define SIS96x_QUICK 0x00
#define SIS96x_BYTE 0x01
#define SIS96x_BYTE_DATA 0x02
#define SIS96x_WORD_DATA 0x03
#define SIS96x_PROC_CALL 0x04
#define SIS96x_BLOCK_DATA 0x05
static struct pci_driver sis96x_driver;
static struct i2c_adapter sis96x_adapter;
static u16 sis96x_smbus_base;
static inline u8 sis96x_read(u8 reg)
{
return inb(sis96x_smbus_base + reg) ;
}
static inline void sis96x_write(u8 reg, u8 data)
{
outb(data, sis96x_smbus_base + reg) ;
}
/* Execute a SMBus transaction.
int size is from SIS96x_QUICK to SIS96x_BLOCK_DATA
*/
static int sis96x_transaction(int size)
{
int temp;
int result = 0;
int timeout = 0;
dev_dbg(&sis96x_adapter.dev, "SMBus transaction %d\n", size);
/* Make sure the SMBus host is ready to start transmitting */
if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
dev_dbg(&sis96x_adapter.dev, "SMBus busy (0x%02x). "
"Resetting...\n", temp);
/* kill the transaction */
sis96x_write(SMB_HOST_CNT, 0x20);
/* check it again */
if (((temp = sis96x_read(SMB_CNT)) & 0x03) != 0x00) {
dev_dbg(&sis96x_adapter.dev, "Failed (0x%02x)\n", temp);
return -EBUSY;
} else {
dev_dbg(&sis96x_adapter.dev, "Successful\n");
}
}
/* Turn off timeout interrupts, set fast host clock */
sis96x_write(SMB_CNT, 0x20);
/* clear all (sticky) status flags */
temp = sis96x_read(SMB_STS);
sis96x_write(SMB_STS, temp & 0x1e);
/* start the transaction by setting bit 4 and size bits */
sis96x_write(SMB_HOST_CNT, 0x10 | (size & 0x07));
/* We will always wait for a fraction of a second! */
do {
msleep(1);
temp = sis96x_read(SMB_STS);
} while (!(temp & 0x0e) && (timeout++ < MAX_TIMEOUT));
/* If the SMBus is still busy, we give up */
if (timeout > MAX_TIMEOUT) {
dev_dbg(&sis96x_adapter.dev, "SMBus Timeout! (0x%02x)\n", temp);
result = -ETIMEDOUT;
}
/* device error - probably missing ACK */
if (temp & 0x02) {
dev_dbg(&sis96x_adapter.dev, "Failed bus transaction!\n");
result = -ENXIO;
}
/* bus collision */
if (temp & 0x04) {
dev_dbg(&sis96x_adapter.dev, "Bus collision!\n");
result = -EIO;
}
/* Finish up by resetting the bus */
sis96x_write(SMB_STS, temp);
if ((temp = sis96x_read(SMB_STS))) {
dev_dbg(&sis96x_adapter.dev, "Failed reset at "
"end of transaction! (0x%02x)\n", temp);
}
return result;
}
/* Return negative errno on error. */
static s32 sis96x_access(struct i2c_adapter * adap, u16 addr,
unsigned short flags, char read_write,
u8 command, int size, union i2c_smbus_data * data)
{
int status;
switch (size) {
case I2C_SMBUS_QUICK:
sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
size = SIS96x_QUICK;
break;
case I2C_SMBUS_BYTE:
sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
if (read_write == I2C_SMBUS_WRITE)
sis96x_write(SMB_CMD, command);
size = SIS96x_BYTE;
break;
case I2C_SMBUS_BYTE_DATA:
sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
sis96x_write(SMB_CMD, command);
if (read_write == I2C_SMBUS_WRITE)
sis96x_write(SMB_BYTE, data->byte);
size = SIS96x_BYTE_DATA;
break;
case I2C_SMBUS_PROC_CALL:
case I2C_SMBUS_WORD_DATA:
sis96x_write(SMB_ADDR, ((addr & 0x7f) << 1) | (read_write & 0x01));
sis96x_write(SMB_CMD, command);
if (read_write == I2C_SMBUS_WRITE) {
sis96x_write(SMB_BYTE, data->word & 0xff);
sis96x_write(SMB_BYTE + 1, (data->word & 0xff00) >> 8);
}
size = (size == I2C_SMBUS_PROC_CALL ?
SIS96x_PROC_CALL : SIS96x_WORD_DATA);
break;
default:
dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
return -EOPNOTSUPP;
}
status = sis96x_transaction(size);
if (status)
return status;
if ((size != SIS96x_PROC_CALL) &&
((read_write == I2C_SMBUS_WRITE) || (size == SIS96x_QUICK)))
return 0;
switch (size) {
case SIS96x_BYTE:
case SIS96x_BYTE_DATA:
data->byte = sis96x_read(SMB_BYTE);
break;
case SIS96x_WORD_DATA:
case SIS96x_PROC_CALL:
data->word = sis96x_read(SMB_BYTE) +
(sis96x_read(SMB_BYTE + 1) << 8);
break;
}
return 0;
}
static u32 sis96x_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_PROC_CALL;
}
static const struct i2c_algorithm smbus_algorithm = {
.smbus_xfer = sis96x_access,
.functionality = sis96x_func,
};
static struct i2c_adapter sis96x_adapter = {
.owner = THIS_MODULE,
.class = I2C_CLASS_HWMON | I2C_CLASS_SPD,
.algo = &smbus_algorithm,
};
static struct pci_device_id sis96x_ids[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_SMBUS) },
{ 0, }
};
MODULE_DEVICE_TABLE (pci, sis96x_ids);
static int __devinit sis96x_probe(struct pci_dev *dev,
const struct pci_device_id *id)
{
u16 ww = 0;
int retval;
if (sis96x_smbus_base) {
dev_err(&dev->dev, "Only one device supported.\n");
return -EBUSY;
}
pci_read_config_word(dev, PCI_CLASS_DEVICE, &ww);
if (PCI_CLASS_SERIAL_SMBUS != ww) {
dev_err(&dev->dev, "Unsupported device class 0x%04x!\n", ww);
return -ENODEV;
}
sis96x_smbus_base = pci_resource_start(dev, SIS96x_BAR);
if (!sis96x_smbus_base) {
dev_err(&dev->dev, "SiS96x SMBus base address "
"not initialized!\n");
return -EINVAL;
}
dev_info(&dev->dev, "SiS96x SMBus base address: 0x%04x\n",
sis96x_smbus_base);
retval = acpi_check_resource_conflict(&dev->resource[SIS96x_BAR]);
if (retval)
return retval;
/* Everything is happy, let's grab the memory and set things up. */
if (!request_region(sis96x_smbus_base, SMB_IOSIZE,
sis96x_driver.name)) {
dev_err(&dev->dev, "SMBus registers 0x%04x-0x%04x "
"already in use!\n", sis96x_smbus_base,
sis96x_smbus_base + SMB_IOSIZE - 1);
sis96x_smbus_base = 0;
return -EINVAL;
}
/* set up the sysfs linkage to our parent device */
sis96x_adapter.dev.parent = &dev->dev;
snprintf(sis96x_adapter.name, sizeof(sis96x_adapter.name),
"SiS96x SMBus adapter at 0x%04x", sis96x_smbus_base);
if ((retval = i2c_add_adapter(&sis96x_adapter))) {
dev_err(&dev->dev, "Couldn't register adapter!\n");
release_region(sis96x_smbus_base, SMB_IOSIZE);
sis96x_smbus_base = 0;
}
return retval;
}
static void __devexit sis96x_remove(struct pci_dev *dev)
{
if (sis96x_smbus_base) {
i2c_del_adapter(&sis96x_adapter);
release_region(sis96x_smbus_base, SMB_IOSIZE);
sis96x_smbus_base = 0;
}
}
static struct pci_driver sis96x_driver = {
.name = "sis96x_smbus",
.id_table = sis96x_ids,
.probe = sis96x_probe,
.remove = __devexit_p(sis96x_remove),
};
static int __init i2c_sis96x_init(void)
{
return pci_register_driver(&sis96x_driver);
}
static void __exit i2c_sis96x_exit(void)
{
pci_unregister_driver(&sis96x_driver);
}
MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
MODULE_DESCRIPTION("SiS96x SMBus driver");
MODULE_LICENSE("GPL");
/* Register initialization functions using helper macros */
module_init(i2c_sis96x_init);
module_exit(i2c_sis96x_exit);
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