- 根目录:
- drivers
- i2c
- busses
- i2c-s6000.c
/*
* drivers/i2c/busses/i2c-s6000.c
*
* Description: Driver for S6000 Family I2C Interface
* Copyright (c) 2008 emlix GmbH
* Author: Oskar Schirmer <oskar@scara.com>
*
* Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
* Copyright (c) 2005-2007 Analog Devices, Inc.
*
* 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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/i2c/s6000.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include "i2c-s6000.h"
#define DRV_NAME "i2c-s6000"
#define POLL_TIMEOUT (2 * HZ)
struct s6i2c_if {
u8 __iomem *reg; /* memory mapped registers */
int irq;
spinlock_t lock;
struct i2c_msg *msgs; /* messages currently handled */
int msgs_num; /* nb of msgs to do */
int msgs_push; /* nb of msgs read/written */
int msgs_done; /* nb of msgs finally handled */
unsigned push; /* nb of bytes read/written in msg */
unsigned done; /* nb of bytes finally handled */
int timeout_count; /* timeout retries left */
struct timer_list timeout_timer;
struct i2c_adapter adap;
struct completion complete;
struct clk *clk;
struct resource *res;
};
static inline u16 i2c_rd16(struct s6i2c_if *iface, unsigned n)
{
return readw(iface->reg + (n));
}
static inline void i2c_wr16(struct s6i2c_if *iface, unsigned n, u16 v)
{
writew(v, iface->reg + (n));
}
static inline u32 i2c_rd32(struct s6i2c_if *iface, unsigned n)
{
return readl(iface->reg + (n));
}
static inline void i2c_wr32(struct s6i2c_if *iface, unsigned n, u32 v)
{
writel(v, iface->reg + (n));
}
static struct s6i2c_if s6i2c_if;
static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
{
if (i2c_rd16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
i2c_rd16(iface, S6_I2C_CLRTXABRT);
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
complete(&iface->complete);
return;
}
if (iface->msgs_done >= iface->msgs_num) {
dev_err(&iface->adap.dev, "s6i2c: spurious I2C irq: %04x\n",
i2c_rd16(iface, S6_I2C_INTRSTAT));
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
return;
}
while ((iface->msgs_push < iface->msgs_num)
&& (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
struct i2c_msg *m = &iface->msgs[iface->msgs_push];
if (!(m->flags & I2C_M_RD))
i2c_wr16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
else
i2c_wr16(iface, S6_I2C_DATACMD,
1 << S6_I2C_DATACMD_READ);
if (++iface->push >= m->len) {
iface->push = 0;
iface->msgs_push += 1;
}
}
do {
struct i2c_msg *m = &iface->msgs[iface->msgs_done];
if (!(m->flags & I2C_M_RD)) {
if (iface->msgs_done < iface->msgs_push)
iface->msgs_done += 1;
else
break;
} else if (i2c_rd16(iface, S6_I2C_STATUS)
& (1 << S6_I2C_STATUS_RFNE)) {
m->buf[iface->done] = i2c_rd16(iface, S6_I2C_DATACMD);
if (++iface->done >= m->len) {
iface->done = 0;
iface->msgs_done += 1;
}
} else{
break;
}
} while (iface->msgs_done < iface->msgs_num);
if (iface->msgs_done >= iface->msgs_num) {
i2c_wr16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
complete(&iface->complete);
} else if (iface->msgs_push >= iface->msgs_num) {
i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
(1 << S6_I2C_INTR_RXFULL));
} else {
i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
(1 << S6_I2C_INTR_TXEMPTY) |
(1 << S6_I2C_INTR_RXFULL));
}
}
static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
{
struct s6i2c_if *iface = dev_id;
if (!(i2c_rd16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
| (1 << S6_I2C_INTR_RXOVER)
| (1 << S6_I2C_INTR_RXFULL)
| (1 << S6_I2C_INTR_TXOVER)
| (1 << S6_I2C_INTR_TXEMPTY)
| (1 << S6_I2C_INTR_RDREQ)
| (1 << S6_I2C_INTR_TXABRT)
| (1 << S6_I2C_INTR_RXDONE)
| (1 << S6_I2C_INTR_ACTIVITY)
| (1 << S6_I2C_INTR_STOPDET)
| (1 << S6_I2C_INTR_STARTDET)
| (1 << S6_I2C_INTR_GENCALL))))
return IRQ_NONE;
spin_lock(&iface->lock);
del_timer(&iface->timeout_timer);
s6i2c_handle_interrupt(iface);
spin_unlock(&iface->lock);
return IRQ_HANDLED;
}
static void s6i2c_timeout(unsigned long data)
{
struct s6i2c_if *iface = (struct s6i2c_if *)data;
unsigned long flags;
spin_lock_irqsave(&iface->lock, flags);
s6i2c_handle_interrupt(iface);
if (--iface->timeout_count > 0) {
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
} else {
complete(&iface->complete);
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
}
spin_unlock_irqrestore(&iface->lock, flags);
}
static int s6i2c_master_xfer(struct i2c_adapter *adap,
struct i2c_msg *msgs, int num)
{
struct s6i2c_if *iface = adap->algo_data;
int i;
if (num == 0)
return 0;
if (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
yield();
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
i2c_rd16(iface, S6_I2C_CLRINTR);
for (i = 0; i < num; i++) {
if (msgs[i].flags & I2C_M_TEN) {
dev_err(&adap->dev,
"s6i2c: 10 bits addr not supported\n");
return -EINVAL;
}
if (msgs[i].len == 0) {
dev_err(&adap->dev,
"s6i2c: zero length message not supported\n");
return -EINVAL;
}
if (msgs[i].addr != msgs[0].addr) {
dev_err(&adap->dev,
"s6i2c: multiple xfer cannot change target\n");
return -EINVAL;
}
}
iface->msgs = msgs;
iface->msgs_num = num;
iface->msgs_push = 0;
iface->msgs_done = 0;
iface->push = 0;
iface->done = 0;
iface->timeout_count = 10;
i2c_wr16(iface, S6_I2C_TAR, msgs[0].addr);
i2c_wr16(iface, S6_I2C_ENABLE, 1);
i2c_wr16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
(1 << S6_I2C_INTR_TXABRT));
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
wait_for_completion(&iface->complete);
del_timer_sync(&iface->timeout_timer);
while (i2c_rd32(iface, S6_I2C_TXFLR) > 0)
schedule();
while (i2c_rd16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
schedule();
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
i2c_wr16(iface, S6_I2C_ENABLE, 0);
return iface->msgs_done;
}
static u32 s6i2c_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static struct i2c_algorithm s6i2c_algorithm = {
.master_xfer = s6i2c_master_xfer,
.functionality = s6i2c_functionality,
};
static u16 nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
{
u32 dividend = ((clk_get_rate(iface->clk) / 1000) * ns) / 1000000;
if (dividend > 0xffff)
return 0xffff;
return dividend;
}
static int s6i2c_probe(struct platform_device *dev)
{
struct s6i2c_if *iface = &s6i2c_if;
struct i2c_adapter *p_adap;
const char *clock;
int bus_num, rc;
spin_lock_init(&iface->lock);
init_completion(&iface->complete);
iface->irq = platform_get_irq(dev, 0);
if (iface->irq < 0) {
rc = iface->irq;
goto err_out;
}
iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!iface->res) {
rc = -ENXIO;
goto err_out;
}
iface->res = request_mem_region(iface->res->start,
resource_size(iface->res),
dev->dev.bus_id);
if (!iface->res) {
rc = -EBUSY;
goto err_out;
}
iface->reg = ioremap_nocache(iface->res->start,
resource_size(iface->res));
if (!iface->reg) {
rc = -ENOMEM;
goto err_reg;
}
clock = 0;
bus_num = -1;
if (dev->dev.platform_data) {
struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
bus_num = pdata->bus_num;
clock = pdata->clock;
}
iface->clk = clk_get(&dev->dev, clock);
if (IS_ERR(iface->clk)) {
rc = PTR_ERR(iface->clk);
goto err_map;
}
rc = clk_enable(iface->clk);
if (rc < 0)
goto err_clk_put;
init_timer(&iface->timeout_timer);
iface->timeout_timer.function = s6i2c_timeout;
iface->timeout_timer.data = (unsigned long)iface;
p_adap = &iface->adap;
strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
p_adap->algo = &s6i2c_algorithm;
p_adap->algo_data = iface;
p_adap->nr = bus_num;
p_adap->class = 0;
p_adap->dev.parent = &dev->dev;
i2c_wr16(iface, S6_I2C_INTRMASK, 0);
rc = request_irq(iface->irq, s6i2c_interrupt_entry,
IRQF_SHARED, dev->name, iface);
if (rc) {
dev_err(&p_adap->dev, "s6i2c: can't get IRQ %d\n", iface->irq);
goto err_clk_dis;
}
i2c_wr16(iface, S6_I2C_ENABLE, 0);
udelay(1);
i2c_wr32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
i2c_wr16(iface, S6_I2C_CLRTXABRT, 1);
i2c_wr16(iface, S6_I2C_CON,
(1 << S6_I2C_CON_MASTER) |
(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
(0 << S6_I2C_CON_10BITSLAVE) |
(0 << S6_I2C_CON_10BITMASTER) |
(1 << S6_I2C_CON_RESTARTENA) |
(1 << S6_I2C_CON_SLAVEDISABLE));
i2c_wr16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
i2c_wr16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
i2c_wr16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
i2c_wr16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
i2c_wr16(iface, S6_I2C_RXTL, 0);
i2c_wr16(iface, S6_I2C_TXTL, 0);
platform_set_drvdata(dev, iface);
rc = i2c_add_numbered_adapter(p_adap);
if (rc)
goto err_irq_free;
return 0;
err_irq_free:
free_irq(iface->irq, iface);
err_clk_dis:
clk_disable(iface->clk);
err_clk_put:
clk_put(iface->clk);
err_map:
iounmap(iface->reg);
err_reg:
release_mem_region(iface->res->start,
resource_size(iface->res));
err_out:
return rc;
}
static int s6i2c_remove(struct platform_device *pdev)
{
struct s6i2c_if *iface = platform_get_drvdata(pdev);
i2c_wr16(iface, S6_I2C_ENABLE, 0);
i2c_del_adapter(&iface->adap);
free_irq(iface->irq, iface);
clk_disable(iface->clk);
clk_put(iface->clk);
iounmap(iface->reg);
release_mem_region(iface->res->start,
resource_size(iface->res));
return 0;
}
static struct platform_driver s6i2c_driver = {
.probe = s6i2c_probe,
.remove = s6i2c_remove,
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
},
};
static int __init s6i2c_init(void)
{
pr_info("I2C: S6000 I2C driver\n");
return platform_driver_register(&s6i2c_driver);
}
static void __exit s6i2c_exit(void)
{
platform_driver_unregister(&s6i2c_driver);
}
MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRV_NAME);
subsys_initcall(s6i2c_init);
module_exit(s6i2c_exit);