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[PATCH v3 0/8] Add support for best effort block read emulation

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  [PATCH v3 0/8] Add support for best effort block read emulation Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 3/8] iio: accel: bmc150: use available_scan_masks Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 5/8] iio: gyro: bmg160: use available_scan_masks Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 2/8] eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 1/8] i2c: core: Add support for best effort block read emulation Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 7/8] iio: accel: kxcjk-1013: use available_scan_masks Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 8/8] iio: accel: kxcjk-1013: optimize i2c transfers in trigger handler Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 4/8] iio: accel: bmc150: optimize i2c transfers in trigger handler Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200
    [PATCH v3 6/8] iio: gyro: bmg160: optimize i2c transfers in trigger handler Irina Tirdea <irina.tirdea@intel.com> - 2015-07-03 11:40 +0200

#1176436 — [PATCH v3 0/8] Add support for best effort block read emulation

This is version 3 for adding i2c_smbus_read_i2c_block_data_or_emulated
to i2c-core. The i2c core part is the same as in v2, but I have added
3 more users for iio drivers.

Changes in v2:
 - changed bmc150-accel, kxcjk-1013 and bmg160 drivers to use
i2c_smbus_read_i2c_block_data_or_emulated

Changes in v1:
 - dropped the RFC tag
 - changed at24 to use i2c_smbus_read_i2c_block_data_or_emulated
 - when reading an odd number of bytes using word emulation, read an even
number of bytes and drop the last one
 - add a comment that this might not be suitable for all I2C slaves 

Adriana Reus (2):
  iio: accel: kxcjk-1013: use available_scan_masks
  iio: accel: kxcjk-1013: optimize i2c transfers in trigger handler

Irina Tirdea (6):
  i2c: core: Add support for best effort block read emulation
  eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated
  iio: accel: bmc150: use available_scan_masks
  iio: accel: bmc150: optimize i2c transfers in trigger handler
  iio: gyro: bmg160: use available_scan_masks
  iio: gyro: bmg160: optimize i2c transfers in trigger handler

 drivers/i2c/i2c-core.c           | 60 ++++++++++++++++++++++++++++++++++++++++
 drivers/iio/accel/bmc150-accel.c | 23 +++++++--------
 drivers/iio/accel/kxcjk-1013.c   | 24 ++++++++--------
 drivers/iio/gyro/bmg160.c        | 23 +++++++--------
 drivers/misc/eeprom/at24.c       | 40 ++++++---------------------
 include/linux/i2c.h              |  3 ++
 6 files changed, 108 insertions(+), 65 deletions(-)

-- 
1.9.1

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#1176440 — [PATCH v3 3/8] iio: accel: bmc150: use available_scan_masks

Use available_scan_masks to allow the iio core to select
the data to send to userspace depending on which axes are
enabled, instead of doing this in the driver's interrupt
handler.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/accel/bmc150-accel.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/accel/bmc150-accel.c b/drivers/iio/accel/bmc150-accel.c
index 73e8773..c6c8416 100644
--- a/drivers/iio/accel/bmc150-accel.c
+++ b/drivers/iio/accel/bmc150-accel.c
@@ -136,6 +136,7 @@ enum bmc150_accel_axis {
 	AXIS_X,
 	AXIS_Y,
 	AXIS_Z,
+	AXIS_MAX,
 };
 
 enum bmc150_power_modes {
@@ -1201,6 +1202,8 @@ static const struct iio_info bmc150_accel_info_fifo = {
 	.driver_module		= THIS_MODULE,
 };
 
+static const unsigned long bmc150_accel_scan_masks[] = {0x7, 0};
+
 static irqreturn_t bmc150_accel_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
@@ -1209,8 +1212,7 @@ static irqreturn_t bmc150_accel_trigger_handler(int irq, void *p)
 	int bit, ret, i = 0;
 
 	mutex_lock(&data->mutex);
-	for_each_set_bit(bit, indio_dev->active_scan_mask,
-			 indio_dev->masklength) {
+	for (bit = 0; bit < AXIS_MAX; bit++) {
 		ret = i2c_smbus_read_word_data(data->client,
 					       BMC150_ACCEL_AXIS_TO_REG(bit));
 		if (ret < 0) {
@@ -1632,6 +1634,7 @@ static int bmc150_accel_probe(struct i2c_client *client,
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->channels = data->chip_info->channels;
 	indio_dev->num_channels = data->chip_info->num_channels;
+	indio_dev->available_scan_masks = bmc150_accel_scan_masks;
 	indio_dev->name = name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &bmc150_accel_info;
-- 
1.9.1

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#1176441 — [PATCH v3 5/8] iio: gyro: bmg160: use available_scan_masks

Use available_scan_masks to allow the iio core to select
the data to send to userspace depending on which axes are
enabled, instead of doing this in the driver's interrupt
handler.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/gyro/bmg160.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/gyro/bmg160.c b/drivers/iio/gyro/bmg160.c
index 4415f55..4b423f2 100644
--- a/drivers/iio/gyro/bmg160.c
+++ b/drivers/iio/gyro/bmg160.c
@@ -115,6 +115,7 @@ enum bmg160_axis {
 	AXIS_X,
 	AXIS_Y,
 	AXIS_Z,
+	AXIS_MAX,
 };
 
 static const struct {
@@ -814,6 +815,8 @@ static const struct iio_info bmg160_info = {
 	.driver_module		= THIS_MODULE,
 };
 
+static const unsigned long bmg160_scan_masks[] = {0x7, 0};
+
 static irqreturn_t bmg160_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
@@ -822,8 +825,7 @@ static irqreturn_t bmg160_trigger_handler(int irq, void *p)
 	int bit, ret, i = 0;
 
 	mutex_lock(&data->mutex);
-	for_each_set_bit(bit, indio_dev->active_scan_mask,
-			 indio_dev->masklength) {
+	for (bit = 0; bit < AXIS_MAX; bit++) {
 		ret = i2c_smbus_read_word_data(data->client,
 					       BMG160_AXIS_TO_REG(bit));
 		if (ret < 0) {
@@ -1056,6 +1058,7 @@ static int bmg160_probe(struct i2c_client *client,
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->channels = bmg160_channels;
 	indio_dev->num_channels = ARRAY_SIZE(bmg160_channels);
+	indio_dev->available_scan_masks = bmg160_scan_masks;
 	indio_dev->name = name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &bmg160_info;
-- 
1.9.1

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#1176445 — [PATCH v3 2/8] eeprom: at24: use i2c_smbus_read_i2c_block_data_or_emulated

For i2c busses that support only SMBUS extensions, the eeprom at24
driver reads data from the device using the SMBus block, word or byte
read protocols depending on availability.

Replace the block read emulation from the driver with the
i2c_smbus_read_i2c_block_data_or_emulated call from i2c core.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/misc/eeprom/at24.c | 40 +++++++++-------------------------------
 1 file changed, 9 insertions(+), 31 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2d3db81..d13795a 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -186,19 +186,11 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	if (count > io_limit)
 		count = io_limit;
 
-	switch (at24->use_smbus) {
-	case I2C_SMBUS_I2C_BLOCK_DATA:
+	if (at24->use_smbus) {
 		/* Smaller eeproms can work given some SMBus extension calls */
 		if (count > I2C_SMBUS_BLOCK_MAX)
 			count = I2C_SMBUS_BLOCK_MAX;
-		break;
-	case I2C_SMBUS_WORD_DATA:
-		count = 2;
-		break;
-	case I2C_SMBUS_BYTE_DATA:
-		count = 1;
-		break;
-	default:
+	} else {
 		/*
 		 * When we have a better choice than SMBus calls, use a
 		 * combined I2C message. Write address; then read up to
@@ -229,27 +221,13 @@ static ssize_t at24_eeprom_read(struct at24_data *at24, char *buf,
 	timeout = jiffies + msecs_to_jiffies(write_timeout);
 	do {
 		read_time = jiffies;
-		switch (at24->use_smbus) {
-		case I2C_SMBUS_I2C_BLOCK_DATA:
-			status = i2c_smbus_read_i2c_block_data(client, offset,
-					count, buf);
-			break;
-		case I2C_SMBUS_WORD_DATA:
-			status = i2c_smbus_read_word_data(client, offset);
-			if (status >= 0) {
-				buf[0] = status & 0xff;
-				buf[1] = status >> 8;
-				status = count;
-			}
-			break;
-		case I2C_SMBUS_BYTE_DATA:
-			status = i2c_smbus_read_byte_data(client, offset);
-			if (status >= 0) {
-				buf[0] = status;
-				status = count;
-			}
-			break;
-		default:
+		if (at24->use_smbus) {
+			status =
+			    i2c_smbus_read_i2c_block_data_or_emulated(client,
+								      offset,
+								      count,
+								      buf);
+		} else {
 			status = i2c_transfer(client->adapter, msg, 2);
 			if (status == 2)
 				status = count;
-- 
1.9.1

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#1176446 — [PATCH v3 1/8] i2c: core: Add support for best effort block read emulation

There are devices that need to handle block transactions
regardless of the capabilities exported by the adapter.
For performance reasons, they need to use i2c read blocks
if available, otherwise emulate the block transaction with word
or byte transactions.

Add support for a helper function that would read a data block
using the best transfer available: I2C_FUNC_SMBUS_READ_I2C_BLOCK,
I2C_FUNC_SMBUS_READ_WORD_DATA or I2C_FUNC_SMBUS_READ_BYTE_DATA.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/i2c/i2c-core.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/i2c.h    |  3 +++
 2 files changed, 63 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 96771ea..55a3455 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -2914,6 +2914,66 @@ trace:
 }
 EXPORT_SYMBOL(i2c_smbus_xfer);
 
+/**
+ * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
+ * @client: Handle to slave device
+ * @command: Byte interpreted by slave
+ * @length: Size of data block; SMBus allows at most 32 bytes
+ * @values: Byte array into which data will be read; big enough to hold
+ *	the data returned by the slave.  SMBus allows at most 32 bytes.
+ *
+ * This executes the SMBus "block read" protocol if supported by the adapter.
+ * If block read is not supported, it emulates it using either word or byte
+ * read protocols depending on availability.
+ *
+ * Before using this function you must double-check if the I2C slave does
+ * support exchanging a block transfer with a byte transfer.
+ */
+s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
+					      u8 command, u8 length, u8 *values)
+{
+	u8 i;
+	int status;
+
+	if (length > I2C_SMBUS_BLOCK_MAX)
+		length = I2C_SMBUS_BLOCK_MAX;
+
+	if (i2c_check_functionality(client->adapter,
+				    I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+		return i2c_smbus_read_i2c_block_data(client, command,
+						     length, values);
+	} else if (i2c_check_functionality(client->adapter,
+					   I2C_FUNC_SMBUS_READ_WORD_DATA)) {
+		for (i = 0; i < length; i += 2) {
+			status = i2c_smbus_read_word_data(client, command + i);
+			if (status < 0)
+				return status;
+			values[i] = status & 0xff;
+			if ((i + 1) < length)
+				values[i + 1] = status >> 8;
+		}
+		if (i > length)
+			return length;
+		return i;
+	} else if (i2c_check_functionality(client->adapter,
+					   I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
+		for (i = 0; i < length; i++) {
+			status = i2c_smbus_read_byte_data(client, command + i);
+			if (status < 0)
+				return status;
+			values[i] = status;
+		}
+		return i;
+	}
+
+	dev_err(&client->adapter->dev, "Unsupported transactions: %d,%d,%d\n",
+		I2C_SMBUS_I2C_BLOCK_DATA, I2C_SMBUS_WORD_DATA,
+		I2C_SMBUS_BYTE_DATA);
+
+	return -EOPNOTSUPP;
+}
+EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
+
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
 {
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index e83a738..faf518d 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -121,6 +121,9 @@ extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
 					  u8 command, u8 length,
 					  const u8 *values);
+extern s32
+i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
+					  u8 command, u8 length, u8 *values);
 #endif /* I2C */
 
 /**
-- 
1.9.1

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#1176447 — [PATCH v3 7/8] iio: accel: kxcjk-1013: use available_scan_masks

From: Adriana Reus <adriana.reus@intel.com>

Use available_scan_masks to allow the iio core to select
the data to send to userspace depending on which axes are
enabled, instead of doing this in the driver's interrupt
handler.

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/accel/kxcjk-1013.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
index 51da369..4960397 100644
--- a/drivers/iio/accel/kxcjk-1013.c
+++ b/drivers/iio/accel/kxcjk-1013.c
@@ -115,6 +115,7 @@ enum kxcjk1013_axis {
 	AXIS_X,
 	AXIS_Y,
 	AXIS_Z,
+	AXIS_MAX,
 };
 
 enum kxcjk1013_mode {
@@ -947,6 +948,8 @@ static const struct iio_info kxcjk1013_info = {
 	.driver_module		= THIS_MODULE,
 };
 
+static const unsigned long kxcjk1013_scan_masks[] = {0x7, 0};
+
 static irqreturn_t kxcjk1013_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
@@ -956,8 +959,7 @@ static irqreturn_t kxcjk1013_trigger_handler(int irq, void *p)
 
 	mutex_lock(&data->mutex);
 
-	for_each_set_bit(bit, indio_dev->active_scan_mask,
-			 indio_dev->masklength) {
+	for (bit = 0; bit < AXIS_MAX; bit++) {
 		ret = kxcjk1013_get_acc_reg(data, bit);
 		if (ret < 0) {
 			mutex_unlock(&data->mutex);
@@ -1224,6 +1226,7 @@ static int kxcjk1013_probe(struct i2c_client *client,
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->channels = kxcjk1013_channels;
 	indio_dev->num_channels = ARRAY_SIZE(kxcjk1013_channels);
+	indio_dev->available_scan_masks = kxcjk1013_scan_masks;
 	indio_dev->name = name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->info = &kxcjk1013_info;
-- 
1.9.1

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#1176448 — [PATCH v3 8/8] iio: accel: kxcjk-1013: optimize i2c transfers in trigger handler

From: Adriana Reus <adriana.reus@intel.com>

Some i2c busses (e.g.: Synopsys DesignWare I2C adapter) need to
enable/disable the bus at each i2c transfer and must wait for
the enable/disable to happen before sending the data.

When reading data in the trigger handler, the kxcjk-1013 accel driver
does one i2c transfer for each axis. This has an impact on the
frequency of the accelerometer at high sample rates due to additional
delays introduced by the i2c bus at each transfer.

Reading all axis values in one i2c transfer reduces the delays
introduced by the i2c bus. Uses i2c_smbus_read_i2c_block_data_or_emulated
that will fallback to reading each axis as a separate word in case i2c
block read is not supported.

Signed-off-by: Adriana Reus <adriana.reus@intel.com>
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/accel/kxcjk-1013.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

diff --git a/drivers/iio/accel/kxcjk-1013.c b/drivers/iio/accel/kxcjk-1013.c
index 4960397..8f401c2 100644
--- a/drivers/iio/accel/kxcjk-1013.c
+++ b/drivers/iio/accel/kxcjk-1013.c
@@ -923,7 +923,7 @@ static const struct iio_event_spec kxcjk1013_event = {
 		.realbits = 12,						\
 		.storagebits = 16,					\
 		.shift = 4,						\
-		.endianness = IIO_CPU,					\
+		.endianness = IIO_LE,					\
 	},								\
 	.event_spec = &kxcjk1013_event,				\
 	.num_event_specs = 1						\
@@ -955,19 +955,16 @@ static irqreturn_t kxcjk1013_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct kxcjk1013_data *data = iio_priv(indio_dev);
-	int bit, ret, i = 0;
+	int ret;
 
 	mutex_lock(&data->mutex);
-
-	for (bit = 0; bit < AXIS_MAX; bit++) {
-		ret = kxcjk1013_get_acc_reg(data, bit);
-		if (ret < 0) {
-			mutex_unlock(&data->mutex);
-			goto err;
-		}
-		data->buffer[i++] = ret;
-	}
+	ret = i2c_smbus_read_i2c_block_data_or_emulated(data->client,
+							KXCJK1013_REG_XOUT_L,
+							AXIS_MAX * 2,
+							(u8 *)data->buffer);
 	mutex_unlock(&data->mutex);
+	if (ret < 0)
+		goto err;
 
 	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 					   data->timestamp);
-- 
1.9.1

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#1176450 — [PATCH v3 4/8] iio: accel: bmc150: optimize i2c transfers in trigger handler

Some i2c busses (e.g.: Synopsys DesignWare I2C adapter) need to
enable/disable the bus at each i2c transfer and must wait for
the enable/disable to happen before sending the data.

When reading data in the trigger handler, the bmc150 accel driver does
one i2c transfer for each axis. This has an impact on the frequency
of the accelerometer at high sample rates due to additional delays
introduced by the i2c bus at each transfer.

Reading all axis values in one i2c transfer reduces the delays
introduced by the i2c bus. Uses i2c_smbus_read_i2c_block_data_or_emulated
that will fallback to reading each axis as a separate word in case i2c
block read is not supported.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/accel/bmc150-accel.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/accel/bmc150-accel.c b/drivers/iio/accel/bmc150-accel.c
index c6c8416..e686add 100644
--- a/drivers/iio/accel/bmc150-accel.c
+++ b/drivers/iio/accel/bmc150-accel.c
@@ -1082,6 +1082,7 @@ static const struct iio_event_spec bmc150_accel_event = {
 		.realbits = (bits),					\
 		.storagebits = 16,					\
 		.shift = 16 - (bits),					\
+		.endianness = IIO_LE,					\
 	},								\
 	.event_spec = &bmc150_accel_event,				\
 	.num_event_specs = 1						\
@@ -1209,19 +1210,16 @@ static irqreturn_t bmc150_accel_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct bmc150_accel_data *data = iio_priv(indio_dev);
-	int bit, ret, i = 0;
+	int ret;
 
 	mutex_lock(&data->mutex);
-	for (bit = 0; bit < AXIS_MAX; bit++) {
-		ret = i2c_smbus_read_word_data(data->client,
-					       BMC150_ACCEL_AXIS_TO_REG(bit));
-		if (ret < 0) {
-			mutex_unlock(&data->mutex);
-			goto err_read;
-		}
-		data->buffer[i++] = ret;
-	}
+	ret = i2c_smbus_read_i2c_block_data_or_emulated(data->client,
+							BMC150_ACCEL_REG_XOUT_L,
+							AXIS_MAX * 2,
+							(u8 *)data->buffer);
 	mutex_unlock(&data->mutex);
+	if (ret < 0)
+		goto err_read;
 
 	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 					   data->timestamp);
-- 
1.9.1

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#1176451 — [PATCH v3 6/8] iio: gyro: bmg160: optimize i2c transfers in trigger handler

Some i2c busses (e.g.: Synopsys DesignWare I2C adapter) need to
enable/disable the bus at each i2c transfer and must wait for
the enable/disable to happen before sending the data.

When reading data in the trigger handler, the bmg160 driver does
one i2c transfer for each axis. This has an impact on the frequency
of the gyroscope at high sample rates due to additional delays
introduced by the i2c bus at each transfer.

Reading all axis values in one i2c transfer reduces the delays
introduced by the i2c bus. Uses i2c_smbus_read_i2c_block_data_or_emulated
that will fallback to reading each axis as a separate word in case i2c
block read is not supported.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/iio/gyro/bmg160.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/gyro/bmg160.c b/drivers/iio/gyro/bmg160.c
index 4b423f2..04e15e9 100644
--- a/drivers/iio/gyro/bmg160.c
+++ b/drivers/iio/gyro/bmg160.c
@@ -784,6 +784,7 @@ static const struct iio_event_spec bmg160_event = {
 		.sign = 's',						\
 		.realbits = 16,					\
 		.storagebits = 16,					\
+		.endianness = IIO_LE,					\
 	},								\
 	.event_spec = &bmg160_event,					\
 	.num_event_specs = 1						\
@@ -822,19 +823,16 @@ static irqreturn_t bmg160_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct bmg160_data *data = iio_priv(indio_dev);
-	int bit, ret, i = 0;
+	int ret = 0;
 
 	mutex_lock(&data->mutex);
-	for (bit = 0; bit < AXIS_MAX; bit++) {
-		ret = i2c_smbus_read_word_data(data->client,
-					       BMG160_AXIS_TO_REG(bit));
-		if (ret < 0) {
-			mutex_unlock(&data->mutex);
-			goto err;
-		}
-		data->buffer[i++] = ret;
-	}
+	ret = i2c_smbus_read_i2c_block_data_or_emulated(data->client,
+							BMG160_REG_XOUT_L,
+							AXIS_MAX * 2,
+							(u8 *)data->buffer);
 	mutex_unlock(&data->mutex);
+	if (ret < 0)
+		goto err;
 
 	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
 					   data->timestamp);
-- 
1.9.1

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