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linux/drivers/i2c/busses/i2c-keywest.c

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/*
i2c Support for Apple Keywest I2C Bus Controller
Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
Original work by
Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
Changes:
2001/12/13 BenH New implementation
2001/12/15 BenH Add support for "byte" and "quick"
transfers. Add i2c_xfer routine.
2003/09/21 BenH Rework state machine with Paulus help
2004/01/21 BenH Merge in Greg KH changes, polled mode is back
2004/02/05 BenH Merge 64 bits fixes from the g5 ppc64 tree
My understanding of the various modes supported by keywest are:
- Dumb mode : not implemented, probably direct tweaking of lines
- Standard mode : simple i2c transaction of type
S Addr R/W A Data A Data ... T
- Standard sub mode : combined 8 bit subaddr write with data read
S Addr R/W A SubAddr A Data A Data ... T
- Combined mode : Subaddress and Data sequences appended with no stop
S Addr R/W A SubAddr S Addr R/W A Data A Data ... T
Currently, this driver uses only Standard mode for i2c xfer, and
smbus byte & quick transfers ; and uses StandardSub mode for
other smbus transfers instead of combined as we need that for the
sound driver to be happy
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#include <asm/pmac_low_i2c.h>
#include "i2c-keywest.h"
#undef POLLED_MODE
/* Some debug macros */
#define WRONG_STATE(name) do {\
pr_debug("KW: wrong state. Got %s, state: %s (isr: %02x)\n", \
name, __kw_state_names[iface->state], isr); \
} while(0)
#ifdef DEBUG
static const char *__kw_state_names[] = {
"state_idle",
"state_addr",
"state_read",
"state_write",
"state_stop",
"state_dead"
};
#endif /* DEBUG */
MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
MODULE_DESCRIPTION("I2C driver for Apple's Keywest");
MODULE_LICENSE("GPL");
#ifdef POLLED_MODE
/* Don't schedule, the g5 fan controller is too
* timing sensitive
*/
static u8
wait_interrupt(struct keywest_iface* iface)
{
int i;
u8 isr;
for (i = 0; i < 200000; i++) {
isr = read_reg(reg_isr) & KW_I2C_IRQ_MASK;
if (isr != 0)
return isr;
udelay(10);
}
return isr;
}
#endif /* POLLED_MODE */
static void
do_stop(struct keywest_iface* iface, int result)
{
write_reg(reg_control, KW_I2C_CTL_STOP);
iface->state = state_stop;
iface->result = result;
}
/* Main state machine for standard & standard sub mode */
static void
handle_interrupt(struct keywest_iface *iface, u8 isr)
{
int ack;
if (isr == 0) {
if (iface->state != state_stop) {
pr_debug("KW: Timeout !\n");
do_stop(iface, -EIO);
}
if (iface->state == state_stop) {
ack = read_reg(reg_status);
if (!(ack & KW_I2C_STAT_BUSY)) {
iface->state = state_idle;
write_reg(reg_ier, 0x00);
#ifndef POLLED_MODE
complete(&iface->complete);
#endif /* POLLED_MODE */
}
}
return;
}
if (isr & KW_I2C_IRQ_ADDR) {
ack = read_reg(reg_status);
if (iface->state != state_addr) {
write_reg(reg_isr, KW_I2C_IRQ_ADDR);
WRONG_STATE("KW_I2C_IRQ_ADDR");
do_stop(iface, -EIO);
return;
}
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
iface->state = state_stop;
iface->result = -ENODEV;
pr_debug("KW: NAK on address\n");
} else {
/* Handle rw "quick" mode */
if (iface->datalen == 0) {
do_stop(iface, 0);
} else if (iface->read_write == I2C_SMBUS_READ) {
iface->state = state_read;
if (iface->datalen > 1)
write_reg(reg_control, KW_I2C_CTL_AAK);
} else {
iface->state = state_write;
write_reg(reg_data, *(iface->data++));
iface->datalen--;
}
}
write_reg(reg_isr, KW_I2C_IRQ_ADDR);
}
if (isr & KW_I2C_IRQ_DATA) {
if (iface->state == state_read) {
*(iface->data++) = read_reg(reg_data);
write_reg(reg_isr, KW_I2C_IRQ_DATA);
iface->datalen--;
if (iface->datalen == 0)
iface->state = state_stop;
else if (iface->datalen == 1)
write_reg(reg_control, 0);
} else if (iface->state == state_write) {
/* Check ack status */
ack = read_reg(reg_status);
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
pr_debug("KW: nack on data write (%x): %x\n",
iface->data[-1], ack);
do_stop(iface, -EIO);
} else if (iface->datalen) {
write_reg(reg_data, *(iface->data++));
iface->datalen--;
} else {
write_reg(reg_control, KW_I2C_CTL_STOP);
iface->state = state_stop;
iface->result = 0;
}
write_reg(reg_isr, KW_I2C_IRQ_DATA);
} else {
write_reg(reg_isr, KW_I2C_IRQ_DATA);
WRONG_STATE("KW_I2C_IRQ_DATA");
if (iface->state != state_stop)
do_stop(iface, -EIO);
}
}
if (isr & KW_I2C_IRQ_STOP) {
write_reg(reg_isr, KW_I2C_IRQ_STOP);
if (iface->state != state_stop) {
WRONG_STATE("KW_I2C_IRQ_STOP");
iface->result = -EIO;
}
iface->state = state_idle;
write_reg(reg_ier, 0x00);
#ifndef POLLED_MODE
complete(&iface->complete);
#endif /* POLLED_MODE */
}
if (isr & KW_I2C_IRQ_START)
write_reg(reg_isr, KW_I2C_IRQ_START);
}
#ifndef POLLED_MODE
/* Interrupt handler */
static irqreturn_t
keywest_irq(int irq, void *dev_id, struct pt_regs *regs)
{
struct keywest_iface *iface = (struct keywest_iface *)dev_id;
unsigned long flags;
spin_lock_irqsave(&iface->lock, flags);
del_timer(&iface->timeout_timer);
handle_interrupt(iface, read_reg(reg_isr));
if (iface->state != state_idle) {
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
}
spin_unlock_irqrestore(&iface->lock, flags);
return IRQ_HANDLED;
}
static void
keywest_timeout(unsigned long data)
{
struct keywest_iface *iface = (struct keywest_iface *)data;
unsigned long flags;
pr_debug("timeout !\n");
spin_lock_irqsave(&iface->lock, flags);
handle_interrupt(iface, read_reg(reg_isr));
if (iface->state != state_idle) {
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
}
spin_unlock_irqrestore(&iface->lock, flags);
}
#endif /* POLLED_MODE */
/*
* SMBUS-type transfer entrypoint
*/
static s32
keywest_smbus_xfer( struct i2c_adapter* adap,
u16 addr,
unsigned short flags,
char read_write,
u8 command,
int size,
union i2c_smbus_data* data)
{
struct keywest_chan* chan = i2c_get_adapdata(adap);
struct keywest_iface* iface = chan->iface;
int len;
u8* buffer;
u16 cur_word;
int rc = 0;
if (iface->state == state_dead)
return -ENXIO;
/* Prepare datas & select mode */
iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
switch (size) {
case I2C_SMBUS_QUICK:
len = 0;
buffer = NULL;
iface->cur_mode |= KW_I2C_MODE_STANDARD;
break;
case I2C_SMBUS_BYTE:
len = 1;
buffer = &data->byte;
iface->cur_mode |= KW_I2C_MODE_STANDARD;
break;
case I2C_SMBUS_BYTE_DATA:
len = 1;
buffer = &data->byte;
iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
break;
case I2C_SMBUS_WORD_DATA:
len = 2;
cur_word = cpu_to_le16(data->word);
buffer = (u8 *)&cur_word;
iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
break;
case I2C_SMBUS_BLOCK_DATA:
len = data->block[0];
buffer = &data->block[1];
iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
break;
default:
return -1;
}
/* Turn a standardsub read into a combined mode access */
if (read_write == I2C_SMBUS_READ
&& (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB) {
iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
iface->cur_mode |= KW_I2C_MODE_COMBINED;
}
/* Original driver had this limitation */
if (len > 32)
len = 32;
if (pmac_low_i2c_lock(iface->node))
return -ENXIO;
pr_debug("chan: %d, addr: 0x%x, transfer len: %d, read: %d\n",
chan->chan_no, addr, len, read_write == I2C_SMBUS_READ);
iface->data = buffer;
iface->datalen = len;
iface->state = state_addr;
iface->result = 0;
iface->read_write = read_write;
/* Setup channel & clear pending irqs */
write_reg(reg_isr, read_reg(reg_isr));
write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4));
write_reg(reg_status, 0);
/* Set up address and r/w bit */
write_reg(reg_addr,
(addr << 1) | ((read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));
/* Set up the sub address */
if ((iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB
|| (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_COMBINED)
write_reg(reg_subaddr, command);
#ifndef POLLED_MODE
/* Arm timeout */
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
#endif
/* Start sending address & enable interrupt*/
write_reg(reg_control, KW_I2C_CTL_XADDR);
write_reg(reg_ier, KW_I2C_IRQ_MASK);
#ifdef POLLED_MODE
pr_debug("using polled mode...\n");
/* State machine, to turn into an interrupt handler */
while(iface->state != state_idle) {
unsigned long flags;
u8 isr = wait_interrupt(iface);
spin_lock_irqsave(&iface->lock, flags);
handle_interrupt(iface, isr);
spin_unlock_irqrestore(&iface->lock, flags);
}
#else /* POLLED_MODE */
pr_debug("using interrupt mode...\n");
wait_for_completion(&iface->complete);
#endif /* POLLED_MODE */
rc = iface->result;
pr_debug("transfer done, result: %d\n", rc);
if (rc == 0 && size == I2C_SMBUS_WORD_DATA && read_write == I2C_SMBUS_READ)
data->word = le16_to_cpu(cur_word);
/* Release sem */
pmac_low_i2c_unlock(iface->node);
return rc;
}
/*
* Generic i2c master transfer entrypoint
*/
static int
keywest_xfer( struct i2c_adapter *adap,
struct i2c_msg *msgs,
int num)
{
struct keywest_chan* chan = i2c_get_adapdata(adap);
struct keywest_iface* iface = chan->iface;
struct i2c_msg *pmsg;
int i, completed;
int rc = 0;
if (iface->state == state_dead)
return -ENXIO;
if (pmac_low_i2c_lock(iface->node))
return -ENXIO;
/* Set adapter to standard mode */
iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
iface->cur_mode |= KW_I2C_MODE_STANDARD;
completed = 0;
for (i = 0; rc >= 0 && i < num;) {
u8 addr;
pmsg = &msgs[i++];
addr = pmsg->addr;
if (pmsg->flags & I2C_M_TEN) {
printk(KERN_ERR "i2c-keywest: 10 bits addr not supported !\n");
rc = -EINVAL;
break;
}
pr_debug("xfer: chan: %d, doing %s %d bytes to 0x%02x - %d of %d messages\n",
chan->chan_no,
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, addr, i, num);
/* Setup channel & clear pending irqs */
write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4));
write_reg(reg_isr, read_reg(reg_isr));
write_reg(reg_status, 0);
iface->data = pmsg->buf;
iface->datalen = pmsg->len;
iface->state = state_addr;
iface->result = 0;
if (pmsg->flags & I2C_M_RD)
iface->read_write = I2C_SMBUS_READ;
else
iface->read_write = I2C_SMBUS_WRITE;
/* Set up address and r/w bit */
if (pmsg->flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
write_reg(reg_addr,
(addr << 1) |
((iface->read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));
#ifndef POLLED_MODE
/* Arm timeout */
iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
add_timer(&iface->timeout_timer);
#endif
/* Start sending address & enable interrupt*/
write_reg(reg_ier, KW_I2C_IRQ_MASK);
write_reg(reg_control, KW_I2C_CTL_XADDR);
#ifdef POLLED_MODE
pr_debug("using polled mode...\n");
/* State machine, to turn into an interrupt handler */
while(iface->state != state_idle) {
u8 isr = wait_interrupt(iface);
handle_interrupt(iface, isr);
}
#else /* POLLED_MODE */
pr_debug("using interrupt mode...\n");
wait_for_completion(&iface->complete);
#endif /* POLLED_MODE */
rc = iface->result;
if (rc == 0)
completed++;
pr_debug("transfer done, result: %d\n", rc);
}
/* Release sem */
pmac_low_i2c_unlock(iface->node);
return completed;
}
static u32
keywest_func(struct i2c_adapter * adapter)
{
return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
I2C_FUNC_SMBUS_BLOCK_DATA;
}
/* For now, we only handle combined mode (smbus) */
static struct i2c_algorithm keywest_algorithm = {
.smbus_xfer = keywest_smbus_xfer,
.master_xfer = keywest_xfer,
.functionality = keywest_func,
};
static int
create_iface(struct device_node *np, struct device *dev)
{
unsigned long steps;
unsigned bsteps, tsize, i, nchan, addroffset;
struct keywest_iface* iface;
u32 *psteps, *prate;
int rc;
if (np->n_intrs < 1 || np->n_addrs < 1) {
printk(KERN_ERR "%s: Missing interrupt or address !\n",
np->full_name);
return -ENODEV;
}
if (pmac_low_i2c_lock(np))
return -ENODEV;
psteps = (u32 *)get_property(np, "AAPL,address-step", NULL);
steps = psteps ? (*psteps) : 0x10;
/* Hrm... maybe we can be smarter here */
for (bsteps = 0; (steps & 0x01) == 0; bsteps++)
steps >>= 1;
if (np->parent->name[0] == 'u') {
nchan = 2;
addroffset = 3;
} else {
addroffset = 0;
nchan = 1;
}
tsize = sizeof(struct keywest_iface) +
(sizeof(struct keywest_chan) + 4) * nchan;
iface = (struct keywest_iface *) kmalloc(tsize, GFP_KERNEL);
if (iface == NULL) {
printk(KERN_ERR "i2c-keywest: can't allocate inteface !\n");
pmac_low_i2c_unlock(np);
return -ENOMEM;
}
memset(iface, 0, tsize);
spin_lock_init(&iface->lock);
init_completion(&iface->complete);
iface->node = of_node_get(np);
iface->bsteps = bsteps;
iface->chan_count = nchan;
iface->state = state_idle;
iface->irq = np->intrs[0].line;
iface->channels = (struct keywest_chan *)
(((unsigned long)(iface + 1) + 3UL) & ~3UL);
iface->base = ioremap(np->addrs[0].address + addroffset,
np->addrs[0].size);
if (!iface->base) {
printk(KERN_ERR "i2c-keywest: can't map inteface !\n");
kfree(iface);
pmac_low_i2c_unlock(np);
return -ENOMEM;
}
#ifndef POLLED_MODE
init_timer(&iface->timeout_timer);
iface->timeout_timer.function = keywest_timeout;
iface->timeout_timer.data = (unsigned long)iface;
#endif
/* Select interface rate */
iface->cur_mode = KW_I2C_MODE_100KHZ;
prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL);
if (prate) switch(*prate) {
case 100:
iface->cur_mode = KW_I2C_MODE_100KHZ;
break;
case 50:
iface->cur_mode = KW_I2C_MODE_50KHZ;
break;
case 25:
iface->cur_mode = KW_I2C_MODE_25KHZ;
break;
default:
printk(KERN_WARNING "i2c-keywest: unknown rate %ldKhz, using 100KHz\n",
(long)*prate);
}
/* Select standard mode by default */
iface->cur_mode |= KW_I2C_MODE_STANDARD;
/* Write mode */
write_reg(reg_mode, iface->cur_mode);
/* Switch interrupts off & clear them*/
write_reg(reg_ier, 0x00);
write_reg(reg_isr, KW_I2C_IRQ_MASK);
#ifndef POLLED_MODE
/* Request chip interrupt */
rc = request_irq(iface->irq, keywest_irq, SA_INTERRUPT, "keywest i2c", iface);
if (rc) {
printk(KERN_ERR "i2c-keywest: can't get IRQ %d !\n", iface->irq);
iounmap(iface->base);
kfree(iface);
pmac_low_i2c_unlock(np);
return -ENODEV;
}
#endif /* POLLED_MODE */
pmac_low_i2c_unlock(np);
dev_set_drvdata(dev, iface);
for (i=0; i<nchan; i++) {
struct keywest_chan* chan = &iface->channels[i];
u8 addr;
sprintf(chan->adapter.name, "%s %d", np->parent->name, i);
chan->iface = iface;
chan->chan_no = i;
chan->adapter.algo = &keywest_algorithm;
chan->adapter.algo_data = NULL;
chan->adapter.client_register = NULL;
chan->adapter.client_unregister = NULL;
i2c_set_adapdata(&chan->adapter, chan);
chan->adapter.dev.parent = dev;
rc = i2c_add_adapter(&chan->adapter);
if (rc) {
printk("i2c-keywest.c: Adapter %s registration failed\n",
chan->adapter.name);
i2c_set_adapdata(&chan->adapter, NULL);
}
}
printk(KERN_INFO "Found KeyWest i2c on \"%s\", %d channel%s, stepping: %d bits\n",
np->parent->name, nchan, nchan > 1 ? "s" : "", bsteps);
return 0;
}
static int
dispose_iface(struct device *dev)
{
struct keywest_iface *iface = dev_get_drvdata(dev);
int i, rc;
/* Make sure we stop all activity */
if (pmac_low_i2c_lock(iface->node))
return -ENODEV;
#ifndef POLLED_MODE
spin_lock_irq(&iface->lock);
while (iface->state != state_idle) {
spin_unlock_irq(&iface->lock);
msleep(100);
spin_lock_irq(&iface->lock);
}
#endif /* POLLED_MODE */
iface->state = state_dead;
#ifndef POLLED_MODE
spin_unlock_irq(&iface->lock);
free_irq(iface->irq, iface);
#endif /* POLLED_MODE */
pmac_low_i2c_unlock(iface->node);
/* Release all channels */
for (i=0; i<iface->chan_count; i++) {
struct keywest_chan* chan = &iface->channels[i];
if (i2c_get_adapdata(&chan->adapter) == NULL)
continue;
rc = i2c_del_adapter(&chan->adapter);
i2c_set_adapdata(&chan->adapter, NULL);
/* We aren't that prepared to deal with this... */
if (rc)
printk("i2c-keywest.c: i2c_del_adapter failed, that's bad !\n");
}
iounmap(iface->base);
dev_set_drvdata(dev, NULL);
of_node_put(iface->node);
kfree(iface);
return 0;
}
static int
create_iface_macio(struct macio_dev* dev, const struct of_device_id *match)
{
return create_iface(dev->ofdev.node, &dev->ofdev.dev);
}
static int
dispose_iface_macio(struct macio_dev* dev)
{
return dispose_iface(&dev->ofdev.dev);
}
static int
create_iface_of_platform(struct of_device* dev, const struct of_device_id *match)
{
return create_iface(dev->node, &dev->dev);
}
static int
dispose_iface_of_platform(struct of_device* dev)
{
return dispose_iface(&dev->dev);
}
static struct of_device_id i2c_keywest_match[] =
{
{
.type = "i2c",
.compatible = "keywest"
},
{},
};
static struct macio_driver i2c_keywest_macio_driver =
{
.name = "i2c-keywest",
.match_table = i2c_keywest_match,
.probe = create_iface_macio,
.remove = dispose_iface_macio
};
static struct of_platform_driver i2c_keywest_of_platform_driver =
{
.name = "i2c-keywest",
.match_table = i2c_keywest_match,
.probe = create_iface_of_platform,
.remove = dispose_iface_of_platform
};
static int __init
i2c_keywest_init(void)
{
of_register_driver(&i2c_keywest_of_platform_driver);
macio_register_driver(&i2c_keywest_macio_driver);
return 0;
}
static void __exit
i2c_keywest_cleanup(void)
{
of_unregister_driver(&i2c_keywest_of_platform_driver);
macio_unregister_driver(&i2c_keywest_macio_driver);
}
module_init(i2c_keywest_init);
module_exit(i2c_keywest_cleanup);
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