blob: 7aa2225e75b907e0d77b7ed0d1a4f5d66120cba2 [file] [log] [blame]
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2012 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/platform_device.h>
#define PIC32_I2CxCON 0x0000
#define PIC32_I2CCON_ON (1<<15)
#define PIC32_I2CCON_ACKDT (1<<5)
#define PIC32_I2CCON_ACKEN (1<<4)
#define PIC32_I2CCON_RCEN (1<<3)
#define PIC32_I2CCON_PEN (1<<2)
#define PIC32_I2CCON_RSEN (1<<1)
#define PIC32_I2CCON_SEN (1<<0)
#define PIC32_I2CxCONCLR 0x0004
#define PIC32_I2CxCONSET 0x0008
#define PIC32_I2CxSTAT 0x0010
#define PIC32_I2CxSTATCLR 0x0014
#define PIC32_I2CSTAT_ACKSTAT (1<<15)
#define PIC32_I2CSTAT_TRSTAT (1<<14)
#define PIC32_I2CSTAT_BCL (1<<10)
#define PIC32_I2CSTAT_IWCOL (1<<7)
#define PIC32_I2CSTAT_I2COV (1<<6)
#define PIC32_I2CxBRG 0x0040
#define PIC32_I2CxTRN 0x0050
#define PIC32_I2CxRCV 0x0060
static DEFINE_SPINLOCK(pic32_bus_lock);
static void __iomem *bus_xfer = (void __iomem *)0xbf000600;
static void __iomem *bus_status = (void __iomem *)0xbf000060;
#define DELAY() udelay(100)
static inline unsigned int ioready(void)
{
return readl(bus_status) & 1;
}
static inline void wait_ioready(void)
{
do { } while (!ioready());
}
static inline void wait_ioclear(void)
{
do { } while (ioready());
}
static inline void check_ioclear(void)
{
if (ioready()) {
do {
(void) readl(bus_xfer);
DELAY();
} while (ioready());
}
}
static u32 pic32_bus_readl(u32 reg)
{
unsigned long flags;
u32 status, val;
spin_lock_irqsave(&pic32_bus_lock, flags);
check_ioclear();
writel((0x01 << 24) | (reg & 0x00ffffff), bus_xfer);
DELAY();
wait_ioready();
status = readl(bus_xfer);
DELAY();
val = readl(bus_xfer);
wait_ioclear();
spin_unlock_irqrestore(&pic32_bus_lock, flags);
return val;
}
static void pic32_bus_writel(u32 val, u32 reg)
{
unsigned long flags;
u32 status;
spin_lock_irqsave(&pic32_bus_lock, flags);
check_ioclear();
writel((0x10 << 24) | (reg & 0x00ffffff), bus_xfer);
DELAY();
writel(val, bus_xfer);
DELAY();
wait_ioready();
status = readl(bus_xfer);
wait_ioclear();
spin_unlock_irqrestore(&pic32_bus_lock, flags);
}
struct pic32_i2c_platform_data {
u32 base;
struct i2c_adapter adap;
u32 xfer_timeout;
u32 ack_timeout;
u32 ctl_timeout;
};
static inline void pic32_i2c_start(struct pic32_i2c_platform_data *adap)
{
pic32_bus_writel(PIC32_I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
}
static inline void pic32_i2c_stop(struct pic32_i2c_platform_data *adap)
{
pic32_bus_writel(PIC32_I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
}
static inline void pic32_i2c_ack(struct pic32_i2c_platform_data *adap)
{
pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
}
static inline void pic32_i2c_nack(struct pic32_i2c_platform_data *adap)
{
pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
}
static inline int pic32_i2c_idle(struct pic32_i2c_platform_data *adap)
{
int i;
for (i = 0; i < adap->ctl_timeout; i++) {
if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
(PIC32_I2CCON_ACKEN | PIC32_I2CCON_RCEN |
PIC32_I2CCON_PEN | PIC32_I2CCON_RSEN |
PIC32_I2CCON_SEN)) == 0) &&
((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
(PIC32_I2CSTAT_TRSTAT)) == 0))
return 0;
udelay(1);
}
return -ETIMEDOUT;
}
static inline u32 pic32_i2c_master_write(struct pic32_i2c_platform_data *adap,
u32 byte)
{
pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
PIC32_I2CSTAT_IWCOL;
}
static inline u32 pic32_i2c_master_read(struct pic32_i2c_platform_data *adap)
{
pic32_bus_writel(PIC32_I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & PIC32_I2CCON_RCEN)
;
pic32_bus_writel(PIC32_I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
}
static int pic32_i2c_address(struct pic32_i2c_platform_data *adap,
unsigned int addr, int rd)
{
pic32_i2c_idle(adap);
pic32_i2c_start(adap);
pic32_i2c_idle(adap);
addr <<= 1;
if (rd)
addr |= 1;
if (pic32_i2c_master_write(adap, addr))
return -EIO;
pic32_i2c_idle(adap);
if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
PIC32_I2CSTAT_ACKSTAT)
return -EIO;
return 0;
}
static int sead3_i2c_read(struct pic32_i2c_platform_data *adap,
unsigned char *buf, unsigned int len)
{
u32 data;
int i;
i = 0;
while (i < len) {
data = pic32_i2c_master_read(adap);
buf[i++] = data;
if (i < len)
pic32_i2c_ack(adap);
else
pic32_i2c_nack(adap);
}
pic32_i2c_stop(adap);
pic32_i2c_idle(adap);
return 0;
}
static int sead3_i2c_write(struct pic32_i2c_platform_data *adap,
unsigned char *buf, unsigned int len)
{
int i;
u32 data;
i = 0;
while (i < len) {
data = buf[i];
if (pic32_i2c_master_write(adap, data))
return -EIO;
pic32_i2c_idle(adap);
if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
PIC32_I2CSTAT_ACKSTAT)
return -EIO;
i++;
}
pic32_i2c_stop(adap);
pic32_i2c_idle(adap);
return 0;
}
static int sead3_pic32_platform_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg *msgs, int num)
{
struct pic32_i2c_platform_data *adap = i2c_adap->algo_data;
struct i2c_msg *p;
int i, err = 0;
for (i = 0; i < num; i++) {
#define __BUFSIZE 80
int ii;
static char buf[__BUFSIZE];
char *b = buf;
p = &msgs[i];
b += sprintf(buf, " [%d bytes]", p->len);
if ((p->flags & I2C_M_RD) == 0) {
for (ii = 0; ii < p->len; ii++) {
if (b < &buf[__BUFSIZE-4]) {
b += sprintf(b, " %02x", p->buf[ii]);
} else {
strcat(b, "...");
break;
}
}
}
}
for (i = 0; !err && i < num; i++) {
p = &msgs[i];
err = pic32_i2c_address(adap, p->addr, p->flags & I2C_M_RD);
if (err || !p->len)
continue;
if (p->flags & I2C_M_RD)
err = sead3_i2c_read(adap, p->buf, p->len);
else
err = sead3_i2c_write(adap, p->buf, p->len);
}
/* Return the number of messages processed, or the error code. */
if (err == 0)
err = num;
return err;
}
static u32 sead3_pic32_platform_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm sead3_platform_algo = {
.master_xfer = sead3_pic32_platform_xfer,
.functionality = sead3_pic32_platform_func,
};
static void sead3_i2c_platform_setup(struct pic32_i2c_platform_data *priv)
{
pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONSET);
pic32_bus_writel(PIC32_I2CSTAT_BCL | PIC32_I2CSTAT_IWCOL,
priv->base + PIC32_I2CxSTATCLR);
}
static int sead3_i2c_platform_probe(struct platform_device *pdev)
{
struct pic32_i2c_platform_data *priv;
struct resource *r;
int ret;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
ret = -ENODEV;
goto out;
}
priv = kzalloc(sizeof(struct pic32_i2c_platform_data), GFP_KERNEL);
if (!priv) {
ret = -ENOMEM;
goto out;
}
priv->base = r->start;
if (!priv->base) {
ret = -EBUSY;
goto out_mem;
}
priv->xfer_timeout = 200;
priv->ack_timeout = 200;
priv->ctl_timeout = 200;
priv->adap.nr = pdev->id;
priv->adap.algo = &sead3_platform_algo;
priv->adap.algo_data = priv;
priv->adap.dev.parent = &pdev->dev;
strlcpy(priv->adap.name, "SEAD3 PIC32", sizeof(priv->adap.name));
sead3_i2c_platform_setup(priv);
ret = i2c_add_numbered_adapter(&priv->adap);
if (ret == 0) {
platform_set_drvdata(pdev, priv);
return 0;
}
out_mem:
kfree(priv);
out:
return ret;
}
static int sead3_i2c_platform_remove(struct platform_device *pdev)
{
struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
platform_set_drvdata(pdev, NULL);
i2c_del_adapter(&priv->adap);
kfree(priv);
return 0;
}
#ifdef CONFIG_PM
static int sead3_i2c_platform_suspend(struct platform_device *pdev,
pm_message_t state)
{
dev_dbg(&pdev->dev, "i2c_platform_disable\n");
return 0;
}
static int sead3_i2c_platform_resume(struct platform_device *pdev)
{
struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
dev_dbg(&pdev->dev, "sead3_i2c_platform_setup\n");
sead3_i2c_platform_setup(priv);
return 0;
}
#else
#define sead3_i2c_platform_suspend NULL
#define sead3_i2c_platform_resume NULL
#endif
static struct platform_driver sead3_i2c_platform_driver = {
.driver = {
.name = "sead3-i2c",
.owner = THIS_MODULE,
},
.probe = sead3_i2c_platform_probe,
.remove = sead3_i2c_platform_remove,
.suspend = sead3_i2c_platform_suspend,
.resume = sead3_i2c_platform_resume,
};
static int __init sead3_i2c_platform_init(void)
{
return platform_driver_register(&sead3_i2c_platform_driver);
}
module_init(sead3_i2c_platform_init);
static void __exit sead3_i2c_platform_exit(void)
{
platform_driver_unregister(&sead3_i2c_platform_driver);
}
module_exit(sead3_i2c_platform_exit);
MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
MODULE_DESCRIPTION("SEAD3 PIC32 I2C driver");
MODULE_LICENSE("GPL");