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/*
* Copyright 2011, Netlogic Microsystems Inc.
* Copyright 2004, Matt Porter <mporter@kernel.crashing.org>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/platform_device.h>
/* XLR I2C REGISTERS */
#define XLR_I2C_CFG 0x00
#define XLR_I2C_CLKDIV 0x01
#define XLR_I2C_DEVADDR 0x02
#define XLR_I2C_ADDR 0x03
#define XLR_I2C_DATAOUT 0x04
#define XLR_I2C_DATAIN 0x05
#define XLR_I2C_STATUS 0x06
#define XLR_I2C_STARTXFR 0x07
#define XLR_I2C_BYTECNT 0x08
#define XLR_I2C_HDSTATIM 0x09
/* XLR I2C REGISTERS FLAGS */
#define XLR_I2C_BUS_BUSY 0x01
#define XLR_I2C_SDOEMPTY 0x02
#define XLR_I2C_RXRDY 0x04
#define XLR_I2C_ACK_ERR 0x08
#define XLR_I2C_ARB_STARTERR 0x30
/* Register Values */
#define XLR_I2C_CFG_ADDR 0xF8
#define XLR_I2C_CFG_NOADDR 0xFA
#define XLR_I2C_STARTXFR_ND 0x02 /* No Data */
#define XLR_I2C_STARTXFR_RD 0x01 /* Read */
#define XLR_I2C_STARTXFR_WR 0x00 /* Write */
#define XLR_I2C_TIMEOUT 10 /* timeout per byte in msec */
/*
* On XLR/XLS, we need to use __raw_ IO to read the I2C registers
* because they are in the big-endian MMIO area on the SoC.
*
* The readl/writel implementation on XLR/XLS byteswaps, because
* those are for its little-endian PCI space (see arch/mips/Kconfig).
*/
static inline void xlr_i2c_wreg(u32 __iomem *base, unsigned int reg, u32 val)
{
__raw_writel(val, base + reg);
}
static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg)
{
return __raw_readl(base + reg);
}
struct xlr_i2c_private {
struct i2c_adapter adap;
u32 __iomem *iobase;
};
static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len,
u8 *buf, u16 addr)
{
struct i2c_adapter *adap = &priv->adap;
unsigned long timeout, stoptime, checktime;
u32 i2c_status;
int pos, timedout;
u8 offset, byte;
offset = buf[0];
xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR);
xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
stoptime = jiffies + timeout;
timedout = 0;
pos = 1;
retry:
if (len == 1) {
xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
XLR_I2C_STARTXFR_ND);
} else {
xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos]);
xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
XLR_I2C_STARTXFR_WR);
}
while (!timedout) {
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
if (i2c_status & XLR_I2C_SDOEMPTY) {
pos++;
/* need to do a empty dataout after the last byte */
byte = (pos < len) ? buf[pos] : 0;
xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, byte);
/* reset timeout on successful xmit */
stoptime = jiffies + timeout;
}
timedout = time_after(checktime, stoptime);
if (i2c_status & XLR_I2C_ARB_STARTERR) {
if (timedout)
break;
goto retry;
}
if (i2c_status & XLR_I2C_ACK_ERR)
return -EIO;
if ((i2c_status & XLR_I2C_BUS_BUSY) == 0 && pos >= len)
return 0;
}
dev_err(&adap->dev, "I2C transmit timeout\n");
return -ETIMEDOUT;
}
static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
{
struct i2c_adapter *adap = &priv->adap;
u32 i2c_status;
unsigned long timeout, stoptime, checktime;
int nbytes, timedout;
u8 byte;
xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR);
xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);
xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
stoptime = jiffies + timeout;
timedout = 0;
nbytes = 0;
retry:
xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, XLR_I2C_STARTXFR_RD);
while (!timedout) {
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
if (i2c_status & XLR_I2C_RXRDY) {
if (nbytes > len)
return -EIO; /* should not happen */
/* we need to do a dummy datain when nbytes == len */
byte = xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
if (nbytes < len)
buf[nbytes] = byte;
nbytes++;
/* reset timeout on successful read */
stoptime = jiffies + timeout;
}
timedout = time_after(checktime, stoptime);
if (i2c_status & XLR_I2C_ARB_STARTERR) {
if (timedout)
break;
goto retry;
}
if (i2c_status & XLR_I2C_ACK_ERR)
return -EIO;
if ((i2c_status & XLR_I2C_BUS_BUSY) == 0)
return 0;
}
dev_err(&adap->dev, "I2C receive timeout\n");
return -ETIMEDOUT;
}
static int xlr_i2c_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct i2c_msg *msg;
int i;
int ret = 0;
struct xlr_i2c_private *priv = i2c_get_adapdata(adap);
for (i = 0; ret == 0 && i < num; i++) {
msg = &msgs[i];
if (msg->flags & I2C_M_RD)
ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0],
msg->addr);
else
ret = xlr_i2c_tx(priv, msg->len, &msg->buf[0],
msg->addr);
}
return (ret != 0) ? ret : num;
}
static u32 xlr_func(struct i2c_adapter *adap)
{
/* Emulate SMBUS over I2C */
return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
}
static struct i2c_algorithm xlr_i2c_algo = {
.master_xfer = xlr_i2c_xfer,
.functionality = xlr_func,
};
static int __devinit xlr_i2c_probe(struct platform_device *pdev)
{
struct xlr_i2c_private *priv;
struct resource *res;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->iobase = devm_request_and_ioremap(&pdev->dev, res);
if (!priv->iobase) {
dev_err(&pdev->dev, "devm_request_and_ioremap failed\n");
return -EBUSY;
}
priv->adap.dev.parent = &pdev->dev;
priv->adap.owner = THIS_MODULE;
priv->adap.algo_data = priv;
priv->adap.algo = &xlr_i2c_algo;
priv->adap.nr = pdev->id;
priv->adap.class = I2C_CLASS_HWMON;
snprintf(priv->adap.name, sizeof(priv->adap.name), "xlr-i2c");
i2c_set_adapdata(&priv->adap, priv);
ret = i2c_add_numbered_adapter(&priv->adap);
if (ret < 0) {
dev_err(&priv->adap.dev, "Failed to add i2c bus.\n");
return ret;
}
platform_set_drvdata(pdev, priv);
dev_info(&priv->adap.dev, "Added I2C Bus.\n");
return 0;
}
static int __devexit xlr_i2c_remove(struct platform_device *pdev)
{
struct xlr_i2c_private *priv;
priv = platform_get_drvdata(pdev);
i2c_del_adapter(&priv->adap);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver xlr_i2c_driver = {
.probe = xlr_i2c_probe,
.remove = __devexit_p(xlr_i2c_remove),
.driver = {
.name = "xlr-i2cbus",
.owner = THIS_MODULE,
},
};
module_platform_driver(xlr_i2c_driver);
MODULE_AUTHOR("Ganesan Ramalingam <ganesanr@netlogicmicro.com>");
MODULE_DESCRIPTION("XLR/XLS SoC I2C Controller driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:xlr-i2cbus");
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