iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver
authorEnric Balletbo i Serra <enric.balletbo@collabora.com>
Mon, 1 Aug 2016 09:54:36 +0000 (11:54 +0200)
committerJonathan Cameron <jic23@kernel.org>
Tue, 25 Oct 2016 17:20:23 +0000 (18:20 +0100)
Handle 3d contiguous sensors like Accelerometers, Gyroscope and
Magnetometer that are presented by the ChromeOS EC Sensor hub.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/common/cros_ec_sensors/Kconfig
drivers/iio/common/cros_ec_sensors/Makefile
drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c [new file with mode: 0644]

index 24743be15a5b6ea1a9b993fe9acbee54db68489f..3349c9d2cf7a53d292e71996fc1b1d805e34d173 100644 (file)
@@ -12,3 +12,12 @@ config IIO_CROS_EC_SENSORS_CORE
          drivers.
          Define common attributes and sysfs interrupt handler.
 
+config IIO_CROS_EC_SENSORS
+       tristate "ChromeOS EC Contiguous Sensors"
+       select IIO_CROS_EC_SENSORS_CORE
+       select MFD_CROSS_EC
+       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.
index 95b690139bfd6320e07e73b351996f22e9cb0120..ec716ff2a7759ab5879db41a53a799d045b12901 100644 (file)
@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
+obj-$(CONFIG_IIO_CROS_EC_SENSORS) += cros_ec_sensors.o
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
new file mode 100644 (file)
index 0000000..48edeba
--- /dev/null
@@ -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 = IIO_VAL_INT;
+       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 = 0;
+       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");