Minimal implementation of an IIO driver for the Sensortek STK8BA50 3-axis accelerometer. Datasheet: http://szgsensor.com/uploads/soft/141229/STK8BA50%D2%E5%BC%CE.pdf Includes: - ACPI support; - read_raw for x,y,z axes; - reading and setting the scale (range) parameter. - power management Signed-off-by: Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx> --- Change log: v2: - addressed Peter & Jon's comments - changed the way read_accel reads data - renamed set_mode to set_power and changed its implementation --- drivers/iio/accel/Kconfig | 10 ++ drivers/iio/accel/Makefile | 1 + drivers/iio/accel/stk8ba50.c | 305 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 316 insertions(+) create mode 100644 drivers/iio/accel/stk8ba50.c diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig index 8bd8ccb..00e7bcb 100644 --- a/drivers/iio/accel/Kconfig +++ b/drivers/iio/accel/Kconfig @@ -147,4 +147,14 @@ config STK8312 Choosing M will build the driver as a module. If so, the module will be called stk8312. +config STK8BA50 + tristate "Sensortek STK8BA50 3-Axis Accelerometer Driver" + depends on I2C + help + Say yes here to get support for the Sensortek STK8BA50 3-axis + accelerometer. + + Choosing M will build the driver as a module. If so, the module + will be called stk8ba50. + endmenu diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile index 8b327c1..ebd2675 100644 --- a/drivers/iio/accel/Makefile +++ b/drivers/iio/accel/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_MMA9551) += mma9551.o obj-$(CONFIG_MMA9553) += mma9553.o obj-$(CONFIG_STK8312) += stk8312.o +obj-$(CONFIG_STK8BA50) += stk8ba50.o obj-$(CONFIG_IIO_SSP_SENSORS_COMMONS) += ssp_accel_sensor.o diff --git a/drivers/iio/accel/stk8ba50.c b/drivers/iio/accel/stk8ba50.c new file mode 100644 index 0000000..8ac2a3b --- /dev/null +++ b/drivers/iio/accel/stk8ba50.c @@ -0,0 +1,305 @@ +/** + * Sensortek STK8BA50 3-Axis Accelerometer + * + * Copyright (c) 2015, Intel Corporation. + * + * This file is subject to the terms and conditions of version 2 of + * the GNU General Public License. See the file COPYING in the main + * directory of this archive for more details. + * + * STK8BA50 7-bit I2C address: 0x18. + */ + +#include <linux/acpi.h> +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define STK8BA50_REG_XOUT 0x02 +#define STK8BA50_REG_YOUT 0x04 +#define STK8BA50_REG_ZOUT 0x06 +#define STK8BA50_REG_RANGE 0x0F +#define STK8BA50_REG_POWMODE 0x11 +#define STK8BA50_REG_SWRST 0x14 + +#define STK8BA50_MODE_NORMAL 0 +#define STK8BA50_MODE_SUSPEND 1 +#define STK8BA50_MODE_POWERBIT BIT(7) +#define STK8BA50_DATA_SHIFT 6 +#define STK8BA50_RESET_CMD 0xB6 + +#define STK8BA50_DRIVER_NAME "stk8ba50" + +#define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069" + +/* + * The accelerometer has four measurement ranges: + * +/-2g; +/-4g; +/-8g; +/-16g + * + * Acceleration values are 10-bit, 2's complement. + * Scales are calculated as following: + * + * scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384 + * scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767 + * etc. + * + * Scales are stored in this format: + * { <register value>, <scale value> } + * + * Locally, the range is stored as a table index. + */ +static const int stk8ba50_scale_table[][2] = { + {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900} +}; + +struct stk8ba50_data { + struct i2c_client *client; + struct mutex lock; + int range; +}; + +#define STK8BA50_ACCEL_CHANNEL(reg, axis) { \ + .type = IIO_ACCEL, \ + .address = reg, \ + .modified = 1, \ + .channel2 = IIO_MOD_##axis, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +static const struct iio_chan_spec stk8ba50_channels[] = { + STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_XOUT, X), + STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_YOUT, Y), + STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_ZOUT, Z), +}; + +static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL); + +static struct attribute *stk8ba50_attributes[] = { + &iio_const_attr_in_accel_scale_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group stk8ba50_attribute_group = { + .attrs = stk8ba50_attributes +}; + +static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg) +{ + int ret; + struct i2c_client *client = data->client; + + ret = i2c_smbus_read_word_data(client, reg); + if (ret < 0) { + dev_err(&client->dev, "register read failed\n"); + return ret; + } + + return sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9); +} + +static int stk8ba50_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct stk8ba50_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + *val = stk8ba50_read_accel(data, chan->address); + mutex_unlock(&data->lock); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = stk8ba50_scale_table[data->range][1]; + return IIO_VAL_INT_PLUS_MICRO; + } + + return -EINVAL; +} + +static int stk8ba50_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + int ret; + int i; + int index = -1; + struct stk8ba50_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SCALE: + if (val != 0) + return -EINVAL; + + for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++) + if (val2 == stk8ba50_scale_table[i][1]) { + index = i; + break; + } + if (index < 0) + return -EINVAL; + + ret = i2c_smbus_write_byte_data(data->client, + STK8BA50_REG_RANGE, + stk8ba50_scale_table[index][0]); + if (ret < 0) + dev_err(&data->client->dev, + "failed to set measurement range\n"); + else + data->range = index; + + return ret; + } + + return -EINVAL; +} + +static const struct iio_info stk8ba50_info = { + .driver_module = THIS_MODULE, + .read_raw = stk8ba50_read_raw, + .write_raw = stk8ba50_write_raw, + .attrs = &stk8ba50_attribute_group, +}; + +static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode) +{ + int ret; + u8 masked_reg; + struct i2c_client *client = data->client; + + if (mode > 1) + return -EINVAL; + + ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE); + if (ret < 0) + goto exit_err; + + if (mode) + masked_reg = ret | STK8BA50_MODE_POWERBIT; + else + masked_reg = ret & (~STK8BA50_MODE_POWERBIT); + + ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE, + masked_reg); + if (ret < 0) + goto exit_err; + + return ret; + +exit_err: + dev_err(&client->dev, "failed to change sensor mode\n"); + return ret; +} + +static int stk8ba50_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int ret; + struct iio_dev *indio_dev; + struct stk8ba50_data *data; + + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); + if (!indio_dev) { + dev_err(&client->dev, "iio allocation failed!\n"); + return -ENOMEM; + } + + data = iio_priv(indio_dev); + data->client = client; + i2c_set_clientdata(client, indio_dev); + mutex_init(&data->lock); + + indio_dev->dev.parent = &client->dev; + indio_dev->info = &stk8ba50_info; + indio_dev->name = STK8BA50_DRIVER_NAME; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = stk8ba50_channels; + indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels); + + /* Reset all registers on startup */ + ret = i2c_smbus_write_byte_data(client, + STK8BA50_REG_SWRST, STK8BA50_RESET_CMD); + if (ret < 0) { + dev_err(&client->dev, "failed to reset sensor\n"); + return ret; + } + + /* The default range is +/-2g */ + data->range = 0; + + ret = iio_device_register(indio_dev); + if (ret < 0) { + dev_err(&client->dev, "device_register failed\n"); + stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND); + } + + return ret; +} + +static int stk8ba50_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + + iio_device_unregister(indio_dev); + + return stk8ba50_set_power(iio_priv(indio_dev), STK8BA50_MODE_SUSPEND); +} + +#ifdef CONFIG_PM_SLEEP +static int stk8ba50_suspend(struct device *dev) +{ + struct stk8ba50_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND); +} + +static int stk8ba50_resume(struct device *dev) +{ + struct stk8ba50_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL); +} + +static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume); + +#define STK8BA50_PM_OPS (&stk8ba50_pm_ops) +#else +#define STK8BA50_PM_OPS NULL +#endif + +static const struct i2c_device_id stk8ba50_i2c_id[] = { + {"stk8ba50", 0}, + {} +}; + +static const struct acpi_device_id stk8ba50_acpi_id[] = { + {"STK8BA50", 0}, + {} +}; + +MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id); + +static struct i2c_driver stk8ba50_driver = { + .driver = { + .name = "stk8ba50", + .pm = STK8BA50_PM_OPS, + .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id), + }, + .probe = stk8ba50_probe, + .remove = stk8ba50_remove, + .id_table = stk8ba50_i2c_id, +}; + +module_i2c_driver(stk8ba50_driver); + +MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx>"); +MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver"); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- 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
