| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Linus Torvalds (pre-git) | 1569 | 54.12% | 22 | 32.35% |
| Jean Delvare | 756 | 26.08% | 17 | 25.00% |
| Christoph Hellwig | 153 | 5.28% | 3 | 4.41% |
| David Brownell | 150 | 5.17% | 4 | 5.88% |
| Heiner Kallweit | 119 | 4.10% | 1 | 1.47% |
| Wolfram Sang | 47 | 1.62% | 4 | 5.88% |
| Nicola Corna | 19 | 0.66% | 1 | 1.47% |
| Alex Deucher | 18 | 0.62% | 1 | 1.47% |
| Jan Kundrát | 12 | 0.41% | 1 | 1.47% |
| Ville Syrjälä | 11 | 0.38% | 1 | 1.47% |
| Kevin O\'Connor | 11 | 0.38% | 1 | 1.47% |
| Greg Kroah-Hartman | 8 | 0.28% | 2 | 2.94% |
| Linus Torvalds | 7 | 0.24% | 2 | 2.94% |
| Daniel Vetter | 5 | 0.17% | 1 | 1.47% |
| Dave Jones | 4 | 0.14% | 1 | 1.47% |
| Peter Rosin | 3 | 0.10% | 1 | 1.47% |
| Jeffrey (Sheng-Hui) Chu | 2 | 0.07% | 1 | 1.47% |
| Mark Brown | 2 | 0.07% | 1 | 1.47% |
| Michele Curti | 1 | 0.03% | 1 | 1.47% |
| Dave Airlie | 1 | 0.03% | 1 | 1.47% |
| Albert Cranford | 1 | 0.03% | 1 | 1.47% |
| Total | 2899 | 68 |
// SPDX-License-Identifier: GPL-2.0+ /* * i2c-algo-bit.c: i2c driver algorithms for bit-shift adapters * * Copyright (C) 1995-2000 Simon G. Vogl * * With some changes from Frodo Looijaard <frodol@dds.nl>, Kyösti Mälkki * <kmalkki@cc.hut.fi> and Jean Delvare <jdelvare@suse.de> */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/delay.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/i2c.h> #include <linux/i2c-algo-bit.h> /* ----- global defines ----------------------------------------------- */ #ifdef DEBUG #define bit_dbg(level, dev, format, args...) \ do { \ if (i2c_debug >= level) \ dev_dbg(dev, format, ##args); \ } while (0) #else #define bit_dbg(level, dev, format, args...) \ do {} while (0) #endif /* DEBUG */ /* ----- global variables --------------------------------------------- */ static int bit_test; /* see if the line-setting functions work */ module_param(bit_test, int, S_IRUGO); MODULE_PARM_DESC(bit_test, "lines testing - 0 off; 1 report; 2 fail if stuck"); #ifdef DEBUG static int i2c_debug = 1; module_param(i2c_debug, int, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(i2c_debug, "debug level - 0 off; 1 normal; 2 verbose; 3 very verbose"); #endif /* --- 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) static inline void sdalo(struct i2c_algo_bit_data *adap) { setsda(adap, 0); udelay((adap->udelay + 1) / 2); } static inline void sdahi(struct i2c_algo_bit_data *adap) { setsda(adap, 1); udelay((adap->udelay + 1) / 2); } static inline void scllo(struct i2c_algo_bit_data *adap) { setscl(adap, 0); udelay(adap->udelay / 2); } /* * Raise scl line, and do checking for delays. This is necessary for slower * devices. */ static int sclhi(struct i2c_algo_bit_data *adap) { unsigned long start; setscl(adap, 1); /* Not all adapters have scl sense line... */ if (!adap->getscl) goto done; 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(jiffies, start + adap->timeout)) { /* Test one last time, as we may have been preempted * between last check and timeout test. */ if (getscl(adap)) break; return -ETIMEDOUT; } cpu_relax(); } #ifdef DEBUG if (jiffies != start && i2c_debug >= 3) pr_debug("i2c-algo-bit: needed %ld jiffies for SCL to go high\n", jiffies - start); #endif done: udelay(adap->udelay); return 0; } /* --- other auxiliary functions -------------------------------------- */ static void i2c_start(struct i2c_algo_bit_data *adap) { /* assert: scl, sda are high */ setsda(adap, 0); udelay(adap->udelay); scllo(adap); } static void i2c_repstart(struct i2c_algo_bit_data *adap) { /* assert: scl is low */ sdahi(adap); sclhi(adap); setsda(adap, 0); udelay(adap->udelay); scllo(adap); } static void i2c_stop(struct i2c_algo_bit_data *adap) { /* assert: scl is low */ sdalo(adap); sclhi(adap); setsda(adap, 1); udelay(adap->udelay); } /* send a byte without start cond., look for arbitration, check ackn. from slave */ /* returns: * 1 if the device acknowledged * 0 if the device did not ack * -ETIMEDOUT if an error occurred (while raising the scl line) */ static int i2c_outb(struct i2c_adapter *i2c_adap, unsigned char c) { int i; int sb; int ack; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; /* assert: scl is low */ for (i = 7; i >= 0; i--) { sb = (c >> i) & 1; setsda(adap, sb); udelay((adap->udelay + 1) / 2); 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; } /* 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 */ 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, or it may * NAK (usually to report problems with the data we wrote). * Always report ACK if SDA is write-only. */ ack = !adap->getsda || !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"); scllo(adap); return ack; /* assert: scl is low (sda undef) */ } 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; 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 */ bit_dbg(1, &i2c_adap->dev, "i2c_inb: timeout at bit #%d\n", 7 - i); return -ETIMEDOUT; } indata *= 2; if (getsda(adap)) indata |= 0x01; setscl(adap, 0); udelay(i == 7 ? adap->udelay / 2 : adap->udelay); } /* assert: scl is low */ return indata; } /* * 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_adapter *i2c_adap) { struct i2c_algo_bit_data *adap = i2c_adap->algo_data; const char *name = i2c_adap->name; int scl, sda, ret; if (adap->pre_xfer) { ret = adap->pre_xfer(i2c_adap); if (ret < 0) return -ENODEV; } if (adap->getsda == NULL) pr_info("%s: SDA is write-only, testing not possible\n", name); if (adap->getscl == NULL) pr_info("%s: SCL is write-only, testing not possible\n", name); sda = adap->getsda ? getsda(adap) : 1; scl = adap->getscl ? getscl(adap) : 1; if (!scl || !sda) { pr_warn("%s: bus seems to be busy (scl=%d, sda=%d)\n", name, scl, sda); goto bailout; } sdalo(adap); if (adap->getsda && getsda(adap)) { pr_warn("%s: SDA stuck high!\n", name); goto bailout; } if (adap->getscl && !getscl(adap)) { pr_warn("%s: SCL unexpected low while pulling SDA low!\n", name); goto bailout; } sdahi(adap); if (adap->getsda && !getsda(adap)) { pr_warn("%s: SDA stuck low!\n", name); goto bailout; } if (adap->getscl && !getscl(adap)) { pr_warn("%s: SCL unexpected low while pulling SDA high!\n", name); goto bailout; } scllo(adap); if (adap->getscl && getscl(adap)) { pr_warn("%s: SCL stuck high!\n", name); goto bailout; } if (adap->getsda && !getsda(adap)) { pr_warn("%s: SDA unexpected low while pulling SCL low!\n", name); goto bailout; } sclhi(adap); if (adap->getscl && !getscl(adap)) { pr_warn("%s: SCL stuck low!\n", name); goto bailout; } if (adap->getsda && !getsda(adap)) { pr_warn("%s: SDA unexpected low while pulling SCL high!\n", name); goto bailout; } if (adap->post_xfer) adap->post_xfer(i2c_adap); pr_info("%s: Test OK\n", name); return 0; bailout: sdahi(adap); sclhi(adap); if (adap->post_xfer) adap->post_xfer(i2c_adap); return -ENODEV; } /* ----- Utility functions */ /* try_address tries to contact a chip for a number of * times before it gives up. * return values: * 1 chip answered * 0 chip did not answer * -x transmission error */ 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 = 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"); i2c_stop(adap); udelay(adap->udelay); yield(); bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); i2c_start(adap); } if (i && ret) bit_dbg(1, &i2c_adap->dev, "Used %d tries to %s client at 0x%02x: %s\n", i + 1, addr & 1 ? "read from" : "write to", addr >> 1, ret == 1 ? "success" : "failed, timeout?"); return ret; } 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; int retval; int wrcount = 0; while (count > 0) { retval = i2c_outb(i2c_adap, *temp); /* OK/ACK; or ignored NAK */ if ((retval > 0) || (nak_ok && (retval == 0))) { count--; temp++; wrcount++; /* 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 */ unsigned char *temp = msg->buf; int count = msg->len; const unsigned flags = msg->flags; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; if (!adap->getsda) return -EOPNOTSUPP; while (count > 0) { inval = i2c_inb(i2c_adap); if (inval >= 0) { *temp = inval; rdcount++; } else { /* read timed out */ break; } temp++; count--; /* Some SMBus transactions require that we receive the transaction length as the first read byte. */ 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 -EPROTO; } /* The original count value accounts for the extra bytes, that is, either 1 for a regular transaction, or 2 for a PEC transaction. */ 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; } /* doAddress initiates the transfer by generating the start condition (in * try_address) and transmits the address in the necessary format to handle * reads, writes as well as 10bit-addresses. * returns: * 0 everything went okay, the chip ack'ed, or IGNORE_NAK flag was set * -x an error occurred (like: -ENXIO if the device did not answer, or * -ETIMEDOUT, for example if the lines are stuck...) */ static int bit_doAddress(struct i2c_adapter *i2c_adap, struct i2c_msg *msg) { unsigned short flags = msg->flags; unsigned short nak_ok = msg->flags & I2C_M_IGNORE_NAK; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; unsigned char addr; int ret, retries; retries = nak_ok ? 0 : i2c_adap->retries; if (flags & I2C_M_TEN) { /* a ten bit address */ addr = 0xf0 | ((msg->addr >> 7) & 0x06); bit_dbg(2, &i2c_adap->dev, "addr0: %d\n", addr); /* try extended address code...*/ ret = try_address(i2c_adap, addr, retries); if ((ret != 1) && !nak_ok) { dev_err(&i2c_adap->dev, "died at extended address code\n"); return -ENXIO; } /* the remaining 8 bit address */ ret = i2c_outb(i2c_adap, msg->addr & 0xff); 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 -ENXIO; } 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) { dev_err(&i2c_adap->dev, "died at repeated address code\n"); return -EIO; } } } else { /* normal 7bit address */ addr = i2c_8bit_addr_from_msg(msg); if (flags & I2C_M_REV_DIR_ADDR) addr ^= 1; ret = try_address(i2c_adap, addr, retries); if ((ret != 1) && !nak_ok) return -ENXIO; } return 0; } static int bit_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num) { struct i2c_msg *pmsg; struct i2c_algo_bit_data *adap = i2c_adap->algo_data; int i, ret; unsigned short nak_ok; if (adap->pre_xfer) { ret = adap->pre_xfer(i2c_adap); if (ret < 0) return ret; } bit_dbg(3, &i2c_adap->dev, "emitting start condition\n"); i2c_start(adap); for (i = 0; i < num; i++) { pmsg = &msgs[i]; nak_ok = pmsg->flags & I2C_M_IGNORE_NAK; if (!(pmsg->flags & I2C_M_NOSTART)) { if (i) { if (msgs[i - 1].flags & I2C_M_STOP) { bit_dbg(3, &i2c_adap->dev, "emitting enforced stop/start condition\n"); i2c_stop(adap); i2c_start(adap); } else { bit_dbg(3, &i2c_adap->dev, "emitting repeated start condition\n"); i2c_repstart(adap); } } ret = bit_doAddress(i2c_adap, pmsg); if ((ret != 0) && !nak_ok) { bit_dbg(1, &i2c_adap->dev, "NAK from device addr 0x%02x msg #%d\n", msgs[i].addr, i); goto bailout; } } if (pmsg->flags & I2C_M_RD) { /* read bytes into buffer*/ ret = readbytes(i2c_adap, pmsg); if (ret >= 1) bit_dbg(2, &i2c_adap->dev, "read %d byte%s\n", ret, ret == 1 ? "" : "s"); if (ret < pmsg->len) { if (ret >= 0) ret = -EIO; goto bailout; } } else { /* write bytes from buffer */ ret = sendbytes(i2c_adap, pmsg); if (ret >= 1) bit_dbg(2, &i2c_adap->dev, "wrote %d byte%s\n", ret, ret == 1 ? "" : "s"); if (ret < pmsg->len) { if (ret >= 0) ret = -EIO; goto bailout; } } } ret = i; bailout: bit_dbg(3, &i2c_adap->dev, "emitting stop condition\n"); i2c_stop(adap); if (adap->post_xfer) adap->post_xfer(i2c_adap); return ret; } /* * We print a warning when we are not flagged to support atomic transfers but * will try anyhow. That's what the I2C core would do as well. Sadly, we can't * modify the algorithm struct at probe time because this struct is exported * 'const'. */ static int bit_xfer_atomic(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[], int num) { struct i2c_algo_bit_data *adap = i2c_adap->algo_data; if (!adap->can_do_atomic) dev_warn(&i2c_adap->dev, "not flagged for atomic transfers\n"); return bit_xfer(i2c_adap, msgs, num); } static u32 bit_func(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_NOSTART | I2C_FUNC_SMBUS_EMUL_ALL | I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING; } /* -----exported algorithm data: ------------------------------------- */ const struct i2c_algorithm i2c_bit_algo = { .master_xfer = bit_xfer, .master_xfer_atomic = bit_xfer_atomic, .functionality = bit_func, }; EXPORT_SYMBOL(i2c_bit_algo); static const struct i2c_adapter_quirks i2c_bit_quirk_no_clk_stretch = { .flags = I2C_AQ_NO_CLK_STRETCH, }; /* * registering functions to load algorithms at runtime */ static int __i2c_bit_add_bus(struct i2c_adapter *adap, int (*add_adapter)(struct i2c_adapter *)) { struct i2c_algo_bit_data *bit_adap = adap->algo_data; int ret; if (bit_test) { ret = test_bus(adap); if (bit_test >= 2 && ret < 0) return -ENODEV; } /* register new adapter to i2c module... */ adap->algo = &i2c_bit_algo; adap->retries = 3; if (bit_adap->getscl == NULL) adap->quirks = &i2c_bit_quirk_no_clk_stretch; /* * We tried forcing SCL/SDA to an initial state here. But that caused a * regression, sadly. Check Bugzilla #200045 for details. */ ret = add_adapter(adap); if (ret < 0) return ret; if (bit_adap->getsda == NULL) dev_warn(&adap->dev, "Not I2C compliant: can't read SDA\n"); if (bit_adap->getscl == NULL) dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); if (bit_adap->getsda == NULL || bit_adap->getscl == NULL) dev_warn(&adap->dev, "Bus may be unreliable\n"); return 0; } int i2c_bit_add_bus(struct i2c_adapter *adap) { return __i2c_bit_add_bus(adap, i2c_add_adapter); } EXPORT_SYMBOL(i2c_bit_add_bus); int i2c_bit_add_numbered_bus(struct i2c_adapter *adap) { return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter); } EXPORT_SYMBOL(i2c_bit_add_numbered_bus); MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); MODULE_DESCRIPTION("I2C-Bus bit-banging algorithm"); MODULE_LICENSE("GPL");
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