Minimal implementation of an IIO driver for the Sensortek STK8312 3-axis accelerometer. Datasheet: http://www.syi-group.com/uploadpic/data/201361817562681623.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> --- drivers/iio/accel/Kconfig | 11 ++ drivers/iio/accel/Makefile | 2 + drivers/iio/accel/stk8312.c | 375 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 388 insertions(+) create mode 100644 drivers/iio/accel/stk8312.c diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig index 7c9a9a9..8bd8ccb 100644 --- a/drivers/iio/accel/Kconfig +++ b/drivers/iio/accel/Kconfig @@ -136,4 +136,15 @@ config MMA9553 To compile this driver as a module, choose M here: the module will be called mma9553. + +config STK8312 + tristate "Sensortek STK8312 3-Axis Accelerometer Driver" + depends on I2C + help + Say yes here to get support for the Sensortek STK8312 3-axis + accelerometer. + + Choosing M will build the driver as a module. If so, the module + will be called stk8312. + endmenu diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile index 99d89e4..8b327c1 100644 --- a/drivers/iio/accel/Makefile +++ b/drivers/iio/accel/Makefile @@ -14,6 +14,8 @@ obj-$(CONFIG_MMA9551_CORE) += mma9551_core.o obj-$(CONFIG_MMA9551) += mma9551.o obj-$(CONFIG_MMA9553) += mma9553.o +obj-$(CONFIG_STK8312) += stk8312.o + obj-$(CONFIG_IIO_SSP_SENSORS_COMMONS) += ssp_accel_sensor.o obj-$(CONFIG_IIO_ST_ACCEL_3AXIS) += st_accel.o diff --git a/drivers/iio/accel/stk8312.c b/drivers/iio/accel/stk8312.c new file mode 100644 index 0000000..ff27e6b --- /dev/null +++ b/drivers/iio/accel/stk8312.c @@ -0,0 +1,375 @@ +/** + * Sensortek STK8312 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. + * + * IIO driver for STK8312; 7-bit I2C address: 0x3D. + */ + +#include <linux/acpi.h> +#include <linux/i2c.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#define STK8312_REG_XOUT 0x00 +#define STK8312_REG_YOUT 0x01 +#define STK8312_REG_ZOUT 0x02 +#define STK8312_REG_MODE 0x07 +#define STK8312_REG_STH 0x13 +#define STK8312_REG_RESET 0x20 + +#define STK8312_MODE_ACTIVE 1 +#define STK8312_MODE_STANDBY 0 +#define STK8312_MODE_MASK 0x01 +#define STK8312_RNG_MASK 0xC0 +#define STK8312_ALERT_MASK 0x40 +#define STK8312_DATA6_MASK 0x3F +#define STK8312_RNG_SHIFT 6 +#define STK8312_READ_RETRIES 16 + +#define STK8312_DRIVER_NAME "stk8312" + +#define STK8312_SCALE_AVAIL "0.4747 0.4632 1.2354" + +static const int stk8312_scale_table[][2] = { + {0, 474700}, {0, 463200}, {1, 235400} +}; + +#define STK8312_ACCEL_CHANNEL(axis) { \ + .type = IIO_ACCEL, \ + .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 stk8312_channels[] = { + STK8312_ACCEL_CHANNEL(X), + STK8312_ACCEL_CHANNEL(Y), + STK8312_ACCEL_CHANNEL(Z), +}; + +struct stk8312_data { + struct i2c_client *client; + struct mutex lock; + int range; + u8 mode; +}; + +static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL); + +static struct attribute *stk8312_attributes[] = { + &iio_const_attr_in_accel_scale_available.dev_attr.attr, + NULL, +}; + +static const struct attribute_group stk8312_attribute_group = { + .attrs = stk8312_attributes +}; + +static int stk8312_set_mode(struct stk8312_data *data, u8 mode) +{ + int ret; + u8 masked_reg; + struct i2c_client *client = data->client; + + if (mode > 1) + return -EINVAL; + else if (mode == data->mode) + return 0; + + ret = i2c_smbus_read_byte_data(client, STK8312_REG_MODE); + if (ret < 0) { + dev_err(&client->dev, "register read failed\n"); + return ret; + } + masked_reg = ret & (~STK8312_MODE_MASK); + masked_reg |= mode; + + ret = i2c_smbus_write_byte_data(client, STK8312_REG_MODE, + masked_reg); + if (ret < 0) + dev_err(&client->dev, "failed to change sensor mode\n"); + else + data->mode = mode; + + return ret; +} + +static int stk8312_set_range(struct stk8312_data *data, u8 range) +{ + int ret; + int masked_reg; + u8 mode; + struct i2c_client *client = data->client; + + if (range < 0 || range > 2) + return -EINVAL; + + if (range == data->range) + return 0; + + mode = data->mode; + /* We need to go in standby mode to modify registers */ + ret = stk8312_set_mode(data, STK8312_MODE_STANDBY); + if (ret < 0) + return ret; + + ret = i2c_smbus_read_byte_data(client, STK8312_REG_STH); + if (ret < 0) { + dev_err(&client->dev, "register read failed\n"); + return ret; + } + + masked_reg = ret & (~STK8312_RNG_MASK); + masked_reg |= range << STK8312_RNG_SHIFT; + + ret = i2c_smbus_write_byte_data(client, STK8312_REG_STH, masked_reg); + if (ret < 0) + dev_err(&client->dev, "failed to change sensor range\n"); + else + data->range = range; + + return stk8312_set_mode(data, mode); +} + +static int stk8312_read_accel(struct stk8312_data *data, int axis) +{ + int ret; + u8 reg; + int retries = STK8312_READ_RETRIES; + struct i2c_client *client = data->client; + + switch (axis) { + case IIO_MOD_X: + reg = STK8312_REG_XOUT; + break; + case IIO_MOD_Y: + reg = STK8312_REG_YOUT; + break; + case IIO_MOD_Z: + reg = STK8312_REG_ZOUT; + break; + default: + return -EINVAL; + } + + ret = i2c_smbus_read_byte_data(client, reg); + if (ret < 0) { + dev_err(&client->dev, "register read failed\n"); + return ret; + } + if (data->range == 0) { + /* 6bit mode */ + while (retries--) { + if (ret & STK8312_ALERT_MASK) { + /* The register is being updated. Try again. */ + msleep(20); + ret = i2c_smbus_read_byte_data(client, reg); + if (ret < 0) { + dev_err(&data->client->dev, + "register read failed\n"); + return ret; + } + } else { + ret &= STK8312_DATA6_MASK; + return sign_extend32(ret, 5); + } + } + dev_err(&data->client->dev, + "register read failed, data not ready\n"); + return -EIO; + } + /* 8bit mode */ + return sign_extend32(ret, 7); +} + +static int stk8312_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct stk8312_data *data = iio_priv(indio_dev); + + if (chan->type != IIO_ACCEL) + return -EINVAL; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + *val = stk8312_read_accel(data, chan->channel2); + mutex_unlock(&data->lock); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = stk8312_scale_table[data->range][0]; + *val2 = stk8312_scale_table[data->range][1]; + return IIO_VAL_INT_PLUS_MICRO; + } + + return -EINVAL; +} + +static int stk8312_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + int i; + int index = -1; + int ret; + struct stk8312_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SCALE: + for (i = 0; i < ARRAY_SIZE(stk8312_scale_table); i++) + if (val == stk8312_scale_table[i][0] && + val2 == stk8312_scale_table[i][1]) { + index = i; + break; + } + if (index < 0) + return -EINVAL; + + mutex_lock(&data->lock); + ret = stk8312_set_range(data, index); + mutex_unlock(&data->lock); + + return ret; + } + + return -EINVAL; +} + +static const struct iio_info stk8312_info = { + .driver_module = THIS_MODULE, + .read_raw = stk8312_read_raw, + .write_raw = stk8312_write_raw, + .attrs = &stk8312_attribute_group, +}; + +static int stk8312_init(struct iio_dev *indio_dev) +{ + int ret; + struct stk8312_data *data = iio_priv(indio_dev); + struct i2c_client *client = data->client; + + /* A software reset is recommended at power-on */ + ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_RESET, 0x00); + if (ret < 0) + dev_err(&client->dev, "failed to reset sensor"); + + ret = stk8312_set_mode(data, STK8312_MODE_ACTIVE); + if (ret < 0) + dev_err(&client->dev, "failed to enable sensor"); + + return ret; +} + +static int stk8312_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + int ret; + struct iio_dev *indio_dev; + struct stk8312_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 = &stk8312_info; + indio_dev->name = STK8312_DRIVER_NAME; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = stk8312_channels; + indio_dev->num_channels = ARRAY_SIZE(stk8312_channels); + + ret = stk8312_init(indio_dev); + if (ret < 0) { + dev_err(&client->dev, "sensor initialization failed\n"); + return ret; + } + + ret = iio_device_register(indio_dev); + if (ret < 0) { + dev_err(&client->dev, "device_register failed\n"); + stk8312_set_mode(data, STK8312_MODE_STANDBY); + } + + return ret; +} + +static int stk8312_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + + iio_device_unregister(indio_dev); + + return stk8312_set_mode(iio_priv(indio_dev), STK8312_MODE_STANDBY); +} + +#ifdef CONFIG_PM_SLEEP +static int stk8312_suspend(struct device *dev) +{ + struct stk8312_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return stk8312_set_mode(data, STK8312_MODE_STANDBY); +} + +static int stk8312_resume(struct device *dev) +{ + struct stk8312_data *data; + + data = iio_priv(i2c_get_clientdata(to_i2c_client(dev))); + + return stk8312_set_mode(data, STK8312_MODE_ACTIVE); +} + +static SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend, stk8312_resume); + +#define STK8312_PM_OPS (&stk8312_pm_ops) +#else +#define STK8312_PM_OPS NULL +#endif + +static const struct i2c_device_id stk8312_i2c_id[] = { + {"STK8312", 0}, + {} +}; + +static const struct acpi_device_id stk8312_acpi_id[] = { + {"STK8312", 0}, + {} +}; + +MODULE_DEVICE_TABLE(acpi, stk8312_acpi_id); + +static struct i2c_driver stk8312_driver = { + .driver = { + .name = "stk8312", + .pm = STK8312_PM_OPS, + .acpi_match_table = ACPI_PTR(stk8312_acpi_id), + }, + .probe = stk8312_probe, + .remove = stk8312_remove, + .id_table = stk8312_i2c_id, +}; + +module_i2c_driver(stk8312_driver); + +MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@xxxxxxxxx>"); +MODULE_DESCRIPTION("STK8312 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
