iio: accel: mma9551: split driver to expose mma955x api

Freescale has the MMA955xL family of devices that use the
same communication protocol (based on i2c messages):
http://www.freescale.com/files/sensors/doc/data_sheet/MMA955xL.pdf.

To support more devices from this family, we need to split the
mma9551 driver so we can export the common functions that will
be used by other mma955x drivers.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Reviewed-by: Vlad Dogaru <vlad.dogaru@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

5 files changed, 693 insertions, 440 deletions

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 9f67c10291bd..c53047d28ad3 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -111,9 +111,14 @@ config KXCJK1013
 	  To compile this driver as a module, choose M here: the module will
 	  be called kxcjk-1013.
 
+config MMA9551_CORE
+	tristate
+
 config MMA9551
 	tristate "Freescale MMA9551L Intelligent Motion-Sensing Platform Driver"
 	depends on I2C
+	select MMA9551_CORE
+
 	help
 	  Say yes here to build support for the Freescale MMA9551L
 	  Intelligent Motion-Sensing Platform Driver.
diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
index de5b9cb9670f..810531610414 100644
--- a/drivers/iio/accel/Makefile
+++ b/drivers/iio/accel/Makefile
@@ -9,7 +9,9 @@ obj-$(CONFIG_HID_SENSOR_ACCEL_3D) += hid-sensor-accel-3d.o
 obj-$(CONFIG_KXCJK1013) += kxcjk-1013.o
 obj-$(CONFIG_KXSD9)	+= kxsd9.o
 obj-$(CONFIG_MMA8452)	+= mma8452.o
-obj-$(CONFIG_MMA9551)	+= mma9551.o
+
+obj-$(CONFIG_MMA9551_CORE)	+= mma9551_core.o
+obj-$(CONFIG_MMA9551)		+= mma9551.o
 
 obj-$(CONFIG_IIO_ST_ACCEL_3AXIS) += st_accel.o
 st_accel-y := st_accel_core.o
diff --git a/drivers/iio/accel/mma9551.c b/drivers/iio/accel/mma9551.c
index f1a5a06a0726..46c38351c6a3 100644
--- a/drivers/iio/accel/mma9551.c
+++ b/drivers/iio/accel/mma9551.c
@@ -23,63 +23,13 @@
 #include <linux/iio/sysfs.h>
 #include <linux/iio/events.h>
 #include <linux/pm_runtime.h>
+#include "mma9551_core.h"
 
 #define MMA9551_DRV_NAME		"mma9551"
 #define MMA9551_IRQ_NAME		"mma9551_event"
 #define MMA9551_GPIO_NAME		"mma9551_int"
 #define MMA9551_GPIO_COUNT		4
 
-/* Applications IDs */
-#define MMA9551_APPID_VERSION		0x00
-#define MMA9551_APPID_GPIO		0x03
-#define MMA9551_APPID_AFE		0x06
-#define MMA9551_APPID_TILT		0x0B
-#define MMA9551_APPID_SLEEP_WAKE	0x12
-#define MMA9551_APPID_RESET		0x17
-#define MMA9551_APPID_NONE		0xff
-
-/* Command masks for mailbox write command */
-#define MMA9551_CMD_READ_VERSION_INFO	0x00
-#define MMA9551_CMD_READ_CONFIG		0x10
-#define MMA9551_CMD_WRITE_CONFIG	0x20
-#define MMA9551_CMD_READ_STATUS		0x30
-
-enum mma9551_gpio_pin {
-	mma9551_gpio6 = 0,
-	mma9551_gpio7,
-	mma9551_gpio8,
-	mma9551_gpio9,
-	mma9551_gpio_max = mma9551_gpio9,
-};
-
-/* Mailbox read command */
-#define MMA9551_RESPONSE_COCO		BIT(7)
-
-/* Error-Status codes returned in mailbox read command */
-#define MMA9551_MCI_ERROR_NONE			0x00
-#define MMA9551_MCI_ERROR_PARAM			0x04
-#define MMA9551_MCI_INVALID_COUNT		0x19
-#define MMA9551_MCI_ERROR_COMMAND		0x1C
-#define MMA9551_MCI_ERROR_INVALID_LENGTH	0x21
-#define MMA9551_MCI_ERROR_FIFO_BUSY		0x22
-#define MMA9551_MCI_ERROR_FIFO_ALLOCATED	0x23
-#define MMA9551_MCI_ERROR_FIFO_OVERSIZE		0x24
-
-/* GPIO Application */
-#define MMA9551_GPIO_POL_MSB		0x08
-#define MMA9551_GPIO_POL_LSB		0x09
-
-/* Sleep/Wake application */
-#define MMA9551_SLEEP_CFG		0x06
-#define MMA9551_SLEEP_CFG_SNCEN		BIT(0)
-#define MMA9551_SLEEP_CFG_FLEEN		BIT(1)
-#define MMA9551_SLEEP_CFG_SCHEN		BIT(2)
-
-/* AFE application */
-#define MMA9551_AFE_X_ACCEL_REG		0x00
-#define MMA9551_AFE_Y_ACCEL_REG		0x02
-#define MMA9551_AFE_Z_ACCEL_REG		0x04
-
 /* Tilt application (inclination in IIO terms). */
 #define MMA9551_TILT_XZ_ANG_REG		0x00
 #define MMA9551_TILT_YZ_ANG_REG		0x01
@@ -92,6 +42,8 @@ enum mma9551_gpio_pin {
 #define MMA9551_TILT_CFG_REG		0x01
 #define MMA9551_TILT_ANG_THRESH_MASK	GENMASK(3, 0)
 
+#define MMA9551_DEFAULT_SAMPLE_RATE	122	/* Hz */
+
 /* Tilt events are mapped to the first three GPIO pins. */
 enum mma9551_tilt_axis {
 	mma9551_x = 0,
@@ -99,64 +51,6 @@ enum mma9551_tilt_axis {
 	mma9551_z,
 };
 
-/*
- * A response is composed of:
- * - control registers: MB0-3
- * - data registers: MB4-31
- *
- * A request is composed of:
- * - mbox to write to (always 0)
- * - control registers: MB1-4
- * - data registers: MB5-31
- */
-#define MMA9551_MAILBOX_CTRL_REGS	4
-#define MMA9551_MAX_MAILBOX_DATA_REGS	28
-#define MMA9551_MAILBOX_REGS		32
-
-#define MMA9551_I2C_READ_RETRIES	5
-#define MMA9551_I2C_READ_DELAY	50	/* us */
-
-#define MMA9551_DEFAULT_SAMPLE_RATE	122	/* Hz */
-#define MMA9551_AUTO_SUSPEND_DELAY_MS	2000
-
-struct mma9551_mbox_request {
-	u8 start_mbox;		/* Always 0. */
-	u8 app_id;
-	/*
-	 * See Section 5.3.1 of the MMA955xL Software Reference Manual.
-	 *
-	 * Bit 7: reserved, always 0
-	 * Bits 6-4: command
-	 * Bits 3-0: upper bits of register offset
-	 */
-	u8 cmd_off;
-	u8 lower_off;
-	u8 nbytes;
-	u8 buf[MMA9551_MAX_MAILBOX_DATA_REGS - 1];
-} __packed;
-
-struct mma9551_mbox_response {
-	u8 app_id;
-	/*
-	 * See Section 5.3.3 of the MMA955xL Software Reference Manual.
-	 *
-	 * Bit 7: COCO
-	 * Bits 6-0: Error code.
-	 */
-	u8 coco_err;
-	u8 nbytes;
-	u8 req_bytes;
-	u8 buf[MMA9551_MAX_MAILBOX_DATA_REGS];
-} __packed;
-
-struct mma9551_version_info {
-	__be32 device_id;
-	u8 rom_version[2];
-	u8 fw_version[2];
-	u8 hw_version[2];
-	u8 fw_build[2];
-};
-
 struct mma9551_data {
 	struct i2c_client *client;
 	struct mutex mutex;
@@ -164,285 +58,6 @@ struct mma9551_data {
 	int irqs[MMA9551_GPIO_COUNT];
 };
 
-static int mma9551_transfer(struct i2c_client *client,
-			    u8 app_id, u8 command, u16 offset,
-			    u8 *inbytes, int num_inbytes,
-			    u8 *outbytes, int num_outbytes)
-{
-	struct mma9551_mbox_request req;
-	struct mma9551_mbox_response rsp;
-	struct i2c_msg in, out;
-	u8 req_len, err_code;
-	int ret, retries;
-
-	if (offset >= 1 << 12) {
-		dev_err(&client->dev, "register offset too large\n");
-		return -EINVAL;
-	}
-
-	req_len = 1 + MMA9551_MAILBOX_CTRL_REGS + num_inbytes;
-	req.start_mbox = 0;
-	req.app_id = app_id;
-	req.cmd_off = command | (offset >> 8);
-	req.lower_off = offset;
-
-	if (command == MMA9551_CMD_WRITE_CONFIG)
-		req.nbytes = num_inbytes;
-	else
-		req.nbytes = num_outbytes;
-	if (num_inbytes)
-		memcpy(req.buf, inbytes, num_inbytes);
-
-	out.addr = client->addr;
-	out.flags = 0;
-	out.len = req_len;
-	out.buf = (u8 *)&req;
-
-	ret = i2c_transfer(client->adapter, &out, 1);
-	if (ret < 0) {
-		dev_err(&client->dev, "i2c write failed\n");
-		return ret;
-	}
-
-	retries = MMA9551_I2C_READ_RETRIES;
-	do {
-		udelay(MMA9551_I2C_READ_DELAY);
-
-		in.addr = client->addr;
-		in.flags = I2C_M_RD;
-		in.len = sizeof(rsp);
-		in.buf = (u8 *)&rsp;
-
-		ret = i2c_transfer(client->adapter, &in, 1);
-		if (ret < 0) {
-			dev_err(&client->dev, "i2c read failed\n");
-			return ret;
-		}
-
-		if (rsp.coco_err & MMA9551_RESPONSE_COCO)
-			break;
-	} while (--retries > 0);
-
-	if (retries == 0) {
-		dev_err(&client->dev,
-			"timed out while waiting for command response\n");
-		return -ETIMEDOUT;
-	}
-
-	if (rsp.app_id != app_id) {
-		dev_err(&client->dev,
-			"app_id mismatch in response got %02x expected %02x\n",
-			rsp.app_id, app_id);
-		return -EINVAL;
-	}
-
-	err_code = rsp.coco_err & ~MMA9551_RESPONSE_COCO;
-	if (err_code != MMA9551_MCI_ERROR_NONE) {
-		dev_err(&client->dev, "read returned error %x\n", err_code);
-		return -EINVAL;
-	}
-
-	if (rsp.nbytes != rsp.req_bytes) {
-		dev_err(&client->dev,
-			"output length mismatch got %d expected %d\n",
-			rsp.nbytes, rsp.req_bytes);
-		return -EINVAL;
-	}
-
-	if (num_outbytes)
-		memcpy(outbytes, rsp.buf, num_outbytes);
-
-	return 0;
-}
-
-static int mma9551_read_config_byte(struct i2c_client *client, u8 app_id,
-				    u16 reg, u8 *val)
-{
-	return mma9551_transfer(client, app_id, MMA9551_CMD_READ_CONFIG,
-				reg, NULL, 0, val, 1);
-}
-
-static int mma9551_write_config_byte(struct i2c_client *client, u8 app_id,
-				     u16 reg, u8 val)
-{
-	return mma9551_transfer(client, app_id, MMA9551_CMD_WRITE_CONFIG, reg,
-				&val, 1, NULL, 0);
-}
-
-static int mma9551_read_status_byte(struct i2c_client *client, u8 app_id,
-				    u16 reg, u8 *val)
-{
-	return mma9551_transfer(client, app_id, MMA9551_CMD_READ_STATUS,
-				reg, NULL, 0, val, 1);
-}
-
-static int mma9551_read_status_word(struct i2c_client *client, u8 app_id,
-				    u16 reg, u16 *val)
-{
-	int ret;
-	__be16 v;
-
-	ret = mma9551_transfer(client, app_id, MMA9551_CMD_READ_STATUS,
-			       reg, NULL, 0, (u8 *)&v, 2);
-	*val = be16_to_cpu(v);
-
-	return ret;
-}
-
-static int mma9551_update_config_bits(struct i2c_client *client, u8 app_id,
-				      u16 reg, u8 mask, u8 val)
-{
-	int ret;
-	u8 tmp, orig;
-
-	ret = mma9551_read_config_byte(client, app_id, reg, &orig);
-	if (ret < 0)
-		return ret;
-
-	tmp = orig & ~mask;
-	tmp |= val & mask;
-
-	if (tmp == orig)
-		return 0;
-
-	return mma9551_write_config_byte(client, app_id, reg, tmp);
-}
-
-/*
- * The polarity parameter is described in section 6.2.2, page 66, of the
- * Software Reference Manual.  Basically, polarity=0 means the interrupt
- * line has the same value as the selected bit, while polarity=1 means
- * the line is inverted.
- */
-static int mma9551_gpio_config(struct i2c_client *client,
-			       enum mma9551_gpio_pin pin,
-			       u8 app_id, u8 bitnum, int polarity)
-{
-	u8 reg, pol_mask, pol_val;
-	int ret;
-
-	if (pin > mma9551_gpio_max) {
-		dev_err(&client->dev, "bad GPIO pin\n");
-		return -EINVAL;
-	}
-
-	/*
-	 * Pin 6 is configured by regs 0x00 and 0x01, pin 7 by 0x02 and
-	 * 0x03, and so on.
-	 */
-	reg = pin * 2;
-
-	ret = mma9551_write_config_byte(client, MMA9551_APPID_GPIO,
-					reg, app_id);
-	if (ret < 0) {
-		dev_err(&client->dev, "error setting GPIO app_id\n");
-		return ret;
-	}
-
-	ret = mma9551_write_config_byte(client, MMA9551_APPID_GPIO,
-					reg + 1, bitnum);
-	if (ret < 0) {
-		dev_err(&client->dev, "error setting GPIO bit number\n");
-		return ret;
-	}
-
-	switch (pin) {
-	case mma9551_gpio6:
-		reg = MMA9551_GPIO_POL_LSB;
-		pol_mask = 1 << 6;
-		break;
-	case mma9551_gpio7:
-		reg = MMA9551_GPIO_POL_LSB;
-		pol_mask = 1 << 7;
-		break;
-	case mma9551_gpio8:
-		reg = MMA9551_GPIO_POL_MSB;
-		pol_mask = 1 << 0;
-		break;
-	case mma9551_gpio9:
-		reg = MMA9551_GPIO_POL_MSB;
-		pol_mask = 1 << 1;
-		break;
-	}
-	pol_val = polarity ? pol_mask : 0;
-
-	ret = mma9551_update_config_bits(client, MMA9551_APPID_GPIO, reg,
-					 pol_mask, pol_val);
-	if (ret < 0)
-		dev_err(&client->dev, "error setting GPIO polarity\n");
-
-	return ret;
-}
-
-static int mma9551_read_version(struct i2c_client *client)
-{
-	struct mma9551_version_info info;
-	int ret;
-
-	ret = mma9551_transfer(client, MMA9551_APPID_VERSION, 0x00, 0x00,
-			       NULL, 0, (u8 *)&info, sizeof(info));
-	if (ret < 0)
-		return ret;
-
-	dev_info(&client->dev, "Device ID 0x%x, firmware version %02x.%02x\n",
-		 be32_to_cpu(info.device_id), info.fw_version[0],
-		 info.fw_version[1]);
-
-	return 0;
-}
-
-/*
- * Power on chip and enable doze mode.
- * Use 'false' as the second parameter to cause the device to enter
- * sleep.
- */
-static int mma9551_set_device_state(struct i2c_client *client, bool enable)
-{
-	return mma9551_update_config_bits(client, MMA9551_APPID_SLEEP_WAKE,
-					  MMA9551_SLEEP_CFG,
-					  MMA9551_SLEEP_CFG_SNCEN |
-					  MMA9551_SLEEP_CFG_FLEEN |
-					  MMA9551_SLEEP_CFG_SCHEN,
-					  enable ? MMA9551_SLEEP_CFG_SCHEN |
-					  MMA9551_SLEEP_CFG_FLEEN :
-					  MMA9551_SLEEP_CFG_SNCEN);
-}
-
-static int mma9551_set_power_state(struct i2c_client *client, bool on)
-{
-#ifdef CONFIG_PM
-	int ret;
-
-	if (on)
-		ret = pm_runtime_get_sync(&client->dev);
-	else {
-		pm_runtime_mark_last_busy(&client->dev);
-		ret = pm_runtime_put_autosuspend(&client->dev);
-	}
-
-	if (ret < 0) {
-		dev_err(&client->dev,
-			"failed to change power state to %d\n", on);
-		if (on)
-			pm_runtime_put_noidle(&client->dev);
-
-		return ret;
-	}
-#endif
-
-	return 0;
-}
-
-static void mma9551_sleep(int freq)
-{
-	int sleep_val = 1000 / freq;
-
-	if (sleep_val < 20)
-		usleep_range(sleep_val * 1000, 20000);
-	else
-		msleep_interruptible(sleep_val);
-}
-
 static int mma9551_read_incli_chan(struct i2c_client *client,
 				   const struct iio_chan_spec *chan,
 				   int *val)
@@ -497,46 +112,6 @@ out_poweroff:
 	return ret;
 }
 
-static int mma9551_read_accel_chan(struct i2c_client *client,
-				   const struct iio_chan_spec *chan,
-				   int *val, int *val2)
-{
-	u16 reg_addr;
-	s16 raw_accel;
-	int ret;
-
-	switch (chan->channel2) {
-	case IIO_MOD_X:
-		reg_addr = MMA9551_AFE_X_ACCEL_REG;
-		break;
-	case IIO_MOD_Y:
-		reg_addr = MMA9551_AFE_Y_ACCEL_REG;
-		break;
-	case IIO_MOD_Z:
-		reg_addr = MMA9551_AFE_Z_ACCEL_REG;
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	ret = mma9551_set_power_state(client, true);
-	if (ret < 0)
-		return ret;
-
-	ret = mma9551_read_status_word(client, MMA9551_APPID_AFE,
-				       reg_addr, &raw_accel);
-	if (ret < 0)
-		goto out_poweroff;
-
-	*val = raw_accel;
-
-	ret = IIO_VAL_INT;
-
-out_poweroff:
-	mma9551_set_power_state(client, false);
-	return ret;
-}
-
 static int mma9551_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long mask)
@@ -569,9 +144,7 @@ static int mma9551_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->type) {
 		case IIO_ACCEL:
-			*val = 0;
-			*val2 = 2440;
-			return IIO_VAL_INT_PLUS_MICRO;
+			return mma9551_read_accel_scale(val, val2);
 		default:
 			return -EINVAL;
 		}
@@ -740,14 +313,6 @@ static const struct iio_event_spec mma9551_incli_event = {
 	.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
 };
 
-#define MMA9551_ACCEL_CHANNEL(axis) {				\
-	.type = IIO_ACCEL,					\
-	.modified = 1,						\
-	.channel2 = axis,					\
-	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
-	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
-}
-
 #define MMA9551_INCLI_CHANNEL(axis) {				\
 	.type = IIO_INCLI,					\
 	.modified = 1,						\
diff --git a/drivers/iio/accel/mma9551_core.c b/drivers/iio/accel/mma9551_core.c
new file mode 100644
index 000000000000..7f1a73e6aa36
--- /dev/null
+++ b/drivers/iio/accel/mma9551_core.c
@@ -0,0 +1,615 @@
+/*
+ * Common code for Freescale MMA955x Intelligent Sensor Platform drivers
+ * 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/module.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/pm_runtime.h>
+#include "mma9551_core.h"
+
+/* Command masks for mailbox write command */
+#define MMA9551_CMD_READ_VERSION_INFO	0x00
+#define MMA9551_CMD_READ_CONFIG		0x10
+#define MMA9551_CMD_WRITE_CONFIG	0x20
+#define MMA9551_CMD_READ_STATUS		0x30
+
+/* Mailbox read command */
+#define MMA9551_RESPONSE_COCO		BIT(7)
+
+/* Error-Status codes returned in mailbox read command */
+#define MMA9551_MCI_ERROR_NONE			0x00
+#define MMA9551_MCI_ERROR_PARAM			0x04
+#define MMA9551_MCI_INVALID_COUNT		0x19
+#define MMA9551_MCI_ERROR_COMMAND		0x1C
+#define MMA9551_MCI_ERROR_INVALID_LENGTH	0x21
+#define MMA9551_MCI_ERROR_FIFO_BUSY		0x22
+#define MMA9551_MCI_ERROR_FIFO_ALLOCATED	0x23
+#define MMA9551_MCI_ERROR_FIFO_OVERSIZE		0x24
+
+/* GPIO Application */
+#define MMA9551_GPIO_POL_MSB		0x08
+#define MMA9551_GPIO_POL_LSB		0x09
+
+/* Sleep/Wake application */
+#define MMA9551_SLEEP_CFG		0x06
+#define MMA9551_SLEEP_CFG_SNCEN		BIT(0)
+#define MMA9551_SLEEP_CFG_FLEEN		BIT(1)
+#define MMA9551_SLEEP_CFG_SCHEN		BIT(2)
+
+/* AFE application */
+#define MMA9551_AFE_X_ACCEL_REG		0x00
+#define MMA9551_AFE_Y_ACCEL_REG		0x02
+#define MMA9551_AFE_Z_ACCEL_REG		0x04
+
+/*
+ * A response is composed of:
+ * - control registers: MB0-3
+ * - data registers: MB4-31
+ *
+ * A request is composed of:
+ * - mbox to write to (always 0)
+ * - control registers: MB1-4
+ * - data registers: MB5-31
+ */
+#define MMA9551_MAILBOX_CTRL_REGS	4
+#define MMA9551_MAX_MAILBOX_DATA_REGS	28
+#define MMA9551_MAILBOX_REGS		32
+
+#define MMA9551_I2C_READ_RETRIES	5
+#define MMA9551_I2C_READ_DELAY	50	/* us */
+
+struct mma9551_mbox_request {
+	u8 start_mbox;		/* Always 0. */
+	u8 app_id;
+	/*
+	 * See Section 5.3.1 of the MMA955xL Software Reference Manual.
+	 *
+	 * Bit 7: reserved, always 0
+	 * Bits 6-4: command
+	 * Bits 3-0: upper bits of register offset
+	 */
+	u8 cmd_off;
+	u8 lower_off;
+	u8 nbytes;
+	u8 buf[MMA9551_MAX_MAILBOX_DATA_REGS - 1];
+} __packed;
+
+struct mma9551_mbox_response {
+	u8 app_id;
+	/*
+	 * See Section 5.3.3 of the MMA955xL Software Reference Manual.
+	 *
+	 * Bit 7: COCO
+	 * Bits 6-0: Error code.
+	 */
+	u8 coco_err;
+	u8 nbytes;
+	u8 req_bytes;
+	u8 buf[MMA9551_MAX_MAILBOX_DATA_REGS];
+} __packed;
+
+struct mma9551_version_info {
+	__be32 device_id;
+	u8 rom_version[2];
+	u8 fw_version[2];
+	u8 hw_version[2];
+	u8 fw_build[2];
+};
+
+static int mma9551_transfer(struct i2c_client *client,
+			    u8 app_id, u8 command, u16 offset,
+			    u8 *inbytes, int num_inbytes,
+			    u8 *outbytes, int num_outbytes)
+{
+	struct mma9551_mbox_request req;
+	struct mma9551_mbox_response rsp;
+	struct i2c_msg in, out;
+	u8 req_len, err_code;
+	int ret, retries;
+
+	if (offset >= 1 << 12) {
+		dev_err(&client->dev, "register offset too large\n");
+		return -EINVAL;
+	}
+
+	req_len = 1 + MMA9551_MAILBOX_CTRL_REGS + num_inbytes;
+	req.start_mbox = 0;
+	req.app_id = app_id;
+	req.cmd_off = command | (offset >> 8);
+	req.lower_off = offset;
+
+	if (command == MMA9551_CMD_WRITE_CONFIG)
+		req.nbytes = num_inbytes;
+	else
+		req.nbytes = num_outbytes;
+	if (num_inbytes)
+		memcpy(req.buf, inbytes, num_inbytes);
+
+	out.addr = client->addr;
+	out.flags = 0;
+	out.len = req_len;
+	out.buf = (u8 *)&req;
+
+	ret = i2c_transfer(client->adapter, &out, 1);
+	if (ret < 0) {
+		dev_err(&client->dev, "i2c write failed\n");
+		return ret;
+	}
+
+	retries = MMA9551_I2C_READ_RETRIES;
+	do {
+		udelay(MMA9551_I2C_READ_DELAY);
+
+		in.addr = client->addr;
+		in.flags = I2C_M_RD;
+		in.len = sizeof(rsp);
+		in.buf = (u8 *)&rsp;
+
+		ret = i2c_transfer(client->adapter, &in, 1);
+		if (ret < 0) {
+			dev_err(&client->dev, "i2c read failed\n");
+			return ret;
+		}
+
+		if (rsp.coco_err & MMA9551_RESPONSE_COCO)
+			break;
+	} while (--retries > 0);
+
+	if (retries == 0) {
+		dev_err(&client->dev,
+			"timed out while waiting for command response\n");
+		return -ETIMEDOUT;
+	}
+
+	if (rsp.app_id != app_id) {
+		dev_err(&client->dev,
+			"app_id mismatch in response got %02x expected %02x\n",
+			rsp.app_id, app_id);
+		return -EINVAL;
+	}
+
+	err_code = rsp.coco_err & ~MMA9551_RESPONSE_COCO;
+	if (err_code != MMA9551_MCI_ERROR_NONE) {
+		dev_err(&client->dev, "read returned error %x\n", err_code);
+		return -EINVAL;
+	}
+
+	if (rsp.nbytes != rsp.req_bytes) {
+		dev_err(&client->dev,
+			"output length mismatch got %d expected %d\n",
+			rsp.nbytes, rsp.req_bytes);
+		return -EINVAL;
+	}
+
+	if (num_outbytes)
+		memcpy(outbytes, rsp.buf, num_outbytes);
+
+	return 0;
+}
+
+/**
+ * mma9551_read_config_byte() - read 1 configuration byte
+ * @client:	I2C client
+ * @app_id:	Application ID
+ * @reg:	Application register
+ * @val:	Pointer to store value read
+ *
+ * Read one configuration byte from the device using MMA955xL command format.
+ * Commands to the MMA955xL platform consist of a write followed
+ * by one or more reads.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_read_config_byte(struct i2c_client *client, u8 app_id,
+			     u16 reg, u8 *val)
+{
+	return mma9551_transfer(client, app_id, MMA9551_CMD_READ_CONFIG,
+				reg, NULL, 0, val, 1);
+}
+EXPORT_SYMBOL(mma9551_read_config_byte);
+
+/**
+ * mma9551_write_config_byte() - write 1 configuration byte
+ * @client:	I2C client
+ * @app_id:	Application ID
+ * @reg:	Application register
+ * @val:	Value to write
+ *
+ * Write one configuration byte from the device using MMA955xL command format.
+ * Commands to the MMA955xL platform consist of a write followed by one or
+ * more reads.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_write_config_byte(struct i2c_client *client, u8 app_id,
+			      u16 reg, u8 val)
+{
+	return mma9551_transfer(client, app_id, MMA9551_CMD_WRITE_CONFIG, reg,
+				&val, 1, NULL, 0);
+}
+EXPORT_SYMBOL(mma9551_write_config_byte);
+
+/**
+ * mma9551_read_status_byte() - read 1 status byte
+ * @client:	I2C client
+ * @app_id:	Application ID
+ * @reg:	Application register
+ * @val:	Pointer to store value read
+ *
+ * Read one status byte from the device using MMA955xL command format.
+ * Commands to the MMA955xL platform consist of a write followed by one or
+ * more reads.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_read_status_byte(struct i2c_client *client, u8 app_id,
+			     u16 reg, u8 *val)
+{
+	return mma9551_transfer(client, app_id, MMA9551_CMD_READ_STATUS,
+				reg, NULL, 0, val, 1);
+}
+EXPORT_SYMBOL(mma9551_read_status_byte);
+
+/**
+ * mma9551_read_status_word() - read 1 status word
+ * @client:	I2C client
+ * @app_id:	Application ID
+ * @reg:	Application register
+ * @val:	Pointer to store value read
+ *
+ * Read one status word from the device using MMA955xL command format.
+ * Commands to the MMA955xL platform consist of a write followed by one or
+ * more reads.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_read_status_word(struct i2c_client *client, u8 app_id,
+			     u16 reg, u16 *val)
+{
+	int ret;
+	__be16 v;
+
+	ret = mma9551_transfer(client, app_id, MMA9551_CMD_READ_STATUS,
+			       reg, NULL, 0, (u8 *)&v, 2);
+	*val = be16_to_cpu(v);
+
+	return ret;
+}
+EXPORT_SYMBOL(mma9551_read_status_word);
+
+/**
+ * mma9551_update_config_bits() - update bits in register
+ * @client:	I2C client
+ * @app_id:	Application ID
+ * @reg:	Application register
+ * @mask:	Mask for the bits to update
+ * @val:	Value of the bits to update
+ *
+ * Update bits in the given register using a bit mask.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_update_config_bits(struct i2c_client *client, u8 app_id,
+			       u16 reg, u8 mask, u8 val)
+{
+	int ret;
+	u8 tmp, orig;
+
+	ret = mma9551_read_config_byte(client, app_id, reg, &orig);
+	if (ret < 0)
+		return ret;
+
+	tmp = orig & ~mask;
+	tmp |= val & mask;
+
+	if (tmp == orig)
+		return 0;
+
+	return mma9551_write_config_byte(client, app_id, reg, tmp);
+}
+EXPORT_SYMBOL(mma9551_update_config_bits);
+
+/**
+ * mma9551_gpio_config() - configure gpio
+ * @client:	I2C client
+ * @pin:	GPIO pin to configure
+ * @app_id:	Application ID
+ * @bitnum:	Bit number of status register being assigned to the GPIO pin.
+ * @polarity:	The polarity parameter is described in section 6.2.2, page 66,
+ *		of the Software Reference Manual.  Basically, polarity=0 means
+ *		the interrupt line has the same value as the selected bit,
+ *		while polarity=1 means the line is inverted.
+ *
+ * Assign a bit from an application’s status register to a specific GPIO pin.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_gpio_config(struct i2c_client *client, enum mma9551_gpio_pin pin,
+			u8 app_id, u8 bitnum, int polarity)
+{
+	u8 reg, pol_mask, pol_val;
+	int ret;
+
+	if (pin > mma9551_gpio_max) {
+		dev_err(&client->dev, "bad GPIO pin\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Pin 6 is configured by regs 0x00 and 0x01, pin 7 by 0x02 and
+	 * 0x03, and so on.
+	 */
+	reg = pin * 2;
+
+	ret = mma9551_write_config_byte(client, MMA9551_APPID_GPIO,
+					reg, app_id);
+	if (ret < 0) {
+		dev_err(&client->dev, "error setting GPIO app_id\n");
+		return ret;
+	}
+
+	ret = mma9551_write_config_byte(client, MMA9551_APPID_GPIO,
+					reg + 1, bitnum);
+	if (ret < 0) {
+		dev_err(&client->dev, "error setting GPIO bit number\n");
+		return ret;
+	}
+
+	switch (pin) {
+	case mma9551_gpio6:
+		reg = MMA9551_GPIO_POL_LSB;
+		pol_mask = 1 << 6;
+		break;
+	case mma9551_gpio7:
+		reg = MMA9551_GPIO_POL_LSB;
+		pol_mask = 1 << 7;
+		break;
+	case mma9551_gpio8:
+		reg = MMA9551_GPIO_POL_MSB;
+		pol_mask = 1 << 0;
+		break;
+	case mma9551_gpio9:
+		reg = MMA9551_GPIO_POL_MSB;
+		pol_mask = 1 << 1;
+		break;
+	}
+	pol_val = polarity ? pol_mask : 0;
+
+	ret = mma9551_update_config_bits(client, MMA9551_APPID_GPIO, reg,
+					 pol_mask, pol_val);
+	if (ret < 0)
+		dev_err(&client->dev, "error setting GPIO polarity\n");
+
+	return ret;
+}
+EXPORT_SYMBOL(mma9551_gpio_config);
+
+/**
+ * mma9551_read_version() - read device version information
+ * @client:	I2C client
+ *
+ * Read version information and print device id and firmware version.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_read_version(struct i2c_client *client)
+{
+	struct mma9551_version_info info;
+	int ret;
+
+	ret = mma9551_transfer(client, MMA9551_APPID_VERSION, 0x00, 0x00,
+			       NULL, 0, (u8 *)&info, sizeof(info));
+	if (ret < 0)
+		return ret;
+
+	dev_info(&client->dev, "device ID 0x%x, firmware version %02x.%02x\n",
+		 be32_to_cpu(info.device_id), info.fw_version[0],
+		 info.fw_version[1]);
+
+	return 0;
+}
+EXPORT_SYMBOL(mma9551_read_version);
+
+/**
+ * mma9551_set_device_state() - sets HW power mode
+ * @client:	I2C client
+ * @enable:	Use true to power on device, false to cause the device
+ *		to enter sleep.
+ *
+ * Set power on/off for device using the Sleep/Wake Application.
+ * When enable is true, power on chip and enable doze mode.
+ * When enable is false, enter sleep mode (device remains in the
+ * lowest-power mode).
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_set_device_state(struct i2c_client *client, bool enable)
+{
+	return mma9551_update_config_bits(client, MMA9551_APPID_SLEEP_WAKE,
+					  MMA9551_SLEEP_CFG,
+					  MMA9551_SLEEP_CFG_SNCEN |
+					  MMA9551_SLEEP_CFG_FLEEN |
+					  MMA9551_SLEEP_CFG_SCHEN,
+					  enable ? MMA9551_SLEEP_CFG_SCHEN |
+					  MMA9551_SLEEP_CFG_FLEEN :
+					  MMA9551_SLEEP_CFG_SNCEN);
+}
+EXPORT_SYMBOL(mma9551_set_device_state);
+
+/**
+ * mma9551_set_power_state() - sets runtime PM state
+ * @client:	I2C client
+ * @on:		Use true to power on device, false to power off
+ *
+ * Resume or suspend the device using Runtime PM.
+ * The device will suspend after the autosuspend delay.
+ *
+ * Returns: 0 on success, negative value on failure.
+ */
+int mma9551_set_power_state(struct i2c_client *client, bool on)
+{
+#ifdef CONFIG_PM
+	int ret;
+
+	if (on)
+		ret = pm_runtime_get_sync(&client->dev);
+	else {
+		pm_runtime_mark_last_busy(&client->dev);
+		ret = pm_runtime_put_autosuspend(&client->dev);
+	}
+
+	if (ret < 0) {
+		dev_err(&client->dev,
+			"failed to change power state to %d\n", on);
+		if (on)
+			pm_runtime_put_noidle(&client->dev);
+
+		return ret;
+	}
+#endif
+
+	return 0;
+}
+EXPORT_SYMBOL(mma9551_set_power_state);
+
+/**
+ * mma9551_sleep() - sleep
+ * @freq:	Application frequency
+ *
+ * Firmware applications run at a certain frequency on the
+ * device. Sleep for one application cycle to make sure the
+ * application had time to run once and initialize set values.
+ */
+void mma9551_sleep(int freq)
+{
+	int sleep_val = 1000 / freq;
+
+	if (sleep_val < 20)
+		usleep_range(sleep_val * 1000, 20000);
+	else
+		msleep_interruptible(sleep_val);
+}
+EXPORT_SYMBOL(mma9551_sleep);
+
+/**
+ * mma9551_read_accel_chan() - read accelerometer channel
+ * @client:	I2C client
+ * @chan:	IIO channel
+ * @val:	Pointer to the accelerometer value read
+ * @val2:	Unused
+ *
+ * Read accelerometer value for the specified channel.
+ *
+ * Locking note: This function must be called with the device lock held.
+ * Locking is not handled inside the function. Callers should ensure they
+ * serialize access to the HW.
+ *
+ * Returns: IIO_VAL_INT on success, negative value on failure.
+ */
+int mma9551_read_accel_chan(struct i2c_client *client,
+			    const struct iio_chan_spec *chan,
+			    int *val, int *val2)
+{
+	u16 reg_addr;
+	s16 raw_accel;
+	int ret;
+
+	switch (chan->channel2) {
+	case IIO_MOD_X:
+		reg_addr = MMA9551_AFE_X_ACCEL_REG;
+		break;
+	case IIO_MOD_Y:
+		reg_addr = MMA9551_AFE_Y_ACCEL_REG;
+		break;
+	case IIO_MOD_Z:
+		reg_addr = MMA9551_AFE_Z_ACCEL_REG;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = mma9551_set_power_state(client, true);
+	if (ret < 0)
+		return ret;
+
+	ret = mma9551_read_status_word(client, MMA9551_APPID_AFE,
+				       reg_addr, &raw_accel);
+	if (ret < 0)
+		goto out_poweroff;
+
+	*val = raw_accel;
+
+	ret = IIO_VAL_INT;
+
+out_poweroff:
+	mma9551_set_power_state(client, false);
+	return ret;
+}
+EXPORT_SYMBOL(mma9551_read_accel_chan);
+
+/**
+ * mma9551_read_accel_scale() - read accelerometer scale
+ * @val:	Pointer to the accelerometer scale (int value)
+ * @val2:	Pointer to the accelerometer scale (micro value)
+ *
+ * Read accelerometer scale.
+ *
+ * Returns: IIO_VAL_INT_PLUS_MICRO.
+ */
+int mma9551_read_accel_scale(int *val, int *val2)
+{
+	*val = 0;
+	*val2 = 2440;
+
+	return IIO_VAL_INT_PLUS_MICRO;
+}
+EXPORT_SYMBOL(mma9551_read_accel_scale);
+
+MODULE_AUTHOR("Irina Tirdea <irina.tirdea@intel.com>");
+MODULE_AUTHOR("Vlad Dogaru <vlad.dogaru@intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MMA955xL sensors core");
diff --git a/drivers/iio/accel/mma9551_core.h b/drivers/iio/accel/mma9551_core.h
new file mode 100644
index 000000000000..e6efd027f49a
--- /dev/null
+++ b/drivers/iio/accel/mma9551_core.h
@@ -0,0 +1,66 @@
+/*
+ * Common code for Freescale MMA955x Intelligent Sensor Platform drivers
+ * 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.
+ */
+
+#ifndef _MMA9551_CORE_H_
+#define _MMA9551_CORE_H_
+
+/* Applications IDs */
+#define MMA9551_APPID_VERSION		0x00
+#define MMA9551_APPID_GPIO		0x03
+#define MMA9551_APPID_AFE		0x06
+#define MMA9551_APPID_TILT		0x0B
+#define MMA9551_APPID_SLEEP_WAKE	0x12
+#define MMA9551_APPID_RESET		0x17
+#define MMA9551_APPID_NONE		0xff
+
+#define MMA9551_AUTO_SUSPEND_DELAY_MS	2000
+
+enum mma9551_gpio_pin {
+	mma9551_gpio6 = 0,
+	mma9551_gpio7,
+	mma9551_gpio8,
+	mma9551_gpio9,
+	mma9551_gpio_max = mma9551_gpio9,
+};
+
+#define MMA9551_ACCEL_CHANNEL(axis) {				\
+	.type = IIO_ACCEL,					\
+	.modified = 1,						\
+	.channel2 = axis,					\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+}
+
+int mma9551_read_config_byte(struct i2c_client *client, u8 app_id,
+			     u16 reg, u8 *val);
+int mma9551_write_config_byte(struct i2c_client *client, u8 app_id,
+			      u16 reg, u8 val);
+int mma9551_read_status_byte(struct i2c_client *client, u8 app_id,
+			     u16 reg, u8 *val);
+int mma9551_read_status_word(struct i2c_client *client, u8 app_id,
+			     u16 reg, u16 *val);
+int mma9551_update_config_bits(struct i2c_client *client, u8 app_id,
+			       u16 reg, u8 mask, u8 val);
+int mma9551_gpio_config(struct i2c_client *client, enum mma9551_gpio_pin pin,
+			u8 app_id, u8 bitnum, int polarity);
+int mma9551_read_version(struct i2c_client *client);
+int mma9551_set_device_state(struct i2c_client *client, bool enable);
+int mma9551_set_power_state(struct i2c_client *client, bool on);
+void mma9551_sleep(int freq);
+int mma9551_read_accel_chan(struct i2c_client *client,
+			    const struct iio_chan_spec *chan,
+			    int *val, int *val2);
+int mma9551_read_accel_scale(int *val, int *val2);
+
+#endif /* _MMA9551_CORE_H_ */