/* ------------------------------------------------------------------------- */ /* 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�sti M�lkki <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/init.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("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 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(KERN_ERR "Timeout waiting for Bus Busy\n"); } return (timeout<=0); } 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); } if (*status & I2C_PCF_LAB) { 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); /* TODO: we should 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. */ DEB2(printk(KERN_INFO "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", get_pcf(adap,1))); return(-EINTR); } #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(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; /* definetly 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: 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; int wfp; for (i=0;i<retries;i++) { i2c_outb(adap, addr); i2c_start(adap); status = get_pcf(adap, 1); if ((wfp = wait_for_pin(adap, &status)) >= 0) { if ((status & I2C_PCF_LRB) == 0) { i2c_stop(adap); break; /* success! */ } } if (wfp == -EINTR) { /* arbitration lost */ udelay(adap->udelay); return -EINTR; } i2c_stop(adap); udelay(adap->udelay); } DEB2(if (i) printk(KERN_DEBUG "i2c-algo-pcf.o: needed %d retries for %d\n",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(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) { /* arbitration lost */ return -EINTR; } i2c_stop(adap); dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); return -EREMOTEIO; /* got a better one ?? */ } #ifndef STUB_I2C 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 ?? */ } #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; 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) { /* arbitration lost */ return -EINTR; } i2c_stop(adap); dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); return (-1); } #ifndef STUB_I2C if ((status & I2C_PCF_LRB) && (i != count)) { i2c_stop(adap); dev_err(&i2c_adap->dev, "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(KERN_DEBUG "addr0: %d\n",addr)); /* try extended address code...*/ ret = try_address(adap, addr, retries); if (ret!=1) { printk(KERN_ERR "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(KERN_ERR "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(KERN_ERR "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(KERN_ERR "i2c-algo-pcf.o: " "Timeout waiting for BB in pcf_xfer\n");) return -EIO; } 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, 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) { if (timeout == -EINTR) { /* arbitration lost */ return (-EINTR); } i2c_stop(adap); DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " "for PIN(1) in pcf_xfer\n");) return (-EREMOTEIO); } #ifndef STUB_I2C /* 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");) return (-EREMOTEIO); } #endif 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);) /* 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(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 { /* Write */ 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)); } } } return (i); } static u32 pcf_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; } /* -----exported algorithm data: ------------------------------------- */ static 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; adap->timeout = 100; /* default values, should */ adap->retries = 3; /* be replaced by defines */ rval = pcf_init_8584(pcf_adap); if (!rval) i2c_add_adapter(adap); return rval; } int i2c_pcf_del_bus(struct i2c_adapter *adap) { return i2c_del_adapter(adap); } EXPORT_SYMBOL(i2c_pcf_add_bus); EXPORT_SYMBOL(i2c_pcf_del_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");