Hi Matt, I am not sure about slave 4. I always use slave0~3. MPU6050 can connect up to 4 slaves by using slave 0~3. However, we only use 3 slaves. Each slave can be configured as read or write independently. For example, AKM8973 compass as a slave, I usually configure slave0 as read and slave 1 as write. The rate is 100Hz, for example, the read will read first and write happens subsequently. Of course, the read will read a dummy data for the first time. However, after first read, it will read the correct data. Write will send AKM the measure command. The measurement takes several mili-seconds to finish. That is why we read like that. For pressure sensor or ALS(light/proximity sensor), they all have autonomous mode. As long as the sample period is longer than the output rate, the data is guaranteed to be new data. Thanks. Ge -----Original Message----- From: Matt Ranostay [mailto:mranostay@xxxxxxxxx] Sent: Thursday, March 17, 2016 10:28 AM To: Daniel Baluta Cc: Jonathan Cameron; Hartmut Knaack; Lars-Peter Clausen; Peter Meerwald-Stadler; Matt Ranostay; Lucas De Marchi; cmo@xxxxxxxxxxx; linux-iio@xxxxxxxxxxxxxxx; Ge Gao; srinivas.pandruvada@xxxxxxxxxxxxxxx; adi.reus@xxxxxxxxx Subject: Re: [PATCH 3/3] iio: imu: mpu6050: Add support for auxiliary I2C master Reviewed-by: Matt Ranostay <matt.ranostay@xxxxxxxxx> On Thu, Mar 17, 2016 at 9:32 AM, Daniel Baluta <daniel.baluta@xxxxxxxxx> wrote: > The MPU-60X0 [1] has an auxiliary I2C bus for connecting external > sensors. This bus has two operating modes: > * pass-through, which connects the primary and auxiliary busses > together [already implemented] > * I2C master mode, where MPU60X0 acts as a master to any > external connected sensors [implemented in this patch] > > I2C master supports up to 5 slaves. Slaves 0-3 have a common operating > mode while slave 4 is different. > > This patch only adds support for slave 4 because it has a cleaner > interface and it has an interrupt that signals when data from slave to > master arrived. > > Registers are described here [2]. > > We use threaded handler for reading slave4 done interrupt bit. > > [1] > https://www.cdiweb.com/datasheets/invensense/MPU-6050_DataSheet_V3%204 > .pdf > [2] > http://www6.in.tum.de/pub/Main/TeachingWs2015SeminarAuonomousFahren/RM > -MPU-6000A.pdf > > Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx> > --- > drivers/iio/imu/inv_mpu6050/inv_mpu_core.c | 137 > ++++++++++++++++++++++++++++- > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h | 38 ++++++++ > 2 files changed, 172 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > index 659a4be..a89854c 100644 > --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c > @@ -25,6 +25,8 @@ > #include <linux/iio/iio.h> > #include <linux/i2c-mux.h> > #include <linux/acpi.h> > +#include <linux/completion.h> > + > #include "inv_mpu_iio.h" > > /* > @@ -57,6 +59,12 @@ static const struct inv_mpu6050_reg_map reg_set_6500 = { > .int_pin_cfg = INV_MPU6050_REG_INT_PIN_CFG, > .accl_offset = INV_MPU6500_REG_ACCEL_OFFSET, > .gyro_offset = INV_MPU6050_REG_GYRO_OFFSET, > + .slv4_addr = INV_MPU6050_REG_I2C_SLV4_ADDR, > + .slv4_reg = INV_MPU6050_REG_I2C_SLV4_REG, > + .slv4_do = INV_MPU6050_REG_I2C_SLV4_DO, > + .slv4_ctrl = INV_MPU6050_REG_I2C_SLV4_CTRL, > + .slv4_di = INV_MPU6050_REG_I2C_SLV4_DI, > + .mst_status = INV_MPU6050_REG_I2C_MST_STATUS, > }; > > static const struct inv_mpu6050_reg_map reg_set_6050 = { @@ -77,6 > +85,12 @@ static const struct inv_mpu6050_reg_map reg_set_6050 = { > .int_pin_cfg = INV_MPU6050_REG_INT_PIN_CFG, > .accl_offset = INV_MPU6050_REG_ACCEL_OFFSET, > .gyro_offset = INV_MPU6050_REG_GYRO_OFFSET, > + .slv4_addr = INV_MPU6050_REG_I2C_SLV4_ADDR, > + .slv4_reg = INV_MPU6050_REG_I2C_SLV4_REG, > + .slv4_do = INV_MPU6050_REG_I2C_SLV4_DO, > + .slv4_ctrl = INV_MPU6050_REG_I2C_SLV4_CTRL, > + .slv4_di = INV_MPU6050_REG_I2C_SLV4_DI, > + .mst_status = INV_MPU6050_REG_I2C_MST_STATUS, > }; > > static const struct inv_mpu6050_chip_config chip_config_6050 = { @@ > -761,6 +775,114 @@ static int inv_check_and_setup_chip(struct inv_mpu6050_state *st) > return 0; > } > > +static irqreturn_t inv_mpu_datardy_irq_handler(int irq, void > +*private) { > + struct inv_mpu6050_state *st = (struct inv_mpu6050_state > +*)private; > + > + iio_trigger_poll(st->trig); > + > + return IRQ_WAKE_THREAD; > +} > + > +static irqreturn_t inv_mpu_datardy_thread_handler(int irq, void > +*private) { > + struct inv_mpu6050_state *st = (struct inv_mpu6050_state *)private; > + int ret, val; > + > + ret = regmap_read(st->map, st->reg->mst_status, &val); > + if (ret < 0) > + return ret; > + > + if (val & INV_MPU6050_BIT_I2C_SLV4_DONE) > + complete(&st->slv4_done); > + > + return IRQ_HANDLED; > +} > + > +static u32 inv_mpu_i2c_functionality(struct i2c_adapter *adap) { > + return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; } > + > +static int > +inv_mpu_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr, > + unsigned short flags, char read_write, u8 command, > + int size, union i2c_smbus_data *data) { > + struct inv_mpu6050_state *st = i2c_get_adapdata(adap); > + > + unsigned long time_left; > + int ret, val; > + u8 ctrl; > + > + ret = inv_mpu6050_set_power_itg(st, true); > + if (ret < 0) > + return ret; > + > + ret = regmap_update_bits(st->map, st->reg->user_ctrl, > + INV_MPU6050_BIT_I2C_MST_EN, > + INV_MPU6050_BIT_I2C_MST_EN); > + if (ret < 0) > + return ret; > + > + ret = regmap_update_bits(st->map, st->reg->int_enable, > + INV_MPU6050_BIT_MST_INT_EN, > + INV_MPU6050_BIT_MST_INT_EN); > + if (ret < 0) > + return ret; > + > + if (read_write == I2C_SMBUS_WRITE) > + addr |= INV_MPU6050_BIT_I2C_SLV4_W; > + else > + addr |= INV_MPU6050_BIT_I2C_SLV4_R; > + > + ret = regmap_write(st->map, st->reg->slv4_addr, addr); > + if (ret < 0) > + return ret; > + > + ret = regmap_write(st->map, st->reg->slv4_reg, command); > + if (ret < 0) > + return ret; > + > + if (read_write == I2C_SMBUS_WRITE) { > + ret = regmap_write(st->map, st->reg->slv4_do, data->byte); > + if (ret < 0) > + return ret; > + } > + > + ctrl = INV_MPU6050_BIT_SLV4_EN | INV_MPU6050_BIT_SLV4_INT_EN; > + ret = regmap_write(st->map, st->reg->slv4_ctrl, ctrl); > + if (ret < 0) > + return ret; > + if (read_write == I2C_SMBUS_READ) { > + time_left = wait_for_completion_timeout(&st->slv4_done, HZ); > + if (!time_left) > + return -ETIMEDOUT; > + > + ret = regmap_read(st->map, st->reg->slv4_di, &val); > + if (ret < 0) > + return ret; > + data->byte = val; > + } > + > + ret = inv_mpu6050_set_power_itg(st, false); > + if (ret < 0) > + return ret; > + return 0; > +} > + > +static const struct i2c_algorithm inv_mpu_i2c_algo = { > + .smbus_xfer = inv_mpu_i2c_smbus_xfer, > + .functionality = inv_mpu_i2c_functionality, > +}; > + > +static struct i2c_adapter inv_mpu_i2c_adapter = { > + .owner = THIS_MODULE, > + .class = I2C_CLASS_HWMON, > + .algo = &inv_mpu_i2c_algo, > + .name = "INV MPU secondary I2C", > +}; > + > int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name, > int (*inv_mpu_bus_setup)(struct iio_dev *), int > chip_type) { @@ -796,6 +918,13 @@ int inv_mpu_core_probe(struct > regmap *regmap, int irq, const char *name, > return result; > } > > + init_completion(&st->slv4_done); > + > + result = i2c_add_adapter(&inv_mpu_i2c_adapter); > + if (result < 0) > + return result; > + > + i2c_set_adapdata(&inv_mpu_i2c_adapter, st); > dev_set_drvdata(dev, indio_dev); > indio_dev->dev.parent = dev; > /* name will be NULL when enumerated via ACPI */ @@ -823,9 > +952,11 @@ int inv_mpu_core_probe(struct regmap *regmap, int irq, const char *name, > goto out_unreg_ring; > } > > - result = devm_request_irq(&indio_dev->dev, st->irq, > - &iio_trigger_generic_data_rdy_poll, > - IRQF_TRIGGER_RISING, "inv_mpu", st->trig); > + result = devm_request_threaded_irq(&indio_dev->dev, st->irq, > + &inv_mpu_datardy_irq_handler, > + &inv_mpu_datardy_thread_handler, > + IRQF_TRIGGER_RISING, "inv_mpu", > + st); > if (result) { > dev_err(dev, "request irq fail %d\n", result); > goto out_remove_trigger; diff --git > a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h > b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h > index e302a49..5c3ea9a 100644 > --- a/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h > +++ b/drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h > @@ -42,6 +42,13 @@ > * @int_pin_cfg; Controls interrupt pin configuration. > * @accl_offset: Controls the accelerometer calibration offset. > * @gyro_offset: Controls the gyroscope calibration offset. > + * @mst_status: secondary I2C master interrupt source status > + * @slv4_addr: I2C slave address for slave 4 transaction > + * @slv4_reg: I2C register used with slave 4 transaction > + * @slv4_di: I2C data in register for slave 4 transaction > + * @slv4_ctrl: I2C slave 4 control register > + * @slv4_do: I2C data out register for slave 4 transaction > + > */ > struct inv_mpu6050_reg_map { > u8 sample_rate_div; > @@ -61,6 +68,15 @@ struct inv_mpu6050_reg_map { > u8 int_pin_cfg; > u8 accl_offset; > u8 gyro_offset; > + u8 mst_status; > + > + /* slave 4 registers */ > + u8 slv4_addr; > + u8 slv4_reg; > + u8 slv4_di; /* data in */ > + u8 slv4_ctrl; > + u8 slv4_do; /* data out */ > + > }; > > /*device enum */ > @@ -133,6 +149,7 @@ struct inv_mpu6050_state { > struct inv_mpu6050_platform_data plat_data; > DECLARE_KFIFO(timestamps, long long, TIMESTAMP_FIFO_SIZE); > struct regmap *map; > + struct completion slv4_done; > int irq; > }; > > @@ -149,9 +166,30 @@ struct inv_mpu6050_state { > #define INV_MPU6050_BIT_ACCEL_OUT 0x08 > #define INV_MPU6050_BITS_GYRO_OUT 0x70 > > +#define INV_MPU6050_REG_I2C_SLV4_ADDR 0x31 > +#define INV_MPU6050_BIT_I2C_SLV4_R 0x80 > +#define INV_MPU6050_BIT_I2C_SLV4_W 0x00 > + > +#define INV_MPU6050_REG_I2C_SLV4_REG 0x32 > +#define INV_MPU6050_REG_I2C_SLV4_DO 0x33 > +#define INV_MPU6050_REG_I2C_SLV4_CTRL 0x34 > + > +#define INV_MPU6050_BIT_SLV4_EN 0x80 > +#define INV_MPU6050_BIT_SLV4_INT_EN 0x40 > +#define INV_MPU6050_BIT_SLV4_DIS 0x20 > + > +#define INV_MPU6050_REG_I2C_SLV4_DI 0x35 > + > +#define INV_MPU6050_REG_I2C_MST_STATUS 0x36 > +#define INV_MPU6050_BIT_I2C_SLV4_DONE 0x40 > + > #define INV_MPU6050_REG_INT_ENABLE 0x38 > #define INV_MPU6050_BIT_DATA_RDY_EN 0x01 > #define INV_MPU6050_BIT_DMP_INT_EN 0x02 > +#define INV_MPU6050_BIT_MST_INT_EN 0x08 > + > +#define INV_MPU6050_REG_INT_STATUS 0x3A > +#define INV_MPU6050_BIT_MST_INT 0x08 > > #define INV_MPU6050_REG_RAW_ACCEL 0x3B > #define INV_MPU6050_REG_TEMPERATURE 0x41 > -- > 2.5.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" > in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo > info at http://vger.kernel.org/majordomo-info.html ��.n��������+%������w��{.n�����{��(��)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
