diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c
index cd5bb63..e88e321 100644
--- a/drivers/char/tpm/tpm_tis.c
+++ b/drivers/char/tpm/tpm_tis.c
@@ -134,11 +134,16 @@ static inline int is_itpm(struct acpi_device *dev)
 static int wait_startup(struct tpm_chip *chip, int l)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	unsigned long stop = jiffies + chip->timeout_a;
+	int rc;
+	u8 access;
+
 	do {
-		if (ioread8(phy->iobase + TPM_ACCESS(l)) &
-		    TPM_ACCESS_VALID)
+		rc = tpm_read8(priv, TPM_ACCESS(l), &access);
+		if (rc < 0)
+			return rc;
+
+		if (access & TPM_ACCESS_VALID)
 			return 0;
 		msleep(TPM_TIMEOUT);
 	} while (time_before(jiffies, stop));
@@ -148,10 +153,14 @@ static int wait_startup(struct tpm_chip *chip, int l)
 static int check_locality(struct tpm_chip *chip, int l)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
+	int rc;
+	u8 access;
+
+	rc = tpm_read8(priv, TPM_ACCESS(l), &access);
+	if (rc < 0)
+		return rc;
 
-	if ((ioread8(phy->iobase + TPM_ACCESS(l)) &
-	     (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
+	if ((access & (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID)) ==
 	    (TPM_ACCESS_ACTIVE_LOCALITY | TPM_ACCESS_VALID))
 		return priv->locality = l;
 
@@ -161,27 +170,32 @@ static int check_locality(struct tpm_chip *chip, int l)
 static void release_locality(struct tpm_chip *chip, int l, int force)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
+	int rc;
+	u8 access;
+
+	rc = tpm_read8(priv, TPM_ACCESS(l), &access);
+	if (rc < 0)
+		return;
 
-	if (force || (ioread8(phy->iobase + TPM_ACCESS(l)) &
+	if (force || (access &
 		      (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID)) ==
 	    (TPM_ACCESS_REQUEST_PENDING | TPM_ACCESS_VALID))
-		iowrite8(TPM_ACCESS_ACTIVE_LOCALITY,
-			 phy->iobase + TPM_ACCESS(l));
+		tpm_write8(priv, TPM_ACCESS(l), TPM_ACCESS_ACTIVE_LOCALITY);
+
 }
 
 static int request_locality(struct tpm_chip *chip, int l)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	unsigned long stop, timeout;
 	long rc;
 
 	if (check_locality(chip, l) >= 0)
 		return l;
 
-	iowrite8(TPM_ACCESS_REQUEST_USE,
-		 phy->iobase + TPM_ACCESS(l));
+	rc = tpm_write8(priv, TPM_ACCESS(l), TPM_ACCESS_REQUEST_USE);
+	if (rc < 0)
+		return rc;
 
 	stop = jiffies + chip->timeout_a;
 
@@ -215,38 +229,45 @@ again:
 static u8 tpm_tis_status(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
+	int rc;
+	u8 status;
+
+	rc = tpm_read8(priv, TPM_STS(priv->locality), &status);
+	if (rc < 0)
+		return 0;
 
-	return ioread8(phy->iobase +
-		       TPM_STS(priv->locality));
+	return status;
 }
 
 static void tpm_tis_ready(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 
 	/* this causes the current command to be aborted */
-	iowrite8(TPM_STS_COMMAND_READY,
-		 phy->iobase + TPM_STS(priv->locality));
+	tpm_write8(priv, TPM_STS(priv->locality), TPM_STS_COMMAND_READY);
 }
 
 static int get_burstcount(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	unsigned long stop;
-	int burstcnt;
+	int burstcnt, rc;
+	u8 value;
 
 	/* wait for burstcount */
 	/* which timeout value, spec has 2 answers (c & d) */
 	stop = jiffies + chip->timeout_d;
 	do {
-		burstcnt = ioread8(phy->iobase +
-				   TPM_STS(priv->locality) + 1);
-		burstcnt += ioread8(phy->iobase +
-				    TPM_STS(priv->locality) +
-				    2) << 8;
+		rc = tpm_read8(priv, TPM_STS(priv->locality) + 1, &value);
+		if (rc < 0)
+			return rc;
+
+		burstcnt = value;
+		rc = tpm_read8(priv, TPM_STS(priv->locality) + 2, &value);
+		if (rc < 0)
+			return rc;
+
+		burstcnt += value << 8;
 		if (burstcnt)
 			return burstcnt;
 		msleep(TPM_TIMEOUT);
@@ -257,18 +278,20 @@ static int get_burstcount(struct tpm_chip *chip)
 static int recv_data(struct tpm_chip *chip, u8 *buf, size_t count)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
-	int size = 0, burstcnt;
+	int size = 0, burstcnt, rc;
+
 	while (size < count &&
 	       wait_for_tpm_stat(chip,
 				 TPM_STS_DATA_AVAIL | TPM_STS_VALID,
 				 chip->timeout_c,
-				 &priv->read_queue, true)
-	       == 0) {
-		burstcnt = get_burstcount(chip);
-		for (; burstcnt > 0 && size < count; burstcnt--)
-			buf[size++] = ioread8(phy->iobase +
-					      TPM_DATA_FIFO(priv->locality));
+				 &priv->read_queue, true) == 0) {
+		burstcnt = min_t(int, get_burstcount(chip), count - size);
+		rc = tpm_read_bytes(priv, TPM_DATA_FIFO(priv->locality),
+				    burstcnt, buf + size);
+		if (rc < 0)
+			return rc;
+
+		size += burstcnt;
 	}
 	return size;
 }
@@ -332,7 +355,6 @@ MODULE_PARM_DESC(itpm, "Force iTPM workarounds (found on some Lenovo laptops)");
 static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	int rc, status, burstcnt;
 	size_t count = 0;
 
@@ -351,12 +373,13 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 	}
 
 	while (count < len - 1) {
-		burstcnt = get_burstcount(chip);
-		for (; burstcnt > 0 && count < len - 1; burstcnt--) {
-			iowrite8(buf[count], phy->iobase +
-				 TPM_DATA_FIFO(priv->locality));
-			count++;
-		}
+		burstcnt = min_t(int, get_burstcount(chip), len - count - 1);
+		rc = tpm_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
+				     burstcnt, buf + count);
+		if (rc < 0)
+			goto out_err;
+
+		count += burstcnt;
 
 		wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
 				  &priv->int_queue, false);
@@ -368,8 +391,10 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
 	}
 
 	/* write last byte */
-	iowrite8(buf[count],
-		 phy->iobase + TPM_DATA_FIFO(priv->locality));
+	rc = tpm_write8(priv, TPM_DATA_FIFO(priv->locality), buf[count]);
+	if (rc < 0)
+		goto out_err;
+
 	wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
 			  &priv->int_queue, false);
 	status = tpm_tis_status(chip);
@@ -389,15 +414,16 @@ out_err:
 static void disable_interrupts(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	u32 intmask;
+	int rc;
+
+	rc = tpm_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
+	if (rc < 0)
+		intmask = 0;
 
-	intmask =
-	    ioread32(phy->iobase +
-		     TPM_INT_ENABLE(priv->locality));
 	intmask &= ~TPM_GLOBAL_INT_ENABLE;
-	iowrite32(intmask,
-		  phy->iobase + TPM_INT_ENABLE(priv->locality));
+	tpm_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
+
 	devm_free_irq(chip->dev.parent, priv->irq, chip);
 	priv->irq = 0;
 	chip->flags &= ~TPM_CHIP_FLAG_IRQ;
@@ -411,7 +437,6 @@ static void disable_interrupts(struct tpm_chip *chip)
 static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	int rc;
 	u32 ordinal;
 	unsigned long dur;
@@ -421,8 +446,9 @@ static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
 		return rc;
 
 	/* go and do it */
-	iowrite8(TPM_STS_GO,
-		 phy->iobase + TPM_STS(priv->locality));
+	rc = tpm_write8(priv, TPM_STS(priv->locality), TPM_STS_GO);
+	if (rc < 0)
+		return rc;
 
 	if (chip->flags & TPM_CHIP_FLAG_IRQ) {
 		ordinal = be32_to_cpu(*((__be32 *) (buf + 6)));
@@ -484,11 +510,12 @@ static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
 				    unsigned long *timeout_cap)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
-	int i;
+	int i, rc;
 	u32 did_vid;
 
-	did_vid = ioread32(phy->iobase + TPM_DID_VID(0));
+	rc = tpm_read32(priv, TPM_DID_VID(0), &did_vid);
+	if (rc < 0)
+		return rc;
 
 	for (i = 0; i != ARRAY_SIZE(vendor_timeout_overrides); i++) {
 		if (vendor_timeout_overrides[i].did_vid != did_vid)
@@ -509,7 +536,6 @@ static bool tpm_tis_update_timeouts(struct tpm_chip *chip,
 static int probe_itpm(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	int rc = 0;
 	u8 cmd_getticks[] = {
 		0x00, 0xc1, 0x00, 0x00, 0x00, 0x0a,
@@ -517,7 +543,11 @@ static int probe_itpm(struct tpm_chip *chip)
 	};
 	size_t len = sizeof(cmd_getticks);
 	bool rem_itpm = itpm;
-	u16 vendor = ioread16(phy->iobase + TPM_DID_VID(0));
+	u16 vendor;
+
+	rc = tpm_read16(priv, TPM_DID_VID(0), &vendor);
+	if (rc < 0)
+		return rc;
 
 	/* probe only iTPMS */
 	if (vendor != TPM_VID_INTEL)
@@ -575,16 +605,68 @@ static const struct tpm_class_ops tpm_tis = {
 	.req_canceled = tpm_tis_req_canceled,
 };
 
+static int tpm_tcg_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
+			      u8 *result)
+{
+	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+
+	while (len--)
+		*result++ = ioread8(phy->iobase + addr);
+	return 0;
+}
+
+static int tpm_tcg_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
+			       u8 *value)
+{
+	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+
+	while (len--)
+		iowrite8(*value++, phy->iobase + addr);
+	return 0;
+}
+
+static int tpm_tcg_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
+{
+	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+
+	*result = ioread16(phy->iobase + addr);
+	return 0;
+}
+
+static int tpm_tcg_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
+{
+	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+
+	*result = ioread32(phy->iobase + addr);
+	return 0;
+}
+
+static int tpm_tcg_write32(struct tpm_tis_data *data, u32 addr, u32 value)
+{
+	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
+
+	iowrite32(value, phy->iobase + addr);
+	return 0;
+}
+
+static const struct tpm_tis_phy_ops tpm_tcg = {
+	.read_bytes = tpm_tcg_read_bytes,
+	.write_bytes = tpm_tcg_write_bytes,
+	.read16 = tpm_tcg_read16,
+	.read32 = tpm_tcg_read32,
+	.write32 = tpm_tcg_write32,
+};
+
 static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 {
 	struct tpm_chip *chip = dev_id;
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	u32 interrupt;
-	int i;
+	int i, rc;
 
-	interrupt = ioread32(phy->iobase +
-			     TPM_INT_STATUS(priv->locality));
+	rc = tpm_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
+	if (rc < 0)
+		return IRQ_NONE;
 
 	if (interrupt == 0)
 		return IRQ_NONE;
@@ -602,10 +684,11 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 		wake_up_interruptible(&priv->int_queue);
 
 	/* Clear interrupts handled with TPM_EOI */
-	iowrite32(interrupt,
-		  phy->iobase +
-		  TPM_INT_STATUS(priv->locality));
-	ioread32(phy->iobase + TPM_INT_STATUS(priv->locality));
+	rc = tpm_write32(priv, TPM_INT_STATUS(priv->locality), interrupt);
+	if (rc < 0)
+		return IRQ_NONE;
+
+	tpm_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
 	return IRQ_HANDLED;
 }
 
@@ -617,8 +700,9 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 				    int flags, int irq)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	u8 original_int_vec;
+	int rc;
+	u32 int_status;
 
 	if (devm_request_irq(chip->dev.parent, irq, tis_int_handler, flags,
 			     dev_name(&chip->dev), chip) != 0) {
@@ -628,19 +712,28 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 	}
 	priv->irq = irq;
 
-	original_int_vec = ioread8(phy->iobase +
-				   TPM_INT_VECTOR(priv->locality));
-	iowrite8(irq,
-		 phy->iobase + TPM_INT_VECTOR(priv->locality));
+	rc = tpm_read8(priv, TPM_INT_VECTOR(priv->locality), &original_int_vec);
+	if (rc < 0)
+		return rc;
+
+	rc = tpm_write8(priv, TPM_INT_VECTOR(priv->locality), irq);
+	if (rc < 0)
+		return rc;
+
+	rc = tpm_read32(priv, TPM_INT_STATUS(priv->locality), &int_status);
+	if (rc < 0)
+		return rc;
 
 	/* Clear all existing */
-	iowrite32(ioread32(phy->iobase +
-			   TPM_INT_STATUS(priv->locality)),
-		  phy->iobase + TPM_INT_STATUS(priv->locality));
+	rc = tpm_write32(priv, TPM_INT_STATUS(priv->locality), int_status);
+	if (rc < 0)
+		return rc;
 
 	/* Turn on */
-	iowrite32(intmask | TPM_GLOBAL_INT_ENABLE,
-		  phy->iobase + TPM_INT_ENABLE(priv->locality));
+	rc = tpm_write32(priv, TPM_INT_ENABLE(priv->locality),
+			 intmask | TPM_GLOBAL_INT_ENABLE);
+	if (rc < 0)
+		return rc;
 
 	priv->irq_tested = false;
 
@@ -656,8 +749,11 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 	 * will call disable_irq which undoes all of the above.
 	 */
 	if (!(chip->flags & TPM_CHIP_FLAG_IRQ)) {
-		iowrite8(original_int_vec,
-			 phy->iobase + TPM_INT_VECTOR(priv->locality));
+		rc = tpm_write8(priv, TPM_INT_VECTOR(priv->locality),
+				original_int_vec);
+		if (rc < 0)
+			return rc;
+
 		return 1;
 	}
 
@@ -671,12 +767,12 @@ static int tpm_tis_probe_irq_single(struct tpm_chip *chip, u32 intmask,
 static void tpm_tis_probe_irq(struct tpm_chip *chip, u32 intmask)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	u8 original_int_vec;
-	int i;
+	int i, rc;
 
-	original_int_vec = ioread8(phy->iobase +
-				   TPM_INT_VECTOR(priv->locality));
+	rc = tpm_read8(priv, TPM_INT_VECTOR(priv->locality), &original_int_vec);
+	if (rc < 0)
+		return;
 
 	if (!original_int_vec) {
 		if (IS_ENABLED(CONFIG_X86))
@@ -696,10 +792,15 @@ MODULE_PARM_DESC(interrupts, "Enable interrupts");
 static void tpm_tis_remove(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
-	void __iomem *reg = phy->iobase + TPM_INT_ENABLE(priv->locality);
+	u32 reg = TPM_INT_ENABLE(priv->locality);
+	u32 interrupt;
+	int rc;
+
+	rc = tpm_read32(priv, reg, &interrupt);
+	if (rc < 0)
+		interrupt = 0;
 
-	iowrite32(~TPM_GLOBAL_INT_ENABLE & ioread32(reg), reg);
+	tpm_write32(priv, reg, ~TPM_GLOBAL_INT_ENABLE & interrupt);
 	release_locality(chip, priv->locality, 1);
 }
 
@@ -707,6 +808,7 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 			acpi_handle acpi_dev_handle)
 {
 	u32 vendor, intfcaps, intmask;
+	u8 rid;
 	int rc, probe;
 	struct tpm_chip *chip;
 	struct tpm_tis_tcg_phy *phy;
@@ -727,6 +829,8 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	if (IS_ERR(phy->iobase))
 		return PTR_ERR(phy->iobase);
 
+	phy->priv.phy_ops = &tpm_tcg;
+
 	/* Maximum timeouts */
 	chip->timeout_a = TIS_TIMEOUT_A_MAX;
 	chip->timeout_b = TIS_TIMEOUT_B_MAX;
@@ -741,13 +845,15 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	}
 
 	/* Take control of the TPM's interrupt hardware and shut it off */
-	intmask = ioread32(phy->iobase +
-			   TPM_INT_ENABLE(phy->priv.locality));
+	rc = tpm_read32(&phy->priv, TPM_INT_ENABLE(phy->priv.locality),
+			&intmask);
+	if (rc < 0)
+		goto out_err;
+
 	intmask |= TPM_INTF_CMD_READY_INT | TPM_INTF_LOCALITY_CHANGE_INT |
 		   TPM_INTF_DATA_AVAIL_INT | TPM_INTF_STS_VALID_INT;
 	intmask &= ~TPM_GLOBAL_INT_ENABLE;
-	iowrite32(intmask,
-		  phy->iobase + TPM_INT_ENABLE(phy->priv.locality));
+	tpm_write32(&phy->priv, TPM_INT_ENABLE(phy->priv.locality), intmask);
 
 	if (request_locality(chip, 0) != 0) {
 		rc = -ENODEV;
@@ -758,12 +864,19 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	if (rc)
 		goto out_err;
 
-	vendor = ioread32(phy->iobase + TPM_DID_VID(0));
+	rc = tpm_read32(&phy->priv, TPM_DID_VID(0), &vendor);
+	if (rc < 0)
+		goto out_err;
+
 	phy->priv.manufacturer_id = vendor;
 
+	rc = tpm_read8(&phy->priv, TPM_RID(0), &rid);
+	if (rc < 0)
+		goto out_err;
+
 	dev_info(dev, "%s TPM (device-id 0x%X, rev-id %d)\n",
 		 (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2",
-		 vendor >> 16, ioread8(phy->iobase + TPM_RID(0)));
+		 vendor >> 16, rid);
 
 	if (!itpm) {
 		probe = probe_itpm(chip);
@@ -777,11 +890,12 @@ static int tpm_tis_init(struct device *dev, struct tpm_info *tpm_info,
 	if (itpm)
 		dev_info(dev, "Intel iTPM workaround enabled\n");
 
-
 	/* Figure out the capabilities */
-	intfcaps =
-	    ioread32(phy->iobase +
-		     TPM_INTF_CAPS(phy->priv.locality));
+	rc = tpm_read32(&phy->priv, TPM_INTF_CAPS(phy->priv.locality),
+			&intfcaps);
+	if (rc < 0)
+		goto out_err;
+
 	dev_dbg(dev, "TPM interface capabilities (0x%x):\n",
 		intfcaps);
 	if (intfcaps & TPM_INTF_BURST_COUNT_STATIC)
@@ -860,23 +974,24 @@ out_err:
 static void tpm_tis_reenable_interrupts(struct tpm_chip *chip)
 {
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
-	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(priv);
 	u32 intmask;
+	int rc;
 
 	/* reenable interrupts that device may have lost or
 	   BIOS/firmware may have disabled */
-	iowrite8(priv->irq, phy->iobase +
-		 TPM_INT_VECTOR(priv->locality));
+	rc = tpm_write8(priv, TPM_INT_VECTOR(priv->locality), priv->irq);
+	if (rc < 0)
+		return;
 
-	intmask =
-	    ioread32(phy->iobase + TPM_INT_ENABLE(priv->locality));
+	rc = tpm_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
+	if (rc < 0)
+		return;
 
 	intmask |= TPM_INTF_CMD_READY_INT
 	    | TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_DATA_AVAIL_INT
 	    | TPM_INTF_STS_VALID_INT | TPM_GLOBAL_INT_ENABLE;
 
-	iowrite32(intmask,
-		  phy->iobase + TPM_INT_ENABLE(priv->locality));
+	tpm_write32(priv, TPM_INT_ENABLE(priv->locality), intmask);
 }
 
 static int tpm_tis_resume(struct device *dev)
diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
index 2260f89..75e16d0 100644
--- a/drivers/char/tpm/tpm_tis_core.h
+++ b/drivers/char/tpm/tpm_tis_core.h
@@ -32,6 +32,54 @@ struct tpm_tis_data {
 	bool irq_tested;
 	wait_queue_head_t int_queue;
 	wait_queue_head_t read_queue;
+	const struct tpm_tis_phy_ops *phy_ops;
 };
 
+struct tpm_tis_phy_ops {
+	int (*read_bytes)(struct tpm_tis_data *data, u32 addr, u16 len,
+			  u8 *result);
+	int (*write_bytes)(struct tpm_tis_data *data, u32 addr, u16 len,
+			   u8 *value);
+	int (*read16)(struct tpm_tis_data *data, u32 addr, u16 *result);
+	int (*read32)(struct tpm_tis_data *data, u32 addr, u32 *result);
+	int (*write32)(struct tpm_tis_data *data, u32 addr, u32 src);
+};
+
+static inline int tpm_read_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
+				 u8 *result)
+{
+	return data->phy_ops->read_bytes(data, addr, len, result);
+}
+
+static inline int tpm_read8(struct tpm_tis_data *data, u32 addr, u8 *result)
+{
+	return data->phy_ops->read_bytes(data, addr, 1, result);
+}
+
+static inline int tpm_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
+{
+	return data->phy_ops->read16(data, addr, result);
+}
+
+static inline int tpm_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
+{
+	return data->phy_ops->read32(data, addr, result);
+}
+
+static inline int tpm_write_bytes(struct tpm_tis_data *data, u32 addr, u16 len,
+				  u8 *value)
+{
+	return data->phy_ops->write_bytes(data, addr, len, value);
+}
+
+static inline int tpm_write8(struct tpm_tis_data *data, u32 addr, u8 value)
+{
+	return data->phy_ops->write_bytes(data, addr, 1, &value);
+}
+
+static inline int tpm_write32(struct tpm_tis_data *data, u32 addr, u32 value)
+{
+	return data->phy_ops->write32(data, addr, value);
+}
+
 #endif
