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linux/drivers/i2c/busses/i2c-iop3xx.c
Jean Delvare 3401b2fff3 i2c: Let bus drivers add SPD to their class 
Let general purpose I2C/SMBus bus drivers add SPD to their class. Once
this is done, we will be able to tell the eeprom driver to only probe
for SPD EEPROMs and similar on these buses.

Note that I took a conservative approach here, adding I2C_CLASS_SPD to
many drivers that have no idea whether they can host SPD EEPROMs or not.
This is to make sure that the eeprom driver doesn't stop probing buses
where SPD EEPROMs or equivalent live.

So, bus driver maintainers and users should feel free to remove the SPD
class from drivers those buses never have SPD EEPROMs or they don't
want the eeprom driver to bind to them. Likewise, feel free to add the
SPD class to any bus driver I might have missed.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
2008-07-14 22:38:29 +02:00

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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
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->id = I2C_HW_IOP3XX;
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");
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