On 17/03/16 18:11, Ge Gao wrote: > 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. Weird ;) Anyhow, the upshot is that practically these are autonomous once setup and will on a cycle continuously 'pinging' the device. If we want to do this in a generic way (i.e. not have to have large amounts of additional code in every driver for devices on the end of this) it will be interesting! Lars, superficially this sounds a bit like it could be done in a similar way to SPI offload. What do you think? Maybe we just ultimately conclude these are too weird to support in any generic way (which would be a pain). Jonathan > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
