On 06/05/15 09:16, Tiberiu Breana wrote: > 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> I'm happy with this appart from the question I raised on what the scale factors 'really' are given inconsistencies in the description on the datasheet. > --- > drivers/iio/accel/Kconfig | 11 ++ > drivers/iio/accel/Makefile | 2 + > drivers/iio/accel/stk8312.c | 364 ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 377 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..708fff4 > --- /dev/null > +++ b/drivers/iio/accel/stk8312.c > @@ -0,0 +1,364 @@ > +/** > + * 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 0.4634 1.2359" > + > +static const int stk8312_scale_table[][2] = { > + {0, 474700}, {0, 463200}, {1, 235400} > +}; > + > +#define STK8312_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 stk8312_channels[] = { > + STK8312_ACCEL_CHANNEL(STK8312_REG_XOUT, X), > + STK8312_ACCEL_CHANNEL(STK8312_REG_YOUT, Y), > + STK8312_ACCEL_CHANNEL(STK8312_REG_ZOUT, 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, "failed to change sensor mode\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; > + u8 masked_reg; > + u8 mode; > + struct i2c_client *client = data->client; > + > + if (range > 2) > + return -EINVAL; > + else 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, "failed to change sensor range\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, u8 address) > +{ > + int ret; > + u8 reg; > + int retries = STK8312_READ_RETRIES; > + struct i2c_client *client = data->client; > + > + if (address > 2) > + return -EINVAL; > + > + ret = i2c_smbus_read_byte_data(client, address); > + 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->address); > + 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"); > + return ret; > + } > + > + 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) > + 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"); 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