Merge branch 'ib-iio-mfd-4.9rc1' into togreg

Immutable branch to allow mfd changes to also be available in Lee's MFD tree.

drivers/iio/common/Kconfig

@@ -2,6 +2,7 @@
 # IIO common modules
 #
 
+source "drivers/iio/common/cros_ec_sensors/Kconfig"
 source "drivers/iio/common/hid-sensors/Kconfig"
 source "drivers/iio/common/ms_sensors/Kconfig"
 source "drivers/iio/common/ssp_sensors/Kconfig"

drivers/iio/common/Makefile

@@ -7,6 +7,7 @@
 #
 
 # When adding new entries keep the list in alphabetical order
+obj-y += cros_ec_sensors/
 obj-y += hid-sensors/
 obj-y += ms_sensors/
 obj-y += ssp_sensors/

drivers/iio/common/cros_ec_sensors/Kconfig

@@ -0,0 +1,22 @@
+#
+# Chrome OS Embedded Controller managed sensors library
+#
+config IIO_CROS_EC_SENSORS_CORE
+	tristate "ChromeOS EC Sensors Core"
+	depends on SYSFS && MFD_CROS_EC
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Base module for the ChromeOS EC Sensors module.
+	  Contains core functions used by other IIO CrosEC sensor
+	  drivers.
+	  Define common attributes and sysfs interrupt handler.
+
+config IIO_CROS_EC_SENSORS
+	tristate "ChromeOS EC Contiguous Sensors"
+	depends on IIO_CROS_EC_SENSORS_CORE
+	help
+	  Module to handle 3d contiguous sensors like
+	  Accelerometers, Gyroscope and Magnetometer that are
+	  presented by the ChromeOS EC Sensor hub.
+	  Creates an IIO device for each functions.

drivers/iio/common/cros_ec_sensors/Makefile

@@ -0,0 +1,6 @@
+#
+# Makefile for sensors seen through the ChromeOS EC sensor hub.
+#
+
+obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
+obj-$(CONFIG_IIO_CROS_EC_SENSORS) += cros_ec_sensors.o

drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c

@@ -0,0 +1,322 @@
+/*
+ * cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ * This driver uses the cros-ec interface to communicate with the Chrome OS
+ * EC about sensors data. Data access is presented through iio sysfs.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/kernel.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include "cros_ec_sensors_core.h"
+
+#define CROS_EC_SENSORS_MAX_CHANNELS 4
+
+/* State data for ec_sensors iio driver. */
+struct cros_ec_sensors_state {
+	/* Shared by all sensors */
+	struct cros_ec_sensors_core_state core;
+
+	struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
+};
+
+static int cros_ec_sensors_read(struct iio_dev *indio_dev,
+			  struct iio_chan_spec const *chan,
+			  int *val, int *val2, long mask)
+{
+	struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+	s16 data = 0;
+	s64 val64;
+	int i;
+	int ret;
+	int idx = chan->scan_index;
+
+	mutex_lock(&st->core.cmd_lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
+		if (ret < 0)
+			break;
+
+		*val = data;
+		break;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
+		st->core.param.sensor_offset.flags = 0;
+
+		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+		if (ret < 0)
+			break;
+
+		/* Save values */
+		for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
+			st->core.calib[i] =
+				st->core.resp->sensor_offset.offset[i];
+
+		*val = st->core.calib[idx];
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
+		st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
+
+		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+		if (ret < 0)
+			break;
+
+		val64 = st->core.resp->sensor_range.ret;
+		switch (st->core.type) {
+		case MOTIONSENSE_TYPE_ACCEL:
+			/*
+			 * EC returns data in g, iio exepects m/s^2.
+			 * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
+			 */
+			*val = div_s64(val64 * 980665, 10);
+			*val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
+			ret = IIO_VAL_FRACTIONAL;
+			break;
+		case MOTIONSENSE_TYPE_GYRO:
+			/*
+			 * EC returns data in dps, iio expects rad/s.
+			 * Do not use IIO_DEGREE_TO_RAD to avoid precision
+			 * loss. Round to the nearest integer.
+			 */
+			*val = div_s64(val64 * 314159 + 9000000ULL, 1000);
+			*val2 = 18000 << (CROS_EC_SENSOR_BITS - 1);
+			ret = IIO_VAL_FRACTIONAL;
+			break;
+		case MOTIONSENSE_TYPE_MAG:
+			/*
+			 * EC returns data in 16LSB / uT,
+			 * iio expects Gauss
+			 */
+			*val = val64;
+			*val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
+			ret = IIO_VAL_FRACTIONAL;
+			break;
+		default:
+			ret = -EINVAL;
+		}
+		break;
+	default:
+		ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
+						mask);
+		break;
+	}
+	mutex_unlock(&st->core.cmd_lock);
+
+	return ret;
+}
+
+static int cros_ec_sensors_write(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask)
+{
+	struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+	int i;
+	int ret;
+	int idx = chan->scan_index;
+
+	mutex_lock(&st->core.cmd_lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		st->core.calib[idx] = val;
+
+		/* Send to EC for each axis, even if not complete */
+		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
+		st->core.param.sensor_offset.flags =
+			MOTION_SENSE_SET_OFFSET;
+		for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
+			st->core.param.sensor_offset.offset[i] =
+				st->core.calib[i];
+		st->core.param.sensor_offset.temp =
+			EC_MOTION_SENSE_INVALID_CALIB_TEMP;
+
+		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		if (st->core.type == MOTIONSENSE_TYPE_MAG) {
+			ret = -EINVAL;
+			break;
+		}
+		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
+		st->core.param.sensor_range.data = val;
+
+		/* Always roundup, so caller gets at least what it asks for. */
+		st->core.param.sensor_range.roundup = 1;
+
+		ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+		break;
+	default:
+		ret = cros_ec_sensors_core_write(
+				&st->core, chan, val, val2, mask);
+		break;
+	}
+
+	mutex_unlock(&st->core.cmd_lock);
+
+	return ret;
+}
+
+static const struct iio_info ec_sensors_info = {
+	.read_raw = &cros_ec_sensors_read,
+	.write_raw = &cros_ec_sensors_write,
+	.driver_module = THIS_MODULE,
+};
+
+static int cros_ec_sensors_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
+	struct cros_ec_device *ec_device;
+	struct iio_dev *indio_dev;
+	struct cros_ec_sensors_state *state;
+	struct iio_chan_spec *channel;
+	int ret, i;
+
+	if (!ec_dev || !ec_dev->ec_dev) {
+		dev_warn(&pdev->dev, "No CROS EC device found.\n");
+		return -EINVAL;
+	}
+	ec_device = ec_dev->ec_dev;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
+	if (ret)
+		return ret;
+
+	indio_dev->info = &ec_sensors_info;
+	state = iio_priv(indio_dev);
+	for (channel = state->channels, i = CROS_EC_SENSOR_X;
+	     i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
+		/* Common part */
+		channel->info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_CALIBBIAS);
+		channel->info_mask_shared_by_all =
+			BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_FREQUENCY) |
+			BIT(IIO_CHAN_INFO_SAMP_FREQ);
+		channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
+		channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
+		channel->scan_index = i;
+		channel->ext_info = cros_ec_sensors_ext_info;
+		channel->modified = 1;
+		channel->channel2 = IIO_MOD_X + i;
+		channel->scan_type.sign = 's';
+
+		/* Sensor specific */
+		switch (state->core.type) {
+		case MOTIONSENSE_TYPE_ACCEL:
+			channel->type = IIO_ACCEL;
+			break;
+		case MOTIONSENSE_TYPE_GYRO:
+			channel->type = IIO_ANGL_VEL;
+			break;
+		case MOTIONSENSE_TYPE_MAG:
+			channel->type = IIO_MAGN;
+			break;
+		default:
+			dev_err(&pdev->dev, "Unknown motion sensor\n");
+			return -EINVAL;
+		}
+	}
+
+	/* Timestamp */
+	channel->type = IIO_TIMESTAMP;
+	channel->channel = -1;
+	channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
+	channel->scan_type.sign = 's';
+	channel->scan_type.realbits = 64;
+	channel->scan_type.storagebits = 64;
+
+	indio_dev->channels = state->channels;
+	indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
+
+	/* There is only enough room for accel and gyro in the io space */
+	if ((state->core.ec->cmd_readmem != NULL) &&
+	    (state->core.type != MOTIONSENSE_TYPE_MAG))
+		state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
+	else
+		state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
+
+	ret = iio_triggered_buffer_setup(indio_dev, NULL,
+					 cros_ec_sensors_capture, NULL);
+	if (ret)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret)
+		goto error_uninit_buffer;
+
+	return 0;
+
+error_uninit_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return ret;
+}
+
+static int cros_ec_sensors_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+	iio_device_unregister(indio_dev);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return 0;
+}
+
+static const struct platform_device_id cros_ec_sensors_ids[] = {
+	{
+		.name = "cros-ec-accel",
+	},
+	{
+		.name = "cros-ec-gyro",
+	},
+	{
+		.name = "cros-ec-mag",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
+
+static struct platform_driver cros_ec_sensors_platform_driver = {
+	.driver = {
+		.name	= "cros-ec-sensors",
+	},
+	.probe		= cros_ec_sensors_probe,
+	.remove		= cros_ec_sensors_remove,
+	.id_table	= cros_ec_sensors_ids,
+};
+module_platform_driver(cros_ec_sensors_platform_driver);
+
+MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
+MODULE_LICENSE("GPL v2");

drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c

@@ -0,0 +1,450 @@
+/*
+ * cros_ec_sensors_core - Common function for Chrome OS EC sensor driver.
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/kernel.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/platform_device.h>
+
+#include "cros_ec_sensors_core.h"
+
+static char *cros_ec_loc[] = {
+	[MOTIONSENSE_LOC_BASE] = "base",
+	[MOTIONSENSE_LOC_LID] = "lid",
+	[MOTIONSENSE_LOC_MAX] = "unknown",
+};
+
+int cros_ec_sensors_core_init(struct platform_device *pdev,
+			      struct iio_dev *indio_dev,
+			      bool physical_device)
+{
+	struct device *dev = &pdev->dev;
+	struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);
+	struct cros_ec_dev *ec = dev_get_drvdata(pdev->dev.parent);
+	struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	state->ec = ec->ec_dev;
+	state->msg = devm_kzalloc(&pdev->dev,
+				max((u16)sizeof(struct ec_params_motion_sense),
+				state->ec->max_response), GFP_KERNEL);
+	if (!state->msg)
+		return -ENOMEM;
+
+	state->resp = (struct ec_response_motion_sense *)state->msg->data;
+
+	mutex_init(&state->cmd_lock);
+
+	/* Set up the host command structure. */
+	state->msg->version = 2;
+	state->msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
+	state->msg->outsize = sizeof(struct ec_params_motion_sense);
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->name = pdev->name;
+
+	if (physical_device) {
+		indio_dev->modes = INDIO_DIRECT_MODE;
+
+		state->param.cmd = MOTIONSENSE_CMD_INFO;
+		state->param.info.sensor_num = sensor_platform->sensor_num;
+		if (cros_ec_motion_send_host_cmd(state, 0)) {
+			dev_warn(dev, "Can not access sensor info\n");
+			return -EIO;
+		}
+		state->type = state->resp->info.type;
+		state->loc = state->resp->info.location;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);
+
+int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *state,
+				 u16 opt_length)
+{
+	int ret;
+
+	if (opt_length)
+		state->msg->insize = min(opt_length, state->ec->max_response);
+	else
+		state->msg->insize = state->ec->max_response;
+
+	memcpy(state->msg->data, &state->param, sizeof(state->param));
+
+	ret = cros_ec_cmd_xfer_status(state->ec, state->msg);
+	if (ret < 0)
+		return -EIO;
+
+	if (ret &&
+	    state->resp != (struct ec_response_motion_sense *)state->msg->data)
+		memcpy(state->resp, state->msg->data, ret);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cros_ec_motion_send_host_cmd);
+
+static ssize_t cros_ec_sensors_calibrate(struct iio_dev *indio_dev,
+		uintptr_t private, const struct iio_chan_spec *chan,
+		const char *buf, size_t len)
+{
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int ret, i;
+	bool calibrate;
+
+	ret = strtobool(buf, &calibrate);
+	if (ret < 0)
+		return ret;
+	if (!calibrate)
+		return -EINVAL;
+
+	mutex_lock(&st->cmd_lock);
+	st->param.cmd = MOTIONSENSE_CMD_PERFORM_CALIB;
+	ret = cros_ec_motion_send_host_cmd(st, 0);
+	if (ret != 0) {
+		dev_warn(&indio_dev->dev, "Unable to calibrate sensor\n");
+	} else {
+		/* Save values */
+		for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
+			st->calib[i] = st->resp->perform_calib.offset[i];
+	}
+	mutex_unlock(&st->cmd_lock);
+
+	return ret ? ret : len;
+}
+
+static ssize_t cros_ec_sensors_loc(struct iio_dev *indio_dev,
+		uintptr_t private, const struct iio_chan_spec *chan,
+		char *buf)
+{
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", cros_ec_loc[st->loc]);
+}
+
+const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
+	{
+		.name = "calibrate",
+		.shared = IIO_SHARED_BY_ALL,
+		.write = cros_ec_sensors_calibrate
+	},
+	{
+		.name = "location",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = cros_ec_sensors_loc
+	},
+	{ },
+};
+EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);
+
+/**
+ * cros_ec_sensors_idx_to_reg - convert index into offset in shared memory
+ * @st:		pointer to state information for device
+ * @idx:	sensor index (should be element of enum sensor_index)
+ *
+ * Return:	address to read at
+ */
+static unsigned int cros_ec_sensors_idx_to_reg(
+					struct cros_ec_sensors_core_state *st,
+					unsigned int idx)
+{
+	/*
+	 * When using LPC interface, only space for 2 Accel and one Gyro.
+	 * First halfword of MOTIONSENSE_TYPE_ACCEL is used by angle.
+	 */
+	if (st->type == MOTIONSENSE_TYPE_ACCEL)
+		return EC_MEMMAP_ACC_DATA + sizeof(u16) *
+			(1 + idx + st->param.info.sensor_num *
+			 CROS_EC_SENSOR_MAX_AXIS);
+
+	return EC_MEMMAP_GYRO_DATA + sizeof(u16) * idx;
+}
+
+static int cros_ec_sensors_cmd_read_u8(struct cros_ec_device *ec,
+				       unsigned int offset, u8 *dest)
+{
+	return ec->cmd_readmem(ec, offset, 1, dest);
+}
+
+static int cros_ec_sensors_cmd_read_u16(struct cros_ec_device *ec,
+					 unsigned int offset, u16 *dest)
+{
+	__le16 tmp;
+	int ret = ec->cmd_readmem(ec, offset, 2, &tmp);
+
+	if (ret >= 0)
+		*dest = le16_to_cpu(tmp);
+
+	return ret;
+}
+
+/**
+ * cros_ec_sensors_read_until_not_busy() - read until is not busy
+ *
+ * @st:	pointer to state information for device
+ *
+ * Read from EC status byte until it reads not busy.
+ * Return: 8-bit status if ok, -errno on failure.
+ */
+static int cros_ec_sensors_read_until_not_busy(
+					struct cros_ec_sensors_core_state *st)
+{
+	struct cros_ec_device *ec = st->ec;
+	u8 status;
+	int ret, attempts = 0;
+
+	ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
+	if (ret < 0)
+		return ret;
+
+	while (status & EC_MEMMAP_ACC_STATUS_BUSY_BIT) {
+		/* Give up after enough attempts, return error. */
+		if (attempts++ >= 50)
+			return -EIO;
+
+		/* Small delay every so often. */
+		if (attempts % 5 == 0)
+			msleep(25);
+
+		ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
+						  &status);
+		if (ret < 0)
+			return ret;
+	}
+
+	return status;
+}
+
+/**
+ * read_ec_sensors_data_unsafe() - read acceleration data from EC shared memory
+ * @indio_dev:	pointer to IIO device
+ * @scan_mask:	bitmap of the sensor indices to scan
+ * @data:	location to store data
+ *
+ * This is the unsafe function for reading the EC data. It does not guarantee
+ * that the EC will not modify the data as it is being read in.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+static int cros_ec_sensors_read_data_unsafe(struct iio_dev *indio_dev,
+			 unsigned long scan_mask, s16 *data)
+{
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	struct cros_ec_device *ec = st->ec;
+	unsigned int i;
+	int ret;
+
+	/* Read all sensors enabled in scan_mask. Each value is 2 bytes. */
+	for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
+		ret = cros_ec_sensors_cmd_read_u16(ec,
+					     cros_ec_sensors_idx_to_reg(st, i),
+					     data);
+		if (ret < 0)
+			return ret;
+
+		data++;
+	}
+
+	return 0;
+}
+
+int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev,
+			     unsigned long scan_mask, s16 *data)
+{
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	struct cros_ec_device *ec = st->ec;
+	u8 samp_id = 0xff, status = 0;
+	int ret, attempts = 0;
+
+	/*
+	 * Continually read all data from EC until the status byte after
+	 * all reads reflects that the EC is not busy and the sample id
+	 * matches the sample id from before all reads. This guarantees
+	 * that data read in was not modified by the EC while reading.
+	 */
+	while ((status & (EC_MEMMAP_ACC_STATUS_BUSY_BIT |
+			  EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK)) != samp_id) {
+		/* If we have tried to read too many times, return error. */
+		if (attempts++ >= 5)
+			return -EIO;
+
+		/* Read status byte until EC is not busy. */
+		status = cros_ec_sensors_read_until_not_busy(st);
+		if (status < 0)
+			return status;
+
+		/*
+		 * Store the current sample id so that we can compare to the
+		 * sample id after reading the data.
+		 */
+		samp_id = status & EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK;
+
+		/* Read all EC data, format it, and store it into data. */
+		ret = cros_ec_sensors_read_data_unsafe(indio_dev, scan_mask,
+						       data);
+		if (ret < 0)
+			return ret;
+
+		/* Read status byte. */
+		ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
+						  &status);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_read_lpc);
+
+int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev,
+			     unsigned long scan_mask, s16 *data)
+{
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int ret;
+	unsigned int i;
+
+	/* Read all sensor data through a command. */
+	st->param.cmd = MOTIONSENSE_CMD_DATA;
+	ret = cros_ec_motion_send_host_cmd(st, sizeof(st->resp->data));
+	if (ret != 0) {
+		dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
+		return ret;
+	}
+
+	for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
+		*data = st->resp->data.data[i];
+		data++;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_read_cmd);
+
+irqreturn_t cros_ec_sensors_capture(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&st->cmd_lock);
+
+	/* Clear capture data. */
+	memset(st->samples, 0, indio_dev->scan_bytes);
+
+	/* Read data based on which channels are enabled in scan mask. */
+	ret = st->read_ec_sensors_data(indio_dev,
+				       *(indio_dev->active_scan_mask),
+				       (s16 *)st->samples);
+	if (ret < 0)
+		goto done;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, st->samples,
+					   iio_get_time_ns(indio_dev));
+
+done:
+	/*
+	 * Tell the core we are done with this trigger and ready for the
+	 * next one.
+	 */
+	iio_trigger_notify_done(indio_dev->trig);
+
+	mutex_unlock(&st->cmd_lock);
+
+	return IRQ_HANDLED;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_capture);
+
+int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
+			  struct iio_chan_spec const *chan,
+			  int *val, int *val2, long mask)
+{
+	int ret = IIO_VAL_INT;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+		st->param.ec_rate.data =
+			EC_MOTION_SENSE_NO_VALUE;
+
+		if (cros_ec_motion_send_host_cmd(st, 0))
+			ret = -EIO;
+		else
+			*val = st->resp->ec_rate.ret;
+		break;
+	case IIO_CHAN_INFO_FREQUENCY:
+		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
+		st->param.sensor_odr.data =
+			EC_MOTION_SENSE_NO_VALUE;
+
+		if (cros_ec_motion_send_host_cmd(st, 0))
+			ret = -EIO;
+		else
+			*val = st->resp->sensor_odr.ret;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_core_read);
+
+int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask)
+{
+	int ret = 0;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_FREQUENCY:
+		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
+		st->param.sensor_odr.data = val;
+
+		/* Always roundup, so caller gets at least what it asks for. */
+		st->param.sensor_odr.roundup = 1;
+
+		if (cros_ec_motion_send_host_cmd(st, 0))
+			ret = -EIO;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+		st->param.ec_rate.data = val;
+
+		if (cros_ec_motion_send_host_cmd(st, 0))
+			ret = -EIO;
+		else
+			st->curr_sampl_freq = val;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(cros_ec_sensors_core_write);
+
+MODULE_DESCRIPTION("ChromeOS EC sensor hub core functions");
+MODULE_LICENSE("GPL v2");

drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h

@@ -0,0 +1,175 @@
+/*
+ * ChromeOS EC sensor hub
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __CROS_EC_SENSORS_CORE_H
+#define __CROS_EC_SENSORS_CORE_H
+
+#include <linux/irqreturn.h>
+
+enum {
+	CROS_EC_SENSOR_X,
+	CROS_EC_SENSOR_Y,
+	CROS_EC_SENSOR_Z,
+	CROS_EC_SENSOR_MAX_AXIS,
+};
+
+/* EC returns sensor values using signed 16 bit registers */
+#define CROS_EC_SENSOR_BITS 16
+
+/*
+ * 4 16 bit channels are allowed.
+ * Good enough for current sensors, they use up to 3 16 bit vectors.
+ */
+#define CROS_EC_SAMPLE_SIZE  (sizeof(s64) * 2)
+
+/* Minimum sampling period to use when device is suspending */
+#define CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY 1000  /* 1 second */
+
+/**
+ * struct cros_ec_sensors_core_state - state data for EC sensors IIO driver
+ * @ec:				cros EC device structure
+ * @cmd_lock:			lock used to prevent simultaneous access to the
+ *				commands.
+ * @msg:			cros EC command structure
+ * @param:			motion sensor parameters structure
+ * @resp:			motion sensor response structure
+ * @type:			type of motion sensor
+ * @loc:			location where the motion sensor is placed
+ * @calib:			calibration parameters. Note that trigger
+ *				captured data will always provide the calibrated
+ *				data
+ * @samples:			static array to hold data from a single capture.
+ *				For each channel we need 2 bytes, except for
+ *				the timestamp. The timestamp is always last and
+ *				is always 8-byte aligned.
+ * @read_ec_sensors_data:	function used for accessing sensors values
+ * @cuur_sampl_freq:		current sampling period
+ */
+struct cros_ec_sensors_core_state {
+	struct cros_ec_device *ec;
+	struct mutex cmd_lock;
+
+	struct cros_ec_command *msg;
+	struct ec_params_motion_sense param;
+	struct ec_response_motion_sense *resp;
+
+	enum motionsensor_type type;
+	enum motionsensor_location loc;
+
+	s16 calib[CROS_EC_SENSOR_MAX_AXIS];
+
+	u8 samples[CROS_EC_SAMPLE_SIZE];
+
+	int (*read_ec_sensors_data)(struct iio_dev *indio_dev,
+				    unsigned long scan_mask, s16 *data);
+
+	int curr_sampl_freq;
+};
+
+/**
+ * cros_ec_sensors_read_lpc() - retrieve data from EC shared memory
+ * @indio_dev:	pointer to IIO device
+ * @scan_mask:	bitmap of the sensor indices to scan
+ * @data:	location to store data
+ *
+ * This is the safe function for reading the EC data. It guarantees that the
+ * data sampled was not modified by the EC while being read.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev, unsigned long scan_mask,
+			     s16 *data);
+
+/**
+ * cros_ec_sensors_read_cmd() - retrieve data using the EC command protocol
+ * @indio_dev:	pointer to IIO device
+ * @scan_mask:	bitmap of the sensor indices to scan
+ * @data:	location to store data
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev, unsigned long scan_mask,
+			     s16 *data);
+
+/**
+ * cros_ec_sensors_core_init() - basic initialization of the core structure
+ * @pdev:		platform device created for the sensors
+ * @indio_dev:		iio device structure of the device
+ * @physical_device:	true if the device refers to a physical device
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int cros_ec_sensors_core_init(struct platform_device *pdev,
+			      struct iio_dev *indio_dev, bool physical_device);
+
+/**
+ * cros_ec_sensors_capture() - the trigger handler function
+ * @irq:	the interrupt number.
+ * @p:		a pointer to the poll function.
+ *
+ * On a trigger event occurring, if the pollfunc is attached then this
+ * handler is called as a threaded interrupt (and hence may sleep). It
+ * is responsible for grabbing data from the device and pushing it into
+ * the associated buffer.
+ *
+ * Return: IRQ_HANDLED
+ */
+irqreturn_t cros_ec_sensors_capture(int irq, void *p);
+
+/**
+ * cros_ec_motion_send_host_cmd() - send motion sense host command
+ * @st:		pointer to state information for device
+ * @opt_length:	optional length to reduce the response size, useful on the data
+ *		path. Otherwise, the maximal allowed response size is used
+ *
+ * When called, the sub-command is assumed to be set in param->cmd.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *st,
+				 u16 opt_length);
+
+/**
+ * cros_ec_sensors_core_read() - function to request a value from the sensor
+ * @st:		pointer to state information for device
+ * @chan:	channel specification structure table
+ * @val:	will contain one element making up the returned value
+ * @val2:	will contain another element making up the returned value
+ * @mask:	specifies which values to be requested
+ *
+ * Return:	the type of value returned by the device
+ */
+int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
+			      struct iio_chan_spec const *chan,
+			      int *val, int *val2, long mask);
+
+/**
+ * cros_ec_sensors_core_write() - function to write a value to the sensor
+ * @st:		pointer to state information for device
+ * @chan:	channel specification structure table
+ * @val:	first part of value to write
+ * @val2:	second part of value to write
+ * @mask:	specifies which values to write
+ *
+ * Return:	the type of value returned by the device
+ */
+int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask);
+
+/* List of extended channel specification for all sensors */
+extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
+
+#endif  /* __CROS_EC_SENSORS_CORE_H */