/*
* i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
* Copyright (C) 2004 Arcom Control Systems
* Copyright (C) 2008 Pengutronix
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>
#define DEB1(fmt, args...) do { if (i2c_debug >= 1) \
printk(KERN_DEBUG fmt, ## args); } while (0)
#define DEB2(fmt, args...) do { if (i2c_debug >= 2) \
printk(KERN_DEBUG fmt, ## args); } while (0)
#define DEB3(fmt, args...) do { if (i2c_debug >= 3) \
printk(KERN_DEBUG fmt, ## args); } while (0)
static int i2c_debug;
#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
#define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
#define pca_clock(adap) adap->i2c_clock
#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
#define pca_wait(adap) adap->wait_for_completion(adap->data)
static void pca_reset(struct i2c_algo_pca_data *adap)
{
if (adap->chip == I2C_PCA_CHIP_9665) {
/* Ignore the reset function from the module,
* we can use the parallel bus reset.
*/
pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
pca_outw(adap, I2C_PCA_IND, 0xA5);
pca_outw(adap, I2C_PCA_IND, 0x5A);
} else {
adap->reset_chip(adap->data);
}
}
/*
* Generate a start condition on the i2c bus.
*
* returns after the start condition has occurred
*/
static int pca_start(struct i2c_algo_pca_data *adap)
{
int sta = pca_get_con(adap);
DEB2("=== START\n");
sta |= I2C_PCA_CON_STA;
sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
pca_set_con(adap, sta);
return pca_wait(adap);
}
/*
* Generate a repeated start condition on the i2c bus
*
* return after the repeated start condition has occurred
*/
static int pca_repeated_start(struct i2c_algo_pca_data *adap)
{
int sta = pca_get_con(adap);
DEB2("=== REPEATED START\n");
sta |= I2C_PCA_CON_STA;
sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
pca_set_con(adap, sta);
return pca_wait(adap);
}
/*
* Generate a stop condition on the i2c bus
*
* returns after the stop condition has been generated
*
* STOPs do not generate an interrupt or set the SI flag, since the
* part returns the idle state (0xf8). Hence we don't need to
* pca_wait here.
*/
static void pca_stop(struct i2c_algo_pca_data *adap)
{
int sta = pca_get_con(adap);
DEB2("=== STOP\n");
sta |= I2C_PCA_CON_STO;
sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
pca_set_con(adap, sta);
}
/*
* Send the slave address and R/W bit
*
* returns after the address has been sent
*/
static int pca_address(struct i2c_algo_pca_data *adap,
struct i2c_msg *msg)
{
int sta = pca_get_con(adap);
int addr;
addr = ((0x7f & msg->addr) << 1);
if (msg->flags & I2C_M_RD)
addr |= 1;
DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
pca_outw(adap, I2C_PCA_DAT, addr);
sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
pca_set_con(adap, sta);
return pca_wait(adap);
}
/*
* Transmit a byte.
*
* Returns after the byte has been transmitted
*/
static int pca_tx_byte(struct i2c_algo_pca_data *adap,
__u8 b)
{
int sta = pca_get_con(adap);
DEB2("=== WRITE %#04x\n", b);
pca_outw(adap, I2C_PCA_DAT, b);
sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
pca_set_con(adap, sta);
return pca_wait(adap);
}
/*
* Receive a byte
*
* returns immediately.
*/
static void pca_rx_byte(struct i2c_algo_pca_data *adap,
__u8 *b, int ack)
{
*b = pca_inw(adap, I2C_PCA_DAT);
DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
}
/*
* Setup ACK or NACK for next received byte and wait for it to arrive.
*
* Returns after next byte has arrived.
*/
static int pca_rx_ack(struct i2c_algo_pca_data *adap,
int ack)
{
int sta = pca_get_con(adap);
sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
if (ack)
sta |= I2C_PCA_CON_AA;
pca_set_con(adap, sta);
return pca_wait(adap);
}
static int pca_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg *msgs,
int num)
{
struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
struct i2c_msg *msg = NULL;
int curmsg;
int numbytes = 0;
int state;
int ret;
int completed = 1;
unsigned long timeout = jiffies + i2c_adap->timeout;
while ((state = pca_status(adap)) != 0xf8) {
if (time_before(jiffies, timeout)) {
msleep(10);
} else {
dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
"%#04x\n", state);
return -EBUSY;
}
}
DEB1("{{{ XFER %d messages\n", num);
if (i2c_debug >= 2) {
for (curmsg = 0; curmsg < num; curmsg++) {
int addr, i;
msg = &msgs[curmsg];
addr = (0x7f & msg->addr) ;
if (msg->flags & I2C_M_RD)
printk(KERN_INFO " [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
curmsg, msg->len, addr, (addr << 1) | 1);
else {
printk(KERN_INFO " [%02d] WR %d bytes to %#02x [%#02x%s",
curmsg, msg->len, addr, addr << 1,
msg->len == 0 ? "" : ", ");
for (i = 0; i < msg->len; i++)
printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
printk("]\n");
}
}
}
curmsg = 0;
ret = -EIO;
while (curmsg < num) {
state = pca_status(adap);
DEB3("STATE is 0x%02x\n", state);
msg = &msgs[curmsg];
switch (state) {
case 0xf8: /* On reset or stop the bus is idle */
completed = pca_start(adap);
break;
case 0x08: /* A START condition has been transmitted */
case 0x10: /* A repeated start condition has been transmitted */
completed = pca_address(adap, msg);
break;
case 0x18: /* SLA+W has been transmitted; ACK has been received */
case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
if (numbytes < msg->len) {
completed = pca_tx_byte(adap,
msg->buf[numbytes]);
numbytes++;
break;
}
curmsg++; numbytes = 0;
if (curmsg == num)
pca_stop(adap);
else
completed = pca_repeated_start(adap);
break;
case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
DEB2("NOT ACK received after SLA+W\n");
pca_stop(adap);
ret = -ENXIO;
goto out;
case 0x40: /* SLA+R has been transmitted; ACK has been received */
completed = pca_rx_ack(adap, msg->len > 1);
break;
case 0x50: /* Data bytes has been received; ACK has been returned */
if (numbytes < msg->len) {
pca_rx_byte(adap, &msg->buf[numbytes], 1);
numbytes++;
completed = pca_rx_ack(adap,
numbytes < msg->len - 1);
break;
}
curmsg++; numbytes = 0;
if (curmsg == num)
pca_stop(adap);
else
completed = pca_repeated_start(adap);
break;
case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
DEB2("NOT ACK received after SLA+R\n");
pca_stop(adap);
ret = -ENXIO;
goto out;
case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
DEB2("NOT ACK received after data byte\n");
pca_stop(adap);
goto out;
case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
DEB2("Arbitration lost\n");
/*
* The PCA9564 data sheet (2006-09-01) says "A
* START condition will be transmitted when the
* bus becomes free (STOP or SCL and SDA high)"
* when the STA bit is set (p. 11).
*
* In case this won't work, try pca_reset()
* instead.
*/
pca_start(adap);
goto out;
case 0x58: /* Data byte has been received; NOT ACK has been returned */
if (numbytes == msg->len - 1) {
pca_rx_byte(adap, &msg->buf[numbytes], 0);
curmsg++; numbytes = 0;
if (curmsg == num)
pca_stop(adap);
else
completed = pca_repeated_start(adap);
} else {
DEB2("NOT ACK sent after data byte received. "
"Not final byte. numbytes %d. len %d\n",
numbytes, msg->len);
pca_stop(adap);
goto out;
}
break;
case 0x70: /* Bus error - SDA stuck low */
DEB2("BUS ERROR - SDA Stuck low\n");
pca_reset(adap);
goto out;
case 0x90: /* Bus error - SCL stuck low */
DEB2("BUS ERROR - SCL Stuck low\n");
pca_reset(adap);
goto out;
case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
DEB2("BUS ERROR - Illegal START or STOP\n");
pca_reset(adap);
goto out;
default:
dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
break;
}
if (!completed)
goto out;
}
ret = curmsg;
out:
DEB1("}}} transferred %d/%d messages. "
"status is %#04x. control is %#04x\n",
curmsg, num, pca_status(adap),
pca_get_con(adap));
return ret;
}
static u32 pca_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm pca_algo = {
.master_xfer = pca_xfer,
.functionality = pca_func,
};
static unsigned int pca_probe_chip(struct i2c_adapter *adap)
{
struct i2c_algo_pca_data *pca_data = adap->algo_data;
/* The trick here is to check if there is an indirect register
* available. If there is one, we will read the value we first
* wrote on I2C_PCA_IADR. Otherwise, we will read the last value
* we wrote on I2C_PCA_ADR
*/
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
pca_outw(pca_data, I2C_PCA_IND, 0xAA);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
pca_outw(pca_data, I2C_PCA_IND, 0x00);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
pca_data->chip = I2C_PCA_CHIP_9665;
} else {
printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
pca_data->chip = I2C_PCA_CHIP_9564;
}
return pca_data->chip;
}
static int pca_init(struct i2c_adapter *adap)
{
struct i2c_algo_pca_data *pca_data = adap->algo_data;
adap->algo = &pca_algo;
if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
int clock;
if (pca_data->i2c_clock > 7) {
switch (pca_data->i2c_clock) {
case 330000:
pca_data->i2c_clock = I2C_PCA_CON_330kHz;
break;
case 288000:
pca_data->i2c_clock = I2C_PCA_CON_288kHz;
break;
case 217000:
pca_data->i2c_clock = I2C_PCA_CON_217kHz;
break;
case 146000:
pca_data->i2c_clock = I2C_PCA_CON_146kHz;
break;
case 88000:
pca_data->i2c_clock = I2C_PCA_CON_88kHz;
break;
case 59000:
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
break;
case 44000:
pca_data->i2c_clock = I2C_PCA_CON_44kHz;
break;
case 36000:
pca_data->i2c_clock = I2C_PCA_CON_36kHz;
break;
default:
printk(KERN_WARNING
"%s: Invalid I2C clock speed selected."
" Using default 59kHz.\n", adap->name);
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
}
} else {
printk(KERN_WARNING "%s: "
"Choosing the clock frequency based on "
"index is deprecated."
" Use the nominal frequency.\n", adap->name);
}
pca_reset(pca_data);
clock = pca_clock(pca_data);
printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
adap->name, freqs[clock]);
pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
} else {
int clock;
int mode;
int tlow, thi;
/* Values can be found on PCA9665 datasheet section 7.3.2.6 */
int min_tlow, min_thi;
/* These values are the maximum raise and fall values allowed
* by the I2C operation mode (Standard, Fast or Fast+)
* They are used (added) below to calculate the clock dividers
* of PCA9665. Note that they are slightly different of the
* real maximum, to allow the change on mode exactly on the
* maximum clock rate for each mode
*/
int raise_fall_time;
if (pca_data->i2c_clock > 1265800) {
printk(KERN_WARNING "%s: I2C clock speed too high."
" Using 1265.8kHz.\n", adap->name);
pca_data->i2c_clock = 1265800;
}
if (pca_data->i2c_clock < 60300) {
printk(KERN_WARNING "%s: I2C clock speed too low."
" Using 60.3kHz.\n", adap->name);
pca_data->i2c_clock = 60300;
}
/* To avoid integer overflow, use clock/100 for calculations */
clock = pca_clock(pca_data) / 100;
if (pca_data->i2c_clock > 1000000) {
mode = I2C_PCA_MODE_TURBO;
min_tlow = 14;
min_thi = 5;
raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
} else if (pca_data->i2c_clock > 400000) {
mode = I2C_PCA_MODE_FASTP;
min_tlow = 17;
min_thi = 9;
raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
} else if (pca_data->i2c_clock > 100000) {
mode = I2C_PCA_MODE_FAST;
min_tlow = 44;
min_thi = 20;
raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
} else {
mode = I2C_PCA_MODE_STD;
min_tlow = 157;
min_thi = 134;
raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
}
/* The minimum clock that respects the thi/tlow = 134/157 is
* 64800 Hz. Below that, we have to fix the tlow to 255 and
* calculate the thi factor.
*/
if (clock < 648) {
tlow = 255;
thi = 1000000 - clock * raise_fall_time;
thi /= (I2C_PCA_OSC_PER * clock) - tlow;
} else {
tlow = (1000000 - clock * raise_fall_time) * min_tlow;
tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
thi = tlow * min_thi / min_tlow;
}
pca_reset(pca_data);
printk(KERN_INFO
"%s: Clock frequency is %dHz\n", adap->name, clock * 100);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IMODE);
pca_outw(pca_data, I2C_PCA_IND, mode);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
pca_outw(pca_data, I2C_PCA_IND, tlow);
pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
pca_outw(pca_data, I2C_PCA_IND, thi);
pca_set_con(pca_data, I2C_PCA_CON_ENSIO);
}
udelay(500); /* 500 us for oscilator to stabilise */
return 0;
}
/*
* registering functions to load algorithms at runtime
*/
int i2c_pca_add_bus(struct i2c_adapter *adap)
{
int rval;
rval = pca_init(adap);
if (rval)
return rval;
return i2c_add_adapter(adap);
}
EXPORT_SYMBOL(i2c_pca_add_bus);
int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
{
int rval;
rval = pca_init(adap);
if (rval)
return rval;
return i2c_add_numbered_adapter(adap);
}
EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
"Wolfram Sang <w.sang@pengutronix.de>");
MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
MODULE_LICENSE("GPL");
module_param(i2c_debug, int, 0);