1 files changed, 302 insertions, 0 deletions

diff --git a/drivers/iio/accel/stk8ba50.c b/drivers/iio/accel/stk8ba50.c
new file mode 100644
index 000000000000..30950c6b36de
--- /dev/null
+++ b/drivers/iio/accel/stk8ba50.c
@@ -0,0 +1,302 @@
+/**
+ * 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;
+
+        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@intel.com>");
+MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
+MODULE_LICENSE("GPL v2");