/*
* drivers/i2c/i2c-ibm_iic.c
*
* Support for the IIC peripheral on IBM PPC 4xx
*
* Copyright (c) 2003 Zultys Technologies.
* Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
*
* Based on original work by
* Ian DaSilva <idasilva@mvista.com>
* Armin Kuster <akuster@mvista.com>
* Matt Porter <mporter@mvista.com>
*
* Copyright 2000-2003 MontaVista Software Inc.
*
* Original driver version was highly leveraged from i2c-elektor.c
*
* Copyright 1995-97 Simon G. Vogl
* 1998-99 Hans Berglund
*
* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
* and even Frodo Looijaard <frodol@dds.nl>
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/ioport.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <asm/ocp.h>
#include <asm/ibm4xx.h>
#include "i2c-ibm_iic.h"
#define DRIVER_VERSION "2.0"
MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION);
MODULE_LICENSE("GPL");
static int iic_scan = 0;
MODULE_PARM(iic_scan, "i");
MODULE_PARM_DESC(iic_scan, "Scan for active chips on the bus");
static int iic_force_poll = 0;
MODULE_PARM(iic_force_poll, "i");
MODULE_PARM_DESC(iic_force_poll, "Force polling mode");
static int iic_force_fast = 0;
MODULE_PARM(iic_force_fast, "i");
MODULE_PARM_DESC(iic_fast_poll, "Force fast mode (400 kHz)");
#define DBG_LEVEL 0
#ifdef DBG
#undef DBG
#endif
#ifdef DBG2
#undef DBG2
#endif
#if DBG_LEVEL > 0
# define DBG(x...) printk(KERN_DEBUG "ibm-iic" ##x)
#else
# define DBG(x...) ((void)0)
#endif
#if DBG_LEVEL > 1
# define DBG2(x...) DBG( ##x )
#else
# define DBG2(x...) ((void)0)
#endif
#if DBG_LEVEL > 2
static void dump_iic_regs(const char* header, struct ibm_iic_private* dev)
{
volatile struct iic_regs *iic = dev->vaddr;
printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header);
printk(KERN_DEBUG " cntl = 0x%02x, mdcntl = 0x%02x\n"
KERN_DEBUG " sts = 0x%02x, extsts = 0x%02x\n"
KERN_DEBUG " clkdiv = 0x%02x, xfrcnt = 0x%02x\n"
KERN_DEBUG " xtcntlss = 0x%02x, directcntl = 0x%02x\n",
in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts),
in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt),
in_8(&iic->xtcntlss), in_8(&iic->directcntl));
}
# define DUMP_REGS(h,dev) dump_iic_regs((h),(dev))
#else
# define DUMP_REGS(h,dev) ((void)0)
#endif
/* Enable/disable interrupt generation */
static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable)
{
out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0);
}
/*
* Initialize IIC interface.
*/
static void iic_dev_init(struct ibm_iic_private* dev)
{
volatile struct iic_regs *iic = dev->vaddr;
DBG("%d: init\n", dev->idx);
/* Clear master address */
out_8(&iic->lmadr, 0);
out_8(&iic->hmadr, 0);
/* Clear slave address */
out_8(&iic->lsadr, 0);
out_8(&iic->hsadr, 0);
/* Clear status & extended status */
out_8(&iic->sts, STS_SCMP | STS_IRQA);
out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA
| EXTSTS_ICT | EXTSTS_XFRA);
/* Set clock divider */
out_8(&iic->clkdiv, dev->clckdiv);
/* Clear transfer count */
out_8(&iic->xfrcnt, 0);
/* Clear extended control and status */
out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC
| XTCNTLSS_SWS);
/* Clear control register */
out_8(&iic->cntl, 0);
/* Enable interrupts if possible */
iic_interrupt_mode(dev, dev->irq >= 0);
/* Set mode control */
out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS
| (dev->fast_mode ? MDCNTL_FSM : 0));
DUMP_REGS("iic_init", dev);
}
/*
* Reset IIC interface
*/
static void iic_dev_reset(struct ibm_iic_private* dev)
{
volatile struct iic_regs *iic = dev->vaddr;
int i;
u8 dc;
DBG("%d: soft reset\n", dev->idx);
DUMP_REGS("reset", dev);
/* Place chip in the reset state */
out_8(&iic->xtcntlss, XTCNTLSS_SRST);
/* Check if bus is free */
dc = in_8(&iic->directcntl);
if (!DIRCTNL_FREE(dc)){
DBG("%d: trying to regain bus control\n", dev->idx);
/* Try to set bus free state */
out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC);
/* Wait until we regain bus control */
for (i = 0; i < 100; ++i){
dc = in_8(&iic->directcntl);
if (DIRCTNL_FREE(dc))
break;
/* Toggle SCL line */
dc ^= DIRCNTL_SCC;
out_8(&iic->directcntl, dc);
udelay(10);
dc ^= DIRCNTL_SCC;
out_8(&iic->directcntl, dc);
/* be nice */
cond_resched();
}
}
/* Remove reset */
out_8(&iic->xtcntlss, 0);
/* Reinitialize interface */
iic_dev_init(dev);
}
/*
* IIC interrupt handler
*/
static irqreturn_t iic_handler(int irq, void *dev_id, struct pt_regs *regs)
{
struct ibm_iic_private* dev = (struct ibm_iic_private*)dev_id;
volatile struct iic_regs* iic = dev->vaddr;
DBG2("%d: irq handler, STS = 0x%02x, EXTSTS = 0x%02x\n",
dev->idx, in_8(&iic->sts), in_8(&iic->extsts));
/* Acknowledge IRQ and wakeup iic_wait_for_tc */
out_8(&iic->sts, STS_IRQA | STS_SCMP);
wake_up_interruptible(&dev->wq);
return IRQ_HANDLED;
}
/*
* Get master transfer result and clear errors if any.
* Returns the number of actually transferred bytes or error (<0)
*/
static int iic_xfer_result(struct ibm_iic_private* dev)
{
volatile struct iic_regs *iic = dev->vaddr;
if (unlikely(in_8(&iic->sts) & STS_ERR)){
DBG("%d: xfer error, EXTSTS = 0x%02x\n", dev->idx,
in_8(&iic->extsts));
/* Clear errors and possible pending IRQs */
out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD |
EXTSTS_LA | EXTSTS_ICT | EXTSTS_XFRA);
/* Flush master data buffer */
out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
/* Is bus free?
* If error happened during combined xfer
* IIC interface is usually stuck in some strange
* state, the only way out - soft reset.
*/
if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
DBG("%d: bus is stuck, resetting\n", dev->idx);
iic_dev_reset(dev);
}
return -EREMOTEIO;
}
else
return in_8(&iic->xfrcnt) & XFRCNT_MTC_MASK;
}
/*
* Try to abort active transfer.
*/
static void iic_abort_xfer(struct ibm_iic_private* dev)
{
volatile struct iic_regs *iic = dev->vaddr;
unsigned long x;
DBG("%d: iic_abort_xfer\n", dev->idx);
out_8(&iic->cntl, CNTL_HMT);
/*
* Wait for the abort command to complete.
* It's not worth to be optimized, just poll (timeout >= 1 tick)
*/
x = jiffies + 2;
while ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
if (time_after(jiffies, x)){
DBG("%d: abort timeout, resetting...\n", dev->idx);
iic_dev_reset(dev);
return;
}
schedule();
}
/* Just to clear errors */
iic_xfer_result(dev);
}
/*
* Wait for master transfer to complete.
* It puts current process to sleep until we get interrupt or timeout expires.
* Returns the number of transferred bytes or error (<0)
*/
static int iic_wait_for_tc(struct ibm_iic_private* dev){
volatile struct iic_regs *iic = dev->vaddr;
int ret = 0;
if (dev->irq >= 0){
/* Interrupt mode */
wait_queue_t wait;
init_waitqueue_entry(&wait, current);
add_wait_queue(&dev->wq, &wait);
set_current_state(TASK_INTERRUPTIBLE);
if (in_8(&iic->sts) & STS_PT)
schedule_timeout(dev->adap.timeout * HZ);
set_current_state(TASK_RUNNING);
remove_wait_queue(&dev->wq, &wait);
if (unlikely(signal_pending(current))){
DBG("%d: wait interrupted\n", dev->idx);
ret = -ERESTARTSYS;
} else if (unlikely(in_8(&iic->sts) & STS_PT)){
DBG("%d: wait timeout\n", dev->idx);
ret = -ETIMEDOUT;
}
}
else {
/* Polling mode */
unsigned long x = jiffies + dev->adap.timeout * HZ;
while (in_8(&iic->sts) & STS_PT){
if (unlikely(time_after(jiffies, x))){
DBG("%d: poll timeout\n", dev->idx);
ret = -ETIMEDOUT;
break;
}
if (unlikely(signal_pending(current))){
DBG("%d: poll interrupted\n", dev->idx);
ret = -ERESTARTSYS;
break;
}
schedule();
}
}
if (unlikely(ret < 0))
iic_abort_xfer(dev);
else
ret = iic_xfer_result(dev);
DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret);
return ret;
}
/*
* Low level master transfer routine
*/
static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm,
int combined_xfer)
{
volatile struct iic_regs *iic = dev->vaddr;
char* buf = pm->buf;
int i, j, loops, ret = 0;
int len = pm->len;
u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT;
if (pm->flags & I2C_M_RD)
cntl |= CNTL_RW;
loops = (len + 3) / 4;
for (i = 0; i < loops; ++i, len -= 4){
int count = len > 4 ? 4 : len;
u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT);
if (!(cntl & CNTL_RW))
for (j = 0; j < count; ++j)
out_8((volatile u8*)&iic->mdbuf, *buf++);
if (i < loops - 1)
cmd |= CNTL_CHT;
else if (combined_xfer)
cmd |= CNTL_RPST;
DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd);
/* Start transfer */
out_8(&iic->cntl, cmd);
/* Wait for completion */
ret = iic_wait_for_tc(dev);
if (unlikely(ret < 0))
break;
else if (unlikely(ret != count)){
DBG("%d: xfer_bytes, requested %d, transfered %d\n",
dev->idx, count, ret);
/* If it's not a last part of xfer, abort it */
if (combined_xfer || (i < loops - 1))
iic_abort_xfer(dev);
ret = -EREMOTEIO;
break;
}
if (cntl & CNTL_RW)
for (j = 0; j < count; ++j)
*buf++ = in_8((volatile u8*)&iic->mdbuf);
}
return ret > 0 ? 0 : ret;
}
/*
* Set target slave address for master transfer
*/
static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg)
{
volatile struct iic_regs *iic = dev->vaddr;
u16 addr = msg->addr;
DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx,
addr, msg->flags & I2C_M_TEN ? 10 : 7);
if (msg->flags & I2C_M_TEN){
out_8(&iic->cntl, CNTL_AMD);
out_8(&iic->lmadr, addr);
out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06));
}
else {
out_8(&iic->cntl, 0);
out_8(&iic->lmadr, addr << 1);
}
}
static inline int iic_invalid_address(const struct i2c_msg* p)
{
return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f));
}
static inline int iic_address_neq(const struct i2c_msg* p1,
const struct i2c_msg* p2)
{
return (p1->addr != p2->addr)
|| ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN));
}
/*
* Generic master transfer entrypoint.
* Returns the number of processed messages or error (<0)
*/
static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap));
volatile struct iic_regs *iic = dev->vaddr;
int i, ret = 0;
DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num);
if (!num)
return 0;
/* Check the sanity of the passed messages.
* Uhh, generic i2c layer is more suitable place for such code...
*/
if (unlikely(iic_invalid_address(&msgs[0]))){
DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx,
msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7);
return -EINVAL;
}
for (i = 0; i < num; ++i){
if (unlikely(msgs[i].len <= 0)){
DBG("%d: invalid len %d in msg[%d]\n", dev->idx,
msgs[i].len, i);
return -EINVAL;
}
if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){
DBG("%d: invalid addr in msg[%d]\n", dev->idx, i);
return -EINVAL;
}
}
/* Check bus state */
if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){
DBG("%d: iic_xfer, bus is not free\n", dev->idx);
/* Usually it means something serious has happend.
* We *cannot* have unfinished previous transfer
* so it doesn't make any sense to try to stop it.
* Probably we were not able to recover from the
* previous error.
* The only *reasonable* thing I can think of here
* is soft reset. --ebs
*/
iic_dev_reset(dev);
if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){
DBG("%d: iic_xfer, bus is still not free\n", dev->idx);
return -EREMOTEIO;
}
}
else {
/* Flush master data buffer (just in case) */
out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB);
}
/* Load slave address */
iic_address(dev, &msgs[0]);
/* Do real transfer */
for (i = 0; i < num && !ret; ++i)
ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1);
return ret < 0 ? ret : num;
}
static u32 iic_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
}
static struct i2c_algorithm iic_algo = {
.name = "IBM IIC algorithm",
.id = I2C_ALGO_OCP,
.master_xfer = iic_xfer,
.smbus_xfer = NULL,
.slave_send = NULL,
.slave_recv = NULL,
.algo_control = NULL,
.functionality = iic_func
};
/*
* Scan bus for valid 7-bit addresses (ie things that ACK on 1 byte read)
* We only scan range [0x08 - 0x77], all other addresses are reserved anyway
*/
static void __devinit iic_scan_bus(struct ibm_iic_private* dev)
{
int found = 0;
char dummy;
struct i2c_msg msg = {
.buf = &dummy,
.len = sizeof(dummy),
.flags = I2C_M_RD
};
printk(KERN_INFO "ibm-iic%d: scanning bus...\n" KERN_INFO, dev->idx);
for (msg.addr = 8; msg.addr < 0x78; ++msg.addr)
if (iic_xfer(&dev->adap, &msg, 1) == 1){
++found;
printk(" 0x%02x", msg.addr);
}
printk("%sibm-iic%d: %d device(s) detected\n",
found ? "\n" KERN_INFO : "", dev->idx, found);
}
/*
* Calculates IICx_CLCKDIV value for a specific OPB clock frequency
*/
static inline u8 iic_clckdiv(unsigned int opb)
{
/* Compatibility kludge, should go away after all cards
* are fixed to fill correct value for opbfreq.
* Previous driver version used hardcoded divider value 4,
* it corresponds to OPB frequency from the range (40, 50] MHz
*/
if (!opb){
printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq,"
" fix your board specific setup\n");
opb = 50000000;
}
/* Convert to MHz */
opb /= 1000000;
if (opb < 20 || opb > 150){
printk(KERN_CRIT "ibm-iic: invalid OPB clock frequency %u MHz\n",
opb);
opb = opb < 20 ? 20 : 150;
}
return (u8)((opb + 9) / 10 - 1);
}
/*
* Register single IIC interface
*/
static int __devinit iic_probe(struct ocp_device *ocp){
struct ibm_iic_private* dev;
struct i2c_adapter* adap;
int ret;
bd_t* bd = (bd_t*)&__res;
if (!(dev = kmalloc(sizeof(*dev), GFP_KERNEL))){
printk(KERN_CRIT "ibm-iic: failed to allocate device data\n");
return -ENOMEM;
}
memset(dev, 0, sizeof(*dev));
dev->idx = ocp->num;
ocp_set_drvdata(ocp, dev);
if (!(dev->vaddr = ioremap(ocp->paddr, sizeof(struct iic_regs)))){
printk(KERN_CRIT "ibm-iic%d: failed to ioremap device registers\n",
dev->idx);
ret = -ENXIO;
goto fail2;
}
init_waitqueue_head(&dev->wq);
dev->irq = iic_force_poll ? -1 : ocp->irq;
if (dev->irq >= 0){
/* Disable interrupts until we finish intialization,
assumes level-sensitive IRQ setup...
*/
iic_interrupt_mode(dev, 0);
if (request_irq(dev->irq, iic_handler, 0, "IBM IIC", dev)){
printk(KERN_ERR "ibm-iic%d: request_irq %d failed\n",
dev->idx, dev->irq);
/* Fallback to the polling mode */
dev->irq = -1;
}
}
if (dev->irq < 0)
printk(KERN_WARNING "ibm-iic%d: using polling mode\n",
dev->idx);
/* Board specific settings */
BUG_ON(dev->idx >= sizeof(bd->bi_iic_fast) / sizeof(bd->bi_iic_fast[0]));
dev->fast_mode = iic_force_fast ? 1 : bd->bi_iic_fast[dev->idx];
/* clckdiv is the same for *all* IIC interfaces,
* but I'd rather make a copy than introduce another global. --ebs
*/
dev->clckdiv = iic_clckdiv(bd->bi_opb_busfreq);
DBG("%d: clckdiv = %d\n", dev->idx, dev->clckdiv);
/* Initialize IIC interface */
iic_dev_init(dev);
/* Register it with i2c layer */
adap = &dev->adap;
strcpy(adap->dev.name, "IBM IIC");
i2c_set_adapdata(adap, dev);
adap->id = I2C_HW_OCP | iic_algo.id;
adap->algo = &iic_algo;
adap->client_register = NULL;
adap->client_unregister = NULL;
adap->timeout = 1;
adap->retries = 1;
if ((ret = i2c_add_adapter(adap)) != 0){
printk(KERN_CRIT "ibm-iic%d: failed to register i2c adapter\n",
dev->idx);
goto fail;
}
printk(KERN_INFO "ibm-iic%d: using %s mode\n", dev->idx,
dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)");
/* Scan bus if requested by user */
if (iic_scan)
iic_scan_bus(dev);
return 0;
fail:
if (dev->irq >= 0){
iic_interrupt_mode(dev, 0);
free_irq(dev->irq, dev);
}
iounmap((void*)dev->vaddr);
fail2:
ocp_set_drvdata(ocp, 0);
kfree(dev);
return ret;
}
/*
* Cleanup initialized IIC interface
*/
static void __devexit iic_remove(struct ocp_device *ocp)
{
struct ibm_iic_private* dev = (struct ibm_iic_private*)ocp_get_drvdata(ocp);
BUG_ON(dev == NULL);
if (i2c_del_adapter(&dev->adap)){
printk(KERN_CRIT "ibm-iic%d: failed to delete i2c adapter :(\n",
dev->idx);
/* That's *very* bad, just shutdown IRQ ... */
if (dev->irq >= 0){
iic_interrupt_mode(dev, 0);
free_irq(dev->irq, dev);
dev->irq = -1;
}
} else {
if (dev->irq >= 0){
iic_interrupt_mode(dev, 0);
free_irq(dev->irq, dev);
}
iounmap((void*)dev->vaddr);
kfree(dev);
}
}
static struct ocp_device_id ibm_iic_ids[] __devinitdata =
{
{ .vendor = OCP_VENDOR_IBM, .device = OCP_FUNC_IIC },
{ .vendor = OCP_VENDOR_INVALID }
};
MODULE_DEVICE_TABLE(ocp, ibm_iic_ids);
static struct ocp_driver ibm_iic_driver =
{
.name = "ocp_iic",
.id_table = ibm_iic_ids,
.probe = iic_probe,
.remove = __devexit_p(iic_remove),
#if defined(CONFIG_PM)
.suspend = NULL,
.resume = NULL,
#endif
};
static int __init iic_init(void)
{
printk(KERN_INFO "IBM IIC driver v" DRIVER_VERSION "\n");
return ocp_module_init(&ibm_iic_driver);
}
static void __exit iic_exit(void)
{
ocp_unregister_driver(&ibm_iic_driver);
}
module_init(iic_init);
module_exit(iic_exit);
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