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Subject[RFC 7/7] iio: inv_mpu6050: Add support for external sensors
Date
This works by copying their channels at probe time.

Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
---
.../devicetree/bindings/iio/imu/inv_mpu6050.txt | 37 +-
drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 420 ++++++++++++++++++++-
drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 63 +++-
drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c | 48 ++-
4 files changed, 555 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt b/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
index aaf12b4..79b8326 100644
--- a/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
+++ b/Documentation/devicetree/bindings/iio/imu/inv_mpu6050.txt
@@ -23,6 +23,28 @@ Devices connected in "bypass" mode must be listed behind i2c@0 with the address

Devices connected in "master" mode must be listed behind i2c@1 with the address 1

+It is possible to configure the MPU to automatically fetch reading for
+devices connected on the auxiliary i2c bus without CPU intervention. When this
+is done the driver will present the channels of the slaved devices as if they
+belong to the MPU device itself.
+
+Reads and write to config values (like scaling factors) are forwarded to the
+other driver while data reads are handled from MPU registers. The channels are
+also available through the MPU's iio triggered buffer mechanism. This feature
+can allow sampling up to 24 bytes from 4 slaves at a much higher rate.
+
+This is be specified in device tree as an "inv,external-sensors" node which
+have children indexed by slave ids 0 to 3. The child node identifying each
+external sensor reading has the following properties:
+ - reg: 0 to 3 slave index
+ - inv,addr : the I2C address to read from
+ - inv,reg : the I2C register to read from
+ - inv,len : read length from the device
+ - inv,external-channels : list of slaved channels specified by config index.
+
+The sum of storagebits for external channels must equal the read length. Only
+16bit channels are currently supported.
+
Example:
mpu6050@68 {
compatible = "invensense,mpu6050";
@@ -61,7 +83,8 @@ Example describing mpu9150 (which includes an ak9875 on chip):
};
};

-Example describing a mpu6500 via SPI with an hmc5883l on auxiliary i2c:
+Example describing a mpu6500 via SPI with an hmc5883l on aux i2c configured for
+automatic external readings as slave 0:
mpu6500@0 {
compatible = "inv,mpu6500";
reg = <0x0>;
@@ -80,4 +103,16 @@ Example describing a mpu6500 via SPI with an hmc5883l on auxiliary i2c:
reg = <0x1e>;
};
};
+
+ inv,external-sensors {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ hmc5833l@0 {
+ reg = <0>;
+ inv,addr = <0x1e>;
+ inv,reg = <3>;
+ inv,len = <6>;
+ inv,external-channels = <0 1 2>;
+ };
+ };
};
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
index 712e901..224be3c 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c
@@ -41,6 +41,8 @@ static const int gyro_scale_6050[] = {133090, 266181, 532362, 1064724};
*/
static const int accel_scale[] = {598, 1196, 2392, 4785};

+#define INV_MPU6050_NUM_INT_CHAN 8
+
static const struct inv_mpu6050_reg_map reg_set_6500 = {
.sample_rate_div = INV_MPU6050_REG_SAMPLE_RATE_DIV,
.lpf = INV_MPU6050_REG_CONFIG,
@@ -136,6 +138,9 @@ static bool inv_mpu6050_volatile_reg(struct device *dev, unsigned int reg)
return true;
if (reg >= INV_MPU6050_REG_RAW_GYRO && reg < INV_MPU6050_REG_RAW_GYRO + 6)
return true;
+ if (reg < INV_MPU6050_REG_EXT_SENS_DATA_00 + INV_MPU6050_CNT_EXT_SENS_DATA &&
+ reg >= INV_MPU6050_REG_EXT_SENS_DATA_00)
+ return true;
switch (reg) {
case INV_MPU6050_REG_TEMPERATURE:
case INV_MPU6050_REG_TEMPERATURE + 1:
@@ -340,13 +345,115 @@ static int inv_mpu6050_sensor_show(struct inv_mpu6050_state *st, int reg,
return IIO_VAL_INT;
}

+static bool iio_chan_needs_swab(const struct iio_chan_spec *chan)
+{
+#if defined(__LITTLE_ENDIAN)
+ return chan->scan_type.endianness == IIO_BE;
+#elif defined(__BIG_ENDIAN)
+ return chan->scan_type.endianness == IIO_LE;
+#else
+ #error undefined endianness
+#endif
+}
+
+/* Convert iio buffer format to IIO_CHAN_INFO_RAW value */
+static int iio_bufval_to_rawval(const struct iio_chan_spec *chan, void *buf, int *val)
+{
+ switch (chan->scan_type.storagebits) {
+ case 8: *val = *((u8*)buf); break;
+ case 16: *val = *(u16*)buf; break;
+ case 32: *val = *(u32*)buf; break;
+ default: return -EINVAL;
+ }
+
+ *val >>= chan->scan_type.shift;
+ *val &= (1 << chan->scan_type.realbits) - 1;
+ if (iio_chan_needs_swab(chan)) {
+ if (chan->scan_type.storagebits == 16)
+ *val = swab16(*val);
+ else if (chan->scan_type.storagebits == 32)
+ *val = swab32(*val);
+ }
+ if (chan->scan_type.sign == 's')
+ *val = sign_extend32(*val, chan->scan_type.storagebits - 1);
+
+ return 0;
+}
+
+static int
+inv_mpu6050_read_raw_external(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ int result;
+ struct inv_mpu6050_state *st = iio_priv(indio_dev);
+ int chan_index = chan - indio_dev->channels;
+ struct inv_mpu6050_ext_chan_state *ext_chan_state =
+ &st->ext_chan[chan_index - INV_MPU6050_NUM_INT_CHAN];
+ struct inv_mpu6050_ext_sens_state *ext_sens_state =
+ &st->ext_sens[ext_chan_state->ext_sens_index];
+ struct iio_dev *orig_dev = ext_sens_state->orig_dev;
+ const struct iio_chan_spec *orig_chan = &orig_dev->channels[ext_chan_state->orig_chan_index];
+ int data_offset;
+ int data_length;
+ u8 buf[4];
+
+ /* Everything but raw data reads is forwarded. */
+ if (mask != IIO_CHAN_INFO_RAW)
+ return orig_dev->info->read_raw(orig_dev, orig_chan, val, val2, mask);
+
+ /* Raw reads are handled directly. */
+ data_offset = INV_MPU6050_REG_EXT_SENS_DATA_00 + ext_chan_state->data_offset;
+ data_length = chan->scan_type.storagebits / 8;
+ if (data_length > sizeof(buf)) {
+ return -EINVAL;
+ }
+
+ mutex_lock(&indio_dev->mlock);
+ if (!st->chip_config.enable) {
+ result = inv_mpu6050_set_power_itg(st, true);
+ if (result)
+ goto error_unlock;
+ }
+ result = regmap_bulk_read(st->map, data_offset, buf, data_length);
+ if (result)
+ goto error_unpower;
+ if (!st->chip_config.enable) {
+ result = inv_mpu6050_set_power_itg(st, false);
+ if (result)
+ goto error_unlock;
+ }
+ mutex_unlock(&indio_dev->mlock);
+
+ /* Convert buf to val and return success */
+ result = iio_bufval_to_rawval(chan, buf, val);
+ if (result)
+ return result;
+ return IIO_VAL_INT;
+
+error_unpower:
+ if (!st->chip_config.enable)
+ inv_mpu6050_set_power_itg(st, false);
+error_unlock:
+ mutex_unlock(&indio_dev->mlock);
+ return result;
+}
+
static int
inv_mpu6050_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
- struct inv_mpu6050_state *st = iio_priv(indio_dev);
+ struct inv_mpu6050_state *st = iio_priv(indio_dev);
int ret = 0;
+ int chan_index;
+
+ if (chan < indio_dev->channels || chan > indio_dev->channels + indio_dev->num_channels) {
+ return -EINVAL;
+ }
+ chan_index = chan - indio_dev->channels;
+ if (chan_index >= INV_MPU6050_NUM_INT_CHAN)
+ return inv_mpu6050_read_raw_external(indio_dev, chan, val, val2, mask);

switch (mask) {
case IIO_CHAN_INFO_RAW:
@@ -819,6 +926,309 @@ static const struct iio_info mpu_info = {
.validate_trigger = inv_mpu6050_validate_trigger,
};

+extern struct device_type iio_device_type;
+
+static int iio_device_from_i2c_client_match(struct device *dev, void *data)
+{
+ return dev->type == &iio_device_type;
+}
+
+static struct iio_dev* iio_device_from_i2c_client(struct i2c_client* i2c)
+{
+ struct device *child;
+
+ child = device_find_child(&i2c->dev, NULL, iio_device_from_i2c_client_match);
+
+ return (child ? dev_to_iio_dev(child) : NULL);
+}
+
+static int inv_mpu_set_external_reads_enabled(struct inv_mpu6050_state *st, bool en)
+{
+ int i, result, error = 0;
+
+ /* Even if there are errors try to disable all slaves. */
+ for (i = 0; i < INV_MPU6050_MAX_EXT_SENSORS; ++i) {
+ result = regmap_update_bits(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(i),
+ INV_MPU6050_BIT_I2C_SLV_EN,
+ en ? INV_MPU6050_BIT_I2C_SLV_EN : 0);
+ if (result) {
+ error = result;
+ }
+ }
+
+ return error;
+}
+
+static int inv_mpu_parse_one_ext_sens(struct device *dev,
+ struct device_node *np,
+ struct inv_mpu6050_ext_sens_spec *spec)
+{
+ int result;
+ u32 addr, reg, len;
+
+ result = of_property_read_u32(np, "inv,addr", &addr);
+ if (result)
+ return result;
+ result = of_property_read_u32(np, "inv,reg", &reg);
+ if (result)
+ return result;
+ result = of_property_read_u32(np, "inv,len", &len);
+ if (result)
+ return result;
+
+ spec->addr = addr;
+ spec->reg = reg;
+ spec->len = len;
+
+ result = of_property_count_u32_elems(np, "inv,external-channels");
+ if (result < 0)
+ return result;
+ spec->num_ext_channels = result;
+ spec->ext_channels = devm_kmalloc(dev, spec->num_ext_channels * sizeof(*spec->ext_channels), GFP_KERNEL);
+ if (!spec->ext_channels)
+ return -ENOMEM;
+ result = of_property_read_u32_array(np, "inv,external-channels",
+ spec->ext_channels,
+ spec->num_ext_channels);
+ if (result)
+ return result;
+
+ return 0;
+}
+
+static int inv_mpu_parse_ext_sens(struct device *dev,
+ struct device_node *node,
+ struct inv_mpu6050_ext_sens_spec *specs)
+{
+ struct device_node *child;
+ int result;
+ u32 reg;
+
+ for_each_available_child_of_node(node, child) {
+ result = of_property_read_u32(child, "reg", &reg);
+ if (result)
+ return result;
+ if (reg > INV_MPU6050_MAX_EXT_SENSORS) {
+ dev_err(dev, "External sensor index %u out of range, max %d\n",
+ reg, INV_MPU6050_MAX_EXT_SENSORS);
+ return -EINVAL;
+ }
+ result = inv_mpu_parse_one_ext_sens(dev, child, &specs[reg]);
+ if (result)
+ return result;
+ }
+
+ return 0;
+}
+
+static int inv_mpu_get_ext_sens_spec(struct iio_dev *indio_dev)
+{
+ struct inv_mpu6050_state *st = iio_priv(indio_dev);
+ struct device *dev = regmap_get_device(st->map);
+ struct device_node *node;
+ int result;
+
+ node = of_get_child_by_name(dev->of_node, "inv,external-sensors");
+ if (node) {
+ result = inv_mpu_parse_ext_sens(dev, node, st->ext_sens_spec);
+ if (result)
+ dev_err(dev, "Failed to parsing external-sensors devicetree data\n");
+ return result;
+ }
+
+ /* Maybe some other way to deal with this? */
+
+ return 0;
+}
+
+/* Struct used while enumerating devices and matching them */
+struct inv_mpu_handle_ext_sensor_fnarg
+{
+ struct iio_dev *indio_dev;
+
+ /* Next scan index */
+ int scan_index;
+ /* Index among external channels */
+ int chan_index;
+ /* Offset in EXTDATA */
+ int data_offset;
+ struct iio_chan_spec *channels;
+};
+
+static int inv_mpu_config_external_read(struct inv_mpu6050_state *st, int index,
+ const struct inv_mpu6050_ext_sens_spec *spec)
+{
+ int result;
+
+ result = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_ADDR(index),
+ INV_MPU6050_BIT_I2C_SLV_RW | spec->addr);
+ if (result)
+ return result;
+ result = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_REG(index), spec->reg);
+ if (result)
+ return result;
+ result = regmap_write(st->map, INV_MPU6050_REG_I2C_SLV_CTRL(index),
+ INV_MPU6050_BIT_I2C_SLV_EN | spec->len);
+
+ return result;
+}
+
+static int inv_mpu_handle_ext_sensor_fn(struct device *dev, void *data)
+{
+ struct inv_mpu_handle_ext_sensor_fnarg *fnarg = data;
+ struct iio_dev *indio_dev = fnarg->indio_dev;
+ struct inv_mpu6050_state *st = iio_priv(indio_dev);
+ struct device *mydev = regmap_get_device(st->map);
+ struct i2c_client *client;
+ struct iio_dev *orig_dev;
+ int i, j;
+
+ client = i2c_verify_client(dev);
+ if (!client)
+ return 0;
+ orig_dev = iio_device_from_i2c_client(client);
+ if (!orig_dev)
+ return 0;
+ for (i = 0; i < INV_MPU6050_MAX_EXT_SENSORS; ++i) {
+ int start_data_offset;
+ struct inv_mpu6050_ext_sens_spec *ext_sens_spec = &st->ext_sens_spec[i];
+ struct inv_mpu6050_ext_sens_state *ext_sens_state = &st->ext_sens[i];
+
+ if (ext_sens_spec->addr != client->addr)
+ continue;
+ if (ext_sens_state->orig_dev) {
+ dev_warn(&indio_dev->dev, "already found slave with at addr %d\n", client->addr);
+ continue;
+ }
+ dev_info(mydev, "external sensor %d is device %s\n",
+ i, orig_dev->name ?: dev_name(&orig_dev->dev));
+ ext_sens_state->orig_dev = orig_dev;
+ ext_sens_state->scan_mask = 0;
+ ext_sens_state->data_len = ext_sens_spec->len;
+ start_data_offset = fnarg->data_offset;
+
+ /* Matched the device (by address). Now process channels: */
+ for (j = 0; j < ext_sens_spec->num_ext_channels; ++j) {
+ int orig_chan_index;
+ const struct iio_chan_spec *orig_chan_spec;
+ struct iio_chan_spec *chan_spec;
+ struct inv_mpu6050_ext_chan_state *chan_state;
+
+ orig_chan_index = ext_sens_spec->ext_channels[j];
+ orig_chan_spec = &orig_dev->channels[orig_chan_index];
+ chan_spec = &fnarg->channels[INV_MPU6050_NUM_INT_CHAN + fnarg->chan_index];
+ chan_state = &st->ext_chan[fnarg->chan_index];
+
+ chan_state->ext_sens_index = i;
+ chan_state->orig_chan_index = orig_chan_index;
+ chan_state->data_offset = fnarg->data_offset;
+ memcpy(chan_spec, orig_chan_spec, sizeof(struct iio_chan_spec));
+ chan_spec->scan_index = fnarg->scan_index;
+ ext_sens_state->scan_mask |= (1 << chan_spec->scan_index);
+ if (orig_chan_spec->scan_type.storagebits != 16) {
+ /*
+ * Supporting other channels sizes would require data read from the
+ * hardware fifo to comply with iio alignment.
+ */
+ dev_err(&indio_dev->dev, "All external channels must have 16 storage bits\n");
+ return -EINVAL;
+ }
+
+ fnarg->scan_index++;
+ fnarg->chan_index++;
+ fnarg->data_offset += chan_spec->scan_type.storagebits / 8;
+ dev_info(mydev, "Reading external channel #%d scan_index %d data_offset %d"
+ " from original device %s chan #%d scan_index %d\n",
+ fnarg->chan_index, chan_spec->scan_index, chan_state->data_offset,
+ orig_dev->name ?: dev_name(&orig_dev->dev), orig_chan_index, orig_chan_spec->scan_index);
+ }
+ if (start_data_offset + ext_sens_spec->len != fnarg->data_offset) {
+ dev_warn(mydev, "length mismatch between i2c slave read length and slave channel spec\n");
+ return -EINVAL;
+ }
+
+ return inv_mpu_config_external_read(st, i, ext_sens_spec);
+ }
+ return 0;
+}
+
+static int inv_mpu6050_handle_ext_sensors(struct iio_dev *indio_dev)
+{
+ struct inv_mpu6050_state *st = iio_priv(indio_dev);
+ struct device *dev = regmap_get_device(st->map);
+ struct inv_mpu_handle_ext_sensor_fnarg fnarg = {
+ .indio_dev = indio_dev,
+ .chan_index = 0,
+ .data_offset = 0,
+ .scan_index = INV_MPU6050_SCAN_TIMESTAMP,
+ };
+ int i, result;
+ int num_ext_chan = 0, sum_data_len = 0;
+
+ inv_mpu_get_ext_sens_spec(indio_dev);
+ for (i = 0; i < INV_MPU6050_MAX_EXT_SENSORS; ++i) {
+ num_ext_chan += st->ext_sens_spec[i].num_ext_channels;
+ sum_data_len += st->ext_sens_spec[i].len;
+ }
+ if (sum_data_len > INV_MPU6050_CNT_EXT_SENS_DATA) {
+ dev_err(dev, "Too many bytes from external sensors:"
+ " requested=%d max=%d\n",
+ sum_data_len, INV_MPU6050_CNT_EXT_SENS_DATA);
+ return -EINVAL;
+ }
+
+ /* Zero length means nothing to do */
+ if (!sum_data_len) {
+ indio_dev->channels = inv_mpu_channels;
+ indio_dev->num_channels = INV_MPU6050_NUM_INT_CHAN;
+ BUILD_BUG_ON(ARRAY_SIZE(inv_mpu_channels) != INV_MPU6050_NUM_INT_CHAN);
+ return 0;
+ }
+
+ fnarg.channels = devm_kmalloc(indio_dev->dev.parent,
+ (num_ext_chan + INV_MPU6050_NUM_INT_CHAN) *
+ sizeof(struct iio_chan_spec),
+ GFP_KERNEL);
+ if (!fnarg.channels)
+ return -ENOMEM;
+ memcpy(fnarg.channels, inv_mpu_channels, sizeof(inv_mpu_channels));
+ memset(fnarg.channels + INV_MPU6050_NUM_INT_CHAN, 0,
+ num_ext_chan * sizeof(struct iio_chan_spec));
+
+ st->ext_chan = devm_kzalloc(indio_dev->dev.parent,
+ (num_ext_chan) * sizeof(*st->ext_chan),
+ GFP_KERNEL);
+ if (!st->ext_chan)
+ return -ENOMEM;
+
+ result = inv_mpu6050_set_power_itg(st, true);
+ if (result < 0)
+ return result;
+
+ result = device_for_each_child(&st->aux_master_adapter.dev, &fnarg,
+ inv_mpu_handle_ext_sensor_fn);
+ if (result)
+ goto out_disable;
+ /* Timestamp channel has index 0 and last scan_index */
+ fnarg.channels[0].scan_index = fnarg.scan_index;
+
+ if (fnarg.chan_index != num_ext_chan) {
+ dev_err(&indio_dev->dev, "Failed to match all external channels!\n");
+ result = -EINVAL;
+ goto out_disable;
+ }
+
+ result = inv_mpu6050_set_power_itg(st, false);
+ indio_dev->channels = fnarg.channels;
+ indio_dev->num_channels = INV_MPU6050_NUM_INT_CHAN + num_ext_chan;
+ return result;
+
+out_disable:
+ inv_mpu6050_set_power_itg(st, false);
+ inv_mpu_set_external_reads_enabled(st, false);
+ return result;
+}
+
/**
* inv_check_and_setup_chip() - check and setup chip.
*/
@@ -1121,8 +1531,6 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
indio_dev->name = name;
else
indio_dev->name = dev_name(dev);
- indio_dev->channels = inv_mpu_channels;
- indio_dev->num_channels = ARRAY_SIZE(inv_mpu_channels);

indio_dev->info = &mpu_info;
indio_dev->modes = INDIO_BUFFER_TRIGGERED;
@@ -1160,6 +1568,12 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name,
}
#endif

+ result = inv_mpu6050_handle_ext_sensors(indio_dev);
+ if (result < 0) {
+ dev_err(dev, "failed to configure channels %d\n", result);
+ goto out_remove_trigger;
+ }
+
INIT_KFIFO(st->timestamps);
spin_lock_init(&st->time_stamp_lock);
result = iio_device_register(indio_dev);
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
index 9d406df..007fe75 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h
@@ -124,6 +124,40 @@ struct inv_mpu6050_hw {
const struct inv_mpu6050_chip_config *config;
};

+#define INV_MPU6050_MAX_EXT_SENSORS 4
+
+/* Specification for an external sensor */
+struct inv_mpu6050_ext_sens_spec {
+ unsigned short addr;
+ u8 reg, len;
+
+ int num_ext_channels;
+ int *ext_channels;
+};
+
+/* Driver state for each external sensor */
+struct inv_mpu6050_ext_sens_state {
+ struct iio_dev *orig_dev;
+
+ /* Mask of all channels in this sensor */
+ unsigned long scan_mask;
+
+ /* Length of reading. */
+ int data_len;
+};
+
+/* Driver state for each external channel */
+struct inv_mpu6050_ext_chan_state {
+ /* Index inside state->ext_sens */
+ int ext_sens_index;
+
+ /* Index inside orig_dev->channels */
+ int orig_chan_index;
+
+ /* Relative to EXT_SENS_DATA_00 */
+ int data_offset;
+};
+
/*
* struct inv_mpu6050_state - Driver state variables.
* @TIMESTAMP_FIFO_SIZE: fifo size for timestamp.
@@ -164,6 +198,10 @@ struct inv_mpu6050_state {
struct i2c_adapter aux_master_adapter;
struct completion slv4_done;
#endif
+
+ struct inv_mpu6050_ext_sens_spec ext_sens_spec[INV_MPU6050_MAX_EXT_SENSORS];
+ struct inv_mpu6050_ext_sens_state ext_sens[INV_MPU6050_MAX_EXT_SENSORS];
+ struct inv_mpu6050_ext_chan_state *ext_chan;
};

/*register and associated bit definition*/
@@ -178,6 +216,24 @@ struct inv_mpu6050_state {
#define INV_MPU6050_REG_FIFO_EN 0x23
#define INV_MPU6050_BIT_ACCEL_OUT 0x08
#define INV_MPU6050_BITS_GYRO_OUT 0x70
+#define INV_MPU6050_BIT_SLV0_FIFO_EN 0x01
+#define INV_MPU6050_BIT_SLV1_FIFO_EN 0x02
+#define INV_MPU6050_BIT_SLV2_FIFO_EN 0x04
+#define INV_MPU6050_BIT_SLV2_FIFO_EN 0x04
+
+/* SLV3 fifo enabling is not in REG_FIFO_EN */
+#define INV_MPU6050_REG_MST_CTRL 0x24
+#define INV_MPU6050_BIT_SLV3_FIFO_EN 0x10
+
+/* For slaves 0-3 */
+#define INV_MPU6050_REG_I2C_SLV_ADDR(i) (0x25 + 3 * (i))
+#define INV_MPU6050_REG_I2C_SLV_REG(i) (0x26 + 3 * (i))
+#define INV_MPU6050_REG_I2C_SLV_CTRL(i) (0x27 + 3 * (i))
+#define INV_MPU6050_BIT_I2C_SLV_RW 0x80
+#define INV_MPU6050_BIT_I2C_SLV_EN 0x80
+#define INV_MPU6050_BIT_I2C_SLV_BYTE_SW 0x40
+#define INV_MPU6050_BIT_I2C_SLV_REG_DIS 0x20
+#define INV_MPU6050_BIT_I2C_SLV_REG_GRP 0x10

#define INV_MPU6050_REG_I2C_SLV4_ADDR 0x31
#define INV_MPU6050_BIT_I2C_SLV4_R 0x80
@@ -252,8 +308,8 @@ struct inv_mpu6050_state {
#define INV_MPU6050_GYRO_CONFIG_FSR_SHIFT 3
#define INV_MPU6050_ACCL_CONFIG_FSR_SHIFT 3

-/* 6 + 6 round up and plus 8 */
-#define INV_MPU6050_OUTPUT_DATA_SIZE 24
+/* max is 3*2 accel + 3*2 gyro + 24 external + 8 ts */
+#define INV_MPU6050_OUTPUT_DATA_SIZE 44

#define INV_MPU6050_REG_INT_PIN_CFG 0x37
#define INV_MPU6050_BIT_BYPASS_EN 0x2
@@ -266,6 +322,9 @@ struct inv_mpu6050_state {
#define INV_MPU6050_MIN_FIFO_RATE 4
#define INV_MPU6050_ONE_K_HZ 1000

+#define INV_MPU6050_REG_EXT_SENS_DATA_00 0x49
+#define INV_MPU6050_CNT_EXT_SENS_DATA 24
+
#define INV_MPU6050_REG_WHOAMI 117

#define INV_MPU6000_WHOAMI_VALUE 0x68
diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
index e8bda7f..8fa5c3d 100644
--- a/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
+++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c
@@ -52,6 +52,10 @@ int inv_reset_fifo(struct iio_dev *indio_dev)
result = regmap_write(st->map, st->reg->fifo_en, 0);
if (result)
goto reset_fifo_fail;
+ result = regmap_update_bits(st->map, INV_MPU6050_REG_MST_CTRL,
+ INV_MPU6050_BIT_SLV3_FIFO_EN, 0);
+ if (result)
+ goto reset_fifo_fail;
/* disable fifo reading */
st->chip_config.user_ctrl &= ~INV_MPU6050_BIT_FIFO_EN;
result = regmap_write(st->map, st->reg->user_ctrl,
@@ -70,7 +74,8 @@ int inv_reset_fifo(struct iio_dev *indio_dev)

/* enable interrupt */
if (st->chip_config.accl_fifo_enable ||
- st->chip_config.gyro_fifo_enable) {
+ st->chip_config.gyro_fifo_enable ||
+ true) {
result = regmap_update_bits(st->map, st->reg->int_enable,
INV_MPU6050_BIT_DATA_RDY_EN,
INV_MPU6050_BIT_DATA_RDY_EN);
@@ -89,10 +94,23 @@ int inv_reset_fifo(struct iio_dev *indio_dev)
d |= INV_MPU6050_BITS_GYRO_OUT;
if (st->chip_config.accl_fifo_enable)
d |= INV_MPU6050_BIT_ACCEL_OUT;
+ if (*indio_dev->active_scan_mask & st->ext_sens[0].scan_mask)
+ d |= INV_MPU6050_BIT_SLV0_FIFO_EN;
+ if (*indio_dev->active_scan_mask & st->ext_sens[1].scan_mask)
+ d |= INV_MPU6050_BIT_SLV1_FIFO_EN;
+ if (*indio_dev->active_scan_mask & st->ext_sens[2].scan_mask)
+ d |= INV_MPU6050_BIT_SLV2_FIFO_EN;
result = regmap_write(st->map, st->reg->fifo_en, d);
if (result)
goto reset_fifo_fail;
-
+ if (*indio_dev->active_scan_mask & st->ext_sens[3].scan_mask)
+ {
+ result = regmap_update_bits(st->map, INV_MPU6050_REG_MST_CTRL,
+ INV_MPU6050_BIT_SLV3_FIFO_EN,
+ INV_MPU6050_BIT_SLV3_FIFO_EN);
+ if (result)
+ goto reset_fifo_fail;
+ }
return 0;

reset_fifo_fail:
@@ -129,8 +147,9 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct inv_mpu6050_state *st = iio_priv(indio_dev);
- size_t bytes_per_datum;
+ size_t bytes_per_datum = 0;
int result;
+ int i;
u8 data[INV_MPU6050_OUTPUT_DATA_SIZE];
u16 fifo_count;
s64 timestamp;
@@ -143,15 +162,18 @@ irqreturn_t inv_mpu6050_read_fifo(int irq, void *p)
spi = i2c ? NULL: to_spi_device(regmap_dev);

mutex_lock(&indio_dev->mlock);
- if (!(st->chip_config.accl_fifo_enable |
- st->chip_config.gyro_fifo_enable))
- goto end_session;
+
+ /* Compute bytes_per_datum */
bytes_per_datum = 0;
if (st->chip_config.accl_fifo_enable)
bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
-
if (st->chip_config.gyro_fifo_enable)
bytes_per_datum += INV_MPU6050_BYTES_PER_3AXIS_SENSOR;
+ for (i = 0; i < INV_MPU6050_MAX_EXT_SENSORS; ++i)
+ if (st->ext_sens[i].scan_mask & *indio_dev->active_scan_mask)
+ bytes_per_datum += st->ext_sens[i].data_len;
+ if (!bytes_per_datum)
+ return 0;

/*
* read fifo_count register to know how many bytes inside FIFO
@@ -228,6 +250,7 @@ static int inv_mpu_buffer_preenable(struct iio_dev *indio_dev)
{
struct inv_mpu6050_state *st = iio_priv(indio_dev);
unsigned long mask = *indio_dev->active_scan_mask;
+ int i;

if ((mask & INV_MPU6050_SCAN_MASK_GYRO) &&
(mask & INV_MPU6050_SCAN_MASK_GYRO) != INV_MPU6050_SCAN_MASK_GYRO)
@@ -245,6 +268,17 @@ static int inv_mpu_buffer_preenable(struct iio_dev *indio_dev)
return -EINVAL;
}

+ for (i = 0; i < INV_MPU6050_MAX_EXT_SENSORS; ++i) {
+ if ((mask & st->ext_sens[i].scan_mask) &&
+ (mask & st->ext_sens[i].scan_mask) != st->ext_sens[i].scan_mask)
+ {
+ dev_warn(regmap_get_device(st->map),
+ "External channels from the same reading "
+ "can only be enabled together\n");
+ return -EINVAL;
+ }
+ }
+
return 0;
}

--
2.5.5
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