7 files changed, 129 insertions, 246 deletions

diff --git a/drivers/hwmon/pmbus/max15301.c b/drivers/hwmon/pmbus/max15301.c
index 986404fe6a31..f5367a7bc0f5 100644
--- a/drivers/hwmon/pmbus/max15301.c
+++ b/drivers/hwmon/pmbus/max15301.c
@@ -31,8 +31,6 @@ MODULE_DEVICE_TABLE(i2c, max15301_id);
 
 struct max15301_data {
 	int id;
-	ktime_t access;		/* Chip access time */
-	int delay;		/* Delay between chip accesses in us */
 	struct pmbus_driver_info info;
 };
 
@@ -55,89 +53,6 @@ static struct max15301_data max15301_data = {
 	}
 };
 
-/* This chip needs a delay between accesses */
-static inline void max15301_wait(const struct max15301_data *data)
-{
-	if (data->delay) {
-		s64 delta = ktime_us_delta(ktime_get(), data->access);
-
-		if (delta < data->delay)
-			udelay(data->delay - delta);
-	}
-}
-
-static int max15301_read_word_data(struct i2c_client *client, int page,
-				   int phase, int reg)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct max15301_data *data = to_max15301_data(info);
-	int ret;
-
-	if (page > 0)
-		return -ENXIO;
-
-	if (reg >= PMBUS_VIRT_BASE)
-		return -ENXIO;
-
-	max15301_wait(data);
-	ret = pmbus_read_word_data(client, page, phase, reg);
-	data->access = ktime_get();
-
-	return ret;
-}
-
-static int max15301_read_byte_data(struct i2c_client *client, int page, int reg)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct max15301_data *data = to_max15301_data(info);
-	int ret;
-
-	if (page > 0)
-		return -ENXIO;
-
-	max15301_wait(data);
-	ret = pmbus_read_byte_data(client, page, reg);
-	data->access = ktime_get();
-
-	return ret;
-}
-
-static int max15301_write_word_data(struct i2c_client *client, int page, int reg,
-				    u16 word)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct max15301_data *data = to_max15301_data(info);
-	int ret;
-
-	if (page > 0)
-		return -ENXIO;
-
-	if (reg >= PMBUS_VIRT_BASE)
-		return -ENXIO;
-
-	max15301_wait(data);
-	ret = pmbus_write_word_data(client, page, reg, word);
-	data->access = ktime_get();
-
-	return ret;
-}
-
-static int max15301_write_byte(struct i2c_client *client, int page, u8 value)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct max15301_data *data = to_max15301_data(info);
-	int ret;
-
-	if (page > 0)
-		return -ENXIO;
-
-	max15301_wait(data);
-	ret = pmbus_write_byte(client, page, value);
-	data->access = ktime_get();
-
-	return ret;
-}
-
 static int max15301_probe(struct i2c_client *client)
 {
 	int status;
@@ -164,12 +79,7 @@ static int max15301_probe(struct i2c_client *client)
 		return -ENODEV;
 	}
 
-	max15301_data.delay = delay;
-
-	info->read_byte_data = max15301_read_byte_data;
-	info->read_word_data = max15301_read_word_data;
-	info->write_byte = max15301_write_byte;
-	info->write_word_data = max15301_write_word_data;
+	info->access_delay = delay;
 
 	return pmbus_do_probe(client, info);
 }
diff --git a/drivers/hwmon/pmbus/mpq7932.c b/drivers/hwmon/pmbus/mpq7932.c
index 67487867c70f..2dcb6da853bd 100644
--- a/drivers/hwmon/pmbus/mpq7932.c
+++ b/drivers/hwmon/pmbus/mpq7932.c
@@ -35,7 +35,7 @@ struct mpq7932_data {
 };
 
 #if IS_ENABLED(CONFIG_SENSORS_MPQ7932_REGULATOR)
-static struct regulator_desc mpq7932_regulators_desc[] = {
+static const struct regulator_desc mpq7932_regulators_desc[] = {
 	PMBUS_REGULATOR_STEP("buck", 0, MPQ7932_N_VOLTAGES,
 			     MPQ7932_UV_STEP, MPQ7932_BUCK_UV_MIN),
 	PMBUS_REGULATOR_STEP("buck", 1, MPQ7932_N_VOLTAGES,
diff --git a/drivers/hwmon/pmbus/pli1209bc.c b/drivers/hwmon/pmbus/pli1209bc.c
index 2c6c9ec2a652..178e0cdb7887 100644
--- a/drivers/hwmon/pmbus/pli1209bc.c
+++ b/drivers/hwmon/pmbus/pli1209bc.c
@@ -54,30 +54,6 @@ static int pli1209bc_read_word_data(struct i2c_client *client, int page,
 	}
 }
 
-static int pli1209bc_write_byte(struct i2c_client *client, int page, u8 reg)
-{
-	int ret;
-
-	switch (reg) {
-	case PMBUS_CLEAR_FAULTS:
-		ret = pmbus_write_byte(client, page, reg);
-		/*
-		 * PLI1209 takes 230 usec to execute the CLEAR_FAULTS command.
-		 * During that time it's busy and NACKs all requests on the
-		 * SMBUS interface. It also NACKs reads on PMBUS_STATUS_BYTE
-		 * making it impossible to poll the BUSY flag.
-		 *
-		 * Just wait for not BUSY unconditionally.
-		 */
-		usleep_range(250, 300);
-		break;
-	default:
-		ret = -ENODATA;
-		break;
-	}
-	return ret;
-}
-
 #if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
 static const struct regulator_desc pli1209bc_reg_desc = {
 	.name = "vout2",
@@ -127,7 +103,7 @@ static struct pmbus_driver_info pli1209bc_info = {
 	    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
 	    | PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT,
 	.read_word_data = pli1209bc_read_word_data,
-	.write_byte = pli1209bc_write_byte,
+	.write_delay = 250,
 #if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
 	.num_regulators = 1,
 	.reg_desc = &pli1209bc_reg_desc,
diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
index fb442fae7b3e..d605412a3173 100644
--- a/drivers/hwmon/pmbus/pmbus.h
+++ b/drivers/hwmon/pmbus/pmbus.h
@@ -418,6 +418,12 @@ enum pmbus_sensor_classes {
 enum pmbus_data_format { linear = 0, ieee754, direct, vid };
 enum vrm_version { vr11 = 0, vr12, vr13, imvp9, amd625mv };
 
+/* PMBus revision identifiers */
+#define PMBUS_REV_10 0x00	/* PMBus revision 1.0 */
+#define PMBUS_REV_11 0x11	/* PMBus revision 1.1 */
+#define PMBUS_REV_12 0x22	/* PMBus revision 1.2 */
+#define PMBUS_REV_13 0x33	/* PMBus revision 1.3 */
+
 struct pmbus_driver_info {
 	int pages;		/* Total number of pages */
 	u8 phases[PMBUS_PAGES];	/* Number of phases per page */
@@ -466,6 +472,16 @@ struct pmbus_driver_info {
 
 	/* custom attributes */
 	const struct attribute_group **groups;
+
+	/*
+	 * Some chips need a little delay between SMBus communication. When
+	 * set, the generic PMBus helper functions will wait if necessary
+	 * to meet this requirement. The access delay is honored after
+	 * every SMBus operation. The write delay is only honored after
+	 * SMBus write operations.
+	 */
+	int access_delay;		/* in microseconds */
+	int write_delay;		/* in microseconds */
 };
 
 /* Regulator ops */
diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index cb4c65a7f288..ce7fd4ca9d89 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/debugfs.h>
+#include <linux/delay.h>
 #include <linux/kernel.h>
 #include <linux/math64.h>
 #include <linux/module.h>
@@ -85,6 +86,8 @@ struct pmbus_data {
 
 	u32 flags;		/* from platform data */
 
+	u8 revision;	/* The PMBus revision the device is compliant with */
+
 	int exponent[PMBUS_PAGES];
 				/* linear mode: exponent for output voltages */
 
@@ -108,6 +111,8 @@ struct pmbus_data {
 
 	int vout_low[PMBUS_PAGES];	/* voltage low margin */
 	int vout_high[PMBUS_PAGES];	/* voltage high margin */
+	ktime_t write_time;		/* Last SMBUS write timestamp */
+	ktime_t access_time;		/* Last SMBUS access timestamp */
 };
 
 struct pmbus_debugfs_entry {
@@ -158,6 +163,39 @@ void pmbus_set_update(struct i2c_client *client, u8 reg, bool update)
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_set_update, PMBUS);
 
+/* Some chips need a delay between accesses. */
+static void pmbus_wait(struct i2c_client *client)
+{
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	const struct pmbus_driver_info *info = data->info;
+	s64 delta;
+
+	if (info->access_delay) {
+		delta = ktime_us_delta(ktime_get(), data->access_time);
+
+		if (delta < info->access_delay)
+			fsleep(info->access_delay - delta);
+	} else if (info->write_delay) {
+		delta = ktime_us_delta(ktime_get(), data->write_time);
+
+		if (delta < info->write_delay)
+			fsleep(info->write_delay - delta);
+	}
+}
+
+/* Sets the last accessed timestamp for pmbus_wait */
+static void pmbus_update_ts(struct i2c_client *client, bool write_op)
+{
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	const struct pmbus_driver_info *info = data->info;
+
+	if (info->access_delay) {
+		data->access_time = ktime_get();
+	} else if (info->write_delay && write_op) {
+		data->write_time = ktime_get();
+	}
+}
+
 int pmbus_set_page(struct i2c_client *client, int page, int phase)
 {
 	struct pmbus_data *data = i2c_get_clientdata(client);
@@ -168,11 +206,15 @@ int pmbus_set_page(struct i2c_client *client, int page, int phase)
 
 	if (!(data->info->func[page] & PMBUS_PAGE_VIRTUAL) &&
 	    data->info->pages > 1 && page != data->currpage) {
+		pmbus_wait(client);
 		rv = i2c_smbus_write_byte_data(client, PMBUS_PAGE, page);
+		pmbus_update_ts(client, true);
 		if (rv < 0)
 			return rv;
 
+		pmbus_wait(client);
 		rv = i2c_smbus_read_byte_data(client, PMBUS_PAGE);
+		pmbus_update_ts(client, false);
 		if (rv < 0)
 			return rv;
 
@@ -183,8 +225,10 @@ int pmbus_set_page(struct i2c_client *client, int page, int phase)
 
 	if (data->info->phases[page] && data->currphase != phase &&
 	    !(data->info->func[page] & PMBUS_PHASE_VIRTUAL)) {
+		pmbus_wait(client);
 		rv = i2c_smbus_write_byte_data(client, PMBUS_PHASE,
 					       phase);
+		pmbus_update_ts(client, true);
 		if (rv)
 			return rv;
 	}
@@ -202,7 +246,11 @@ int pmbus_write_byte(struct i2c_client *client, int page, u8 value)
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_write_byte(client, value);
+	pmbus_wait(client);
+	rv = i2c_smbus_write_byte(client, value);
+	pmbus_update_ts(client, true);
+
+	return rv;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_write_byte, PMBUS);
 
@@ -233,7 +281,11 @@ int pmbus_write_word_data(struct i2c_client *client, int page, u8 reg,
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_write_word_data(client, reg, word);
+	pmbus_wait(client);
+	rv = i2c_smbus_write_word_data(client, reg, word);
+	pmbus_update_ts(client, true);
+
+	return rv;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_write_word_data, PMBUS);
 
@@ -351,7 +403,11 @@ int pmbus_read_word_data(struct i2c_client *client, int page, int phase, u8 reg)
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_read_word_data(client, reg);
+	pmbus_wait(client);
+	rv = i2c_smbus_read_word_data(client, reg);
+	pmbus_update_ts(client, false);
+
+	return rv;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_read_word_data, PMBUS);
 
@@ -410,7 +466,11 @@ int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg)
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_read_byte_data(client, reg);
+	pmbus_wait(client);
+	rv = i2c_smbus_read_byte_data(client, reg);
+	pmbus_update_ts(client, false);
+
+	return rv;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_read_byte_data, PMBUS);
 
@@ -422,7 +482,11 @@ int pmbus_write_byte_data(struct i2c_client *client, int page, u8 reg, u8 value)
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_write_byte_data(client, reg, value);
+	pmbus_wait(client);
+	rv = i2c_smbus_write_byte_data(client, reg, value);
+	pmbus_update_ts(client, true);
+
+	return rv;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_write_byte_data, PMBUS);
 
@@ -454,7 +518,11 @@ static int pmbus_read_block_data(struct i2c_client *client, int page, u8 reg,
 	if (rv < 0)
 		return rv;
 
-	return i2c_smbus_read_block_data(client, reg, data_buf);
+	pmbus_wait(client);
+	rv = i2c_smbus_read_block_data(client, reg, data_buf);
+	pmbus_update_ts(client, false);
+
+	return rv;
 }
 
 static struct pmbus_sensor *pmbus_find_sensor(struct pmbus_data *data, int page,
@@ -1095,9 +1163,14 @@ static int pmbus_get_boolean(struct i2c_client *client, struct pmbus_boolean *b,
 
 	regval = status & mask;
 	if (regval) {
-		ret = _pmbus_write_byte_data(client, page, reg, regval);
-		if (ret)
-			goto unlock;
+		if (data->revision >= PMBUS_REV_12) {
+			ret = _pmbus_write_byte_data(client, page, reg, regval);
+			if (ret)
+				goto unlock;
+		} else {
+			pmbus_clear_fault_page(client, page);
+		}
+
 	}
 	if (s1 && s2) {
 		s64 v1, v2;
@@ -2450,9 +2523,11 @@ static int pmbus_read_coefficients(struct i2c_client *client,
 	data.block[1] = attr->reg;
 	data.block[2] = 0x01;
 
+	pmbus_wait(client);
 	rv = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
 			    I2C_SMBUS_WRITE, PMBUS_COEFFICIENTS,
 			    I2C_SMBUS_BLOCK_PROC_CALL, &data);
+	pmbus_update_ts(client, true);
 
 	if (rv < 0)
 		return rv;
@@ -2604,7 +2679,10 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
 
 	/* Enable PEC if the controller and bus supports it */
 	if (!(data->flags & PMBUS_NO_CAPABILITY)) {
+		pmbus_wait(client);
 		ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY);
+		pmbus_update_ts(client, false);
+
 		if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK)) {
 			if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_PEC))
 				client->flags |= I2C_CLIENT_PEC;
@@ -2617,10 +2695,16 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
 	 * Bail out if both registers are not supported.
 	 */
 	data->read_status = pmbus_read_status_word;
+	pmbus_wait(client);
 	ret = i2c_smbus_read_word_data(client, PMBUS_STATUS_WORD);
+	pmbus_update_ts(client, false);
+
 	if (ret < 0 || ret == 0xffff) {
 		data->read_status = pmbus_read_status_byte;
+		pmbus_wait(client);
 		ret = i2c_smbus_read_byte_data(client, PMBUS_STATUS_BYTE);
+		pmbus_update_ts(client, false);
+
 		if (ret < 0 || ret == 0xff) {
 			dev_err(dev, "PMBus status register not found\n");
 			return -ENODEV;
@@ -2635,11 +2719,18 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
 	 * limit registers need to be disabled.
 	 */
 	if (!(data->flags & PMBUS_NO_WRITE_PROTECT)) {
+		pmbus_wait(client);
 		ret = i2c_smbus_read_byte_data(client, PMBUS_WRITE_PROTECT);
+		pmbus_update_ts(client, false);
+
 		if (ret > 0 && (ret & PB_WP_ANY))
 			data->flags |= PMBUS_WRITE_PROTECTED | PMBUS_SKIP_STATUS_CHECK;
 	}
 
+	ret = i2c_smbus_read_byte_data(client, PMBUS_REVISION);
+	if (ret >= 0)
+		data->revision = ret;
+
 	if (data->info->pages)
 		pmbus_clear_faults(client);
 	else
diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index d817c719b90b..5d3d1773bf52 100644
--- a/drivers/hwmon/pmbus/ucd9000.c
+++ b/drivers/hwmon/pmbus/ucd9000.c
@@ -67,7 +67,6 @@ struct ucd9000_data {
 	struct gpio_chip gpio;
 #endif
 	struct dentry *debugfs;
-	ktime_t write_time;
 };
 #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
 
@@ -86,63 +85,6 @@ struct ucd9000_debugfs_entry {
  */
 #define UCD90320_WAIT_DELAY_US 500
 
-static inline void ucd90320_wait(const struct ucd9000_data *data)
-{
-	s64 delta = ktime_us_delta(ktime_get(), data->write_time);
-
-	if (delta < UCD90320_WAIT_DELAY_US)
-		udelay(UCD90320_WAIT_DELAY_US - delta);
-}
-
-static int ucd90320_read_word_data(struct i2c_client *client, int page,
-				   int phase, int reg)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct ucd9000_data *data = to_ucd9000_data(info);
-
-	if (reg >= PMBUS_VIRT_BASE)
-		return -ENXIO;
-
-	ucd90320_wait(data);
-	return pmbus_read_word_data(client, page, phase, reg);
-}
-
-static int ucd90320_read_byte_data(struct i2c_client *client, int page, int reg)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct ucd9000_data *data = to_ucd9000_data(info);
-
-	ucd90320_wait(data);
-	return pmbus_read_byte_data(client, page, reg);
-}
-
-static int ucd90320_write_word_data(struct i2c_client *client, int page,
-				    int reg, u16 word)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct ucd9000_data *data = to_ucd9000_data(info);
-	int ret;
-
-	ucd90320_wait(data);
-	ret = pmbus_write_word_data(client, page, reg, word);
-	data->write_time = ktime_get();
-
-	return ret;
-}
-
-static int ucd90320_write_byte(struct i2c_client *client, int page, u8 value)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct ucd9000_data *data = to_ucd9000_data(info);
-	int ret;
-
-	ucd90320_wait(data);
-	ret = pmbus_write_byte(client, page, value);
-	data->write_time = ktime_get();
-
-	return ret;
-}
-
 static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
 {
 	int fan_config = 0;
@@ -667,10 +609,8 @@ static int ucd9000_probe(struct i2c_client *client)
 		info->func[0] |= PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12
 		  | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
 	} else if (mid->driver_data == ucd90320) {
-		info->read_byte_data = ucd90320_read_byte_data;
-		info->read_word_data = ucd90320_read_word_data;
-		info->write_byte = ucd90320_write_byte;
-		info->write_word_data = ucd90320_write_word_data;
+		/* Delay SMBus operations after a write */
+		info->write_delay = UCD90320_WAIT_DELAY_US;
 	}
 
 	ucd9000_probe_gpio(client, mid, data);
diff --git a/drivers/hwmon/pmbus/zl6100.c b/drivers/hwmon/pmbus/zl6100.c
index 83458df0d0cf..7920a16203e1 100644
--- a/drivers/hwmon/pmbus/zl6100.c
+++ b/drivers/hwmon/pmbus/zl6100.c
@@ -22,8 +22,6 @@ enum chips { zl2004, zl2005, zl2006, zl2008, zl2105, zl2106, zl6100, zl6105,
 
 struct zl6100_data {
 	int id;
-	ktime_t access;		/* chip access time */
-	int delay;		/* Delay between chip accesses in uS */
 	struct pmbus_driver_info info;
 };
 
@@ -122,16 +120,6 @@ static u16 zl6100_d2l(long val)
 	return (mantissa & 0x7ff) | ((exponent << 11) & 0xf800);
 }
 
-/* Some chips need a delay between accesses */
-static inline void zl6100_wait(const struct zl6100_data *data)
-{
-	if (data->delay) {
-		s64 delta = ktime_us_delta(ktime_get(), data->access);
-		if (delta < data->delay)
-			udelay(data->delay - delta);
-	}
-}
-
 static int zl6100_read_word_data(struct i2c_client *client, int page,
 				 int phase, int reg)
 {
@@ -174,9 +162,7 @@ static int zl6100_read_word_data(struct i2c_client *client, int page,
 		break;
 	}
 
-	zl6100_wait(data);
 	ret = pmbus_read_word_data(client, page, phase, vreg);
-	data->access = ktime_get();
 	if (ret < 0)
 		return ret;
 
@@ -195,14 +181,11 @@ static int zl6100_read_word_data(struct i2c_client *client, int page,
 static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct zl6100_data *data = to_zl6100_data(info);
 	int ret, status;
 
 	if (page >= info->pages)
 		return -ENXIO;
 
-	zl6100_wait(data);
-
 	switch (reg) {
 	case PMBUS_VIRT_STATUS_VMON:
 		ret = pmbus_read_byte_data(client, 0,
@@ -225,7 +208,6 @@ static int zl6100_read_byte_data(struct i2c_client *client, int page, int reg)
 		ret = pmbus_read_byte_data(client, page, reg);
 		break;
 	}
-	data->access = ktime_get();
 
 	return ret;
 }
@@ -234,8 +216,7 @@ static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
 				  u16 word)
 {
 	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct zl6100_data *data = to_zl6100_data(info);
-	int ret, vreg;
+	int vreg;
 
 	if (page >= info->pages)
 		return -ENXIO;
@@ -265,27 +246,7 @@ static int zl6100_write_word_data(struct i2c_client *client, int page, int reg,
 		vreg = reg;
 	}
 
-	zl6100_wait(data);
-	ret = pmbus_write_word_data(client, page, vreg, word);
-	data->access = ktime_get();
-
-	return ret;
-}
-
-static int zl6100_write_byte(struct i2c_client *client, int page, u8 value)
-{
-	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
-	struct zl6100_data *data = to_zl6100_data(info);
-	int ret;
-
-	if (page >= info->pages)
-		return -ENXIO;
-
-	zl6100_wait(data);
-	ret = pmbus_write_byte(client, page, value);
-	data->access = ktime_get();
-
-	return ret;
+	return pmbus_write_word_data(client, page, vreg, word);
 }
 
 static const struct i2c_device_id zl6100_id[] = {
@@ -363,14 +324,7 @@ static int zl6100_probe(struct i2c_client *client)
 	 * supported chips are known to require a wait time between I2C
 	 * accesses.
 	 */
-	data->delay = delay;
-
-	/*
-	 * Since there was a direct I2C device access above, wait before
-	 * accessing the chip again.
-	 */
-	data->access = ktime_get();
-	zl6100_wait(data);
+	udelay(delay);
 
 	info = &data->info;
 
@@ -404,8 +358,7 @@ static int zl6100_probe(struct i2c_client *client)
 		if (ret < 0)
 			return ret;
 
-		data->access = ktime_get();
-		zl6100_wait(data);
+		udelay(delay);
 
 		if (ret & ZL8802_MFR_PHASES_MASK)
 			info->func[1] |= PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT;
@@ -418,8 +371,7 @@ static int zl6100_probe(struct i2c_client *client)
 			if (ret < 0)
 				return ret;
 
-			data->access = ktime_get();
-			zl6100_wait(data);
+			udelay(delay);
 
 			ret = i2c_smbus_read_word_data(client, ZL8802_MFR_USER_CONFIG);
 			if (ret < 0)
@@ -428,8 +380,7 @@ static int zl6100_probe(struct i2c_client *client)
 			if (ret & ZL8802_MFR_XTEMP_ENABLE_2)
 				info->func[i] |= PMBUS_HAVE_TEMP2;
 
-			data->access = ktime_get();
-			zl6100_wait(data);
+			udelay(delay);
 		}
 		ret = i2c_smbus_read_word_data(client, ZL8802_MFR_USER_GLOBAL_CONFIG);
 		if (ret < 0)
@@ -446,13 +397,12 @@ static int zl6100_probe(struct i2c_client *client)
 			info->func[0] |= PMBUS_HAVE_TEMP2;
 	}
 
-	data->access = ktime_get();
-	zl6100_wait(data);
+	udelay(delay);
 
+	info->access_delay = delay;
 	info->read_word_data = zl6100_read_word_data;
 	info->read_byte_data = zl6100_read_byte_data;
 	info->write_word_data = zl6100_write_word_data;
-	info->write_byte = zl6100_write_byte;
 
 	return pmbus_do_probe(client, info);
 }