linux/drivers/i2c/algos/i2c-algo-pcf.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  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

  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 [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] 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

  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 [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] 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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

424 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters
*
* Copyright (C) 1995-1997 Simon G. Vogl
* 1998-2000 Hans Berglund
*
* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
* Frodo Looijaard <frodol@dds.nl>, and also from Martin Bailey
* <mbailey@littlefeet-inc.com>
*
* Partially rewriten by Oleg I. Vdovikin <vdovikin@jscc.ru> to handle multiple
* messages, proper stop/repstart signaling during receive, added detect code
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pcf.h>
#include "i2c-algo-pcf.h"
#define DEB2(x) if (i2c_debug >= 2) x
#define DEB3(x) if (i2c_debug >= 3) x /* print several statistical values */
#define DEBPROTO(x) if (i2c_debug >= 9) x;
/* debug the protocol by showing transferred bits */
#define DEF_TIMEOUT 16
/*
* module parameters:
*/
static int i2c_debug;
/* setting states on the bus with the right timing: */
#define set_pcf(adap, ctl, val) adap->setpcf(adap->data, ctl, val)
#define get_pcf(adap, ctl) adap->getpcf(adap->data, ctl)
#define get_own(adap) adap->getown(adap->data)
#define get_clock(adap) adap->getclock(adap->data)
#define i2c_outb(adap, val) adap->setpcf(adap->data, 0, val)
#define i2c_inb(adap) adap->getpcf(adap->data, 0)
/* other auxiliary functions */
static void i2c_start(struct i2c_algo_pcf_data *adap)
{
DEBPROTO(printk(KERN_DEBUG "S "));
set_pcf(adap, 1, I2C_PCF_START);
}
static void i2c_repstart(struct i2c_algo_pcf_data *adap)
{
DEBPROTO(printk(" Sr "));
set_pcf(adap, 1, I2C_PCF_REPSTART);
}
static void i2c_stop(struct i2c_algo_pcf_data *adap)
{
DEBPROTO(printk("P\n"));
set_pcf(adap, 1, I2C_PCF_STOP);
}
static void handle_lab(struct i2c_algo_pcf_data *adap, const int *status)
{
DEB2(printk(KERN_INFO
"i2c-algo-pcf.o: lost arbitration (CSR 0x%02x)\n",
*status));
/*
* Cleanup from LAB -- reset and enable ESO.
* This resets the PCF8584; since we've lost the bus, no
* further attempts should be made by callers to clean up
* (no i2c_stop() etc.)
*/
set_pcf(adap, 1, I2C_PCF_PIN);
set_pcf(adap, 1, I2C_PCF_ESO);
/*
* We pause for a time period sufficient for any running
* I2C transaction to complete -- the arbitration logic won't
* work properly until the next START is seen.
* It is assumed the bus driver or client has set a proper value.
*
* REVISIT: should probably use msleep instead of mdelay if we
* know we can sleep.
*/
if (adap->lab_mdelay)
mdelay(adap->lab_mdelay);
DEB2(printk(KERN_INFO
"i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n",
get_pcf(adap, 1)));
}
static int wait_for_bb(struct i2c_algo_pcf_data *adap)
{
int timeout = DEF_TIMEOUT;
int status;
status = get_pcf(adap, 1);
while (!(status & I2C_PCF_BB) && --timeout) {
udelay(100); /* wait for 100 us */
status = get_pcf(adap, 1);
}
if (timeout == 0) {
printk(KERN_ERR "Timeout waiting for Bus Busy\n");
return -ETIMEDOUT;
}
return 0;
}
static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status)
{
int timeout = DEF_TIMEOUT;
*status = get_pcf(adap, 1);
while ((*status & I2C_PCF_PIN) && --timeout) {
adap->waitforpin(adap->data);
*status = get_pcf(adap, 1);
}
if (*status & I2C_PCF_LAB) {
handle_lab(adap, status);
return -EINTR;
}
if (timeout == 0)
return -ETIMEDOUT;
return 0;
}
/*
* This should perform the 'PCF8584 initialization sequence' as described
* in the Philips IC12 data book (1995, Aug 29).
* There should be a 30 clock cycle wait after reset, I assume this
* has been fulfilled.
* There should be a delay at the end equal to the longest I2C message
* to synchronize the BB-bit (in multimaster systems). How long is
* this? I assume 1 second is always long enough.
*
* vdovikin: added detect code for PCF8584
*/
static int pcf_init_8584 (struct i2c_algo_pcf_data *adap)
{
unsigned char temp;
DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: PCF state 0x%02x\n",
get_pcf(adap, 1)));
/* S1=0x80: S0 selected, serial interface off */
set_pcf(adap, 1, I2C_PCF_PIN);
/*
* check to see S1 now used as R/W ctrl -
* PCF8584 does that when ESO is zero
*/
if (((temp = get_pcf(adap, 1)) & 0x7f) != (0)) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).\n", temp));
return -ENXIO; /* definitely not PCF8584 */
}
/* load own address in S0, effective address is (own << 1) */
i2c_outb(adap, get_own(adap));
/* check it's really written */
if ((temp = i2c_inb(adap)) != get_own(adap)) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S0 (0x%02x).\n", temp));
return -ENXIO;
}
/* S1=0xA0, next byte in S2 */
set_pcf(adap, 1, I2C_PCF_PIN | I2C_PCF_ES1);
/* check to see S2 now selected */
if (((temp = get_pcf(adap, 1)) & 0x7f) != I2C_PCF_ES1) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S2 (0x%02x).\n", temp));
return -ENXIO;
}
/* load clock register S2 */
i2c_outb(adap, get_clock(adap));
/* check it's really written, the only 5 lowest bits does matter */
if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't set S2 (0x%02x).\n", temp));
return -ENXIO;
}
/* Enable serial interface, idle, S0 selected */
set_pcf(adap, 1, I2C_PCF_IDLE);
/* check to see PCF is really idled and we can access status register */
if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).\n", temp));
return -ENXIO;
}
printk(KERN_DEBUG "i2c-algo-pcf.o: detected and initialized PCF8584.\n");
return 0;
}
static int pcf_sendbytes(struct i2c_adapter *i2c_adap, const char *buf,
int count, int last)
{
struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
int wrcount, status, timeout;
for (wrcount=0; wrcount<count; ++wrcount) {
DEB2(dev_dbg(&i2c_adap->dev, "i2c_write: writing %2.2X\n",
buf[wrcount] & 0xff));
i2c_outb(adap, buf[wrcount]);
timeout = wait_for_pin(adap, &status);
if (timeout) {
if (timeout == -EINTR)
return -EINTR; /* arbitration lost */
i2c_stop(adap);
dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n");
return -EREMOTEIO; /* got a better one ?? */
}
if (status & I2C_PCF_LRB) {
i2c_stop(adap);
dev_err(&i2c_adap->dev, "i2c_write: error - no ack.\n");
return -EREMOTEIO; /* got a better one ?? */
}
}
if (last)
i2c_stop(adap);
else
i2c_repstart(adap);
return wrcount;
}
static int pcf_readbytes(struct i2c_adapter *i2c_adap, char *buf,
int count, int last)
{
int i, status;
struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
int wfp;
/* increment number of bytes to read by one -- read dummy byte */
for (i = 0; i <= count; i++) {
if ((wfp = wait_for_pin(adap, &status))) {
if (wfp == -EINTR)
return -EINTR; /* arbitration lost */
i2c_stop(adap);
dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n");
return -1;
}
if ((status & I2C_PCF_LRB) && (i != count)) {
i2c_stop(adap);
dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n");
return -1;
}
if (i == count - 1) {
set_pcf(adap, 1, I2C_PCF_ESO);
} else if (i == count) {
if (last)
i2c_stop(adap);
else
i2c_repstart(adap);
}
if (i)
buf[i - 1] = i2c_inb(adap);
else
i2c_inb(adap); /* dummy read */
}
return i - 1;
}
static int pcf_doAddress(struct i2c_algo_pcf_data *adap,
struct i2c_msg *msg)
{
unsigned char addr = i2c_8bit_addr_from_msg(msg);
if (msg->flags & I2C_M_REV_DIR_ADDR)
addr ^= 1;
i2c_outb(adap, addr);
return 0;
}
static int pcf_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg *msgs,
int num)
{
struct i2c_algo_pcf_data *adap = i2c_adap->algo_data;
struct i2c_msg *pmsg;
int i;
int ret=0, timeout, status;
if (adap->xfer_begin)
adap->xfer_begin(adap->data);
/* Check for bus busy */
timeout = wait_for_bb(adap);
if (timeout) {
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: "
"Timeout waiting for BB in pcf_xfer\n");)
i = -EIO;
goto out;
}
for (i = 0;ret >= 0 && i < num; i++) {
pmsg = &msgs[i];
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messages\n",
pmsg->flags & I2C_M_RD ? "read" : "write",
pmsg->len, pmsg->addr, i + 1, num);)
ret = pcf_doAddress(adap, pmsg);
/* Send START */
if (i == 0)
i2c_start(adap);
/* Wait for PIN (pending interrupt NOT) */
timeout = wait_for_pin(adap, &status);
if (timeout) {
if (timeout == -EINTR) {
/* arbitration lost */
i = -EINTR;
goto out;
}
i2c_stop(adap);
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting "
"for PIN(1) in pcf_xfer\n");)
i = -EREMOTEIO;
goto out;
}
/* Check LRB (last rcvd bit - slave ack) */
if (status & I2C_PCF_LRB) {
i2c_stop(adap);
DEB2(printk(KERN_ERR "i2c-algo-pcf.o: No LRB(1) in pcf_xfer\n");)
i = -EREMOTEIO;
goto out;
}
DEB3(printk(KERN_DEBUG "i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%d\n",
i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
if (pmsg->flags & I2C_M_RD) {
ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
(i + 1 == num));
if (ret != pmsg->len) {
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
"only read %d bytes.\n",ret));
} else {
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: read %d bytes.\n",ret));
}
} else {
ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
(i + 1 == num));
if (ret != pmsg->len) {
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: fail: "
"only wrote %d bytes.\n",ret));
} else {
DEB2(printk(KERN_DEBUG "i2c-algo-pcf.o: wrote %d bytes.\n",ret));
}
}
}
out:
if (adap->xfer_end)
adap->xfer_end(adap->data);
return i;
}
static u32 pcf_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
I2C_FUNC_PROTOCOL_MANGLING;
}
/* exported algorithm data: */
static const struct i2c_algorithm pcf_algo = {
.master_xfer = pcf_xfer,
.functionality = pcf_func,
};
/*
* registering functions to load algorithms at runtime
*/
int i2c_pcf_add_bus(struct i2c_adapter *adap)
{
struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
int rval;
DEB2(dev_dbg(&adap->dev, "hw routines registered.\n"));
/* register new adapter to i2c module... */
adap->algo = &pcf_algo;
if ((rval = pcf_init_8584(pcf_adap)))
return rval;
rval = i2c_add_adapter(adap);
return rval;
}
EXPORT_SYMBOL(i2c_pcf_add_bus);
MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
MODULE_LICENSE("GPL");
module_param(i2c_debug, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(i2c_debug,
"debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");