diff options
Diffstat (limited to 'drivers/iio/accel/stk8312.c')
| -rw-r--r-- | drivers/iio/accel/stk8312.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/drivers/iio/accel/stk8312.c b/drivers/iio/accel/stk8312.c new file mode 100644 index 000000000000..d211d9f3975b --- /dev/null +++ b/drivers/iio/accel/stk8312.c @@ -0,0 +1,390 @@ +/** + * 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_REG_AFECTRL 0x24 +#define STK8312_REG_OTPADDR 0x3D +#define STK8312_REG_OTPDATA 0x3E +#define STK8312_REG_OTPCTRL 0x3F + +#define STK8312_MODE_ACTIVE 1 +#define STK8312_MODE_STANDBY 0 +#define STK8312_MODE_MASK 0x01 +#define STK8312_RNG_MASK 0xC0 +#define STK8312_RNG_SHIFT 6 +#define STK8312_READ_RETRIES 16 + +#define STK8312_DRIVER_NAME "stk8312" + +/* + * The accelerometer has two measurement ranges: + * + * -6g - +6g (8-bit, signed) + * -16g - +16g (8-bit, signed) + * + * scale1 = (6 + 6) * 9.81 / (2^8 - 1) = 0.4616 + * scale2 = (16 + 16) * 9.81 / (2^8 - 1) = 1.2311 + */ +#define STK8312_SCALE_AVAIL "0.4616 1.2311" + +static const int stk8312_scale_table[][2] = { + {0, 461600}, {1, 231100} +}; + +#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_otp_init(struct stk8312_data *data) +{ + int ret; + int count = 10; + struct i2c_client *client = data->client; + + ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPADDR, 0x70); + if (ret < 0) + goto exit_err; + ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPCTRL, 0x02); + if (ret < 0) + goto exit_err; + + do { + usleep_range(1000, 5000); + ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPCTRL); + if (ret < 0) + goto exit_err; + count--; + } while (!(ret & 0x80) && count > 0); + + if (count == 0) + goto exit_err; + + ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPDATA); + if (ret < 0) + goto exit_err; + + ret = i2c_smbus_write_byte_data(data->client, + STK8312_REG_AFECTRL, ret); + if (ret < 0) + goto exit_err; + msleep(150); + + return ret; + +exit_err: + dev_err(&client->dev, "failed to initialize sensor\n"); + return ret; +} + +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"); + return ret; + } + + data->mode = mode; + if (mode == STK8312_MODE_ACTIVE) { + /* Need to run OTP sequence before entering active mode */ + usleep_range(1000, 5000); + ret = stk8312_otp_init(data); + } + + 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 != 1 && 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; + 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; + } + + 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 - 1][0]; + *val2 = stk8312_scale_table[data->range - 1][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 + 1; + 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_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); + + /* 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\n"); + return ret; + } + ret = stk8312_set_range(data, 1); + if (ret < 0) + return ret; + + ret = stk8312_set_mode(data, STK8312_MODE_ACTIVE); + 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@intel.com>"); +MODULE_DESCRIPTION("STK8312 3-Axis Accelerometer driver"); +MODULE_LICENSE("GPL v2"); |