Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 1772 insertions, 0 deletions

diff --git a/drivers/i2c/algos/Kconfig b/drivers/i2c/algos/Kconfig
new file mode 100644
index 000000000..aea523529
--- /dev/null
+++ b/drivers/i2c/algos/Kconfig
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# I2C algorithm drivers configuration
+#
+
+menu "I2C Algorithms"
+	visible if !I2C_HELPER_AUTO
+
+config I2C_ALGOBIT
+	tristate "I2C bit-banging interfaces"
+
+config I2C_ALGOPCF
+	tristate "I2C PCF 8584 interfaces"
+
+config I2C_ALGOPCA
+	tristate "I2C PCA 9564 interfaces"
+
+endmenu
diff --git a/drivers/i2c/algos/Makefile b/drivers/i2c/algos/Makefile
new file mode 100644
index 000000000..9b319a30d
--- /dev/null
+++ b/drivers/i2c/algos/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the i2c algorithms
+#
+
+obj-$(CONFIG_I2C_ALGOBIT)	+= i2c-algo-bit.o
+obj-$(CONFIG_I2C_ALGOPCF)	+= i2c-algo-pcf.o
+obj-$(CONFIG_I2C_ALGOPCA)	+= i2c-algo-pca.o
+
+ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
new file mode 100644
index 000000000..fc90293af
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -0,0 +1,695 @@
+// 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).
+	 */
+	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;
+	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->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) {
+		printk(KERN_WARNING
+		       "%s: bus seems to be busy (scl=%d, sda=%d)\n",
+		       name, scl, sda);
+		goto bailout;
+	}
+
+	sdalo(adap);
+	sda = getsda(adap);
+	scl = (adap->getscl == NULL) ? 1 : getscl(adap);
+	if (sda) {
+		printk(KERN_WARNING "%s: SDA stuck high!\n", name);
+		goto bailout;
+	}
+	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 (!sda) {
+		printk(KERN_WARNING "%s: SDA stuck low!\n", name);
+		goto bailout;
+	}
+	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 (scl) {
+		printk(KERN_WARNING "%s: SCL stuck high!\n", name);
+		goto bailout;
+	}
+	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 (!scl) {
+		printk(KERN_WARNING "%s: SCL stuck low!\n", name);
+		goto bailout;
+	}
+	if (!sda) {
+		printk(KERN_WARNING
+		       "%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;
+
+	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;
+
+	/* 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_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");
diff --git a/drivers/i2c/algos/i2c-algo-pca.c b/drivers/i2c/algos/i2c-algo-pca.c
new file mode 100644
index 000000000..384af88e5
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-pca.c
@@ -0,0 +1,561 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
+ *    Copyright (C) 2004 Arcom Control Systems
+ *    Copyright (C) 2008 Pengutronix
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-pca.h>
+
+#define DEB1(fmt, args...) do { if (i2c_debug >= 1)			\
+				 printk(KERN_DEBUG fmt, ## args); } while (0)
+#define DEB2(fmt, args...) do { if (i2c_debug >= 2)			\
+				 printk(KERN_DEBUG fmt, ## args); } while (0)
+#define DEB3(fmt, args...) do { if (i2c_debug >= 3)			\
+				 printk(KERN_DEBUG fmt, ## args); } while (0)
+
+static int i2c_debug;
+
+#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
+#define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
+
+#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
+#define pca_clock(adap) adap->i2c_clock
+#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
+#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
+#define pca_wait(adap) adap->wait_for_completion(adap->data)
+
+static void pca_reset(struct i2c_algo_pca_data *adap)
+{
+	if (adap->chip == I2C_PCA_CHIP_9665) {
+		/* Ignore the reset function from the module,
+		 * we can use the parallel bus reset.
+		 */
+		pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IPRESET);
+		pca_outw(adap, I2C_PCA_IND, 0xA5);
+		pca_outw(adap, I2C_PCA_IND, 0x5A);
+
+		/*
+		 * After a reset we need to re-apply any configuration
+		 * (calculated in pca_init) to get the bus in a working state.
+		 */
+		pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_IMODE);
+		pca_outw(adap, I2C_PCA_IND, adap->bus_settings.mode);
+		pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLL);
+		pca_outw(adap, I2C_PCA_IND, adap->bus_settings.tlow);
+		pca_outw(adap, I2C_PCA_INDPTR, I2C_PCA_ISCLH);
+		pca_outw(adap, I2C_PCA_IND, adap->bus_settings.thi);
+
+		pca_set_con(adap, I2C_PCA_CON_ENSIO);
+	} else {
+		adap->reset_chip(adap->data);
+		pca_set_con(adap, I2C_PCA_CON_ENSIO | adap->bus_settings.clock_freq);
+	}
+}
+
+/*
+ * Generate a start condition on the i2c bus.
+ *
+ * returns after the start condition has occurred
+ */
+static int pca_start(struct i2c_algo_pca_data *adap)
+{
+	int sta = pca_get_con(adap);
+	DEB2("=== START\n");
+	sta |= I2C_PCA_CON_STA;
+	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
+	pca_set_con(adap, sta);
+	return pca_wait(adap);
+}
+
+/*
+ * Generate a repeated start condition on the i2c bus
+ *
+ * return after the repeated start condition has occurred
+ */
+static int pca_repeated_start(struct i2c_algo_pca_data *adap)
+{
+	int sta = pca_get_con(adap);
+	DEB2("=== REPEATED START\n");
+	sta |= I2C_PCA_CON_STA;
+	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_SI);
+	pca_set_con(adap, sta);
+	return pca_wait(adap);
+}
+
+/*
+ * Generate a stop condition on the i2c bus
+ *
+ * returns after the stop condition has been generated
+ *
+ * STOPs do not generate an interrupt or set the SI flag, since the
+ * part returns the idle state (0xf8). Hence we don't need to
+ * pca_wait here.
+ */
+static void pca_stop(struct i2c_algo_pca_data *adap)
+{
+	int sta = pca_get_con(adap);
+	DEB2("=== STOP\n");
+	sta |= I2C_PCA_CON_STO;
+	sta &= ~(I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+	pca_set_con(adap, sta);
+}
+
+/*
+ * Send the slave address and R/W bit
+ *
+ * returns after the address has been sent
+ */
+static int pca_address(struct i2c_algo_pca_data *adap,
+		       struct i2c_msg *msg)
+{
+	int sta = pca_get_con(adap);
+	int addr = i2c_8bit_addr_from_msg(msg);
+
+	DEB2("=== SLAVE ADDRESS %#04x+%c=%#04x\n",
+	     msg->addr, msg->flags & I2C_M_RD ? 'R' : 'W', addr);
+
+	pca_outw(adap, I2C_PCA_DAT, addr);
+
+	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+	pca_set_con(adap, sta);
+
+	return pca_wait(adap);
+}
+
+/*
+ * Transmit a byte.
+ *
+ * Returns after the byte has been transmitted
+ */
+static int pca_tx_byte(struct i2c_algo_pca_data *adap,
+		       __u8 b)
+{
+	int sta = pca_get_con(adap);
+	DEB2("=== WRITE %#04x\n", b);
+	pca_outw(adap, I2C_PCA_DAT, b);
+
+	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI);
+	pca_set_con(adap, sta);
+
+	return pca_wait(adap);
+}
+
+/*
+ * Receive a byte
+ *
+ * returns immediately.
+ */
+static void pca_rx_byte(struct i2c_algo_pca_data *adap,
+			__u8 *b, int ack)
+{
+	*b = pca_inw(adap, I2C_PCA_DAT);
+	DEB2("=== READ %#04x %s\n", *b, ack ? "ACK" : "NACK");
+}
+
+/*
+ * Setup ACK or NACK for next received byte and wait for it to arrive.
+ *
+ * Returns after next byte has arrived.
+ */
+static int pca_rx_ack(struct i2c_algo_pca_data *adap,
+		      int ack)
+{
+	int sta = pca_get_con(adap);
+
+	sta &= ~(I2C_PCA_CON_STO|I2C_PCA_CON_STA|I2C_PCA_CON_SI|I2C_PCA_CON_AA);
+
+	if (ack)
+		sta |= I2C_PCA_CON_AA;
+
+	pca_set_con(adap, sta);
+	return pca_wait(adap);
+}
+
+static int pca_xfer(struct i2c_adapter *i2c_adap,
+		    struct i2c_msg *msgs,
+		    int num)
+{
+	struct i2c_algo_pca_data *adap = i2c_adap->algo_data;
+	struct i2c_msg *msg = NULL;
+	int curmsg;
+	int numbytes = 0;
+	int state;
+	int ret;
+	int completed = 1;
+	unsigned long timeout = jiffies + i2c_adap->timeout;
+
+	while ((state = pca_status(adap)) != 0xf8) {
+		if (time_before(jiffies, timeout)) {
+			msleep(10);
+		} else {
+			dev_dbg(&i2c_adap->dev, "bus is not idle. status is "
+				"%#04x\n", state);
+			return -EBUSY;
+		}
+	}
+
+	DEB1("{{{ XFER %d messages\n", num);
+
+	if (i2c_debug >= 2) {
+		for (curmsg = 0; curmsg < num; curmsg++) {
+			int addr, i;
+			msg = &msgs[curmsg];
+
+			addr = (0x7f & msg->addr) ;
+
+			if (msg->flags & I2C_M_RD)
+				printk(KERN_INFO "    [%02d] RD %d bytes from %#02x [%#02x, ...]\n",
+				       curmsg, msg->len, addr, (addr << 1) | 1);
+			else {
+				printk(KERN_INFO "    [%02d] WR %d bytes to %#02x [%#02x%s",
+				       curmsg, msg->len, addr, addr << 1,
+				       msg->len == 0 ? "" : ", ");
+				for (i = 0; i < msg->len; i++)
+					printk("%#04x%s", msg->buf[i], i == msg->len - 1 ? "" : ", ");
+				printk("]\n");
+			}
+		}
+	}
+
+	curmsg = 0;
+	ret = -EIO;
+	while (curmsg < num) {
+		state = pca_status(adap);
+
+		DEB3("STATE is 0x%02x\n", state);
+		msg = &msgs[curmsg];
+
+		switch (state) {
+		case 0xf8: /* On reset or stop the bus is idle */
+			completed = pca_start(adap);
+			break;
+
+		case 0x08: /* A START condition has been transmitted */
+		case 0x10: /* A repeated start condition has been transmitted */
+			completed = pca_address(adap, msg);
+			break;
+
+		case 0x18: /* SLA+W has been transmitted; ACK has been received */
+		case 0x28: /* Data byte in I2CDAT has been transmitted; ACK has been received */
+			if (numbytes < msg->len) {
+				completed = pca_tx_byte(adap,
+							msg->buf[numbytes]);
+				numbytes++;
+				break;
+			}
+			curmsg++; numbytes = 0;
+			if (curmsg == num)
+				pca_stop(adap);
+			else
+				completed = pca_repeated_start(adap);
+			break;
+
+		case 0x20: /* SLA+W has been transmitted; NOT ACK has been received */
+			DEB2("NOT ACK received after SLA+W\n");
+			pca_stop(adap);
+			ret = -ENXIO;
+			goto out;
+
+		case 0x40: /* SLA+R has been transmitted; ACK has been received */
+			completed = pca_rx_ack(adap, msg->len > 1);
+			break;
+
+		case 0x50: /* Data bytes has been received; ACK has been returned */
+			if (numbytes < msg->len) {
+				pca_rx_byte(adap, &msg->buf[numbytes], 1);
+				numbytes++;
+				completed = pca_rx_ack(adap,
+						       numbytes < msg->len - 1);
+				break;
+			}
+			curmsg++; numbytes = 0;
+			if (curmsg == num)
+				pca_stop(adap);
+			else
+				completed = pca_repeated_start(adap);
+			break;
+
+		case 0x48: /* SLA+R has been transmitted; NOT ACK has been received */
+			DEB2("NOT ACK received after SLA+R\n");
+			pca_stop(adap);
+			ret = -ENXIO;
+			goto out;
+
+		case 0x30: /* Data byte in I2CDAT has been transmitted; NOT ACK has been received */
+			DEB2("NOT ACK received after data byte\n");
+			pca_stop(adap);
+			goto out;
+
+		case 0x38: /* Arbitration lost during SLA+W, SLA+R or data bytes */
+			DEB2("Arbitration lost\n");
+			/*
+			 * The PCA9564 data sheet (2006-09-01) says "A
+			 * START condition will be transmitted when the
+			 * bus becomes free (STOP or SCL and SDA high)"
+			 * when the STA bit is set (p. 11).
+			 *
+			 * In case this won't work, try pca_reset()
+			 * instead.
+			 */
+			pca_start(adap);
+			goto out;
+
+		case 0x58: /* Data byte has been received; NOT ACK has been returned */
+			if (numbytes == msg->len - 1) {
+				pca_rx_byte(adap, &msg->buf[numbytes], 0);
+				curmsg++; numbytes = 0;
+				if (curmsg == num)
+					pca_stop(adap);
+				else
+					completed = pca_repeated_start(adap);
+			} else {
+				DEB2("NOT ACK sent after data byte received. "
+				     "Not final byte. numbytes %d. len %d\n",
+				     numbytes, msg->len);
+				pca_stop(adap);
+				goto out;
+			}
+			break;
+		case 0x70: /* Bus error - SDA stuck low */
+			DEB2("BUS ERROR - SDA Stuck low\n");
+			pca_reset(adap);
+			goto out;
+		case 0x78: /* Bus error - SCL stuck low (PCA9665) */
+		case 0x90: /* Bus error - SCL stuck low (PCA9564) */
+			DEB2("BUS ERROR - SCL Stuck low\n");
+			pca_reset(adap);
+			goto out;
+		case 0x00: /* Bus error during master or slave mode due to illegal START or STOP condition */
+			DEB2("BUS ERROR - Illegal START or STOP\n");
+			pca_reset(adap);
+			goto out;
+		default:
+			dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
+			break;
+		}
+
+		if (!completed)
+			goto out;
+	}
+
+	ret = curmsg;
+ out:
+	DEB1("}}} transferred %d/%d messages. "
+	     "status is %#04x. control is %#04x\n",
+	     curmsg, num, pca_status(adap),
+	     pca_get_con(adap));
+	return ret;
+}
+
+static u32 pca_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm pca_algo = {
+	.master_xfer	= pca_xfer,
+	.functionality	= pca_func,
+};
+
+static unsigned int pca_probe_chip(struct i2c_adapter *adap)
+{
+	struct i2c_algo_pca_data *pca_data = adap->algo_data;
+	/* The trick here is to check if there is an indirect register
+	 * available. If there is one, we will read the value we first
+	 * wrote on I2C_PCA_IADR. Otherwise, we will read the last value
+	 * we wrote on I2C_PCA_ADR
+	 */
+	pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
+	pca_outw(pca_data, I2C_PCA_IND, 0xAA);
+	pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_ITO);
+	pca_outw(pca_data, I2C_PCA_IND, 0x00);
+	pca_outw(pca_data, I2C_PCA_INDPTR, I2C_PCA_IADR);
+	if (pca_inw(pca_data, I2C_PCA_IND) == 0xAA) {
+		printk(KERN_INFO "%s: PCA9665 detected.\n", adap->name);
+		pca_data->chip = I2C_PCA_CHIP_9665;
+	} else {
+		printk(KERN_INFO "%s: PCA9564 detected.\n", adap->name);
+		pca_data->chip = I2C_PCA_CHIP_9564;
+	}
+	return pca_data->chip;
+}
+
+static int pca_init(struct i2c_adapter *adap)
+{
+	struct i2c_algo_pca_data *pca_data = adap->algo_data;
+
+	adap->algo = &pca_algo;
+
+	if (pca_probe_chip(adap) == I2C_PCA_CHIP_9564) {
+		static int freqs[] = {330, 288, 217, 146, 88, 59, 44, 36};
+		int clock;
+
+		if (pca_data->i2c_clock > 7) {
+			switch (pca_data->i2c_clock) {
+			case 330000:
+				pca_data->i2c_clock = I2C_PCA_CON_330kHz;
+				break;
+			case 288000:
+				pca_data->i2c_clock = I2C_PCA_CON_288kHz;
+				break;
+			case 217000:
+				pca_data->i2c_clock = I2C_PCA_CON_217kHz;
+				break;
+			case 146000:
+				pca_data->i2c_clock = I2C_PCA_CON_146kHz;
+				break;
+			case 88000:
+				pca_data->i2c_clock = I2C_PCA_CON_88kHz;
+				break;
+			case 59000:
+				pca_data->i2c_clock = I2C_PCA_CON_59kHz;
+				break;
+			case 44000:
+				pca_data->i2c_clock = I2C_PCA_CON_44kHz;
+				break;
+			case 36000:
+				pca_data->i2c_clock = I2C_PCA_CON_36kHz;
+				break;
+			default:
+				printk(KERN_WARNING
+					"%s: Invalid I2C clock speed selected."
+					" Using default 59kHz.\n", adap->name);
+			pca_data->i2c_clock = I2C_PCA_CON_59kHz;
+			}
+		} else {
+			printk(KERN_WARNING "%s: "
+				"Choosing the clock frequency based on "
+				"index is deprecated."
+				" Use the nominal frequency.\n", adap->name);
+		}
+
+		clock = pca_clock(pca_data);
+		printk(KERN_INFO "%s: Clock frequency is %dkHz\n",
+		     adap->name, freqs[clock]);
+
+		/* Store settings as these will be needed when the PCA chip is reset */
+		pca_data->bus_settings.clock_freq = clock;
+
+		pca_reset(pca_data);
+	} else {
+		int clock;
+		int mode;
+		int tlow, thi;
+		/* Values can be found on PCA9665 datasheet section 7.3.2.6 */
+		int min_tlow, min_thi;
+		/* These values are the maximum raise and fall values allowed
+		 * by the I2C operation mode (Standard, Fast or Fast+)
+		 * They are used (added) below to calculate the clock dividers
+		 * of PCA9665. Note that they are slightly different of the
+		 * real maximum, to allow the change on mode exactly on the
+		 * maximum clock rate for each mode
+		 */
+		int raise_fall_time;
+
+		if (pca_data->i2c_clock > 1265800) {
+			printk(KERN_WARNING "%s: I2C clock speed too high."
+				" Using 1265.8kHz.\n", adap->name);
+			pca_data->i2c_clock = 1265800;
+		}
+
+		if (pca_data->i2c_clock < 60300) {
+			printk(KERN_WARNING "%s: I2C clock speed too low."
+				" Using 60.3kHz.\n", adap->name);
+			pca_data->i2c_clock = 60300;
+		}
+
+		/* To avoid integer overflow, use clock/100 for calculations */
+		clock = pca_clock(pca_data) / 100;
+
+		if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_PLUS_FREQ) {
+			mode = I2C_PCA_MODE_TURBO;
+			min_tlow = 14;
+			min_thi  = 5;
+			raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
+		} else if (pca_data->i2c_clock > I2C_MAX_FAST_MODE_FREQ) {
+			mode = I2C_PCA_MODE_FASTP;
+			min_tlow = 17;
+			min_thi  = 9;
+			raise_fall_time = 22; /* Raise 11e-8s, Fall 11e-8s */
+		} else if (pca_data->i2c_clock > I2C_MAX_STANDARD_MODE_FREQ) {
+			mode = I2C_PCA_MODE_FAST;
+			min_tlow = 44;
+			min_thi  = 20;
+			raise_fall_time = 58; /* Raise 29e-8s, Fall 29e-8s */
+		} else {
+			mode = I2C_PCA_MODE_STD;
+			min_tlow = 157;
+			min_thi  = 134;
+			raise_fall_time = 127; /* Raise 29e-8s, Fall 98e-8s */
+		}
+
+		/* The minimum clock that respects the thi/tlow = 134/157 is
+		 * 64800 Hz. Below that, we have to fix the tlow to 255 and
+		 * calculate the thi factor.
+		 */
+		if (clock < 648) {
+			tlow = 255;
+			thi = 1000000 - clock * raise_fall_time;
+			thi /= (I2C_PCA_OSC_PER * clock) - tlow;
+		} else {
+			tlow = (1000000 - clock * raise_fall_time) * min_tlow;
+			tlow /= I2C_PCA_OSC_PER * clock * (min_thi + min_tlow);
+			thi = tlow * min_thi / min_tlow;
+		}
+
+		/* Store settings as these will be needed when the PCA chip is reset */
+		pca_data->bus_settings.mode = mode;
+		pca_data->bus_settings.tlow = tlow;
+		pca_data->bus_settings.thi = thi;
+
+		pca_reset(pca_data);
+
+		printk(KERN_INFO
+		     "%s: Clock frequency is %dHz\n", adap->name, clock * 100);
+	}
+	udelay(500); /* 500 us for oscillator to stabilise */
+
+	return 0;
+}
+
+/*
+ * registering functions to load algorithms at runtime
+ */
+int i2c_pca_add_bus(struct i2c_adapter *adap)
+{
+	int rval;
+
+	rval = pca_init(adap);
+	if (rval)
+		return rval;
+
+	return i2c_add_adapter(adap);
+}
+EXPORT_SYMBOL(i2c_pca_add_bus);
+
+int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
+{
+	int rval;
+
+	rval = pca_init(adap);
+	if (rval)
+		return rval;
+
+	return i2c_add_numbered_adapter(adap);
+}
+EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
+
+MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
+MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("I2C-Bus PCA9564/PCA9665 algorithm");
+MODULE_LICENSE("GPL");
+
+module_param(i2c_debug, int, 0);
diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c
new file mode 100644
index 000000000..7a01f2687
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-pcf.c
@@ -0,0 +1,423 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * i2c-algo-pcf.c i2c driver algorithms for PCF8584 adapters
+ *
+ *   Copyright (C) 1995-1997 Simon G. Vogl
+ *		   1998-2000 Hans Berglund
+ *
+ * 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 char addr = i2c_8bit_addr_from_msg(msg);
+
+	if (msg->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");
diff --git a/drivers/i2c/algos/i2c-algo-pcf.h b/drivers/i2c/algos/i2c-algo-pcf.h
new file mode 100644
index 000000000..2448ab192
--- /dev/null
+++ b/drivers/i2c/algos/i2c-algo-pcf.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* -------------------------------------------------------------------- */
+/* i2c-pcf8584.h: PCF 8584 global defines				*/
+/* -------------------------------------------------------------------- */
+/*   Copyright (C) 1996 Simon G. Vogl
+                   1999 Hans Berglund
+
+ */
+/* --------------------------------------------------------------------	*/
+
+/* With some changes from Frodo Looijaard <frodol@dds.nl> */
+
+#ifndef I2C_PCF8584_H
+#define I2C_PCF8584_H 1
+
+/* ----- Control register bits ----------------------------------------	*/
+#define I2C_PCF_PIN	0x80
+#define I2C_PCF_ESO	0x40
+#define I2C_PCF_ES1	0x20
+#define I2C_PCF_ES2	0x10
+#define I2C_PCF_ENI	0x08
+#define I2C_PCF_STA	0x04
+#define I2C_PCF_STO	0x02
+#define I2C_PCF_ACK	0x01
+
+#define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
+#define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
+#define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
+#define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)
+
+/* ----- Status register bits -----------------------------------------	*/
+/*#define I2C_PCF_PIN  0x80    as above*/
+
+#define I2C_PCF_INI 0x40   /* 1 if not initialized */
+#define I2C_PCF_STS 0x20
+#define I2C_PCF_BER 0x10
+#define I2C_PCF_AD0 0x08
+#define I2C_PCF_LRB 0x08
+#define I2C_PCF_AAS 0x04
+#define I2C_PCF_LAB 0x02
+#define I2C_PCF_BB  0x01
+
+/* ----- Chip clock frequencies ---------------------------------------	*/
+#define I2C_PCF_CLK3	0x00
+#define I2C_PCF_CLK443	0x10
+#define I2C_PCF_CLK6	0x14
+#define I2C_PCF_CLK	0x18
+#define I2C_PCF_CLK12	0x1c
+
+/* ----- transmission frequencies -------------------------------------	*/
+#define I2C_PCF_TRNS90 0x00	/*  90 kHz */
+#define I2C_PCF_TRNS45 0x01	/*  45 kHz */
+#define I2C_PCF_TRNS11 0x02	/*  11 kHz */
+#define I2C_PCF_TRNS15 0x03	/* 1.5 kHz */
+
+
+/* ----- Access to internal registers according to ES1,ES2 ------------	*/
+/* they are mapped to the data port ( a0 = 0 ) 				*/
+/* available when ESO == 0 :						*/
+
+#define I2C_PCF_OWNADR	0
+#define I2C_PCF_INTREG	I2C_PCF_ES2
+#define I2C_PCF_CLKREG	I2C_PCF_ES1
+
+#endif /* I2C_PCF8584_H */