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linux/drivers/i2c/busses/i2c-mv64xxx.c
David Brownell 2096b956d2 i2c: Shrink struct i2c_client 
This shrinks the size of "struct i2c_client" by 40 bytes:

 - Substantially shrinks the string used to identify the chip type
 - The "flags" don't need to be so big
 - Removes some internal padding

It also adds kerneldoc for that struct, explaining how "name" is really a
chip type identifier; it's otherwise potentially confusing.

Because the I2C_NAME_SIZE symbol was abused for both i2c_client.name
and for i2c_adapter.name, this needed to affect i2c_adapter too.  The
adapters which used that symbol now use the more-obviously-correct
idiom of taking the size of that field.

JD: Shorten i2c_adapter.name from 50 to 48 bytes while we're here, to
avoid wasting space in padding.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
2007-05-01 23:26:28 +02:00

600 lines
17 KiB
C
Raw Blame History

/*
* Driver for the i2c controller on the Marvell line of host bridges for MIPS
* and PPC (e.g, gt642[46]0, mv643[46]0, mv644[46]0).
*
* Author: Mark A. Greer <mgreer@mvista.com>
*
* 2005 (c) MontaVista, Software, Inc. 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/spinlock.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mv643xx.h>
#include <linux/platform_device.h>
#include <asm/io.h>
/* Register defines */
#define MV64XXX_I2C_REG_SLAVE_ADDR 0x00
#define MV64XXX_I2C_REG_DATA 0x04
#define MV64XXX_I2C_REG_CONTROL 0x08
#define MV64XXX_I2C_REG_STATUS 0x0c
#define MV64XXX_I2C_REG_BAUD 0x0c
#define MV64XXX_I2C_REG_EXT_SLAVE_ADDR 0x10
#define MV64XXX_I2C_REG_SOFT_RESET 0x1c
#define MV64XXX_I2C_REG_CONTROL_ACK 0x00000004
#define MV64XXX_I2C_REG_CONTROL_IFLG 0x00000008
#define MV64XXX_I2C_REG_CONTROL_STOP 0x00000010
#define MV64XXX_I2C_REG_CONTROL_START 0x00000020
#define MV64XXX_I2C_REG_CONTROL_TWSIEN 0x00000040
#define MV64XXX_I2C_REG_CONTROL_INTEN 0x00000080
/* Ctlr status values */
#define MV64XXX_I2C_STATUS_BUS_ERR 0x00
#define MV64XXX_I2C_STATUS_MAST_START 0x08
#define MV64XXX_I2C_STATUS_MAST_REPEAT_START 0x10
#define MV64XXX_I2C_STATUS_MAST_WR_ADDR_ACK 0x18
#define MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK 0x20
#define MV64XXX_I2C_STATUS_MAST_WR_ACK 0x28
#define MV64XXX_I2C_STATUS_MAST_WR_NO_ACK 0x30
#define MV64XXX_I2C_STATUS_MAST_LOST_ARB 0x38
#define MV64XXX_I2C_STATUS_MAST_RD_ADDR_ACK 0x40
#define MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK 0x48
#define MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK 0x50
#define MV64XXX_I2C_STATUS_MAST_RD_DATA_NO_ACK 0x58
#define MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK 0xd0
#define MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_NO_ACK 0xd8
#define MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_ACK 0xe0
#define MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_NO_ACK 0xe8
#define MV64XXX_I2C_STATUS_NO_STATUS 0xf8
/* Driver states */
enum {
MV64XXX_I2C_STATE_INVALID,
MV64XXX_I2C_STATE_IDLE,
MV64XXX_I2C_STATE_WAITING_FOR_START_COND,
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK,
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA,
};
/* Driver actions */
enum {
MV64XXX_I2C_ACTION_INVALID,
MV64XXX_I2C_ACTION_CONTINUE,
MV64XXX_I2C_ACTION_SEND_START,
MV64XXX_I2C_ACTION_SEND_ADDR_1,
MV64XXX_I2C_ACTION_SEND_ADDR_2,
MV64XXX_I2C_ACTION_SEND_DATA,
MV64XXX_I2C_ACTION_RCV_DATA,
MV64XXX_I2C_ACTION_RCV_DATA_STOP,
MV64XXX_I2C_ACTION_SEND_STOP,
};
struct mv64xxx_i2c_data {
int irq;
u32 state;
u32 action;
u32 aborting;
u32 cntl_bits;
void __iomem *reg_base;
u32 reg_base_p;
u32 addr1;
u32 addr2;
u32 bytes_left;
u32 byte_posn;
u32 block;
int rc;
u32 freq_m;
u32 freq_n;
wait_queue_head_t waitq;
spinlock_t lock;
struct i2c_msg *msg;
struct i2c_adapter adapter;
};
/*
*****************************************************************************
*
* Finite State Machine & Interrupt Routines
*
*****************************************************************************
*/
static void
mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
{
/*
* If state is idle, then this is likely the remnants of an old
* operation that driver has given up on or the user has killed.
* If so, issue the stop condition and go to idle.
*/
if (drv_data->state == MV64XXX_I2C_STATE_IDLE) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
return;
}
/* The status from the ctlr [mostly] tells us what to do next */
switch (status) {
/* Start condition interrupt */
case MV64XXX_I2C_STATUS_MAST_START: /* 0x08 */
case MV64XXX_I2C_STATUS_MAST_REPEAT_START: /* 0x10 */
drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_1;
drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_ADDR_1_ACK;
break;
/* Performing a write */
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_ACK: /* 0x18 */
if (drv_data->msg->flags & I2C_M_TEN) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_2;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
break;
}
/* FALLTHRU */
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_2_ACK: /* 0xd0 */
case MV64XXX_I2C_STATUS_MAST_WR_ACK: /* 0x28 */
if ((drv_data->bytes_left == 0)
|| (drv_data->aborting
&& (drv_data->byte_posn != 0))) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK;
drv_data->bytes_left--;
}
break;
/* Performing a read */
case MV64XXX_I2C_STATUS_MAST_RD_ADDR_ACK: /* 40 */
if (drv_data->msg->flags & I2C_M_TEN) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_ADDR_2;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_ADDR_2_ACK;
break;
}
/* FALLTHRU */
case MV64XXX_I2C_STATUS_MAST_RD_ADDR_2_ACK: /* 0xe0 */
if (drv_data->bytes_left == 0) {
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
break;
}
/* FALLTHRU */
case MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK: /* 0x50 */
if (status != MV64XXX_I2C_STATUS_MAST_RD_DATA_ACK)
drv_data->action = MV64XXX_I2C_ACTION_CONTINUE;
else {
drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA;
drv_data->bytes_left--;
}
drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA;
if ((drv_data->bytes_left == 1) || drv_data->aborting)
drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_ACK;
break;
case MV64XXX_I2C_STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
drv_data->action = MV64XXX_I2C_ACTION_RCV_DATA_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
break;
case MV64XXX_I2C_STATUS_MAST_WR_ADDR_NO_ACK: /* 0x20 */
case MV64XXX_I2C_STATUS_MAST_WR_NO_ACK: /* 30 */
case MV64XXX_I2C_STATUS_MAST_RD_ADDR_NO_ACK: /* 48 */
/* Doesn't seem to be a device at other end */
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
drv_data->rc = -ENODEV;
break;
default:
dev_err(&drv_data->adapter.dev,
"mv64xxx_i2c_fsm: Ctlr Error -- state: 0x%x, "
"status: 0x%x, addr: 0x%x, flags: 0x%x\n",
drv_data->state, status, drv_data->msg->addr,
drv_data->msg->flags);
drv_data->action = MV64XXX_I2C_ACTION_SEND_STOP;
drv_data->state = MV64XXX_I2C_STATE_IDLE;
drv_data->rc = -EIO;
}
}
static void
mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
{
switch(drv_data->action) {
case MV64XXX_I2C_ACTION_CONTINUE:
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_SEND_START:
writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_START,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_SEND_ADDR_1:
writel(drv_data->addr1,
drv_data->reg_base + MV64XXX_I2C_REG_DATA);
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_SEND_ADDR_2:
writel(drv_data->addr2,
drv_data->reg_base + MV64XXX_I2C_REG_DATA);
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_SEND_DATA:
writel(drv_data->msg->buf[drv_data->byte_posn++],
drv_data->reg_base + MV64XXX_I2C_REG_DATA);
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_RCV_DATA:
drv_data->msg->buf[drv_data->byte_posn++] =
readl(drv_data->reg_base + MV64XXX_I2C_REG_DATA);
writel(drv_data->cntl_bits,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
break;
case MV64XXX_I2C_ACTION_RCV_DATA_STOP:
drv_data->msg->buf[drv_data->byte_posn++] =
readl(drv_data->reg_base + MV64XXX_I2C_REG_DATA);
drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
drv_data->block = 0;
wake_up_interruptible(&drv_data->waitq);
break;
case MV64XXX_I2C_ACTION_INVALID:
default:
dev_err(&drv_data->adapter.dev,
"mv64xxx_i2c_do_action: Invalid action: %d\n",
drv_data->action);
drv_data->rc = -EIO;
/* FALLTHRU */
case MV64XXX_I2C_ACTION_SEND_STOP:
drv_data->cntl_bits &= ~MV64XXX_I2C_REG_CONTROL_INTEN;
writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
drv_data->block = 0;
wake_up_interruptible(&drv_data->waitq);
break;
}
}
static int
mv64xxx_i2c_intr(int irq, void *dev_id)
{
struct mv64xxx_i2c_data *drv_data = dev_id;
unsigned long flags;
u32 status;
int rc = IRQ_NONE;
spin_lock_irqsave(&drv_data->lock, flags);
while (readl(drv_data->reg_base + MV64XXX_I2C_REG_CONTROL) &
MV64XXX_I2C_REG_CONTROL_IFLG) {
status = readl(drv_data->reg_base + MV64XXX_I2C_REG_STATUS);
mv64xxx_i2c_fsm(drv_data, status);
mv64xxx_i2c_do_action(drv_data);
rc = IRQ_HANDLED;
}
spin_unlock_irqrestore(&drv_data->lock, flags);
return rc;
}
/*
*****************************************************************************
*
* I2C Msg Execution Routines
*
*****************************************************************************
*/
static void
mv64xxx_i2c_prepare_for_io(struct mv64xxx_i2c_data *drv_data,
struct i2c_msg *msg)
{
u32 dir = 0;
drv_data->msg = msg;
drv_data->byte_posn = 0;
drv_data->bytes_left = msg->len;
drv_data->aborting = 0;
drv_data->rc = 0;
drv_data->cntl_bits = MV64XXX_I2C_REG_CONTROL_ACK |
MV64XXX_I2C_REG_CONTROL_INTEN | MV64XXX_I2C_REG_CONTROL_TWSIEN;
if (msg->flags & I2C_M_RD)
dir = 1;
if (msg->flags & I2C_M_REV_DIR_ADDR)
dir ^= 1;
if (msg->flags & I2C_M_TEN) {
drv_data->addr1 = 0xf0 | (((u32)msg->addr & 0x300) >> 7) | dir;
drv_data->addr2 = (u32)msg->addr & 0xff;
} else {
drv_data->addr1 = ((u32)msg->addr & 0x7f) << 1 | dir;
drv_data->addr2 = 0;
}
}
static void
mv64xxx_i2c_wait_for_completion(struct mv64xxx_i2c_data *drv_data)
{
long time_left;
unsigned long flags;
char abort = 0;
time_left = wait_event_interruptible_timeout(drv_data->waitq,
!drv_data->block, msecs_to_jiffies(drv_data->adapter.timeout));
spin_lock_irqsave(&drv_data->lock, flags);
if (!time_left) { /* Timed out */
drv_data->rc = -ETIMEDOUT;
abort = 1;
} else if (time_left < 0) { /* Interrupted/Error */
drv_data->rc = time_left; /* errno value */
abort = 1;
}
if (abort && drv_data->block) {
drv_data->aborting = 1;
spin_unlock_irqrestore(&drv_data->lock, flags);
time_left = wait_event_timeout(drv_data->waitq,
!drv_data->block,
msecs_to_jiffies(drv_data->adapter.timeout));
if ((time_left <= 0) && drv_data->block) {
drv_data->state = MV64XXX_I2C_STATE_IDLE;
dev_err(&drv_data->adapter.dev,
"mv64xxx: I2C bus locked, block: %d, "
"time_left: %d\n", drv_data->block,
(int)time_left);
}
} else
spin_unlock_irqrestore(&drv_data->lock, flags);
}
static int
mv64xxx_i2c_execute_msg(struct mv64xxx_i2c_data *drv_data, struct i2c_msg *msg)
{
unsigned long flags;
spin_lock_irqsave(&drv_data->lock, flags);
mv64xxx_i2c_prepare_for_io(drv_data, msg);
if (unlikely(msg->flags & I2C_M_NOSTART)) { /* Skip start/addr phases */
if (drv_data->msg->flags & I2C_M_RD) {
/* No action to do, wait for slave to send a byte */
drv_data->action = MV64XXX_I2C_ACTION_CONTINUE;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_DATA;
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_DATA;
drv_data->state =
MV64XXX_I2C_STATE_WAITING_FOR_SLAVE_ACK;
drv_data->bytes_left--;
}
} else {
drv_data->action = MV64XXX_I2C_ACTION_SEND_START;
drv_data->state = MV64XXX_I2C_STATE_WAITING_FOR_START_COND;
}
drv_data->block = 1;
mv64xxx_i2c_do_action(drv_data);
spin_unlock_irqrestore(&drv_data->lock, flags);
mv64xxx_i2c_wait_for_completion(drv_data);
return drv_data->rc;
}
/*
*****************************************************************************
*
* I2C Core Support Routines (Interface to higher level I2C code)
*
*****************************************************************************
*/
static u32
mv64xxx_i2c_functionality(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR | I2C_FUNC_SMBUS_EMUL;
}
static int
mv64xxx_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
int i, rc;
for (i=0; i<num; i++)
if ((rc = mv64xxx_i2c_execute_msg(drv_data, &msgs[i])) < 0)
return rc;
return num;
}
static const struct i2c_algorithm mv64xxx_i2c_algo = {
.master_xfer = mv64xxx_i2c_xfer,
.functionality = mv64xxx_i2c_functionality,
};
/*
*****************************************************************************
*
* Driver Interface & Early Init Routines
*
*****************************************************************************
*/
static void __devinit
mv64xxx_i2c_hw_init(struct mv64xxx_i2c_data *drv_data)
{
writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SOFT_RESET);
writel((((drv_data->freq_m & 0xf) << 3) | (drv_data->freq_n & 0x7)),
drv_data->reg_base + MV64XXX_I2C_REG_BAUD);
writel(0, drv_data->reg_base + MV64XXX_I2C_REG_SLAVE_ADDR);
writel(0, drv_data->reg_base + MV64XXX_I2C_REG_EXT_SLAVE_ADDR);
writel(MV64XXX_I2C_REG_CONTROL_TWSIEN | MV64XXX_I2C_REG_CONTROL_STOP,
drv_data->reg_base + MV64XXX_I2C_REG_CONTROL);
drv_data->state = MV64XXX_I2C_STATE_IDLE;
}
static int __devinit
mv64xxx_i2c_map_regs(struct platform_device *pd,
struct mv64xxx_i2c_data *drv_data)
{
struct resource *r;
if ((r = platform_get_resource(pd, IORESOURCE_MEM, 0)) &&
request_mem_region(r->start, MV64XXX_I2C_REG_BLOCK_SIZE,
drv_data->adapter.name)) {
drv_data->reg_base = ioremap(r->start,
MV64XXX_I2C_REG_BLOCK_SIZE);
drv_data->reg_base_p = r->start;
} else
return -ENOMEM;
return 0;
}
static void __devexit
mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data)
{
if (drv_data->reg_base) {
iounmap(drv_data->reg_base);
release_mem_region(drv_data->reg_base_p,
MV64XXX_I2C_REG_BLOCK_SIZE);
}
drv_data->reg_base = NULL;
drv_data->reg_base_p = 0;
}
static int __devinit
mv64xxx_i2c_probe(struct platform_device *pd)
{
struct mv64xxx_i2c_data *drv_data;
struct mv64xxx_i2c_pdata *pdata = pd->dev.platform_data;
int rc;
if ((pd->id != 0) || !pdata)
return -ENODEV;
drv_data = kzalloc(sizeof(struct mv64xxx_i2c_data), GFP_KERNEL);
if (!drv_data)
return -ENOMEM;
if (mv64xxx_i2c_map_regs(pd, drv_data)) {
rc = -ENODEV;
goto exit_kfree;
}
strlcpy(drv_data->adapter.name, MV64XXX_I2C_CTLR_NAME " adapter",
sizeof(drv_data->adapter.name));
init_waitqueue_head(&drv_data->waitq);
spin_lock_init(&drv_data->lock);
drv_data->freq_m = pdata->freq_m;
drv_data->freq_n = pdata->freq_n;
drv_data->irq = platform_get_irq(pd, 0);
if (drv_data->irq < 0) {
rc = -ENXIO;
goto exit_unmap_regs;
}
drv_data->adapter.dev.parent = &pd->dev;
drv_data->adapter.id = I2C_HW_MV64XXX;
drv_data->adapter.algo = &mv64xxx_i2c_algo;
drv_data->adapter.owner = THIS_MODULE;
drv_data->adapter.class = I2C_CLASS_HWMON;
drv_data->adapter.timeout = pdata->timeout;
drv_data->adapter.retries = pdata->retries;
platform_set_drvdata(pd, drv_data);
i2c_set_adapdata(&drv_data->adapter, drv_data);
mv64xxx_i2c_hw_init(drv_data);
if (request_irq(drv_data->irq, mv64xxx_i2c_intr, 0,
MV64XXX_I2C_CTLR_NAME, drv_data)) {
dev_err(&drv_data->adapter.dev,
"mv64xxx: Can't register intr handler irq: %d\n",
drv_data->irq);
rc = -EINVAL;
goto exit_unmap_regs;
} else if ((rc = i2c_add_adapter(&drv_data->adapter)) != 0) {
dev_err(&drv_data->adapter.dev,
"mv64xxx: Can't add i2c adapter, rc: %d\n", -rc);
goto exit_free_irq;
}
return 0;
exit_free_irq:
free_irq(drv_data->irq, drv_data);
exit_unmap_regs:
mv64xxx_i2c_unmap_regs(drv_data);
exit_kfree:
kfree(drv_data);
return rc;
}
static int __devexit
mv64xxx_i2c_remove(struct platform_device *dev)
{
struct mv64xxx_i2c_data *drv_data = platform_get_drvdata(dev);
int rc;
rc = i2c_del_adapter(&drv_data->adapter);
free_irq(drv_data->irq, drv_data);
mv64xxx_i2c_unmap_regs(drv_data);
kfree(drv_data);
return rc;
}
static struct platform_driver mv64xxx_i2c_driver = {
.probe = mv64xxx_i2c_probe,
.remove = mv64xxx_i2c_remove,
.driver = {
.owner = THIS_MODULE,
.name = MV64XXX_I2C_CTLR_NAME,
},
};
static int __init
mv64xxx_i2c_init(void)
{
return platform_driver_register(&mv64xxx_i2c_driver);
}
static void __exit
mv64xxx_i2c_exit(void)
{
platform_driver_unregister(&mv64xxx_i2c_driver);
}
module_init(mv64xxx_i2c_init);
module_exit(mv64xxx_i2c_exit);
MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>");
MODULE_DESCRIPTION("Marvell mv64xxx host bridge i2c ctlr driver");
MODULE_LICENSE("GPL");
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