i2c-algo-pcf.c
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上传日期:2013-04-10
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- /* ------------------------------------------------------------------------- */
- /* i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters */
- /* ------------------------------------------------------------------------- */
- /* Copyright (C) 1995-1997 Simon G. Vogl
- 1998-2000 Hans Berglund
- 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., 675 Mass Ave, Cambridge, MA 02139, USA. */
- /* ------------------------------------------------------------------------- */
- /* With some changes from Ky鰏ti M鋖kki <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/slab.h>
- #include <linux/version.h>
- #include <linux/init.h>
- #include <asm/uaccess.h>
- #include <linux/ioport.h>
- #include <linux/errno.h>
- #include <linux/sched.h>
- #include <linux/i2c.h>
- #include <linux/i2c-algo-pcf.h>
- #include "i2c-pcf8584.h"
- /* ----- global defines ----------------------------------------------- */
- #define DEB(x) if (i2c_debug>=1) x
- #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=0;
- static int pcf_scan=0; /* have a look at what's hanging 'round */
- /* --- 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("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("Pn"));
- set_pcf(adap, 1, I2C_PCF_STOP);
- }
- static int wait_for_bb(struct i2c_algo_pcf_data *adap) {
- int timeout = DEF_TIMEOUT;
- int status;
- status = get_pcf(adap, 1);
- #ifndef STUB_I2C
- while (timeout-- && !(status & I2C_PCF_BB)) {
- udelay(100); /* wait for 100 us */
- status = get_pcf(adap, 1);
- }
- #endif
- if (timeout <= 0) {
- printk("Timeout waiting for Bus Busyn");
- }
-
- return (timeout<=0);
- }
- static inline void pcf_sleep(unsigned long timeout)
- {
- schedule_timeout( timeout * HZ);
- }
- static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) {
- int timeout = DEF_TIMEOUT;
- *status = get_pcf(adap, 1);
- #ifndef STUB_I2C
- while (timeout-- && (*status & I2C_PCF_PIN)) {
- adap->waitforpin();
- *status = get_pcf(adap, 1);
- }
- #endif
- if (timeout <= 0)
- return(-1);
- else
- 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("i2c-algo-pcf.o: PCF state 0x%02xn", 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 */
- /* PCF also resets PIN bit */
- if ((temp = get_pcf(adap, 1)) != (0)) {
- DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't select S0 (0x%02x).n", temp));
- return -ENXIO; /* definetly not PCF8584 */
- }
- /* load own address in S0, effective address is (own << 1) */
- i2c_outb(adap, get_own(adap));
- /* check it's realy writen */
- if ((temp = i2c_inb(adap)) != get_own(adap)) {
- DEB2(printk("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)) != I2C_PCF_ES1) {
- DEB2(printk("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 realy writen, the only 5 lowest bits does matter */
- if (((temp = i2c_inb(adap)) & 0x1f) != get_clock(adap)) {
- DEB2(printk("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 realy idled and we can access status register */
- if ((temp = get_pcf(adap, 1)) != (I2C_PCF_PIN | I2C_PCF_BB)) {
- DEB2(printk("i2c-algo-pcf.o: PCF detection failed -- can't select S1` (0x%02x).n", temp));
- return -ENXIO;
- }
-
- printk("i2c-algo-pcf.o: deteted and initialized PCF8584.n");
- return 0;
- }
- /* ----- Utility functions
- */
- static inline int try_address(struct i2c_algo_pcf_data *adap,
- unsigned char addr, int retries)
- {
- int i, status, ret = -1;
- for (i=0;i<retries;i++) {
- i2c_outb(adap, addr);
- i2c_start(adap);
- status = get_pcf(adap, 1);
- if (wait_for_pin(adap, &status) >= 0) {
- if ((status & I2C_PCF_LRB) == 0) {
- i2c_stop(adap);
- break; /* success! */
- }
- }
- i2c_stop(adap);
- udelay(adap->udelay);
- }
- DEB2(if (i) printk("i2c-algo-pcf.o: needed %d retries for %dn",i,
- addr));
- return ret;
- }
- 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(printk("i2c-algo-pcf.o: %s i2c_write: writing %2.2Xn",
- i2c_adap->name, buf[wrcount]&0xff));
- i2c_outb(adap, buf[wrcount]);
- timeout = wait_for_pin(adap, &status);
- if (timeout) {
- i2c_stop(adap);
- printk("i2c-algo-pcf.o: %s i2c_write: "
- "error - timeout.n", i2c_adap->name);
- return -EREMOTEIO; /* got a better one ?? */
- }
- #ifndef STUB_I2C
- if (status & I2C_PCF_LRB) {
- i2c_stop(adap);
- printk("i2c-algo-pcf.o: %s i2c_write: "
- "error - no ack.n", i2c_adap->name);
- return -EREMOTEIO; /* got a better one ?? */
- }
- #endif
- }
- 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;
- /* increment number of bytes to read by one -- read dummy byte */
- for (i = 0; i <= count; i++) {
- if (wait_for_pin(adap, &status)) {
- i2c_stop(adap);
- printk("i2c-algo-pcf.o: pcf_readbytes timed out.n");
- return (-1);
- }
- #ifndef STUB_I2C
- if ((status & I2C_PCF_LRB) && (i != count)) {
- i2c_stop(adap);
- printk("i2c-algo-pcf.o: i2c_read: i2c_inb, No ack.n");
- return (-1);
- }
- #endif
-
- 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 inline int pcf_doAddress(struct i2c_algo_pcf_data *adap,
- struct i2c_msg *msg, int retries)
- {
- unsigned short flags = msg->flags;
- unsigned char addr;
- int ret;
- if ( (flags & I2C_M_TEN) ) {
- /* a ten bit address */
- addr = 0xf0 | (( msg->addr >> 7) & 0x03);
- DEB2(printk("addr0: %dn",addr));
- /* try extended address code...*/
- ret = try_address(adap, addr, retries);
- if (ret!=1) {
- printk("died at extended address code.n");
- return -EREMOTEIO;
- }
- /* the remaining 8 bit address */
- i2c_outb(adap,msg->addr & 0x7f);
- /* Status check comes here */
- if (ret != 1) {
- printk("died at 2nd address code.n");
- return -EREMOTEIO;
- }
- if ( flags & I2C_M_RD ) {
- i2c_repstart(adap);
- /* okay, now switch into reading mode */
- addr |= 0x01;
- ret = try_address(adap, addr, retries);
- if (ret!=1) {
- printk("died at extended address code.n");
- return -EREMOTEIO;
- }
- }
- } else { /* normal 7bit address */
- addr = ( msg->addr << 1 );
- if (flags & I2C_M_RD )
- addr |= 1;
- if (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;
-
- /* Check for bus busy */
- timeout = wait_for_bb(adap);
- if (timeout) {
- DEB2(printk("i2c-algo-pcf.o: "
- "Timeout waiting for BB in pcf_xfern");)
- return -EIO;
- }
-
- for (i = 0;ret >= 0 && i < num; i++) {
- pmsg = &msgs[i];
- DEB2(printk("i2c-algo-pcf.o: Doing %s %d bytes to 0x%02x - %d of %d messagesn",
- pmsg->flags & I2C_M_RD ? "read" : "write",
- pmsg->len, pmsg->addr, i + 1, num);)
-
- ret = pcf_doAddress(adap, pmsg, i2c_adap->retries);
- /* Send START */
- if (i == 0) {
- i2c_start(adap);
- }
-
- /* Wait for PIN (pending interrupt NOT) */
- timeout = wait_for_pin(adap, &status);
- if (timeout) {
- i2c_stop(adap);
- DEB2(printk("i2c-algo-pcf.o: Timeout waiting "
- "for PIN(1) in pcf_xfern");)
- return (-EREMOTEIO);
- }
-
- #ifndef STUB_I2C
- /* Check LRB (last rcvd bit - slave ack) */
- if (status & I2C_PCF_LRB) {
- i2c_stop(adap);
- DEB2(printk("i2c-algo-pcf.o: No LRB(1) in pcf_xfern");)
- return (-EREMOTEIO);
- }
- #endif
-
- DEB3(printk("i2c-algo-pcf.o: Msg %d, addr=0x%x, flags=0x%x, len=%dn",
- i, msgs[i].addr, msgs[i].flags, msgs[i].len);)
-
- /* Read */
- if (pmsg->flags & I2C_M_RD) {
- /* read bytes into buffer*/
- ret = pcf_readbytes(i2c_adap, pmsg->buf, pmsg->len,
- (i + 1 == num));
-
- if (ret != pmsg->len) {
- DEB2(printk("i2c-algo-pcf.o: fail: "
- "only read %d bytes.n",ret));
- } else {
- DEB2(printk("i2c-algo-pcf.o: read %d bytes.n",ret));
- }
- } else { /* Write */
- ret = pcf_sendbytes(i2c_adap, pmsg->buf, pmsg->len,
- (i + 1 == num));
-
- if (ret != pmsg->len) {
- DEB2(printk("i2c-algo-pcf.o: fail: "
- "only wrote %d bytes.n",ret));
- } else {
- DEB2(printk("i2c-algo-pcf.o: wrote %d bytes.n",ret));
- }
- }
- }
- return (i);
- }
- static int algo_control(struct i2c_adapter *adapter,
- unsigned int cmd, unsigned long arg)
- {
- return 0;
- }
- static u32 pcf_func(struct i2c_adapter *adap)
- {
- return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
- I2C_FUNC_PROTOCOL_MANGLING;
- }
- /* -----exported algorithm data: ------------------------------------- */
- static struct i2c_algorithm pcf_algo = {
- "PCF8584 algorithm",
- I2C_ALGO_PCF,
- pcf_xfer,
- NULL,
- NULL, /* slave_xmit */
- NULL, /* slave_recv */
- algo_control, /* ioctl */
- pcf_func, /* functionality */
- };
- /*
- * registering functions to load algorithms at runtime
- */
- int i2c_pcf_add_bus(struct i2c_adapter *adap)
- {
- int i, status;
- struct i2c_algo_pcf_data *pcf_adap = adap->algo_data;
- DEB2(printk("i2c-algo-pcf.o: hw routines for %s registered.n",
- adap->name));
- /* register new adapter to i2c module... */
- adap->id |= pcf_algo.id;
- adap->algo = &pcf_algo;
- adap->timeout = 100; /* default values, should */
- adap->retries = 3; /* be replaced by defines */
- if ((i = pcf_init_8584(pcf_adap))) {
- return i;
- }
- #ifdef MODULE
- MOD_INC_USE_COUNT;
- #endif
- i2c_add_adapter(adap);
- /* scan bus */
- if (pcf_scan) {
- printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s.n",
- adap->name);
- for (i = 0x00; i < 0xff; i+=2) {
- if (wait_for_bb(pcf_adap)) {
- printk(KERN_INFO " i2c-algo-pcf.o: scanning bus %s - TIMEOUTed.n",
- adap->name);
- break;
- }
- i2c_outb(pcf_adap, i);
- i2c_start(pcf_adap);
- if ((wait_for_pin(pcf_adap, &status) >= 0) &&
- ((status & I2C_PCF_LRB) == 0)) {
- printk("(%02x)",i>>1);
- } else {
- printk(".");
- }
- i2c_stop(pcf_adap);
- udelay(pcf_adap->udelay);
- }
- printk("n");
- }
- return 0;
- }
- int i2c_pcf_del_bus(struct i2c_adapter *adap)
- {
- int res;
- if ((res = i2c_del_adapter(adap)) < 0)
- return res;
- DEB2(printk("i2c-algo-pcf.o: adapter unregistered: %sn",adap->name));
- #ifdef MODULE
- MOD_DEC_USE_COUNT;
- #endif
- return 0;
- }
- int __init i2c_algo_pcf_init (void)
- {
- printk("i2c-algo-pcf.o: i2c pcf8584 algorithm modulen");
- return 0;
- }
- EXPORT_SYMBOL(i2c_pcf_add_bus);
- EXPORT_SYMBOL(i2c_pcf_del_bus);
- #ifdef MODULE
- MODULE_AUTHOR("Hans Berglund <hb@spacetec.no>");
- MODULE_DESCRIPTION("I2C-Bus PCF8584 algorithm");
- MODULE_LICENSE("GPL");
- MODULE_PARM(pcf_scan, "i");
- MODULE_PARM(i2c_debug,"i");
- MODULE_PARM_DESC(pcf_scan, "Scan for active chips on the bus");
- MODULE_PARM_DESC(i2c_debug,
- "debug level - 0 off; 1 normal; 2,3 more verbose; 9 pcf-protocol");
- int init_module(void)
- {
- return i2c_algo_pcf_init();
- }
- void cleanup_module(void)
- {
- }
- #endif