This driver has been clean and correct for quite some time.
It is simple and uses only straight forward standard
interfaces.
Signed-off-by: Jonathan Cameron <jic23@xxxxxxxxxx>
---
drivers/iio/magnetometer/Kconfig | 11 +
drivers/iio/magnetometer/Makefile | 1 +
drivers/iio/magnetometer/ak8975.c | 520 ++++++++++++++++++++++++++++++
drivers/staging/iio/magnetometer/Kconfig | 11 -
drivers/staging/iio/magnetometer/Makefile | 1 -
drivers/staging/iio/magnetometer/ak8975.c | 520 ------------------------------
6 files changed, 532 insertions(+), 532 deletions(-)
diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index cd29be5..1087709 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -3,6 +3,17 @@
#
menu "Magnetometer sensors"
+config SENSORS_AK8975
+ tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
+ depends on I2C
+ depends on GPIOLIB
+ help
+ Say yes here to build support for Asahi Kasei AK8975 3-Axis
+ Magnetometer.
+
+ To compile this driver as a module, choose M here: the module
+ will be called ak8975.
+
config HID_SENSOR_MAGNETOMETER_3D
depends on HID_SENSOR_HUB
select IIO_BUFFER
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index e786728..2c6fa7f 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -2,6 +2,7 @@
# Makefile for industrial I/O Magnetometer sensor drivers
#
+obj-$(CONFIG_SENSORS_AK8975) += ak8975.o
obj-$(CONFIG_HID_SENSOR_MAGNETOMETER_3D) += hid-sensor-magn-3d.o
obj-$(CONFIG_IIO_ST_MAGN_3AXIS) += st_magn.o
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
new file mode 100644
index 0000000..28f080e
--- /dev/null
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -0,0 +1,520 @@
+/*
+ * A sensor driver for the magnetometer AK8975.
+ *
+ * Magnetic compass sensor driver for monitoring magnetic flux information.
+ *
+ * Copyright (c) 2010, NVIDIA Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+
+#include <linux/gpio.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+/*
+ * Register definitions, as well as various shifts and masks to get at the
+ * individual fields of the registers.
+ */
+#define AK8975_REG_WIA 0x00
+#define AK8975_DEVICE_ID 0x48
+
+#define AK8975_REG_INFO 0x01
+
+#define AK8975_REG_ST1 0x02
+#define AK8975_REG_ST1_DRDY_SHIFT 0
+#define AK8975_REG_ST1_DRDY_MASK (1 << AK8975_REG_ST1_DRDY_SHIFT)
+
+#define AK8975_REG_HXL 0x03
+#define AK8975_REG_HXH 0x04
+#define AK8975_REG_HYL 0x05
+#define AK8975_REG_HYH 0x06
+#define AK8975_REG_HZL 0x07
+#define AK8975_REG_HZH 0x08
+#define AK8975_REG_ST2 0x09
+#define AK8975_REG_ST2_DERR_SHIFT 2
+#define AK8975_REG_ST2_DERR_MASK (1 << AK8975_REG_ST2_DERR_SHIFT)
+
+#define AK8975_REG_ST2_HOFL_SHIFT 3
+#define AK8975_REG_ST2_HOFL_MASK (1 << AK8975_REG_ST2_HOFL_SHIFT)
+
+#define AK8975_REG_CNTL 0x0A
+#define AK8975_REG_CNTL_MODE_SHIFT 0
+#define AK8975_REG_CNTL_MODE_MASK (0xF << AK8975_REG_CNTL_MODE_SHIFT)
+#define AK8975_REG_CNTL_MODE_POWER_DOWN 0
+#define AK8975_REG_CNTL_MODE_ONCE 1
+#define AK8975_REG_CNTL_MODE_SELF_TEST 8
+#define AK8975_REG_CNTL_MODE_FUSE_ROM 0xF
+
+#define AK8975_REG_RSVC 0x0B
+#define AK8975_REG_ASTC 0x0C
+#define AK8975_REG_TS1 0x0D
+#define AK8975_REG_TS2 0x0E
+#define AK8975_REG_I2CDIS 0x0F
+#define AK8975_REG_ASAX 0x10
+#define AK8975_REG_ASAY 0x11
+#define AK8975_REG_ASAZ 0x12
+
+#define AK8975_MAX_REGS AK8975_REG_ASAZ
+
+/*
+ * Miscellaneous values.
+ */
+#define AK8975_MAX_CONVERSION_TIMEOUT 500
+#define AK8975_CONVERSION_DONE_POLL_TIME 10
+
+/*
+ * Per-instance context data for the device.
+ */
+struct ak8975_data {
+ struct i2c_client *client;
+ struct attribute_group attrs;
+ struct mutex lock;
+ u8 asa[3];
+ long raw_to_gauss[3];
+ u8 reg_cache[AK8975_MAX_REGS];
+ int eoc_gpio;
+ int eoc_irq;
+};
+
+static const int ak8975_index_to_reg[] = {
+ AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL,
+};
+
+/*
+ * Helper function to write to the I2C device's registers.
+ */
+static int ak8975_write_data(struct i2c_client *client,
+ u8 reg, u8 val, u8 mask, u8 shift)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ak8975_data *data = iio_priv(indio_dev);
+ u8 regval;
+ int ret;
+
+ regval = (data->reg_cache[reg] & ~mask) | (val << shift);
+ ret = i2c_smbus_write_byte_data(client, reg, regval);
+ if (ret < 0) {
+ dev_err(&client->dev, "Write to device fails status %x\n", ret);
+ return ret;
+ }
+ data->reg_cache[reg] = regval;
+
+ return 0;
+}
+
+/*
+ * Helper function to read a contiguous set of the I2C device's registers.
+ */
+static int ak8975_read_data(struct i2c_client *client,
+ u8 reg, u8 length, u8 *buffer)
+{
+ int ret;
+ struct i2c_msg msg[2] = {
+ {
+ .addr = client->addr,
+ .flags = I2C_M_NOSTART,
+ .len = 1,
+ .buf = ®,
+ }, {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = length,
+ .buf = buffer,
+ }
+ };
+
+ ret = i2c_transfer(client->adapter, msg, 2);
+ if (ret < 0) {
+ dev_err(&client->dev, "Read from device fails\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+/*
+ * Perform some start-of-day setup, including reading the asa calibration
+ * values and caching them.
+ */
+static int ak8975_setup(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ak8975_data *data = iio_priv(indio_dev);
+ u8 device_id;
+ int ret;
+
+ /* Confirm that the device we're talking to is really an AK8975. */
+ ret = ak8975_read_data(client, AK8975_REG_WIA, 1, &device_id);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error reading WIA\n");
+ return ret;
+ }
+ if (device_id != AK8975_DEVICE_ID) {
+ dev_err(&client->dev, "Device ak8975 not found\n");
+ return -ENODEV;
+ }
+
+ /* Write the fused rom access mode. */
+ ret = ak8975_write_data(client,
+ AK8975_REG_CNTL,
+ AK8975_REG_CNTL_MODE_FUSE_ROM,
+ AK8975_REG_CNTL_MODE_MASK,
+ AK8975_REG_CNTL_MODE_SHIFT);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in setting fuse access mode\n");
+ return ret;
+ }
+
+ /* Get asa data and store in the device data. */
+ ret = ak8975_read_data(client, AK8975_REG_ASAX, 3, data->asa);
+ if (ret < 0) {
+ dev_err(&client->dev, "Not able to read asa data\n");
+ return ret;
+ }
+
+ /* After reading fuse ROM data set power-down mode */
+ ret = ak8975_write_data(client,
+ AK8975_REG_CNTL,
+ AK8975_REG_CNTL_MODE_POWER_DOWN,
+ AK8975_REG_CNTL_MODE_MASK,
+ AK8975_REG_CNTL_MODE_SHIFT);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in setting power-down mode\n");
+ return ret;
+ }
+
+/*
+ * Precalculate scale factor (in Gauss units) for each axis and
+ * store in the device data.
+ *
+ * This scale factor is axis-dependent, and is derived from 3 calibration
+ * factors ASA(x), ASA(y), and ASA(z).
+ *
+ * These ASA values are read from the sensor device at start of day, and
+ * cached in the device context struct.
+ *
+ * Adjusting the flux value with the sensitivity adjustment value should be
+ * done via the following formula:
+ *
+ * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
+ *
+ * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
+ * is the resultant adjusted value.
+ *
+ * We reduce the formula to:
+ *
+ * Hadj = H * (ASA + 128) / 256
+ *
+ * H is in the range of -4096 to 4095. The magnetometer has a range of
+ * +-1229uT. To go from the raw value to uT is:
+ *
+ * HuT = H * 1229/4096, or roughly, 3/10.
+ *
+ * Since 1uT = 100 gauss, our final scale factor becomes:
+ *
+ * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100
+ * Hadj = H * ((ASA + 128) * 30 / 256
+ *
+ * Since ASA doesn't change, we cache the resultant scale factor into the
+ * device context in ak8975_setup().
+ */
+ data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8;
+ data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8;
+ data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8;
+
+ return 0;
+}
+
+static int wait_conversion_complete_gpio(struct ak8975_data *data)
+{
+ struct i2c_client *client = data->client;
+ u8 read_status;
+ u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
+ int ret;
+
+ /* Wait for the conversion to complete. */
+ while (timeout_ms) {
+ msleep(AK8975_CONVERSION_DONE_POLL_TIME);
+ if (gpio_get_value(data->eoc_gpio))
+ break;
+ timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
+ }
+ if (!timeout_ms) {
+ dev_err(&client->dev, "Conversion timeout happened\n");
+ return -EINVAL;
+ }
+
+ ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in reading ST1\n");
+ return ret;
+ }
+ return read_status;
+}
+
+static int wait_conversion_complete_polled(struct ak8975_data *data)
+{
+ struct i2c_client *client = data->client;
+ u8 read_status;
+ u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
+ int ret;
+
+ /* Wait for the conversion to complete. */
+ while (timeout_ms) {
+ msleep(AK8975_CONVERSION_DONE_POLL_TIME);
+ ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in reading ST1\n");
+ return ret;
+ }
+ if (read_status)
+ break;
+ timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
+ }
+ if (!timeout_ms) {
+ dev_err(&client->dev, "Conversion timeout happened\n");
+ return -EINVAL;
+ }
+ return read_status;
+}
+
+/*
+ * Emits the raw flux value for the x, y, or z axis.
+ */
+static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
+{
+ struct ak8975_data *data = iio_priv(indio_dev);
+ struct i2c_client *client = data->client;
+ u16 meas_reg;
+ s16 raw;
+ u8 read_status;
+ int ret;
+
+ mutex_lock(&data->lock);
+
+ /* Set up the device for taking a sample. */
+ ret = ak8975_write_data(client,
+ AK8975_REG_CNTL,
+ AK8975_REG_CNTL_MODE_ONCE,
+ AK8975_REG_CNTL_MODE_MASK,
+ AK8975_REG_CNTL_MODE_SHIFT);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in setting operating mode\n");
+ goto exit;
+ }
+
+ /* Wait for the conversion to complete. */
+ if (gpio_is_valid(data->eoc_gpio))
+ ret = wait_conversion_complete_gpio(data);
+ else
+ ret = wait_conversion_complete_polled(data);
+ if (ret < 0)
+ goto exit;
+
+ read_status = ret;
+
+ if (read_status & AK8975_REG_ST1_DRDY_MASK) {
+ ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status);
+ if (ret < 0) {
+ dev_err(&client->dev, "Error in reading ST2\n");
+ goto exit;
+ }
+ if (read_status & (AK8975_REG_ST2_DERR_MASK |
+ AK8975_REG_ST2_HOFL_MASK)) {
+ dev_err(&client->dev, "ST2 status error 0x%x\n",
+ read_status);
+ ret = -EINVAL;
+ goto exit;
+ }
+ }
+
+ /* Read the flux value from the appropriate register
+ (the register is specified in the iio device attributes). */
+ ret = ak8975_read_data(client, ak8975_index_to_reg[index],
+ 2, (u8 *)&meas_reg);
+ if (ret < 0) {
+ dev_err(&client->dev, "Read axis data fails\n");
+ goto exit;
+ }
+
+ mutex_unlock(&data->lock);
+
+ /* Endian conversion of the measured values. */
+ raw = (s16) (le16_to_cpu(meas_reg));
+
+ /* Clamp to valid range. */
+ raw = clamp_t(s16, raw, -4096, 4095);
+ *val = raw;
+ return IIO_VAL_INT;
+
+exit:
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+static int ak8975_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2,
+ long mask)
+{
+ struct ak8975_data *data = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return ak8975_read_axis(indio_dev, chan->address, val);
+ case IIO_CHAN_INFO_SCALE:
+ *val = data->raw_to_gauss[chan->address];
+ return IIO_VAL_INT;
+ }
+ return -EINVAL;
+}
+
+#define AK8975_CHANNEL(axis, index) \
+ { \
+ .type = IIO_MAGN, \
+ .modified = 1, \
+ .channel2 = IIO_MOD_##axis, \
+ .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
+ IIO_CHAN_INFO_SCALE_SEPARATE_BIT, \
+ .address = index, \
+ }
+
+static const struct iio_chan_spec ak8975_channels[] = {
+ AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
+};
+
+static const struct iio_info ak8975_info = {
+ .read_raw = &ak8975_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int ak8975_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ak8975_data *data;
+ struct iio_dev *indio_dev;
+ int eoc_gpio;
+ int err;
+
+ /* Grab and set up the supplied GPIO. */
+ if (client->dev.platform_data == NULL)
+ eoc_gpio = -1;
+ else
+ eoc_gpio = *(int *)(client->dev.platform_data);
+
+ /* We may not have a GPIO based IRQ to scan, that is fine, we will
+ poll if so */
+ if (gpio_is_valid(eoc_gpio)) {
+ err = gpio_request_one(eoc_gpio, GPIOF_IN, "ak_8975");
+ if (err < 0) {
+ dev_err(&client->dev,
+ "failed to request GPIO %d, error %d\n",
+ eoc_gpio, err);
+ goto exit;
+ }
+ }
+
+ /* Register with IIO */
+ indio_dev = iio_device_alloc(sizeof(*data));
+ if (indio_dev == NULL) {
+ err = -ENOMEM;
+ goto exit_gpio;
+ }
+ data = iio_priv(indio_dev);
+ i2c_set_clientdata(client, indio_dev);
+ /* Perform some basic start-of-day setup of the device. */
+ err = ak8975_setup(client);
+ if (err < 0) {
+ dev_err(&client->dev, "AK8975 initialization fails\n");
+ goto exit_free_iio;
+ }
+
+ data->client = client;
+ mutex_init(&data->lock);
+ data->eoc_irq = client->irq;
+ data->eoc_gpio = eoc_gpio;
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->channels = ak8975_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
+ indio_dev->info = &ak8975_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ err = iio_device_register(indio_dev);
+ if (err < 0)
+ goto exit_free_iio;
+
+ return 0;
+
+exit_free_iio:
+ iio_device_free(indio_dev);
+exit_gpio:
+ if (gpio_is_valid(eoc_gpio))
+ gpio_free(eoc_gpio);
+exit:
+ return err;
+}
+
+static int ak8975_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ak8975_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ if (gpio_is_valid(data->eoc_gpio))
+ gpio_free(data->eoc_gpio);
+
+ iio_device_free(indio_dev);
+
+ return 0;
+}
+
+static const struct i2c_device_id ak8975_id[] = {
+ {"ak8975", 0},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, ak8975_id);
+
+static const struct of_device_id ak8975_of_match[] = {
+ { .compatible = "asahi-kasei,ak8975", },
+ { .compatible = "ak8975", },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ak8975_of_match);
+
+static struct i2c_driver ak8975_driver = {
+ .driver = {
+ .name = "ak8975",
+ .of_match_table = ak8975_of_match,
+ },
+ .probe = ak8975_probe,
+ .remove = ak8975_remove,
+ .id_table = ak8975_id,
+};
+module_i2c_driver(ak8975_driver);
+
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@xxxxxxxxxx>");
+MODULE_DESCRIPTION("AK8975 magnetometer driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/staging/iio/magnetometer/Kconfig b/drivers/staging/iio/magnetometer/Kconfig
index df5e0d4..a3ea69e 100644
--- a/drivers/staging/iio/magnetometer/Kconfig
+++ b/drivers/staging/iio/magnetometer/Kconfig
@@ -3,17 +3,6 @@
#
menu "Magnetometer sensors"
-config SENSORS_AK8975
- tristate "Asahi Kasei AK8975 3-Axis Magnetometer"
- depends on I2C
- depends on GPIOLIB
- help
- Say yes here to build support for Asahi Kasei AK8975 3-Axis
- Magnetometer.
-
- To compile this driver as a module, choose M here: the module
- will be called ak8975.
-
config SENSORS_HMC5843
tristate "Honeywell HMC5843/5883/5883L 3-Axis Magnetometer"
depends on I2C
diff --git a/drivers/staging/iio/magnetometer/Makefile b/drivers/staging/iio/magnetometer/Makefile
index f2a753f..f9bfb2e 100644
--- a/drivers/staging/iio/magnetometer/Makefile
+++ b/drivers/staging/iio/magnetometer/Makefile
@@ -2,5 +2,4 @@
# Makefile for industrial I/O Magnetometer sensors
#
-obj-$(CONFIG_SENSORS_AK8975) += ak8975.o
obj-$(CONFIG_SENSORS_HMC5843) += hmc5843.o
diff --git a/drivers/staging/iio/magnetometer/ak8975.c b/drivers/staging/iio/magnetometer/ak8975.c
deleted file mode 100644
index 28f080e..0000000
--- a/drivers/staging/iio/magnetometer/ak8975.c
+++ /dev/null
@@ -1,520 +0,0 @@
-/*
- * A sensor driver for the magnetometer AK8975.
- *
- * Magnetic compass sensor driver for monitoring magnetic flux information.
- *
- * Copyright (c) 2010, NVIDIA Corporation.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that 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.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- */
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/i2c.h>
-#include <linux/err.h>
-#include <linux/mutex.h>
-#include <linux/delay.h>
-
-#include <linux/gpio.h>
-
-#include <linux/iio/iio.h>
-#include <linux/iio/sysfs.h>
-/*
- * Register definitions, as well as various shifts and masks to get at the
- * individual fields of the registers.
- */
-#define AK8975_REG_WIA 0x00
-#define AK8975_DEVICE_ID 0x48
-
-#define AK8975_REG_INFO 0x01
-
-#define AK8975_REG_ST1 0x02
-#define AK8975_REG_ST1_DRDY_SHIFT 0
-#define AK8975_REG_ST1_DRDY_MASK (1 << AK8975_REG_ST1_DRDY_SHIFT)
-
-#define AK8975_REG_HXL 0x03
-#define AK8975_REG_HXH 0x04
-#define AK8975_REG_HYL 0x05
-#define AK8975_REG_HYH 0x06
-#define AK8975_REG_HZL 0x07
-#define AK8975_REG_HZH 0x08
-#define AK8975_REG_ST2 0x09
-#define AK8975_REG_ST2_DERR_SHIFT 2
-#define AK8975_REG_ST2_DERR_MASK (1 << AK8975_REG_ST2_DERR_SHIFT)
-
-#define AK8975_REG_ST2_HOFL_SHIFT 3
-#define AK8975_REG_ST2_HOFL_MASK (1 << AK8975_REG_ST2_HOFL_SHIFT)
-
-#define AK8975_REG_CNTL 0x0A
-#define AK8975_REG_CNTL_MODE_SHIFT 0
-#define AK8975_REG_CNTL_MODE_MASK (0xF << AK8975_REG_CNTL_MODE_SHIFT)
-#define AK8975_REG_CNTL_MODE_POWER_DOWN 0
-#define AK8975_REG_CNTL_MODE_ONCE 1
-#define AK8975_REG_CNTL_MODE_SELF_TEST 8
-#define AK8975_REG_CNTL_MODE_FUSE_ROM 0xF
-
-#define AK8975_REG_RSVC 0x0B
-#define AK8975_REG_ASTC 0x0C
-#define AK8975_REG_TS1 0x0D
-#define AK8975_REG_TS2 0x0E
-#define AK8975_REG_I2CDIS 0x0F
-#define AK8975_REG_ASAX 0x10
-#define AK8975_REG_ASAY 0x11
-#define AK8975_REG_ASAZ 0x12
-
-#define AK8975_MAX_REGS AK8975_REG_ASAZ
-
-/*
- * Miscellaneous values.
- */
-#define AK8975_MAX_CONVERSION_TIMEOUT 500
-#define AK8975_CONVERSION_DONE_POLL_TIME 10
-
-/*
- * Per-instance context data for the device.
- */
-struct ak8975_data {
- struct i2c_client *client;
- struct attribute_group attrs;
- struct mutex lock;
- u8 asa[3];
- long raw_to_gauss[3];
- u8 reg_cache[AK8975_MAX_REGS];
- int eoc_gpio;
- int eoc_irq;
-};
-
-static const int ak8975_index_to_reg[] = {
- AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL,
-};
-
-/*
- * Helper function to write to the I2C device's registers.
- */
-static int ak8975_write_data(struct i2c_client *client,
- u8 reg, u8 val, u8 mask, u8 shift)
-{
- struct iio_dev *indio_dev = i2c_get_clientdata(client);
- struct ak8975_data *data = iio_priv(indio_dev);
- u8 regval;
- int ret;
-
- regval = (data->reg_cache[reg] & ~mask) | (val << shift);
- ret = i2c_smbus_write_byte_data(client, reg, regval);
- if (ret < 0) {
- dev_err(&client->dev, "Write to device fails status %x\n", ret);
- return ret;
- }
- data->reg_cache[reg] = regval;
-
- return 0;
-}
-
-/*
- * Helper function to read a contiguous set of the I2C device's registers.
- */
-static int ak8975_read_data(struct i2c_client *client,
- u8 reg, u8 length, u8 *buffer)
-{
- int ret;
- struct i2c_msg msg[2] = {
- {
- .addr = client->addr,
- .flags = I2C_M_NOSTART,
- .len = 1,
- .buf = ®,
- }, {
- .addr = client->addr,
- .flags = I2C_M_RD,
- .len = length,
- .buf = buffer,
- }
- };
-
- ret = i2c_transfer(client->adapter, msg, 2);
- if (ret < 0) {
- dev_err(&client->dev, "Read from device fails\n");
- return ret;
- }
-
- return 0;
-}
-
-/*
- * Perform some start-of-day setup, including reading the asa calibration
- * values and caching them.
- */
-static int ak8975_setup(struct i2c_client *client)
-{
- struct iio_dev *indio_dev = i2c_get_clientdata(client);
- struct ak8975_data *data = iio_priv(indio_dev);
- u8 device_id;
- int ret;
-
- /* Confirm that the device we're talking to is really an AK8975. */
- ret = ak8975_read_data(client, AK8975_REG_WIA, 1, &device_id);
- if (ret < 0) {
- dev_err(&client->dev, "Error reading WIA\n");
- return ret;
- }
- if (device_id != AK8975_DEVICE_ID) {
- dev_err(&client->dev, "Device ak8975 not found\n");
- return -ENODEV;
- }
-
- /* Write the fused rom access mode. */
- ret = ak8975_write_data(client,
- AK8975_REG_CNTL,
- AK8975_REG_CNTL_MODE_FUSE_ROM,
- AK8975_REG_CNTL_MODE_MASK,
- AK8975_REG_CNTL_MODE_SHIFT);
- if (ret < 0) {
- dev_err(&client->dev, "Error in setting fuse access mode\n");
- return ret;
- }
-
- /* Get asa data and store in the device data. */
- ret = ak8975_read_data(client, AK8975_REG_ASAX, 3, data->asa);
- if (ret < 0) {
- dev_err(&client->dev, "Not able to read asa data\n");
- return ret;
- }
-
- /* After reading fuse ROM data set power-down mode */
- ret = ak8975_write_data(client,
- AK8975_REG_CNTL,
- AK8975_REG_CNTL_MODE_POWER_DOWN,
- AK8975_REG_CNTL_MODE_MASK,
- AK8975_REG_CNTL_MODE_SHIFT);
- if (ret < 0) {
- dev_err(&client->dev, "Error in setting power-down mode\n");
- return ret;
- }
-
-/*
- * Precalculate scale factor (in Gauss units) for each axis and
- * store in the device data.
- *
- * This scale factor is axis-dependent, and is derived from 3 calibration
- * factors ASA(x), ASA(y), and ASA(z).
- *
- * These ASA values are read from the sensor device at start of day, and
- * cached in the device context struct.
- *
- * Adjusting the flux value with the sensitivity adjustment value should be
- * done via the following formula:
- *
- * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
- *
- * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
- * is the resultant adjusted value.
- *
- * We reduce the formula to:
- *
- * Hadj = H * (ASA + 128) / 256
- *
- * H is in the range of -4096 to 4095. The magnetometer has a range of
- * +-1229uT. To go from the raw value to uT is:
- *
- * HuT = H * 1229/4096, or roughly, 3/10.
- *
- * Since 1uT = 100 gauss, our final scale factor becomes:
- *
- * Hadj = H * ((ASA + 128) / 256) * 3/10 * 100
- * Hadj = H * ((ASA + 128) * 30 / 256
- *
- * Since ASA doesn't change, we cache the resultant scale factor into the
- * device context in ak8975_setup().
- */
- data->raw_to_gauss[0] = ((data->asa[0] + 128) * 30) >> 8;
- data->raw_to_gauss[1] = ((data->asa[1] + 128) * 30) >> 8;
- data->raw_to_gauss[2] = ((data->asa[2] + 128) * 30) >> 8;
-
- return 0;
-}
-
-static int wait_conversion_complete_gpio(struct ak8975_data *data)
-{
- struct i2c_client *client = data->client;
- u8 read_status;
- u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
- int ret;
-
- /* Wait for the conversion to complete. */
- while (timeout_ms) {
- msleep(AK8975_CONVERSION_DONE_POLL_TIME);
- if (gpio_get_value(data->eoc_gpio))
- break;
- timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
- }
- if (!timeout_ms) {
- dev_err(&client->dev, "Conversion timeout happened\n");
- return -EINVAL;
- }
-
- ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
- if (ret < 0) {
- dev_err(&client->dev, "Error in reading ST1\n");
- return ret;
- }
- return read_status;
-}
-
-static int wait_conversion_complete_polled(struct ak8975_data *data)
-{
- struct i2c_client *client = data->client;
- u8 read_status;
- u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
- int ret;
-
- /* Wait for the conversion to complete. */
- while (timeout_ms) {
- msleep(AK8975_CONVERSION_DONE_POLL_TIME);
- ret = ak8975_read_data(client, AK8975_REG_ST1, 1, &read_status);
- if (ret < 0) {
- dev_err(&client->dev, "Error in reading ST1\n");
- return ret;
- }
- if (read_status)
- break;
- timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
- }
- if (!timeout_ms) {
- dev_err(&client->dev, "Conversion timeout happened\n");
- return -EINVAL;
- }
- return read_status;
-}
-
-/*
- * Emits the raw flux value for the x, y, or z axis.
- */
-static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
-{
- struct ak8975_data *data = iio_priv(indio_dev);
- struct i2c_client *client = data->client;
- u16 meas_reg;
- s16 raw;
- u8 read_status;
- int ret;
-
- mutex_lock(&data->lock);
-
- /* Set up the device for taking a sample. */
- ret = ak8975_write_data(client,
- AK8975_REG_CNTL,
- AK8975_REG_CNTL_MODE_ONCE,
- AK8975_REG_CNTL_MODE_MASK,
- AK8975_REG_CNTL_MODE_SHIFT);
- if (ret < 0) {
- dev_err(&client->dev, "Error in setting operating mode\n");
- goto exit;
- }
-
- /* Wait for the conversion to complete. */
- if (gpio_is_valid(data->eoc_gpio))
- ret = wait_conversion_complete_gpio(data);
- else
- ret = wait_conversion_complete_polled(data);
- if (ret < 0)
- goto exit;
-
- read_status = ret;
-
- if (read_status & AK8975_REG_ST1_DRDY_MASK) {
- ret = ak8975_read_data(client, AK8975_REG_ST2, 1, &read_status);
- if (ret < 0) {
- dev_err(&client->dev, "Error in reading ST2\n");
- goto exit;
- }
- if (read_status & (AK8975_REG_ST2_DERR_MASK |
- AK8975_REG_ST2_HOFL_MASK)) {
- dev_err(&client->dev, "ST2 status error 0x%x\n",
- read_status);
- ret = -EINVAL;
- goto exit;
- }
- }
-
- /* Read the flux value from the appropriate register
- (the register is specified in the iio device attributes). */
- ret = ak8975_read_data(client, ak8975_index_to_reg[index],
- 2, (u8 *)&meas_reg);
- if (ret < 0) {
- dev_err(&client->dev, "Read axis data fails\n");
- goto exit;
- }
-
- mutex_unlock(&data->lock);
-
- /* Endian conversion of the measured values. */
- raw = (s16) (le16_to_cpu(meas_reg));
-
- /* Clamp to valid range. */
- raw = clamp_t(s16, raw, -4096, 4095);
- *val = raw;
- return IIO_VAL_INT;
-
-exit:
- mutex_unlock(&data->lock);
- return ret;
-}
-
-static int ak8975_read_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int *val, int *val2,
- long mask)
-{
- struct ak8975_data *data = iio_priv(indio_dev);
-
- switch (mask) {
- case IIO_CHAN_INFO_RAW:
- return ak8975_read_axis(indio_dev, chan->address, val);
- case IIO_CHAN_INFO_SCALE:
- *val = data->raw_to_gauss[chan->address];
- return IIO_VAL_INT;
- }
- return -EINVAL;
-}
-
-#define AK8975_CHANNEL(axis, index) \
- { \
- .type = IIO_MAGN, \
- .modified = 1, \
- .channel2 = IIO_MOD_##axis, \
- .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | \
- IIO_CHAN_INFO_SCALE_SEPARATE_BIT, \
- .address = index, \
- }
-
-static const struct iio_chan_spec ak8975_channels[] = {
- AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
-};
-
-static const struct iio_info ak8975_info = {
- .read_raw = &ak8975_read_raw,
- .driver_module = THIS_MODULE,
-};
-
-static int ak8975_probe(struct i2c_client *client,
- const struct i2c_device_id *id)
-{
- struct ak8975_data *data;
- struct iio_dev *indio_dev;
- int eoc_gpio;
- int err;
-
- /* Grab and set up the supplied GPIO. */
- if (client->dev.platform_data == NULL)
- eoc_gpio = -1;
- else
- eoc_gpio = *(int *)(client->dev.platform_data);
-
- /* We may not have a GPIO based IRQ to scan, that is fine, we will
- poll if so */
- if (gpio_is_valid(eoc_gpio)) {
- err = gpio_request_one(eoc_gpio, GPIOF_IN, "ak_8975");
- if (err < 0) {
- dev_err(&client->dev,
- "failed to request GPIO %d, error %d\n",
- eoc_gpio, err);
- goto exit;
- }
- }
-
- /* Register with IIO */
- indio_dev = iio_device_alloc(sizeof(*data));
- if (indio_dev == NULL) {
- err = -ENOMEM;
- goto exit_gpio;
- }
- data = iio_priv(indio_dev);
- i2c_set_clientdata(client, indio_dev);
- /* Perform some basic start-of-day setup of the device. */
- err = ak8975_setup(client);
- if (err < 0) {
- dev_err(&client->dev, "AK8975 initialization fails\n");
- goto exit_free_iio;
- }
-
- data->client = client;
- mutex_init(&data->lock);
- data->eoc_irq = client->irq;
- data->eoc_gpio = eoc_gpio;
- indio_dev->dev.parent = &client->dev;
- indio_dev->channels = ak8975_channels;
- indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
- indio_dev->info = &ak8975_info;
- indio_dev->modes = INDIO_DIRECT_MODE;
-
- err = iio_device_register(indio_dev);
- if (err < 0)
- goto exit_free_iio;
-
- return 0;
-
-exit_free_iio:
- iio_device_free(indio_dev);
-exit_gpio:
- if (gpio_is_valid(eoc_gpio))
- gpio_free(eoc_gpio);
-exit:
- return err;
-}
-
-static int ak8975_remove(struct i2c_client *client)
-{
- struct iio_dev *indio_dev = i2c_get_clientdata(client);
- struct ak8975_data *data = iio_priv(indio_dev);
-
- iio_device_unregister(indio_dev);
-
- if (gpio_is_valid(data->eoc_gpio))
- gpio_free(data->eoc_gpio);
-
- iio_device_free(indio_dev);
-
- return 0;
-}
-
-static const struct i2c_device_id ak8975_id[] = {
- {"ak8975", 0},
- {}
-};
-
-MODULE_DEVICE_TABLE(i2c, ak8975_id);
-
-static const struct of_device_id ak8975_of_match[] = {
- { .compatible = "asahi-kasei,ak8975", },
- { .compatible = "ak8975", },
- { }
-};
-MODULE_DEVICE_TABLE(of, ak8975_of_match);
-
-static struct i2c_driver ak8975_driver = {
- .driver = {
- .name = "ak8975",
- .of_match_table = ak8975_of_match,
- },
- .probe = ak8975_probe,
- .remove = ak8975_remove,
- .id_table = ak8975_id,
-};
-module_i2c_driver(ak8975_driver);
-
-MODULE_AUTHOR("Laxman Dewangan <ldewangan@xxxxxxxxxx>");
-MODULE_DESCRIPTION("AK8975 magnetometer driver");
-MODULE_LICENSE("GPL");
--
1.8.1.1
--
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