From: Linus Walleij Date: Fri, 30 Dec 2016 22:54:18 +0000 (+0100) Subject: iio: accel: st_accel: fix LIS3LV02 reading and scaling X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=65e4345c8ef8811bbb4860fe5f2df10646b7f2e1;p=linux-beck.git iio: accel: st_accel: fix LIS3LV02 reading and scaling The LIS3LV02 has a special bit that need to be set to get the read values left aligned. Before this patch we get gibberish like this: iio_generic_buffer -a -c10 -n lis3lv02dl_accel (...) 0.000000 -0.010042 -0.642688 19155832931907 0.000000 -0.010042 -0.642688 19155858751073 Which is because we read a raw value for 1g as 64 which is the nominal 1024 for 1g shifted 4 bits to the left by being right-aligned rather than left aligned. Since all other sensors are left aligned, add some code to set the special DAS (data alignment setting) bit to 1 so that the right value is now read like this: iio_generic_buffer -a -c10 -n lis3lv02dl_accel (...) 0.000000 -0.147095 -10.120135 24761614364956 -0.029419 -0.176514 -10.120135 24761631624540 The scaling was weird as well: we have a gain of 1000 for 1g and 3000 for 6g. I don't even remember how I came up with the old values but they are wrong. Fixes: 3acddf74f807 ("iio: st-sensors: add support for lis3lv02d accelerometer") Cc: Lorenzo Bianconi Cc: Giuseppe Barba Cc: Denis Ciocca Signed-off-by: Linus Walleij Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c index f6b6d42385e1..784670e2736b 100644 --- a/drivers/iio/accel/st_accel_core.c +++ b/drivers/iio/accel/st_accel_core.c @@ -353,12 +353,12 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = { [0] = { .num = ST_ACCEL_FS_AVL_2G, .value = 0x00, - .gain = IIO_G_TO_M_S_2(1024), + .gain = IIO_G_TO_M_S_2(1000), }, [1] = { .num = ST_ACCEL_FS_AVL_6G, .value = 0x01, - .gain = IIO_G_TO_M_S_2(340), + .gain = IIO_G_TO_M_S_2(3000), }, }, }, @@ -366,6 +366,14 @@ static const struct st_sensor_settings st_accel_sensors_settings[] = { .addr = 0x21, .mask = 0x40, }, + /* + * Data Alignment Setting - needs to be set to get + * left-justified data like all other sensors. + */ + .das = { + .addr = 0x21, + .mask = 0x01, + }, .drdy_irq = { .addr = 0x21, .mask_int1 = 0x04, diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c index d5cf7f31eaf9..79c8c7cd70d5 100644 --- a/drivers/iio/common/st_sensors/st_sensors_core.c +++ b/drivers/iio/common/st_sensors/st_sensors_core.c @@ -401,6 +401,15 @@ int st_sensors_init_sensor(struct iio_dev *indio_dev, return err; } + /* set DAS */ + if (sdata->sensor_settings->das.addr) { + err = st_sensors_write_data_with_mask(indio_dev, + sdata->sensor_settings->das.addr, + sdata->sensor_settings->das.mask, 1); + if (err < 0) + return err; + } + if (sdata->int_pin_open_drain) { dev_info(&indio_dev->dev, "set interrupt line to open drain mode\n"); diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h index 228bd44efa4c..497f2b3a5a62 100644 --- a/include/linux/iio/common/st_sensors.h +++ b/include/linux/iio/common/st_sensors.h @@ -115,6 +115,16 @@ struct st_sensor_bdu { u8 mask; }; +/** + * struct st_sensor_das - ST sensor device data alignment selection + * @addr: address of the register. + * @mask: mask to write the das flag for left alignment. + */ +struct st_sensor_das { + u8 addr; + u8 mask; +}; + /** * struct st_sensor_data_ready_irq - ST sensor device data-ready interrupt * @addr: address of the register. @@ -185,6 +195,7 @@ struct st_sensor_transfer_function { * @enable_axis: Enable one or more axis of the sensor. * @fs: Full scale register and full scale list available. * @bdu: Block data update register. + * @das: Data Alignment Selection register. * @drdy_irq: Data ready register of the sensor. * @multi_read_bit: Use or not particular bit for [I2C/SPI] multi-read. * @bootime: samples to discard when sensor passing from power-down to power-up. @@ -200,6 +211,7 @@ struct st_sensor_settings { struct st_sensor_axis enable_axis; struct st_sensor_fullscale fs; struct st_sensor_bdu bdu; + struct st_sensor_das das; struct st_sensor_data_ready_irq drdy_irq; bool multi_read_bit; unsigned int bootime;