X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fi2c%2Falgos%2Fi2c-algo-bit.c;h=eb8f72ca02f45cfe954da3a1240e5a18fdd5d2bd;hb=db563fc2e80534f98c7f9121a6f7dfe41f177a79;hp=8a5f5825bb7294ea3056695748bd824df089d4f2;hpb=ec4883b015c3212f6f6d04fb2ff45f528492f598;p=linux-2.6-omap-h63xx.git diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c index 8a5f5825bb7..eb8f72ca02f 100644 --- a/drivers/i2c/algos/i2c-algo-bit.c +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -1,7 +1,7 @@ -/* ------------------------------------------------------------------------- */ -/* i2c-algo-bit.c i2c driver algorithms for bit-shift adapters */ -/* ------------------------------------------------------------------------- */ -/* Copyright (C) 1995-2000 Simon G. Vogl +/* ------------------------------------------------------------------------- + * i2c-algo-bit.c i2c driver algorithms for bit-shift adapters + * ------------------------------------------------------------------------- + * Copyright (C) 1995-2000 Simon G. Vogl 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 @@ -15,10 +15,10 @@ 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. */ -/* ------------------------------------------------------------------------- */ + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + * ------------------------------------------------------------------------- */ -/* With some changes from Frodo Looijaard , Kyösti Mälkki +/* With some changes from Frodo Looijaard , Kyösti Mälkki and Jean Delvare */ #include @@ -60,26 +60,26 @@ MODULE_PARM_DESC(i2c_debug, /* --- setting states on the bus with the right timing: --------------- */ -#define setsda(adap,val) adap->setsda(adap->data, val) -#define setscl(adap,val) adap->setscl(adap->data, val) -#define getsda(adap) adap->getsda(adap->data) -#define getscl(adap) adap->getscl(adap->data) +#define setsda(adap, val) adap->setsda(adap->data, val) +#define setscl(adap, val) adap->setscl(adap->data, val) +#define getsda(adap) adap->getsda(adap->data) +#define getscl(adap) adap->getscl(adap->data) static inline void sdalo(struct i2c_algo_bit_data *adap) { - setsda(adap,0); + setsda(adap, 0); udelay((adap->udelay + 1) / 2); } static inline void sdahi(struct i2c_algo_bit_data *adap) { - setsda(adap,1); + setsda(adap, 1); udelay((adap->udelay + 1) / 2); } static inline void scllo(struct i2c_algo_bit_data *adap) { - setscl(adap,0); + setscl(adap, 0); udelay(adap->udelay / 2); } @@ -91,22 +91,21 @@ static int sclhi(struct i2c_algo_bit_data *adap) { unsigned long start; - setscl(adap,1); + setscl(adap, 1); /* Not all adapters have scl sense line... */ if (!adap->getscl) goto done; - start=jiffies; - while (! getscl(adap) ) { - /* the hw knows how to read the clock line, - * so we wait until it actually gets high. - * This is safer as some chips may hold it low - * while they are processing data internally. - */ - if (time_after_eq(jiffies, start+adap->timeout)) { + start = jiffies; + while (!getscl(adap)) { + /* This hw knows how to read the clock line, so we wait + * until it actually gets high. This is safer as some + * chips may hold it low ("clock stretching") while they + * are processing data internally. + */ + if (time_after_eq(jiffies, start + adap->timeout)) return -ETIMEDOUT; - } cond_resched(); } #ifdef DEBUG @@ -118,11 +117,11 @@ static int sclhi(struct i2c_algo_bit_data *adap) done: udelay(adap->udelay); return 0; -} +} /* --- other auxiliary functions -------------------------------------- */ -static void i2c_start(struct i2c_algo_bit_data *adap) +static void i2c_start(struct i2c_algo_bit_data *adap) { /* assert: scl, sda are high */ setsda(adap, 0); @@ -130,7 +129,7 @@ static void i2c_start(struct i2c_algo_bit_data *adap) scllo(adap); } -static void i2c_repstart(struct i2c_algo_bit_data *adap) +static void i2c_repstart(struct i2c_algo_bit_data *adap) { /* assert: scl is low */ sdahi(adap); @@ -141,18 +140,18 @@ static void i2c_repstart(struct i2c_algo_bit_data *adap) } -static void i2c_stop(struct i2c_algo_bit_data *adap) +static void i2c_stop(struct i2c_algo_bit_data *adap) { /* assert: scl is low */ sdalo(adap); - sclhi(adap); + sclhi(adap); setsda(adap, 1); udelay(adap->udelay); } -/* send a byte without start cond., look for arbitration, +/* send a byte without start cond., look for arbitration, check ackn. from slave */ /* returns: * 1 if the device acknowledged @@ -167,27 +166,33 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) struct i2c_algo_bit_data *adap = i2c_adap->algo_data; /* assert: scl is low */ - for ( i=7 ; i>=0 ; i-- ) { + for (i = 7; i >= 0; i--) { sb = (c >> i) & 1; - setsda(adap,sb); + setsda(adap, sb); udelay((adap->udelay + 1) / 2); - if (sclhi(adap)<0) { /* timed out */ + if (sclhi(adap) < 0) { /* timed out */ bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " "timeout at bit #%d\n", (int)c, i); return -ETIMEDOUT; - }; - /* do arbitration here: - * if ( sb && ! getsda(adap) ) -> ouch! Get out of here. + } + /* FIXME do arbitration here: + * if (sb && !getsda(adap)) -> ouch! Get out of here. + * + * Report a unique code, so higher level code can retry + * the whole (combined) message and *NOT* issue STOP. */ scllo(adap); } sdahi(adap); - if (sclhi(adap)<0){ /* timeout */ + if (sclhi(adap) < 0) { /* timeout */ bit_dbg(1, &i2c_adap->dev, "i2c_outb: 0x%02x, " "timeout at ack\n", (int)c); return -ETIMEDOUT; - }; - /* read ack: SDA should be pulled down by slave */ + } + + /* read ack: SDA should be pulled down by slave, or it may + * NAK (usually to report problems with the data we wrote). + */ ack = !getsda(adap); /* ack: sda is pulled low -> success */ bit_dbg(2, &i2c_adap->dev, "i2c_outb: 0x%02x %s\n", (int)c, ack ? "A" : "NA"); @@ -198,24 +203,24 @@ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) } -static int i2c_inb(struct i2c_adapter *i2c_adap) +static int i2c_inb(struct i2c_adapter *i2c_adap) { /* read byte via i2c port, without start/stop sequence */ /* acknowledge is sent in i2c_read. */ int i; - unsigned char indata=0; + unsigned char indata = 0; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; /* assert: scl is low */ sdahi(adap); - for (i=0;i<8;i++) { - if (sclhi(adap)<0) { /* timeout */ + for (i = 0; i < 8; i++) { + if (sclhi(adap) < 0) { /* timeout */ bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit " "#%d\n", 7 - i); return -ETIMEDOUT; - }; + } indata *= 2; - if ( getsda(adap) ) + if (getsda(adap)) indata |= 0x01; setscl(adap, 0); udelay(i == 7 ? adap->udelay / 2 : adap->udelay); @@ -228,66 +233,67 @@ static int i2c_inb(struct i2c_adapter *i2c_adap) * Sanity check for the adapter hardware - check the reaction of * the bus lines only if it seems to be idle. */ -static int test_bus(struct i2c_algo_bit_data *adap, char* name) { - int scl,sda; +static int test_bus(struct i2c_algo_bit_data *adap, char *name) +{ + int scl, sda; - if (adap->getscl==NULL) + if (adap->getscl == NULL) pr_info("%s: Testing SDA only, SCL is not readable\n", name); - sda=getsda(adap); - scl=(adap->getscl==NULL?1:getscl(adap)); - if (!scl || !sda ) { + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!scl || !sda) { printk(KERN_WARNING "%s: bus seems to be busy\n", name); goto bailout; } sdalo(adap); - sda=getsda(adap); - scl=(adap->getscl==NULL?1:getscl(adap)); - if ( 0 != sda ) { + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (sda) { printk(KERN_WARNING "%s: SDA stuck high!\n", name); goto bailout; } - if ( 0 == scl ) { + if (!scl) { printk(KERN_WARNING "%s: SCL unexpected low " "while pulling SDA low!\n", name); goto bailout; - } + } sdahi(adap); - sda=getsda(adap); - scl=(adap->getscl==NULL?1:getscl(adap)); - if ( 0 == sda ) { + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!sda) { printk(KERN_WARNING "%s: SDA stuck low!\n", name); goto bailout; } - if ( 0 == scl ) { + if (!scl) { printk(KERN_WARNING "%s: SCL unexpected low " "while pulling SDA high!\n", name); goto bailout; } scllo(adap); - sda=getsda(adap); - scl=(adap->getscl==NULL?0:getscl(adap)); - if ( 0 != scl ) { + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 0 : getscl(adap); + if (scl) { printk(KERN_WARNING "%s: SCL stuck high!\n", name); goto bailout; } - if ( 0 == sda ) { + if (!sda) { printk(KERN_WARNING "%s: SDA unexpected low " "while pulling SCL low!\n", name); goto bailout; } - + sclhi(adap); - sda=getsda(adap); - scl=(adap->getscl==NULL?1:getscl(adap)); - if ( 0 == scl ) { + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!scl) { printk(KERN_WARNING "%s: SCL stuck low!\n", name); goto bailout; } - if ( 0 == sda ) { + if (!sda) { printk(KERN_WARNING "%s: SDA unexpected low " "while pulling SCL high!\n", name); goto bailout; @@ -314,9 +320,10 @@ static int try_address(struct i2c_adapter *i2c_adap, unsigned char addr, int retries) { struct i2c_algo_bit_data *adap = i2c_adap->algo_data; - int i,ret = -1; - for (i=0;i<=retries;i++) { - ret = i2c_outb(i2c_adap,addr); + int i, ret = 0; + + for (i = 0; i <= retries; i++) { + ret = i2c_outb(i2c_adap, addr); if (ret == 1 || i == retries) break; bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); @@ -338,36 +345,70 @@ static int sendbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) { const unsigned char *temp = msg->buf; int count = msg->len; - unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; + unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; int retval; - int wrcount=0; + int wrcount = 0; while (count > 0) { retval = i2c_outb(i2c_adap, *temp); - if ((retval>0) || (nak_ok && (retval==0))) { /* ok or ignored NAK */ - count--; + + /* OK/ACK; or ignored NAK */ + if ((retval > 0) || (nak_ok && (retval == 0))) { + count--; temp++; wrcount++; - } else { /* arbitration or no acknowledge */ - dev_err(&i2c_adap->dev, "sendbytes: error - bailout.\n"); - return (retval<0)? retval : -EFAULT; - /* got a better one ?? */ + + /* A slave NAKing the master means the slave didn't like + * something about the data it saw. For example, maybe + * the SMBus PEC was wrong. + */ + } else if (retval == 0) { + dev_err(&i2c_adap->dev, "sendbytes: NAK bailout.\n"); + return -EIO; + + /* Timeout; or (someday) lost arbitration + * + * FIXME Lost ARB implies retrying the transaction from + * the first message, after the "winning" master issues + * its STOP. As a rule, upper layer code has no reason + * to know or care about this ... it is *NOT* an error. + */ + } else { + dev_err(&i2c_adap->dev, "sendbytes: error %d\n", + retval); + return retval; } } return wrcount; } +static int acknak(struct i2c_adapter *i2c_adap, int is_ack) +{ + struct i2c_algo_bit_data *adap = i2c_adap->algo_data; + + /* assert: sda is high */ + if (is_ack) /* send ack */ + setsda(adap, 0); + udelay((adap->udelay + 1) / 2); + if (sclhi(adap) < 0) { /* timeout */ + dev_err(&i2c_adap->dev, "readbytes: ack/nak timeout\n"); + return -ETIMEDOUT; + } + scllo(adap); + return 0; +} + static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) { int inval; - int rdcount=0; /* counts bytes read */ - struct i2c_algo_bit_data *adap = i2c_adap->algo_data; + int rdcount = 0; /* counts bytes read */ unsigned char *temp = msg->buf; int count = msg->len; + const unsigned flags = msg->flags; while (count > 0) { inval = i2c_inb(i2c_adap); - if (inval>=0) { + if (inval >= 0) { *temp = inval; rdcount++; } else { /* read timed out */ @@ -377,28 +418,12 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) temp++; count--; - if (msg->flags & I2C_M_NO_RD_ACK) { - bit_dbg(2, &i2c_adap->dev, "i2c_inb: 0x%02x\n", - inval); - continue; - } - - /* assert: sda is high */ - if (count) /* send ack */ - setsda(adap, 0); - udelay((adap->udelay + 1) / 2); - bit_dbg(2, &i2c_adap->dev, "i2c_inb: 0x%02x %s\n", inval, - count ? "A" : "NA"); - if (sclhi(adap)<0) { /* timeout */ - dev_err(&i2c_adap->dev, "readbytes: timeout at ack\n"); - return -ETIMEDOUT; - }; - scllo(adap); - /* Some SMBus transactions require that we receive the transaction length as the first read byte. */ - if (rdcount == 1 && (msg->flags & I2C_M_RECV_LEN)) { + if (rdcount == 1 && (flags & I2C_M_RECV_LEN)) { if (inval <= 0 || inval > I2C_SMBUS_BLOCK_MAX) { + if (!(flags & I2C_M_NO_RD_ACK)) + acknak(i2c_adap, 0); dev_err(&i2c_adap->dev, "readbytes: invalid " "block length (%d)\n", inval); return -EREMOTEIO; @@ -409,6 +434,18 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) count += inval; msg->len += inval; } + + bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", + inval, + (flags & I2C_M_NO_RD_ACK) + ? "(no ack/nak)" + : (count ? "A" : "NA")); + + if (!(flags & I2C_M_NO_RD_ACK)) { + inval = acknak(i2c_adap, count); + if (inval < 0) + return inval; + } } return rdcount; } @@ -419,7 +456,7 @@ static int readbytes(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) * returns: * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set * -x an error occurred (like: -EREMOTEIO if the device did not answer, or - * -ETIMEDOUT, for example if the lines are stuck...) + * -ETIMEDOUT, for example if the lines are stuck...) */ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) { @@ -431,10 +468,10 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) int ret, retries; retries = nak_ok ? 0 : i2c_adap->retries; - - if ( (flags & I2C_M_TEN) ) { + + if (flags & I2C_M_TEN) { /* a ten bit address */ - addr = 0xf0 | (( msg->addr >> 7) & 0x03); + addr = 0xf0 | ((msg->addr >> 7) & 0x03); bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); /* try extended address code...*/ ret = try_address(i2c_adap, addr, retries); @@ -444,34 +481,34 @@ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) return -EREMOTEIO; } /* the remaining 8 bit address */ - ret = i2c_outb(i2c_adap,msg->addr & 0x7f); + ret = i2c_outb(i2c_adap, msg->addr & 0x7f); if ((ret != 1) && !nak_ok) { /* the chip did not ack / xmission error occurred */ dev_err(&i2c_adap->dev, "died at 2nd address code\n"); return -EREMOTEIO; } - if ( flags & I2C_M_RD ) { + if (flags & I2C_M_RD) { bit_dbg(3, &i2c_adap->dev, "emitting repeated " "start condition\n"); i2c_repstart(adap); /* okay, now switch into reading mode */ addr |= 0x01; ret = try_address(i2c_adap, addr, retries); - if ((ret!=1) && !nak_ok) { + if ((ret != 1) && !nak_ok) { dev_err(&i2c_adap->dev, "died at repeated address code\n"); return -EREMOTEIO; } } } else { /* normal 7bit address */ - addr = ( msg->addr << 1 ); - if (flags & I2C_M_RD ) + addr = msg->addr << 1; + if (flags & I2C_M_RD) addr |= 1; - if (flags & I2C_M_REV_DIR_ADDR ) + if (flags & I2C_M_REV_DIR_ADDR) addr ^= 1; ret = try_address(i2c_adap, addr, retries); - if ((ret!=1) && !nak_ok) - return -EREMOTEIO; + if ((ret != 1) && !nak_ok) + return -ENXIO; } return 0; @@ -482,15 +519,14 @@ static int bit_xfer(struct i2c_adapter *i2c_adap, { struct i2c_msg *pmsg; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; - - int i,ret; + int i, ret; unsigned short nak_ok; bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); i2c_start(adap); - for (i=0;iflags & I2C_M_IGNORE_NAK; + nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; if (!(pmsg->flags & I2C_M_NOSTART)) { if (i) { bit_dbg(3, &i2c_adap->dev, "emitting " @@ -505,7 +541,7 @@ static int bit_xfer(struct i2c_adapter *i2c_adap, goto bailout; } } - if (pmsg->flags & I2C_M_RD ) { + if (pmsg->flags & I2C_M_RD) { /* read bytes into buffer*/ ret = readbytes(i2c_adap, pmsg); if (ret >= 1) @@ -539,7 +575,7 @@ bailout: static u32 bit_func(struct i2c_adapter *adap) { - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; @@ -553,8 +589,8 @@ static const struct i2c_algorithm i2c_bit_algo = { .functionality = bit_func, }; -/* - * registering functions to load algorithms at runtime +/* + * registering functions to load algorithms at runtime */ static int i2c_bit_prepare_bus(struct i2c_adapter *adap) { @@ -562,7 +598,7 @@ static int i2c_bit_prepare_bus(struct i2c_adapter *adap) if (bit_test) { int ret = test_bus(bit_adap, adap->name); - if (ret<0) + if (ret < 0) return -ENODEV; }