--- /dev/null
+/*
+ * 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 <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/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(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; 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)
+ 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 <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");
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