// SPDX-License-Identifier: GPL-2.0-only
/* ------------------------------------------------------------------------- */
/* 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. [email protected]
*
* 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 <[email protected]>,
* Frodo Looijaard <[email protected]>, Martin Bailey<[email protected]>
*
* Major cleanup by Deepak Saxena <[email protected]>, 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 local target address causes latchup on iop331.
* fix: driver refuses to address self.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/gpio/consumer.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 = i2c_8bit_addr_from_msg(msg);
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. We use the
* gpiod_set_raw_value() to make sure the 0 hits the hardware
* GPOD register. These descriptors are only passed along to
* the device if this is necessary.
*/
if (iop3xx_adap->gpio_scl)
gpiod_set_raw_value(iop3xx_adap->gpio_scl, 0);
if (iop3xx_adap->gpio_sda)
gpiod_set_raw_value(iop3xx_adap->gpio_sda, 0);
/* 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 local target 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);
}
}
static int
iop3xx_i2c_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 = {
.xfer = iop3xx_i2c_xfer,
.functionality = iop3xx_i2c_func,
};
static void
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(adapter_data->ioaddr);
release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
kfree(adapter_data);
kfree(padapter);
}
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;
}
adapter_data->gpio_scl = devm_gpiod_get_optional(&pdev->dev,
"scl",
GPIOD_ASIS);
if (IS_ERR(adapter_data->gpio_scl)) {
ret = PTR_ERR(adapter_data->gpio_scl);
goto free_both;
}
adapter_data->gpio_sda = devm_gpiod_get_optional(&pdev->dev,
"sda",
GPIOD_ASIS);
if (IS_ERR(adapter_data->gpio_sda)) {
ret = PTR_ERR(adapter_data->gpio_sda);
goto free_both;
}
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 = 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 = irq;
goto unmap;
}
ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
pdev->name, adapter_data);
if (ret)
goto unmap;
memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
new_adapter->owner = THIS_MODULE;
new_adapter->class = I2C_CLASS_HWMON;
new_adapter->dev.parent = &pdev->dev;
new_adapter->dev.of_node = pdev->dev.of_node;
new_adapter->nr = pdev->id;
/*
* Default values...should these come in from board code?
*/
new_adapter->timeout = HZ;
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(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 const struct of_device_id i2c_iop3xx_match[] = {
{ .compatible = "intel,iop3xx-i2c", },
{ .compatible = "intel,ixp4xx-i2c", },
{},
};
MODULE_DEVICE_TABLE(of, i2c_iop3xx_match);
static struct platform_driver iop3xx_i2c_driver = {
.probe = iop3xx_i2c_probe,
.remove_new = iop3xx_i2c_remove,
.driver = {
.name = "IOP3xx-I2C",
.of_match_table = i2c_iop3xx_match,
},
};
module_platform_driver(iop3xx_i2c_driver);
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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