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3904b28efb
This adds a new driver for the Invensense MPU-3050 gyroscope. This driver is based on information from the rough input driver in drivers/input/misc/mpu3050.c and the scratch misc driver posted by Nathan Royer in 2011. Some years have passed but this is finally a fully-fledged driver for this gyroscope. It was developed and tested on the Qualcomm APQ8060 Dragonboard. The driver supports both raw and buffered input. It also supports the internal trigger mechanism by registering a trigger that can fire in response to the internal sample engine of the component. In addition to reading out the gyroscope sensor values, the driver also supports reading the temperature from the sensor. The driver currently only supports I2C but the MPU-3050 can also be used from SPI, so the I2C portions are split in their own file and we just use regmap to access all registers, so it will be trivial to plug in SPI support if/when someone has a system requiring this. To conserve power, the driver utilizes the runtime PM framework and will put the sensor in off mode and disable the regulators when unused, after a timeout of 10 seconds. The fullscale can be set for the sensor to 250, 500, 1000 or 2000 deg/s. This corresponds to scale values of rougly 0.000122, 0.000275, 0.000512 or 0.001068. By writing such values (or close to these) into "in_anglevel_scale", the corresponding fullscale can be chosen. It will default to 2000 deg/s (~35 rad/s). The gyro component can have DC offsets on all axes. These can be compensated using the standard sysfs ABI property "in_anglevel_[xyz]_calibbias". This is in positive/negative values of the raw values, so a suitable calibration bias can be determined by userspace by reading the "in_anglevel_[xyz]_raw" for a few iterations while holding the sensor still, create an average integer, and writing the negative inverse of that into "in_anglevel_[xyz]_calibbias". After this the hardware will automatically subtract the bias, also when using buffered readings. Since the MPU-3050 has an outgoing I2C port it needs to act as an I2C mux. This means that the device is switching I2C traffic to devices beyond it. On my system this is the only way to reach the accelerometer. The "sensor fusion" ability of the MPU-3050 to directly talk to the device on the outgoing I2C port is currently not used by the driver, but it has code to allow I2C traffic to pass through so that the Linux kernel can reach the device on the other side with a kernel driver. Example usage with the native trigger: $ generic_buffer -a -c10 -n mpu3050 iio device number being used is 0 iio trigger number being used is 0 No channels are enabled, enabling all channels Enabling: in_anglvel_z_en Enabling: in_timestamp_en Enabling: in_anglvel_y_en Enabling: in_temp_en Enabling: in_anglvel_x_en /sys/bus/iio/devices/iio:device0 mpu3050-dev0 29607.142578 -0.117493 0.074768 0.012817 180788797150 29639.285156 -0.117493 0.076904 0.013885 180888982335 29696.427734 -0.116425 0.076904 0.012817 180989178039 29742.857422 -0.117493 0.076904 0.012817 181089377742 29764.285156 -0.116425 0.077972 0.012817 181189574187 29860.714844 -0.115356 0.076904 0.012817 181289772705 29864.285156 -0.117493 0.076904 0.012817 181389971520 29910.714844 -0.115356 0.076904 0.013885 181490170483 29917.857422 -0.116425 0.076904 0.011749 181590369742 29975.000000 -0.116425 0.076904 0.012817 181690567075 Disabling: in_anglvel_z_en Disabling: in_timestamp_en Disabling: in_anglvel_y_en Disabling: in_temp_en Disabling: in_anglvel_x_en The first column is the temperature in millidegrees, then the x,y,z axes in succession followed by the timestamp. Also tested successfully using the HRTimer trigger. Cc: Nick Vaccaro <nvaccaro@google.com> Cc: Ge Gao <ggao@invensense.com> Cc: Anna Si <asi@invensense.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Cc: Crestez Dan Leonard <leonard.crestez@intel.com> Cc: Daniel Baluta <daniel.baluta@intel.com> Cc: Gregor Boirie <gregor.boirie@parrot.com> Cc: Peter Rosin <peda@axentia.se> Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
96 lines
2.7 KiB
C
96 lines
2.7 KiB
C
#include <linux/iio/iio.h>
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#include <linux/mutex.h>
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#include <linux/regmap.h>
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#include <linux/regulator/consumer.h>
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#include <linux/i2c.h>
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/**
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* enum mpu3050_fullscale - indicates the full range of the sensor in deg/sec
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*/
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enum mpu3050_fullscale {
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FS_250_DPS = 0,
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FS_500_DPS,
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FS_1000_DPS,
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FS_2000_DPS,
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};
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/**
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* enum mpu3050_lpf - indicates the low pass filter width
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*/
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enum mpu3050_lpf {
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/* This implicity sets sample frequency to 8 kHz */
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LPF_256_HZ_NOLPF = 0,
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/* All others sets the sample frequency to 1 kHz */
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LPF_188_HZ,
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LPF_98_HZ,
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LPF_42_HZ,
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LPF_20_HZ,
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LPF_10_HZ,
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LPF_5_HZ,
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LPF_2100_HZ_NOLPF,
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};
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enum mpu3050_axis {
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AXIS_X = 0,
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AXIS_Y,
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AXIS_Z,
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AXIS_MAX,
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};
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/**
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* struct mpu3050 - instance state container for the device
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* @dev: parent device for this instance
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* @orientation: mounting matrix, flipped axis etc
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* @map: regmap to reach the registers
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* @lock: serialization lock to marshal all requests
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* @irq: the IRQ used for this device
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* @regs: the regulators to power this device
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* @fullscale: the current fullscale setting for the device
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* @lpf: digital low pass filter setting for the device
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* @divisor: base frequency divider: divides 8 or 1 kHz
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* @calibration: the three signed 16-bit calibration settings that
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* get written into the offset registers for each axis to compensate
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* for DC offsets
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* @trig: trigger for the MPU-3050 interrupt, if present
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* @hw_irq_trigger: hardware interrupt trigger is in use
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* @irq_actl: interrupt is active low
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* @irq_latch: latched IRQ, this means that it is a level IRQ
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* @irq_opendrain: the interrupt line shall be configured open drain
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* @pending_fifo_footer: tells us if there is a pending footer in the FIFO
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* that we have to read out first when handling the FIFO
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* @hw_timestamp: latest hardware timestamp from the trigger IRQ, when in
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* use
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* @i2cmux: an I2C mux reflecting the fact that this sensor is a hub with
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* a pass-through I2C interface coming out of it: this device needs to be
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* powered up in order to reach devices on the other side of this mux
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*/
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struct mpu3050 {
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struct device *dev;
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struct iio_mount_matrix orientation;
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struct regmap *map;
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struct mutex lock;
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int irq;
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struct regulator_bulk_data regs[2];
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enum mpu3050_fullscale fullscale;
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enum mpu3050_lpf lpf;
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u8 divisor;
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s16 calibration[3];
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struct iio_trigger *trig;
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bool hw_irq_trigger;
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bool irq_actl;
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bool irq_latch;
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bool irq_opendrain;
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bool pending_fifo_footer;
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s64 hw_timestamp;
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struct i2c_mux_core *i2cmux;
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};
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/* Probe called from different transports */
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int mpu3050_common_probe(struct device *dev,
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struct regmap *map,
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int irq,
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const char *name);
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int mpu3050_common_remove(struct device *dev);
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/* PM ops */
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extern const struct dev_pm_ops mpu3050_dev_pm_ops;
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