3 files changed, 337 insertions, 0 deletions

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index 05a364c543f8..b2dba9e506ab 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -17,6 +17,16 @@ config AK8975
           To compile this driver as a module, choose M here: the module
           will be called ak8975.
 
+config AK09911
+        tristate "Asahi Kasei AK09911 3-axis Compass"
+        depends on I2C
+        help
+          Say yes here to build support for Asahi Kasei AK09911 3-Axis
+          Magnetometer.
+
+          To compile this driver as a module, choose M here: the module
+          will be called ak09911.
+
 config MAG3110
         tristate "Freescale MAG3110 3-Axis Magnetometer"
         depends on I2C
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index 0f5d3c985799..b91315e0b826 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -3,6 +3,7 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-$(CONFIG_AK09911)   += ak09911.o
 obj-$(CONFIG_AK8975)    += ak8975.o
 obj-$(CONFIG_MAG3110)   += mag3110.o
 obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
diff --git a/drivers/iio/magnetometer/ak09911.c b/drivers/iio/magnetometer/ak09911.c
new file mode 100644
index 000000000000..b2bc942ff6b8
--- /dev/null
+++ b/drivers/iio/magnetometer/ak09911.c
@@ -0,0 +1,326 @@
+/*
+ * AK09911 3-axis compass driver
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/iio/iio.h>
+
+#define AK09911_REG_WIA1                0x00
+#define AK09911_REG_WIA2                0x01
+#define AK09911_WIA1_VALUE              0x48
+#define AK09911_WIA2_VALUE              0x05
+
+#define AK09911_REG_ST1                 0x10
+#define AK09911_REG_HXL                 0x11
+#define AK09911_REG_HXH                 0x12
+#define AK09911_REG_HYL                 0x13
+#define AK09911_REG_HYH                 0x14
+#define AK09911_REG_HZL                 0x15
+#define AK09911_REG_HZH                 0x16
+
+#define AK09911_REG_ASAX                0x60
+#define AK09911_REG_ASAY                0x61
+#define AK09911_REG_ASAZ                0x62
+
+#define AK09911_REG_CNTL1               0x30
+#define AK09911_REG_CNTL2               0x31
+#define AK09911_REG_CNTL3               0x32
+
+#define AK09911_MODE_SNG_MEASURE        0x01
+#define AK09911_MODE_SELF_TEST          0x10
+#define AK09911_MODE_FUSE_ACCESS        0x1F
+#define AK09911_MODE_POWERDOWN          0x00
+#define AK09911_RESET_DATA              0x01
+
+#define AK09911_REG_CNTL1               0x30
+#define AK09911_REG_CNTL2               0x31
+#define AK09911_REG_CNTL3               0x32
+
+#define AK09911_RAW_TO_GAUSS(asa)       ((((asa) + 128) * 6000) / 256)
+
+#define AK09911_MAX_CONVERSION_TIMEOUT_MS       500
+#define AK09911_CONVERSION_DONE_POLL_TIME_MS    10
+
+struct ak09911_data {
+        struct i2c_client       *client;
+        struct mutex            lock;
+        u8                      asa[3];
+        long                    raw_to_gauss[3];
+};
+
+static const int ak09911_index_to_reg[] = {
+        AK09911_REG_HXL, AK09911_REG_HYL, AK09911_REG_HZL,
+};
+
+static int ak09911_set_mode(struct i2c_client *client, u8 mode)
+{
+        int ret;
+
+        switch (mode) {
+        case AK09911_MODE_SNG_MEASURE:
+        case AK09911_MODE_SELF_TEST:
+        case AK09911_MODE_FUSE_ACCESS:
+        case AK09911_MODE_POWERDOWN:
+                ret = i2c_smbus_write_byte_data(client,
+                                                AK09911_REG_CNTL2, mode);
+                if (ret < 0) {
+                        dev_err(&client->dev, "set_mode error\n");
+                        return ret;
+                }
+                /* After mode change wait atleast 100us */
+                usleep_range(100, 500);
+                break;
+        default:
+                dev_err(&client->dev,
+                        "%s: Unknown mode(%d).", __func__, mode);
+                return -EINVAL;
+        }
+
+        return ret;
+}
+
+/* Get Sensitivity Adjustment value */
+static int ak09911_get_asa(struct i2c_client *client)
+{
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+        struct ak09911_data *data = iio_priv(indio_dev);
+        int ret;
+
+        ret = ak09911_set_mode(client, AK09911_MODE_FUSE_ACCESS);
+        if (ret < 0)
+                return ret;
+
+        /* Get asa data and store in the device data. */
+        ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_ASAX,
+                                            3, data->asa);
+        if (ret < 0) {
+                dev_err(&client->dev, "Not able to read asa data\n");
+                return ret;
+        }
+
+        ret = ak09911_set_mode(client,  AK09911_MODE_POWERDOWN);
+        if (ret < 0)
+                return ret;
+
+        data->raw_to_gauss[0] = AK09911_RAW_TO_GAUSS(data->asa[0]);
+        data->raw_to_gauss[1] = AK09911_RAW_TO_GAUSS(data->asa[1]);
+        data->raw_to_gauss[2] = AK09911_RAW_TO_GAUSS(data->asa[2]);
+
+        return 0;
+}
+
+static int ak09911_verify_chip_id(struct i2c_client *client)
+{
+        u8 wia_val[2];
+        int ret;
+
+        ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_WIA1,
+                                            2, wia_val);
+        if (ret < 0) {
+                dev_err(&client->dev, "Error reading WIA\n");
+                return ret;
+        }
+
+        dev_dbg(&client->dev, "WIA %02x %02x\n", wia_val[0], wia_val[1]);
+
+        if (wia_val[0] != AK09911_WIA1_VALUE ||
+                wia_val[1] != AK09911_WIA2_VALUE) {
+                dev_err(&client->dev, "Device ak09911 not found\n");
+                return -ENODEV;
+        }
+
+        return 0;
+}
+
+static int wait_conversion_complete_polled(struct ak09911_data *data)
+{
+        struct i2c_client *client = data->client;
+        u8 read_status;
+        u32 timeout_ms = AK09911_MAX_CONVERSION_TIMEOUT_MS;
+        int ret;
+
+        /* Wait for the conversion to complete. */
+        while (timeout_ms) {
+                msleep_interruptible(AK09911_CONVERSION_DONE_POLL_TIME_MS);
+                ret = i2c_smbus_read_byte_data(client, AK09911_REG_ST1);
+                if (ret < 0) {
+                        dev_err(&client->dev, "Error in reading ST1\n");
+                        return ret;
+                }
+                read_status = ret & 0x01;
+                if (read_status)
+                        break;
+                timeout_ms -= AK09911_CONVERSION_DONE_POLL_TIME_MS;
+        }
+        if (!timeout_ms) {
+                dev_err(&client->dev, "Conversion timeout happened\n");
+                return -EIO;
+        }
+
+        return read_status;
+}
+
+static int ak09911_read_axis(struct iio_dev *indio_dev, int index, int *val)
+{
+        struct ak09911_data *data = iio_priv(indio_dev);
+        struct i2c_client *client = data->client;
+        int ret;
+
+        mutex_lock(&data->lock);
+
+        ret = ak09911_set_mode(client, AK09911_MODE_SNG_MEASURE);
+        if (ret < 0)
+                goto fn_exit;
+
+        ret = wait_conversion_complete_polled(data);
+        if (ret < 0)
+                goto fn_exit;
+
+        /* Read data */
+        ret = i2c_smbus_read_word_data(client, ak09911_index_to_reg[index]);
+        if (ret < 0) {
+                dev_err(&client->dev, "Read axis data fails\n");
+                goto fn_exit;
+        }
+
+        mutex_unlock(&data->lock);
+
+        /* Clamp to valid range. */
+        *val = sign_extend32(clamp_t(s16, ret, -8192, 8191), 13);
+
+        return IIO_VAL_INT;
+
+fn_exit:
+        mutex_unlock(&data->lock);
+
+        return ret;
+}
+
+static int ak09911_read_raw(struct iio_dev *indio_dev,
+                            struct iio_chan_spec const *chan,
+                            int *val, int *val2,
+                            long mask)
+{
+        struct ak09911_data *data = iio_priv(indio_dev);
+
+        switch (mask) {
+        case IIO_CHAN_INFO_RAW:
+                return ak09911_read_axis(indio_dev, chan->address, val);
+        case IIO_CHAN_INFO_SCALE:
+                *val = 0;
+                *val2 = data->raw_to_gauss[chan->address];
+                return IIO_VAL_INT_PLUS_MICRO;
+        }
+
+        return -EINVAL;
+}
+
+#define AK09911_CHANNEL(axis, index)                                    \
+        {                                                               \
+                .type = IIO_MAGN,                                       \
+                .modified = 1,                                          \
+                .channel2 = IIO_MOD_##axis,                             \
+                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
+                             BIT(IIO_CHAN_INFO_SCALE),                  \
+                .address = index,                                       \
+        }
+
+static const struct iio_chan_spec ak09911_channels[] = {
+        AK09911_CHANNEL(X, 0), AK09911_CHANNEL(Y, 1), AK09911_CHANNEL(Z, 2),
+};
+
+static const struct iio_info ak09911_info = {
+        .read_raw = &ak09911_read_raw,
+        .driver_module = THIS_MODULE,
+};
+
+static const struct acpi_device_id ak_acpi_match[] = {
+        {"AK009911", 0},
+        { },
+};
+MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
+
+static int ak09911_probe(struct i2c_client *client,
+                         const struct i2c_device_id *id)
+{
+        struct iio_dev *indio_dev;
+        struct ak09911_data *data;
+        const char *name;
+        int ret;
+
+        ret = ak09911_verify_chip_id(client);
+        if (ret) {
+                dev_err(&client->dev, "AK00911 not detected\n");
+                return -ENODEV;
+        }
+
+        indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
+        if (indio_dev == NULL)
+                return -ENOMEM;
+
+        data = iio_priv(indio_dev);
+        i2c_set_clientdata(client, indio_dev);
+
+        data->client = client;
+        mutex_init(&data->lock);
+
+        ret = ak09911_get_asa(client);
+        if (ret)
+                return ret;
+
+        if (id)
+                name = id->name;
+        else if (ACPI_HANDLE(&client->dev))
+                name = dev_name(&client->dev);
+        else
+                return -ENODEV;
+
+        dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
+
+        indio_dev->dev.parent = &client->dev;
+        indio_dev->channels = ak09911_channels;
+        indio_dev->num_channels = ARRAY_SIZE(ak09911_channels);
+        indio_dev->info = &ak09911_info;
+        indio_dev->modes = INDIO_DIRECT_MODE;
+        indio_dev->name = name;
+
+        return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id ak09911_id[] = {
+        {"ak09911", 0},
+        {}
+};
+
+MODULE_DEVICE_TABLE(i2c, ak09911_id);
+
+static struct i2c_driver ak09911_driver = {
+        .driver = {
+                .name   = "ak09911",
+                .acpi_match_table = ACPI_PTR(ak_acpi_match),
+        },
+        .probe          = ak09911_probe,
+        .id_table       = ak09911_id,
+};
+module_i2c_driver(ak09911_driver);
+
+MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("AK09911 Compass driver");