[PATCH 10/11] misc: Add slave driver for ak8975 compass driver

[Nathan Royer <nroyer@invensense.com>]

Signed-off-by: Nathan Royer <nroyer@invensense.com>
---
 drivers/misc/inv_mpu/Kconfig          |    1 +
 drivers/misc/inv_mpu/Makefile         |    1 +
 drivers/misc/inv_mpu/compass/Kconfig  |   21 ++
 drivers/misc/inv_mpu/compass/Makefile |    7 +
 drivers/misc/inv_mpu/compass/ak8975.c |  500 +++++++++++++++++++++++++++++++++
 5 files changed, 530 insertions(+), 0 deletions(-)
 create mode 100644 drivers/misc/inv_mpu/compass/Kconfig
 create mode 100644 drivers/misc/inv_mpu/compass/Makefile
 create mode 100644 drivers/misc/inv_mpu/compass/ak8975.c

diff --git a/drivers/misc/inv_mpu/Kconfig b/drivers/misc/inv_mpu/Kconfig
index 6116010..7d9f2c3 100644
--- a/drivers/misc/inv_mpu/Kconfig
+++ b/drivers/misc/inv_mpu/Kconfig
@@ -56,5 +56,6 @@ config MPU_SENSORS_MPU6050_GYRO
 endchoice
 
 source "drivers/misc/inv_mpu/accel/Kconfig"
+source "drivers/misc/inv_mpu/compass/Kconfig"
 
 endif #INV_SENSORS
diff --git a/drivers/misc/inv_mpu/Makefile b/drivers/misc/inv_mpu/Makefile
index d2c2c9a..dc77a1b 100644
--- a/drivers/misc/inv_mpu/Makefile
+++ b/drivers/misc/inv_mpu/Makefile
@@ -17,3 +17,4 @@ mpu3050-objs += mldl_print_cfg.o
 EXTRA_CFLAGS += -Idrivers/misc/inv_mpu
 
 obj-y			+= accel/
+obj-y			+= compass/
diff --git a/drivers/misc/inv_mpu/compass/Kconfig b/drivers/misc/inv_mpu/compass/Kconfig
new file mode 100644
index 0000000..f4106d8
--- /dev/null
+++ b/drivers/misc/inv_mpu/compass/Kconfig
@@ -0,0 +1,21 @@
+menuconfig INV_SENSORS_COMPASS
+	bool "Compass Slave Sensors"
+	default y
+	---help---
+	  Say Y here to get to see options for device drivers for various
+	  compasses. This option alone does not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and disabled.
+
+if INV_SENSORS_COMPASS
+
+config MPU_SENSORS_AK8975
+	tristate "AKM ak8975"
+	help
+	  This enables support for the AKM ak8975 compass
+	  This support is for integration with the MPU3050 or MPU6050 gyroscope
+	  device driver.  Only one compass can be registered at a time.
+	  Specifying more that one compass in the board file will result
+	  in runtime errors.
+
+endif
diff --git a/drivers/misc/inv_mpu/compass/Makefile b/drivers/misc/inv_mpu/compass/Makefile
new file mode 100644
index 0000000..a529476
--- /dev/null
+++ b/drivers/misc/inv_mpu/compass/Makefile
@@ -0,0 +1,7 @@
+#
+# Compass Slaves MPUxxxx
+#
+obj-$(CONFIG_MPU_SENSORS_AK8975) += inv_mpu_ak8975.o
+inv_mpu_ak8975-objs +=	ak8975.o
+
+EXTRA_CFLAGS += -Idrivers/misc/inv_mpu
diff --git a/drivers/misc/inv_mpu/compass/ak8975.c b/drivers/misc/inv_mpu/compass/ak8975.c
new file mode 100644
index 0000000..1d43d5a
--- /dev/null
+++ b/drivers/misc/inv_mpu/compass/ak8975.c
@@ -0,0 +1,500 @@
+/*
+	$License:
+	Copyright (C) 2011 InvenSense Corporation, All Rights Reserved.
+
+	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, see <http://www.gnu.org/licenses/>.
+	$
+ */
+
+/**
+ *  @addtogroup COMPASSDL
+ *
+ *  @{
+ *      @file   ak8975.c
+ *      @brief  Magnetometer setup and handling methods for the AKM AK8975,
+ *              AKM AK8975B, and AKM AK8975C compass devices.
+ */
+
+/* -------------------------------------------------------------------------- */
+
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include "mpu-dev.h"
+
+#include <log.h>
+#include <linux/mpu.h>
+#include "mlsl.h"
+#include "mldl_cfg.h"
+#undef MPL_LOG_TAG
+#define MPL_LOG_TAG "MPL-compass"
+
+/* -------------------------------------------------------------------------- */
+#define AK8975_REG_ST1  (0x02)
+#define AK8975_REG_HXL  (0x03)
+#define AK8975_REG_ST2  (0x09)
+
+#define AK8975_REG_CNTL (0x0A)
+#define AK8975_REG_ASAX (0x10)
+#define AK8975_REG_ASAY (0x11)
+#define AK8975_REG_ASAZ (0x12)
+
+#define AK8975_CNTL_MODE_POWER_DOWN         (0x00)
+#define AK8975_CNTL_MODE_SINGLE_MEASUREMENT (0x01)
+#define AK8975_CNTL_MODE_FUSE_ROM_ACCESS    (0x0f)
+
+/* -------------------------------------------------------------------------- */
+struct ak8975_config {
+	char asa[COMPASS_NUM_AXES];	/* axis sensitivity adjustment */
+};
+
+struct ak8975_private_data {
+	struct ak8975_config init;
+};
+
+/* -------------------------------------------------------------------------- */
+static int ak8975_init(void *mlsl_handle,
+		       struct ext_slave_descr *slave,
+		       struct ext_slave_platform_data *pdata)
+{
+	int result;
+	unsigned char serial_data[COMPASS_NUM_AXES];
+
+	struct ak8975_private_data *private_data;
+	private_data = (struct ak8975_private_data *)
+	    kzalloc(sizeof(struct ak8975_private_data), GFP_KERNEL);
+
+	if (!private_data)
+		return INV_ERROR_MEMORY_EXAUSTED;
+
+	result = inv_serial_single_write(mlsl_handle, pdata->address,
+					 AK8975_REG_CNTL,
+					 AK8975_CNTL_MODE_POWER_DOWN);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+	/* Wait at least 100us */
+	udelay(100);
+
+	result = inv_serial_single_write(mlsl_handle, pdata->address,
+					 AK8975_REG_CNTL,
+					 AK8975_CNTL_MODE_FUSE_ROM_ACCESS);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+
+	/* Wait at least 200us */
+	udelay(200);
+
+	result = inv_serial_read(mlsl_handle, pdata->address,
+				 AK8975_REG_ASAX,
+				 COMPASS_NUM_AXES, serial_data);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+
+	pdata->private_data = private_data;
+
+	private_data->init.asa[0] = serial_data[0];
+	private_data->init.asa[1] = serial_data[1];
+	private_data->init.asa[2] = serial_data[2];
+
+	result = inv_serial_single_write(mlsl_handle, pdata->address,
+					 AK8975_REG_CNTL,
+					 AK8975_CNTL_MODE_POWER_DOWN);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+
+	udelay(100);
+	return INV_SUCCESS;
+}
+
+static int ak8975_exit(void *mlsl_handle,
+		       struct ext_slave_descr *slave,
+		       struct ext_slave_platform_data *pdata)
+{
+	kfree(pdata->private_data);
+	return INV_SUCCESS;
+}
+
+static int ak8975_suspend(void *mlsl_handle,
+		   struct ext_slave_descr *slave,
+		   struct ext_slave_platform_data *pdata)
+{
+	int result = INV_SUCCESS;
+	result =
+	    inv_serial_single_write(mlsl_handle, pdata->address,
+				    AK8975_REG_CNTL,
+				    AK8975_CNTL_MODE_POWER_DOWN);
+	msleep(1);		/* wait at least 100us */
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+	return result;
+}
+
+static int ak8975_resume(void *mlsl_handle,
+		  struct ext_slave_descr *slave,
+		  struct ext_slave_platform_data *pdata)
+{
+	int result = INV_SUCCESS;
+	result =
+	    inv_serial_single_write(mlsl_handle, pdata->address,
+				    AK8975_REG_CNTL,
+				    AK8975_CNTL_MODE_SINGLE_MEASUREMENT);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+	return result;
+}
+
+static int ak8975_read(void *mlsl_handle,
+		struct ext_slave_descr *slave,
+		struct ext_slave_platform_data *pdata, unsigned char *data)
+{
+	unsigned char regs[8];
+	unsigned char *stat = &regs[0];
+	unsigned char *stat2 = &regs[7];
+	int result = INV_SUCCESS;
+	int status = INV_SUCCESS;
+
+	result =
+	    inv_serial_read(mlsl_handle, pdata->address, AK8975_REG_ST1,
+			    8, regs);
+	if (result) {
+		LOG_RESULT_LOCATION(result);
+		return result;
+	}
+
+	/* Always return the data and the status registers */
+	memcpy(data, &regs[1], 6);
+	data[6] = regs[0];
+	data[7] = regs[7];
+
+	/*
+	 * ST : data ready -
+	 * Measurement has been completed and data is ready to be read.
+	 */
+	if (*stat & 0x01)
+		status = INV_SUCCESS;
+
+	/*
+	 * ST2 : data error -
+	 * occurs when data read is started outside of a readable period;
+	 * data read would not be correct.
+	 * Valid in continuous measurement mode only.
+	 * In single measurement mode this error should not occour but we
+	 * stil account for it and return an error, since the data would be
+	 * corrupted.
+	 * DERR bit is self-clearing when ST2 register is read.
+	 */
+	if (*stat2 & 0x04)
+		status = INV_ERROR_COMPASS_DATA_ERROR;
+	/*
+	 * ST2 : overflow -
+	 * the sum of the absolute values of all axis |X|+|Y|+|Z| < 2400uT.
+	 * This is likely to happen in presence of an external magnetic
+	 * disturbance; it indicates, the sensor data is incorrect and should
+	 * be ignored.
+	 * An error is returned.
+	 * HOFL bit clears when a new measurement starts.
+	 */
+	if (*stat2 & 0x08)
+		status = INV_ERROR_COMPASS_DATA_OVERFLOW;
+	/*
+	 * ST : overrun -
+	 * the previous sample was not fetched and lost.
+	 * Valid in continuous measurement mode only.
+	 * In single measurement mode this error should not occour and we
+	 * don't consider this condition an error.
+	 * DOR bit is self-clearing when ST2 or any meas. data register is
+	 * read.
+	 */
+	if (*stat & 0x02) {
+		/* status = INV_ERROR_COMPASS_DATA_UNDERFLOW; */
+		status = INV_SUCCESS;
+	}
+
+	/*
+	 * trigger next measurement if:
+	 *    - stat is non zero;
+	 *    - if stat is zero and stat2 is non zero.
+	 * Won't trigger if data is not ready and there was no error.
+	 */
+	if (*stat != 0x00 || *stat2 != 0x00) {
+		result = inv_serial_single_write(
+		    mlsl_handle, pdata->address,
+		    AK8975_REG_CNTL, AK8975_CNTL_MODE_SINGLE_MEASUREMENT);
+		if (result) {
+			LOG_RESULT_LOCATION(result);
+			return result;
+		}
+	}
+
+	return status;
+}
+
+static int ak8975_config(void *mlsl_handle,
+			 struct ext_slave_descr *slave,
+			 struct ext_slave_platform_data *pdata,
+			 struct ext_slave_config *data)
+{
+	int result;
+	if (!data->data)
+		return INV_ERROR_INVALID_PARAMETER;
+
+	switch (data->key) {
+	case MPU_SLAVE_WRITE_REGISTERS:
+		result = inv_serial_write(mlsl_handle, pdata->address,
+					  data->len,
+					  (unsigned char *)data->data);
+		if (result) {
+			LOG_RESULT_LOCATION(result);
+			return result;
+		}
+		break;
+	case MPU_SLAVE_CONFIG_ODR_SUSPEND:
+	case MPU_SLAVE_CONFIG_ODR_RESUME:
+	case MPU_SLAVE_CONFIG_FSR_SUSPEND:
+	case MPU_SLAVE_CONFIG_FSR_RESUME:
+	case MPU_SLAVE_CONFIG_MOT_THS:
+	case MPU_SLAVE_CONFIG_NMOT_THS:
+	case MPU_SLAVE_CONFIG_MOT_DUR:
+	case MPU_SLAVE_CONFIG_NMOT_DUR:
+	case MPU_SLAVE_CONFIG_IRQ_SUSPEND:
+	case MPU_SLAVE_CONFIG_IRQ_RESUME:
+	default:
+		return INV_ERROR_FEATURE_NOT_IMPLEMENTED;
+	};
+
+	return INV_SUCCESS;
+}
+
+static int ak8975_get_config(void *mlsl_handle,
+			     struct ext_slave_descr *slave,
+			     struct ext_slave_platform_data *pdata,
+			     struct ext_slave_config *data)
+{
+	struct ak8975_private_data *private_data = pdata->private_data;
+	int result;
+	if (!data->data)
+		return INV_ERROR_INVALID_PARAMETER;
+
+	switch (data->key) {
+	case MPU_SLAVE_READ_REGISTERS:
+		{
+			unsigned char *serial_data =
+			    (unsigned char *)data->data;
+			result =
+			    inv_serial_read(mlsl_handle, pdata->address,
+					    serial_data[0], data->len - 1,
+					    &serial_data[1]);
+			if (result) {
+				LOG_RESULT_LOCATION(result);
+				return result;
+			}
+			break;
+		}
+	case MPU_SLAVE_READ_SCALE:
+		{
+			unsigned char *serial_data =
+			    (unsigned char *)data->data;
+			serial_data[0] = private_data->init.asa[0];
+			serial_data[1] = private_data->init.asa[1];
+			serial_data[2] = private_data->init.asa[2];
+			result = INV_SUCCESS;
+			if (result) {
+				LOG_RESULT_LOCATION(result);
+				return result;
+			}
+			break;
+		}
+	case MPU_SLAVE_CONFIG_ODR_SUSPEND:
+		(*(unsigned long *)data->data) = 0;
+		break;
+	case MPU_SLAVE_CONFIG_ODR_RESUME:
+		(*(unsigned long *)data->data) = 8000;
+		break;
+	case MPU_SLAVE_CONFIG_FSR_SUSPEND:
+	case MPU_SLAVE_CONFIG_FSR_RESUME:
+	case MPU_SLAVE_CONFIG_MOT_THS:
+	case MPU_SLAVE_CONFIG_NMOT_THS:
+	case MPU_SLAVE_CONFIG_MOT_DUR:
+	case MPU_SLAVE_CONFIG_NMOT_DUR:
+	case MPU_SLAVE_CONFIG_IRQ_SUSPEND:
+	case MPU_SLAVE_CONFIG_IRQ_RESUME:
+	default:
+		return INV_ERROR_FEATURE_NOT_IMPLEMENTED;
+	};
+
+	return INV_SUCCESS;
+}
+
+static struct ext_slave_read_trigger ak8975_read_trigger = {
+	/*.reg              = */ 0x0A,
+	/*.value            = */ 0x01
+};
+
+static struct ext_slave_descr ak8975_descr = {
+	.init             = ak8975_init,
+	.exit             = ak8975_exit,
+	.suspend          = ak8975_suspend,
+	.resume           = ak8975_resume,
+	.read             = ak8975_read,
+	.config           = ak8975_config,
+	.get_config       = ak8975_get_config,
+	.name             = "ak8975",
+	.type             = EXT_SLAVE_TYPE_COMPASS,
+	.id               = COMPASS_ID_AK8975,
+	.read_reg         = 0x01,
+	.read_len         = 9,
+	.endian           = EXT_SLAVE_LITTLE_ENDIAN,
+	.range            = {9830, 4000},
+	.trigger          = &ak8975_read_trigger,
+};
+
+static
+struct ext_slave_descr *ak8975_get_slave_descr(void)
+{
+	return &ak8975_descr;
+}
+
+/* -------------------------------------------------------------------------- */
+struct ak8975_mod_private_data {
+	struct i2c_client *client;
+	struct ext_slave_platform_data *pdata;
+};
+
+static unsigned short normal_i2c[] = { I2C_CLIENT_END };
+
+static int ak8975_mod_probe(struct i2c_client *client,
+			   const struct i2c_device_id *devid)
+{
+	struct ext_slave_platform_data *pdata;
+	struct ak8975_mod_private_data *private_data;
+	int result = 0;
+
+	dev_info(&client->adapter->dev, "%s: %s\n", __func__, devid->name);
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		result = -ENODEV;
+		goto out_no_free;
+	}
+
+	pdata = client->dev.platform_data;
+	if (!pdata) {
+		dev_err(&client->adapter->dev,
+			"Missing platform data for slave %s\n", devid->name);
+		result = -EFAULT;
+		goto out_no_free;
+	}
+
+	private_data = kzalloc(sizeof(*private_data), GFP_KERNEL);
+	if (!private_data) {
+		result = -ENOMEM;
+		goto out_no_free;
+	}
+
+	i2c_set_clientdata(client, private_data);
+	private_data->client = client;
+	private_data->pdata = pdata;
+
+	result = inv_mpu_register_slave(THIS_MODULE, client, pdata,
+					ak8975_get_slave_descr);
+	if (result) {
+		dev_err(&client->adapter->dev,
+			"Slave registration failed: %s, %d\n",
+			devid->name, result);
+		goto out_free_memory;
+	}
+
+	return result;
+
+out_free_memory:
+	kfree(private_data);
+out_no_free:
+	dev_err(&client->adapter->dev, "%s failed %d\n", __func__, result);
+	return result;
+
+}
+
+static int ak8975_mod_remove(struct i2c_client *client)
+{
+	struct ak8975_mod_private_data *private_data =
+		i2c_get_clientdata(client);
+
+	dev_dbg(&client->adapter->dev, "%s\n", __func__);
+	inv_mpu_unregister_slave(client, private_data->pdata,
+				ak8975_get_slave_descr);
+
+	kfree(private_data);
+	return 0;
+}
+
+static const struct i2c_device_id ak8975_mod_id[] = {
+	{ "ak8975", COMPASS_ID_AK8975 },
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, ak8975_mod_id);
+
+static struct i2c_driver ak8975_mod_driver = {
+	.class = I2C_CLASS_HWMON,
+	.probe = ak8975_mod_probe,
+	.remove = ak8975_mod_remove,
+	.id_table = ak8975_mod_id,
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = "ak8975_mod",
+		   },
+	.address_list = normal_i2c,
+};
+
+static int __init ak8975_mod_init(void)
+{
+	int res = i2c_add_driver(&ak8975_mod_driver);
+	pr_info("%s: Probe name %s\n", __func__, "ak8975_mod");
+	if (res)
+		pr_err("%s failed\n", __func__);
+	return res;
+}
+
+static void __exit ak8975_mod_exit(void)
+{
+	pr_info("%s\n", __func__);
+	i2c_del_driver(&ak8975_mod_driver);
+}
+
+module_init(ak8975_mod_init);
+module_exit(ak8975_mod_exit);
+
+MODULE_AUTHOR("Invensense Corporation");
+MODULE_DESCRIPTION("Driver to integrate AK8975 sensor with the MPU");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("ak8975_mod");
+
+/**
+ *  @}
+ */
-- 
1.7.4.1