linux/drivers/i2c/busses/i2c-iop3xx.c

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/* ------------------------------------------------------------------------- */
/* i2c-iop3xx.c i2c driver algorithms for Intel XScale IOP3xx & IXP46x */
/* ------------------------------------------------------------------------- */
/* Copyright (C) 2003 Peter Milne, D-TACQ Solutions Ltd
* <Peter dot Milne at D hyphen TACQ dot com>
*
* With acknowledgements to i2c-algo-ibm_ocp.c by
* Ian DaSilva, MontaVista Software, Inc. idasilva@mvista.com
*
* And i2c-algo-pcf.c, which was created by Simon G. Vogl and Hans Berglund:
*
* Copyright (C) 1995-1997 Simon G. Vogl, 1998-2000 Hans Berglund
*
* And which acknowledged Kyösti Mälkki <kmalkki@cc.hut.fi>,
* Frodo Looijaard <frodol@dds.nl>, Martin Bailey<mbailey@littlefeet-inc.com>
*
* Major cleanup by Deepak Saxena <dsaxena@plexity.net>, 01/2005:
*
* - Use driver model to pass per-chip info instead of hardcoding and #ifdefs
* - Use ioremap/__raw_readl/__raw_writel instead of direct dereference
* - Make it work with IXP46x chips
* - Cleanup function names, coding style, etc
*
* - writing to slave address causes latchup on iop331.
* fix: driver refuses to address self.
*
* 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, version 2.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <asm/io.h>
#include "i2c-iop3xx.h"
/* global unit counter */
static int i2c_id;
static inline unsigned char
iic_cook_addr(struct i2c_msg *msg)
{
unsigned char addr;
addr = (msg->addr << 1);
if (msg->flags & I2C_M_RD)
addr |= 1;
/*
* Read or Write?
*/
if (msg->flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
return addr;
}
static void
iop3xx_i2c_reset(struct i2c_algo_iop3xx_data *iop3xx_adap)
{
/* Follows devman 9.3 */
__raw_writel(IOP3XX_ICR_UNIT_RESET, iop3xx_adap->ioaddr + CR_OFFSET);
__raw_writel(IOP3XX_ISR_CLEARBITS, iop3xx_adap->ioaddr + SR_OFFSET);
__raw_writel(0, iop3xx_adap->ioaddr + CR_OFFSET);
}
static void
iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
{
u32 cr = IOP3XX_ICR_GCD | IOP3XX_ICR_SCLEN | IOP3XX_ICR_UE;
/*
* Every time unit enable is asserted, GPOD needs to be cleared
* on IOP3XX to avoid data corruption on the bus.
*/
#if defined(CONFIG_ARCH_IOP32X) || defined(CONFIG_ARCH_IOP33X)
if (iop3xx_adap->id == 0) {
gpio_line_set(IOP3XX_GPIO_LINE(7), GPIO_LOW);
gpio_line_set(IOP3XX_GPIO_LINE(6), GPIO_LOW);
} else {
gpio_line_set(IOP3XX_GPIO_LINE(5), GPIO_LOW);
gpio_line_set(IOP3XX_GPIO_LINE(4), GPIO_LOW);
}
#endif
/* NB SR bits not same position as CR IE bits :-( */
iop3xx_adap->SR_enabled =
IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
}
static void
iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
{
unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
}
/*
* NB: the handler has to clear the source of the interrupt!
* Then it passes the SR flags of interest to BH via adap data
*/
static irqreturn_t
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
iop3xx_i2c_irq_handler(int this_irq, void *dev_id)
{
struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
if ((sr &= iop3xx_adap->SR_enabled)) {
__raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
iop3xx_adap->SR_received |= sr;
wake_up_interruptible(&iop3xx_adap->waitq);
}
return IRQ_HANDLED;
}
/* check all error conditions, clear them , report most important */
static int
iop3xx_i2c_error(u32 sr)
{
int rc = 0;
if ((sr & IOP3XX_ISR_BERRD)) {
if ( !rc ) rc = -I2C_ERR_BERR;
}
if ((sr & IOP3XX_ISR_ALD)) {
if ( !rc ) rc = -I2C_ERR_ALD;
}
return rc;
}
static inline u32
iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
{
unsigned long flags;
u32 sr;
spin_lock_irqsave(&iop3xx_adap->lock, flags);
sr = iop3xx_adap->SR_received;
iop3xx_adap->SR_received = 0;
spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
return sr;
}
/*
* sleep until interrupted, then recover and analyse the SR
* saved by handler
*/
typedef int (* compare_func)(unsigned test, unsigned mask);
/* returns 1 on correct comparison */
static int
iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
unsigned flags, unsigned* status,
compare_func compare)
{
unsigned sr = 0;
int interrupted;
int done;
int rc = 0;
do {
interrupted = wait_event_interruptible_timeout (
iop3xx_adap->waitq,
(done = compare( sr = iop3xx_i2c_get_srstat(iop3xx_adap) ,flags )),
1 * HZ;
);
if ((rc = iop3xx_i2c_error(sr)) < 0) {
*status = sr;
return rc;
} else if (!interrupted) {
*status = sr;
return -ETIMEDOUT;
}
} while(!done);
*status = sr;
return 0;
}
/*
* Concrete compare_funcs
*/
static int
all_bits_clear(unsigned test, unsigned mask)
{
return (test & mask) == 0;
}
static int
any_bits_set(unsigned test, unsigned mask)
{
return (test & mask) != 0;
}
static int
iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
{
return iop3xx_i2c_wait_event(
iop3xx_adap,
IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
status, any_bits_set);
}
static int
iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
{
return iop3xx_i2c_wait_event(
iop3xx_adap,
IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
status, any_bits_set);
}
static int
iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
{
return iop3xx_i2c_wait_event(
iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
}
static int
iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
struct i2c_msg* msg)
{
unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
int status;
int rc;
/* avoid writing to my slave address (hangs on 80331),
* forbidden in Intel developer manual
*/
if (msg->addr == MYSAR) {
return -EBUSY;
}
__raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
return rc;
}
static int
iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
int stop)
{
unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
int status;
int rc = 0;
__raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
cr &= ~IOP3XX_ICR_MSTART;
if (stop) {
cr |= IOP3XX_ICR_MSTOP;
} else {
cr &= ~IOP3XX_ICR_MSTOP;
}
cr |= IOP3XX_ICR_TBYTE;
__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
return rc;
}
static int
iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char* byte,
int stop)
{
unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
int status;
int rc = 0;
cr &= ~IOP3XX_ICR_MSTART;
if (stop) {
cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
} else {
cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
}
cr |= IOP3XX_ICR_TBYTE;
__raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
*byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
return rc;
}
static int
iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
{
struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
int ii;
int rc = 0;
for (ii = 0; rc == 0 && ii != count; ++ii)
rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii==count-1);
return rc;
}
static int
iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
{
struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
int ii;
int rc = 0;
for (ii = 0; rc == 0 && ii != count; ++ii)
rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii==count-1);
return rc;
}
/*
* Description: This function implements combined transactions. Combined
* transactions consist of combinations of reading and writing blocks of data.
* FROM THE SAME ADDRESS
* Each transfer (i.e. a read or a write) is separated by a repeated start
* condition.
*/
static int
iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg* pmsg)
{
struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
int rc;
rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
if (rc < 0) {
return rc;
}
if ((pmsg->flags&I2C_M_RD)) {
return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
} else {
return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
}
}
/*
* master_xfer() - main read/write entry
*/
static int
iop3xx_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
int num)
{
struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
int im = 0;
int ret = 0;
int status;
iop3xx_i2c_wait_idle(iop3xx_adap, &status);
iop3xx_i2c_reset(iop3xx_adap);
iop3xx_i2c_enable(iop3xx_adap);
for (im = 0; ret == 0 && im != num; im++) {
ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
}
iop3xx_i2c_transaction_cleanup(iop3xx_adap);
if(ret)
return ret;
return im;
}
static u32
iop3xx_i2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm iop3xx_i2c_algo = {
.master_xfer = iop3xx_i2c_master_xfer,
.functionality = iop3xx_i2c_func,
};
static int
iop3xx_i2c_remove(struct platform_device *pdev)
{
struct i2c_adapter *padapter = platform_get_drvdata(pdev);
struct i2c_algo_iop3xx_data *adapter_data =
(struct i2c_algo_iop3xx_data *)padapter->algo_data;
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
/*
* Disable the actual HW unit
*/
cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
__raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
iounmap((void __iomem*)adapter_data->ioaddr);
release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
kfree(adapter_data);
kfree(padapter);
platform_set_drvdata(pdev, NULL);
return 0;
}
static int
iop3xx_i2c_probe(struct platform_device *pdev)
{
struct resource *res;
int ret, irq;
struct i2c_adapter *new_adapter;
struct i2c_algo_iop3xx_data *adapter_data;
new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
if (!new_adapter) {
ret = -ENOMEM;
goto out;
}
adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
if (!adapter_data) {
ret = -ENOMEM;
goto free_adapter;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
ret = -ENODEV;
goto free_both;
}
if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
ret = -EBUSY;
goto free_both;
}
/* set the adapter enumeration # */
adapter_data->id = i2c_id++;
adapter_data->ioaddr = (u32)ioremap(res->start, IOP3XX_I2C_IO_SIZE);
if (!adapter_data->ioaddr) {
ret = -ENOMEM;
goto release_region;
}
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
ret = -ENXIO;
goto unmap;
}
ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
pdev->name, adapter_data);
if (ret) {
ret = -EIO;
goto unmap;
}
memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
new_adapter->owner = THIS_MODULE;
new_adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
new_adapter->dev.parent = &pdev->dev;
new_adapter->nr = pdev->id;
/*
* Default values...should these come in from board code?
*/
new_adapter->timeout = 100;
new_adapter->algo = &iop3xx_i2c_algo;
init_waitqueue_head(&adapter_data->waitq);
spin_lock_init(&adapter_data->lock);
iop3xx_i2c_reset(adapter_data);
iop3xx_i2c_enable(adapter_data);
platform_set_drvdata(pdev, new_adapter);
new_adapter->algo_data = adapter_data;
i2c_add_numbered_adapter(new_adapter);
return 0;
unmap:
iounmap((void __iomem*)adapter_data->ioaddr);
release_region:
release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
free_both:
kfree(adapter_data);
free_adapter:
kfree(new_adapter);
out:
return ret;
}
static struct platform_driver iop3xx_i2c_driver = {
.probe = iop3xx_i2c_probe,
.remove = iop3xx_i2c_remove,
.driver = {
.owner = THIS_MODULE,
.name = "IOP3xx-I2C",
},
};
static int __init
i2c_iop3xx_init (void)
{
return platform_driver_register(&iop3xx_i2c_driver);
}
static void __exit
i2c_iop3xx_exit (void)
{
platform_driver_unregister(&iop3xx_i2c_driver);
return;
}
module_init (i2c_iop3xx_init);
module_exit (i2c_iop3xx_exit);
MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:IOP3xx-I2C");