From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/i2c/algos/i2c-algo-pcf.c | 436 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 436 insertions(+) create mode 100644 drivers/i2c/algos/i2c-algo-pcf.c (limited to 'drivers/i2c/algos/i2c-algo-pcf.c') diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c new file mode 100644 index 000000000..270d84bfc --- /dev/null +++ b/drivers/i2c/algos/i2c-algo-pcf.c @@ -0,0 +1,436 @@ +/* + * 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. + * + * With some changes from Kyösti Mälkki and + * Frodo Looijaard , and also from Martin Bailey + * + * + * Partially rewriten by Oleg I. Vdovikin to handle multiple + * messages, proper stop/repstart signaling during receive, added detect code + */ + +#include +#include +#include +#include +#include +#include +#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(KERN_DEBUG "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 void handle_lab(struct i2c_algo_pcf_data *adap, const int *status) +{ + 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); + /* + * We 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. + * It is assumed the bus driver or client has set a proper value. + * + * REVISIT: should probably use msleep instead of mdelay if we + * know we can sleep. + */ + if (adap->lab_mdelay) + mdelay(adap->lab_mdelay); + + DEB2(printk(KERN_INFO + "i2c-algo-pcf.o: reset LAB condition (CSR 0x%02x)\n", + get_pcf(adap, 1))); +} + +static int wait_for_bb(struct i2c_algo_pcf_data *adap) +{ + + int timeout = DEF_TIMEOUT; + int status; + + status = get_pcf(adap, 1); + + while (!(status & I2C_PCF_BB) && --timeout) { + udelay(100); /* wait for 100 us */ + status = get_pcf(adap, 1); + } + + if (timeout == 0) { + printk(KERN_ERR "Timeout waiting for Bus Busy\n"); + return -ETIMEDOUT; + } + + return 0; +} + +static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) +{ + + int timeout = DEF_TIMEOUT; + + *status = get_pcf(adap, 1); + + while ((*status & I2C_PCF_PIN) && --timeout) { + adap->waitforpin(adap->data); + *status = get_pcf(adap, 1); + } + if (*status & I2C_PCF_LAB) { + handle_lab(adap, status); + return -EINTR; + } + + if (timeout == 0) + return -ETIMEDOUT; + + 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; /* definitely 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: detected and initialized PCF8584.\n"); + + return 0; +} + +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; wrcountdev, "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) + return -EINTR; /* arbitration lost */ + + i2c_stop(adap); + dev_err(&i2c_adap->dev, "i2c_write: error - timeout.\n"); + return -EREMOTEIO; /* got a better one ?? */ + } + 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 ?? */ + } + } + 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) + return -EINTR; /* arbitration lost */ + + i2c_stop(adap); + dev_err(&i2c_adap->dev, "pcf_readbytes timed out.\n"); + return -1; + } + + if ((status & I2C_PCF_LRB) && (i != count)) { + i2c_stop(adap); + dev_err(&i2c_adap->dev, "i2c_read: i2c_inb, No ack.\n"); + return -1; + } + + 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 int pcf_doAddress(struct i2c_algo_pcf_data *adap, + struct i2c_msg *msg) +{ + unsigned short flags = msg->flags; + unsigned char addr; + + 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; + + if (adap->xfer_begin) + adap->xfer_begin(adap->data); + + /* 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");) + i = -EIO; + goto out; + } + + 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); + + /* 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 */ + i = -EINTR; + goto out; + } + i2c_stop(adap); + DEB2(printk(KERN_ERR "i2c-algo-pcf.o: Timeout waiting " + "for PIN(1) in pcf_xfer\n");) + i = -EREMOTEIO; + goto out; + } + + /* 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");) + i = -EREMOTEIO; + goto out; + } + + 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);) + + if (pmsg->flags & I2C_M_RD) { + 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 { + 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)); + } + } + } + +out: + if (adap->xfer_end) + adap->xfer_end(adap->data); + return i; +} + +static u32 pcf_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | + I2C_FUNC_PROTOCOL_MANGLING; +} + +/* exported algorithm data: */ +static const 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; + + if ((rval = pcf_init_8584(pcf_adap))) + return rval; + + rval = i2c_add_adapter(adap); + + return rval; +} +EXPORT_SYMBOL(i2c_pcf_add_bus); + +MODULE_AUTHOR("Hans Berglund "); +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"); -- cgit v1.2.3-54-g00ecf