/*
* SuperH Mobile I2C Controller
*
* Copyright (C) 2008 Magnus Damm
*
* Portions of the code based on out-of-tree driver i2c-sh7343.c
* Copyright (c) 2006 Carlos Munoz <carlos@kenati.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
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
enum sh_mobile_i2c_op {
OP_START = 0,
OP_TX_ONLY,
OP_TX_STOP,
OP_TX_TO_RX,
OP_RX_ONLY,
OP_RX_STOP,
};
struct sh_mobile_i2c_data {
struct device *dev;
void __iomem *reg;
struct i2c_adapter adap;
struct clk *clk;
u_int8_t iccl;
u_int8_t icch;
spinlock_t lock;
wait_queue_head_t wait;
struct i2c_msg *msg;
int pos;
int sr;
};
#define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */
/* Register offsets */
#define ICDR(pd) (pd->reg + 0x00)
#define ICCR(pd) (pd->reg + 0x04)
#define ICSR(pd) (pd->reg + 0x08)
#define ICIC(pd) (pd->reg + 0x0c)
#define ICCL(pd) (pd->reg + 0x10)
#define ICCH(pd) (pd->reg + 0x14)
/* Register bits */
#define ICCR_ICE 0x80
#define ICCR_RACK 0x40
#define ICCR_TRS 0x10
#define ICCR_BBSY 0x04
#define ICCR_SCP 0x01
#define ICSR_SCLM 0x80
#define ICSR_SDAM 0x40
#define SW_DONE 0x20
#define ICSR_BUSY 0x10
#define ICSR_AL 0x08
#define ICSR_TACK 0x04
#define ICSR_WAIT 0x02
#define ICSR_DTE 0x01
#define ICIC_ALE 0x08
#define ICIC_TACKE 0x04
#define ICIC_WAITE 0x02
#define ICIC_DTEE 0x01
static void activate_ch(struct sh_mobile_i2c_data *pd)
{
/* Make sure the clock is enabled */
clk_enable(pd->clk);
/* Enable channel and configure rx ack */
iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
/* Mask all interrupts */
iowrite8(0, ICIC(pd));
/* Set the clock */
iowrite8(pd->iccl, ICCL(pd));
iowrite8(pd->icch, ICCH(pd));
}
static void deactivate_ch(struct sh_mobile_i2c_data *pd)
{
/* Clear/disable interrupts */
iowrite8(0, ICSR(pd));
iowrite8(0, ICIC(pd));
/* Disable channel */
iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
/* Disable clock */
clk_disable(pd->clk);
}
static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
enum sh_mobile_i2c_op op, unsigned char data)
{
unsigned char ret = 0;
unsigned long flags;
dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
spin_lock_irqsave(&pd->lock, flags);
switch (op) {
case OP_START:
iowrite8(0x94, ICCR(pd));
break;
case OP_TX_ONLY:
iowrite8(data, ICDR(pd));
break;
case OP_TX_STOP:
iowrite8(data, ICDR(pd));
iowrite8(0x90, ICCR(pd));
iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
break;
case OP_TX_TO_RX:
iowrite8(data, ICDR(pd));
iowrite8(0x81, ICCR(pd));
break;
case OP_RX_ONLY:
ret = ioread8(ICDR(pd));
break;
case OP_RX_STOP:
ret = ioread8(ICDR(pd));
iowrite8(0xc0, ICCR(pd));
break;
}
spin_unlock_irqrestore(&pd->lock, flags);
dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
return ret;
}
static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
{
struct platform_device *dev = dev_id;
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
struct i2c_msg *msg = pd->msg;
unsigned char data, sr;
int wakeup = 0;
sr = ioread8(ICSR(pd));
pd->sr |= sr;
dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
(msg->flags & I2C_M_RD) ? "read" : "write",
pd->pos, msg->len);
if (sr & (ICSR_AL | ICSR_TACK)) {
iowrite8(0, ICIC(pd)); /* disable interrupts */
wakeup = 1;
goto do_wakeup;
}
if (pd->pos == msg->len) {
i2c_op(pd, OP_RX_ONLY, 0);
wakeup = 1;
goto do_wakeup;
}
if (pd->pos == -1) {
data = (msg->addr & 0x7f) << 1;
data |= (msg->flags & I2C_M_RD) ? 1 : 0;
} else
data = msg->buf[pd->pos];
if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {
if (msg->flags & I2C_M_RD)
i2c_op(pd, OP_TX_TO_RX, data);
else if (pd->pos == (msg->len - 1)) {
i2c_op(pd, OP_TX_STOP, data);
wakeup = 1;
} else
i2c_op(pd, OP_TX_ONLY, data);
} else {
if (pd->pos == (msg->len - 1))
data = i2c_op(pd, OP_RX_STOP, 0);
else
data = i2c_op(pd, OP_RX_ONLY, 0);
msg->buf[pd->pos] = data;
}
pd->pos++;
do_wakeup:
if (wakeup) {
pd->sr |= SW_DONE;
wake_up(&pd->wait);
}
return IRQ_HANDLED;
}
static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
{
/* Initialize channel registers */
iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
/* Enable channel and configure rx ack */
iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
/* Set the clock */
iowrite8(pd->iccl, ICCL(pd));
iowrite8(pd->icch, ICCH(pd));
pd->msg = usr_msg;
pd->pos = -1;
pd->sr = 0;
/* Enable all interrupts except wait */
iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,
ICIC(pd));
return 0;
}
static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs,
int num)
{
struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
struct i2c_msg *msg;
int err = 0;
u_int8_t val;
int i, k, retry_count;
activate_ch(pd);
/* Process all messages */
for (i = 0; i < num; i++) {
msg = &msgs[i];
err = start_ch(pd, msg);
if (err)
break;
i2c_op(pd, OP_START, 0);
/* The interrupt handler takes care of the rest... */
k = wait_event_timeout(pd->wait,
pd->sr & (ICSR_TACK | SW_DONE),
5 * HZ);
if (!k)
dev_err(pd->dev, "Transfer request timed out\n");
retry_count = 10;
again:
val = ioread8(ICSR(pd));
dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
err = -EIO;
break;
}
/* the interrupt handler may wake us up before the
* transfer is finished, so poll the hardware
* until we're done.
*/
if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
(val & ICSR_SDAM))) {
msleep(1);
if (retry_count--)
goto again;
err = -EIO;
dev_err(pd->dev, "Polling timed out\n");
break;
}
}
deactivate_ch(pd);
if (!err)
err = num;
return err;
}
static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm sh_mobile_i2c_algorithm = {
.functionality = sh_mobile_i2c_func,
.master_xfer = sh_mobile_i2c_xfer,
};
static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
unsigned long peripheral_clk = clk_get_rate(pd->clk);
u_int32_t num;
u_int32_t denom;
u_int32_t tmp;
spin_lock_init(&pd->lock);
init_waitqueue_head(&pd->wait);
/* Calculate the value for iccl. From the data sheet:
* iccl = (p clock / transfer rate) * (L / (L + H))
* where L and H are the SCL low/high ratio (5/4 in this case).
* We also round off the result.
*/
num = peripheral_clk * 5;
denom = NORMAL_SPEED * 9;
tmp = num * 10 / denom;
if (tmp % 10 >= 5)
pd->iccl = (u_int8_t)((num/denom) + 1);
else
pd->iccl = (u_int8_t)(num/denom);
/* Calculate the value for icch. From the data sheet:
icch = (p clock / transfer rate) * (H / (L + H)) */
num = peripheral_clk * 4;
tmp = num * 10 / denom;
if (tmp % 10 >= 5)
pd->icch = (u_int8_t)((num/denom) + 1);
else
pd->icch = (u_int8_t)(num/denom);
}
static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
{
struct resource *res;
int ret = -ENXIO;
int q, m;
int k = 0;
int n = 0;
while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
for (n = res->start; hook && n <= res->end; n++) {
if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
dev->dev.bus_id, dev))
goto rollback;
}
k++;
}
if (hook)
return k > 0 ? 0 : -ENOENT;
k--;
ret = 0;
rollback:
for (q = k; k >= 0; k--) {
for (m = n; m >= res->start; m--)
free_irq(m, dev);
res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
m = res->end;
}
return ret;
}
static int sh_mobile_i2c_probe(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd;
struct i2c_adapter *adap;
struct resource *res;
int size;
int ret;
pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
if (pd == NULL) {
dev_err(&dev->dev, "cannot allocate private data\n");
return -ENOMEM;
}
pd->clk = clk_get(&dev->dev, "peripheral_clk");
if (IS_ERR(pd->clk)) {
dev_err(&dev->dev, "cannot get peripheral clock\n");
ret = PTR_ERR(pd->clk);
goto err;
}
ret = sh_mobile_i2c_hook_irqs(dev, 1);
if (ret) {
dev_err(&dev->dev, "cannot request IRQ\n");
goto err_clk;
}
pd->dev = &dev->dev;
platform_set_drvdata(dev, pd);
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (res == NULL) {
dev_err(&dev->dev, "cannot find IO resource\n");
ret = -ENOENT;
goto err_irq;
}
size = (res->end - res->start) + 1;
pd->reg = ioremap(res->start, size);
if (pd->reg == NULL) {
dev_err(&dev->dev, "cannot map IO\n");
ret = -ENXIO;
goto err_irq;
}
/* setup the private data */
adap = &pd->adap;
i2c_set_adapdata(adap, pd);
adap->owner = THIS_MODULE;
adap->algo = &sh_mobile_i2c_algorithm;
adap->dev.parent = &dev->dev;
adap->retries = 5;
adap->nr = dev->id;
strlcpy(adap->name, dev->name, sizeof(adap->name));
sh_mobile_i2c_setup_channel(dev);
ret = i2c_add_numbered_adapter(adap);
if (ret < 0) {
dev_err(&dev->dev, "cannot add numbered adapter\n");
goto err_all;
}
return 0;
err_all:
iounmap(pd->reg);
err_irq:
sh_mobile_i2c_hook_irqs(dev, 0);
err_clk:
clk_put(pd->clk);
err:
kfree(pd);
return ret;
}
static int sh_mobile_i2c_remove(struct platform_device *dev)
{
struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
i2c_del_adapter(&pd->adap);
iounmap(pd->reg);
sh_mobile_i2c_hook_irqs(dev, 0);
clk_put(pd->clk);
kfree(pd);
return 0;
}
static struct platform_driver sh_mobile_i2c_driver = {
.driver = {
.name = "i2c-sh_mobile",
.owner = THIS_MODULE,
},
.probe = sh_mobile_i2c_probe,
.remove = sh_mobile_i2c_remove,
};
static int __init sh_mobile_i2c_adap_init(void)
{
return platform_driver_register(&sh_mobile_i2c_driver);
}
static void __exit sh_mobile_i2c_adap_exit(void)
{
platform_driver_unregister(&sh_mobile_i2c_driver);
}
module_init(sh_mobile_i2c_adap_init);
module_exit(sh_mobile_i2c_adap_exit);
MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
MODULE_AUTHOR("Magnus Damm");
MODULE_LICENSE("GPL v2");
