This is needed for i2c-gpio support Based on linux 3.7-rc2
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <[email protected]> --- drivers/i2c/Kconfig | 1 + drivers/i2c/Makefile | 2 +- drivers/i2c/algos/Kconfig | 6 + drivers/i2c/algos/Makefile | 5 + drivers/i2c/algos/i2c-algo-bit.c | 585 ++++++++++++++++++++++++++++++++++++++ include/i2c/i2c-algo-bit.h | 55 ++++ include/i2c/i2c.h | 2 + 7 files changed, 655 insertions(+), 1 deletion(-) create mode 100644 drivers/i2c/algos/Kconfig create mode 100644 drivers/i2c/algos/Makefile create mode 100644 drivers/i2c/algos/i2c-algo-bit.c create mode 100644 include/i2c/i2c-algo-bit.h diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index c2af818..038e2ee 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -3,6 +3,7 @@ menuconfig I2C if I2C +source drivers/i2c/algos/Kconfig source drivers/i2c/busses/Kconfig endif diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index 42e22c0..5ce0324 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -1 +1 @@ -obj-$(CONFIG_I2C) += i2c.o busses/ +obj-$(CONFIG_I2C) += i2c.o busses/ algos/ diff --git a/drivers/i2c/algos/Kconfig b/drivers/i2c/algos/Kconfig new file mode 100644 index 0000000..c74b148 --- /dev/null +++ b/drivers/i2c/algos/Kconfig @@ -0,0 +1,6 @@ +# +# I2C algorithm drivers configuration +# + +config I2C_ALGOBIT + bool diff --git a/drivers/i2c/algos/Makefile b/drivers/i2c/algos/Makefile new file mode 100644 index 0000000..e0a0399 --- /dev/null +++ b/drivers/i2c/algos/Makefile @@ -0,0 +1,5 @@ +# +# Makefile for the i2c algorithms +# + +obj-$(CONFIG_I2C_ALGOBIT) += i2c-algo-bit.o diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c new file mode 100644 index 0000000..37af27c --- /dev/null +++ b/drivers/i2c/algos/i2c-algo-bit.c @@ -0,0 +1,585 @@ +/* ------------------------------------------------------------------------- + * 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 + 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., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301 USA. + * ------------------------------------------------------------------------- */ + +/* With some changes from Frodo Looijaard <[email protected]>, Kyösti Mälkki + <[email protected]> and Jean Delvare <[email protected]> */ + +#include <common.h> +#include <init.h> +#include <errno.h> +#include <clock.h> +#include <i2c/i2c.h> +#include <i2c/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 */ + +#ifdef DEBUG +static int i2c_debug = 1; +#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) +{ + uint64_t start; + + setscl(adap, 1); + + /* Not all adapters have scl sense line... */ + if (!adap->getscl) + goto done; + + start = get_time_ns(); + 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 (is_timeout(start, adap->timeout_ms * MSECOND)) { + /* Test one last time, as we may have been preempted + * between last check and timeout test. + */ + if (getscl(adap)) + break; + return -ETIMEDOUT; + } + } +#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). + */ + 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"); + + 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; + struct device_d *dev = &i2c_adap->dev; + int scl, sda, ret; + + if (adap->pre_xfer) { + ret = adap->pre_xfer(i2c_adap); + if (ret < 0) + return -ENODEV; + } + + if (adap->getscl == NULL) + dev_info(dev, "Testing SDA only, SCL is not readable\n"); + + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!scl || !sda) { + dev_warn(dev, "bus seems to be busy (scl=%d, sda=%d)\n", scl, sda); + goto bailout; + } + + sdalo(adap); + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (sda) { + dev_warn(dev, "SDA stuck high!\n"); + goto bailout; + } + if (!scl) { + dev_warn(dev, "SCL unexpected low while pulling SDA low!\n"); + goto bailout; + } + + sdahi(adap); + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!sda) { + dev_warn(dev, "SDA stuck low!\n"); + goto bailout; + } + if (!scl) { + dev_warn(dev, "SCL unexpected low while pulling SDA high!\n"); + goto bailout; + } + + scllo(adap); + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 0 : getscl(adap); + if (scl) { + dev_warn(dev, "SCL stuck high!\n"); + goto bailout; + } + if (!sda) { + dev_warn(dev, "SDA unexpected low while pulling SCL low!\n"); + goto bailout; + } + + sclhi(adap); + sda = getsda(adap); + scl = (adap->getscl == NULL) ? 1 : getscl(adap); + if (!scl) { + dev_warn(dev, "SCL stuck low!\n"); + goto bailout; + } + if (!sda) { + dev_warn(dev, "SDA unexpected low while pulling SCL high!\n"); + goto bailout; + } + + if (adap->post_xfer) + adap->post_xfer(i2c_adap); + + dev_info(dev, "Test OK\n"); + 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); + 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 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; + + while (count > 0) { + inval = i2c_inb(i2c_adap); + if (inval >= 0) { + *temp = inval; + rdcount++; + } else { /* read timed out */ + break; + } + + temp++; + count--; + + bit_dbg(2, &i2c_adap->dev, "readbytes: 0x%02x %s\n", + inval, + (flags & I2C_M_NO_RD_ACK) + ? "(no ack/nak)" + : (count ? "A" : "NA")); + } + 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 = msg->addr << 1; + if (flags & I2C_M_RD) + 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 (i) { + 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; +} + +/* + * 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; + adap->master_xfer = bit_xfer; + + ret = add_adapter(adap); + if (ret < 0) + return ret; + + /* Complain if SCL can't be read */ + if (bit_adap->getscl == NULL) { + dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n"); + dev_warn(&adap->dev, "Bus may be unreliable\n"); + } + return 0; +} + +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); diff --git a/include/i2c/i2c-algo-bit.h b/include/i2c/i2c-algo-bit.h new file mode 100644 index 0000000..1b72219 --- /dev/null +++ b/include/i2c/i2c-algo-bit.h @@ -0,0 +1,55 @@ +/* ------------------------------------------------------------------------- */ +/* i2c-algo-bit.h i2c driver algorithms for bit-shift adapters */ +/* ------------------------------------------------------------------------- */ +/* Copyright (C) 1995-99 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 + 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., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301 USA. */ +/* ------------------------------------------------------------------------- */ + +/* With some changes from Kyösti Mälkki <[email protected]> and even + Frodo Looijaard <[email protected]> */ + +#ifndef _LINUX_I2C_ALGO_BIT_H +#define _LINUX_I2C_ALGO_BIT_H + +/* --- Defines for bit-adapters --------------------------------------- */ +/* + * This struct contains the hw-dependent functions of bit-style adapters to + * manipulate the line states, and to init any hw-specific features. This is + * only used if you have more than one hw-type of adapter running. + */ +struct i2c_algo_bit_data { + void *data; /* private data for lowlevel routines */ + void (*setsda) (void *data, int state); + void (*setscl) (void *data, int state); + int (*getsda) (void *data); + int (*getscl) (void *data); + int (*pre_xfer) (struct i2c_adapter *); + void (*post_xfer) (struct i2c_adapter *); + + /* local settings */ + int udelay; /* half clock cycle time in us, + minimum 2 us for fast-mode I2C, + minimum 5 us for standard-mode I2C and SMBus, + maximum 50 us for SMBus */ + int timeout_ms; /* in ms */ +}; + +int i2c_bit_add_bus(struct i2c_adapter *); +int i2c_bit_add_numbered_bus(struct i2c_adapter *); +extern const struct i2c_algorithm i2c_bit_algo; + +#endif /* _LINUX_I2C_ALGO_BIT_H */ diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h index 5021dd4..b059119 100644 --- a/include/i2c/i2c.h +++ b/include/i2c/i2c.h @@ -70,6 +70,8 @@ struct i2c_adapter { int nr; /* bus number */ int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num); struct list_head list; + int retries; + void *algo_data; }; -- 1.7.10.4 _______________________________________________ barebox mailing list [email protected] http://lists.infradead.org/mailman/listinfo/barebox
