[PATCH v4 02/17] platform: cros_ec: Add cros_ec_sensor_hub driver

Gwendal Grignou
2019-11-05T22:28:16Z

Similar to HID sensor stack, the new driver sits between cros_ec_dev
and the iio device drivers:

EC based iio device topology would be:
iio:device1 ->
...0/0000:00:1f.0/PNP0C09:00/GOOG0004:00/cros-ec-dev.6.auto/
cros-ec-sensorhub.7.auto/
cros-ec-accel.15.auto/
iio:device1

It will be expanded to control EC sensor FIFO.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
---
Changes in v4:
- Use platform_device_register_data in children registration.
- Free registered pdev children at remove time.
- Remove useless includes
- Check patch with --strict option
Use sizeof(*obj) instead of sizeof(struct ...obj)
Alignement
- Describe cros_ec_sensorhub in kernel-doc format.
Changes in v3:
- Fix doxygen comments
- Fix use of ret |=
- Remove unncessary goto.
Changes in v2:
- Remove unerelated changes.
- Fix spelling.
- Use !x instead of x == NULL
- Use platform_ API directly to register IIO sensors from
cros_ec_sensorhub.

drivers/iio/common/cros_ec_sensors/Kconfig | 2 +-
drivers/platform/chrome/Kconfig | 12 +
drivers/platform/chrome/Makefile | 1 +
drivers/platform/chrome/cros_ec_sensorhub.c | 223 ++++++++++++++++++
.../linux/platform_data/cros_ec_sensorhub.h | 33 +++
5 files changed, 270 insertions(+), 1 deletion(-)
create mode 100644 drivers/platform/chrome/cros_ec_sensorhub.c
create mode 100644 include/linux/platform_data/cros_ec_sensorhub.h

diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
index cdbb29cfb907..fefad9572790 100644
--- a/drivers/iio/common/cros_ec_sensors/Kconfig
+++ b/drivers/iio/common/cros_ec_sensors/Kconfig
@@ -4,7 +4,7 @@
#
config IIO_CROS_EC_SENSORS_CORE
tristate "ChromeOS EC Sensors Core"
- depends on SYSFS && CROS_EC
+ depends on SYSFS && CROS_EC_SENSORHUB
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
help
diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index ee5f08ea57b6..56a25317a6be 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -190,6 +190,18 @@ config CROS_EC_DEBUGFS
To compile this driver as a module, choose M here: the
module will be called cros_ec_debugfs.

+config CROS_EC_SENSORHUB
+ tristate "ChromeOS EC MEMS Sensor Hub"
+ depends on CROS_EC && IIO
+ help
+ Allow loading IIO sensors. This driver is loaded by MFD and will in
+ turn query the EC and register the sensors.
+ It also spreads the sensor data coming from the EC to the IIO sensor
+ object.
+
+ To compile this driver as a module, choose M here: the
+ module will be called cros_ec_sensorhub.
+
config CROS_EC_SYSFS
tristate "ChromeOS EC control and information through sysfs"
depends on MFD_CROS_EC_DEV && SYSFS
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 477ec3d1d1c9..a164c40dc099 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_chardev.o
obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o
+obj-$(CONFIG_CROS_EC_SENSORHUB) += cros_ec_sensorhub.o
obj-$(CONFIG_CROS_EC_VBC) += cros_ec_vbc.o
obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o
obj-$(CONFIG_CROS_EC_SYSFS) += cros_ec_sysfs.o
diff --git a/drivers/platform/chrome/cros_ec_sensorhub.c b/drivers/platform/chrome/cros_ec_sensorhub.c
new file mode 100644
index 000000000000..6a0aa84cf092
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_sensorhub.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SensorHub: driver that discover sensors behind
+ * a ChromeOS Embedded controller.
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/platform_data/cros_ec_commands.h>
+#include <linux/platform_data/cros_ec_proto.h>
+#include <linux/platform_data/cros_ec_sensorhub.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define DRV_NAME "cros-ec-sensorhub"
+
+static struct platform_device *cros_ec_sensorhub_allocate_single_sensor(
+ struct device *parent,
+ char *sensor_name,
+ int sensor_num)
+{
+ struct cros_ec_sensor_platform sensor_platforms = {
+ .sensor_num = sensor_num,
+ };
+
+ return platform_device_register_data(parent, sensor_name,
+ PLATFORM_DEVID_AUTO,
+ &sensor_platforms,
+ sizeof(sensor_platforms));
+}
+
+static int cros_ec_sensorhub_register(struct device *dev,
+ struct cros_ec_sensorhub *sensorhub)
+{
+ int ret, i, id, sensor_num;
+ struct cros_ec_dev *ec = sensorhub->ec;
+ int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
+ struct ec_params_motion_sense *params;
+ struct ec_response_motion_sense *resp;
+ struct cros_ec_command *msg;
+ struct platform_device *pdev;
+ char *name;
+
+ sensor_num = cros_ec_get_sensor_count(ec);
+ if (sensor_num < 0) {
+ dev_err(dev,
+ "Unable to retrieve sensor information (err:%d)\n",
+ sensor_num);
+ return sensor_num;
+ }
+
+ if (sensor_num == 0) {
+ dev_err(dev, "Zero sensors reported.\n");
+ return -EINVAL;
+ }
+
+ /* Prepare a message to send INFO command to each sensor. */
+ msg = kzalloc(sizeof(*msg) + max(sizeof(*params), sizeof(*resp)),
+ GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
+
+ msg->version = 1;
+ msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
+ msg->outsize = sizeof(*params);
+ msg->insize = sizeof(*resp);
+ params = (struct ec_params_motion_sense *)msg->data;
+ resp = (struct ec_response_motion_sense *)msg->data;
+
+ id = 0;
+ for (i = 0; i < sensor_num; i++) {
+ params->cmd = MOTIONSENSE_CMD_INFO;
+ params->info.sensor_num = i;
+ ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+ if (ret < 0) {
+ dev_warn(dev, "no info for EC sensor %d : %d/%d\n",
+ i, ret, msg->result);
+ continue;
+ }
+ switch (resp->info.type) {
+ case MOTIONSENSE_TYPE_ACCEL:
+ name = "cros-ec-accel";
+ break;
+ case MOTIONSENSE_TYPE_BARO:
+ name = "cros-ec-baro";
+ break;
+ case MOTIONSENSE_TYPE_GYRO:
+ name = "cros-ec-gyro";
+ break;
+ case MOTIONSENSE_TYPE_MAG:
+ name = "cros-ec-mag";
+ break;
+ case MOTIONSENSE_TYPE_PROX:
+ name = "cros-ec-prox";
+ break;
+ case MOTIONSENSE_TYPE_LIGHT:
+ name = "cros-ec-light";
+ break;
+ case MOTIONSENSE_TYPE_ACTIVITY:
+ name = "cros-ec-activity";
+ break;
+ default:
+ dev_warn(dev, "unknown type %d\n", resp->info.type);
+ continue;
+ }
+ pdev = cros_ec_sensorhub_allocate_single_sensor(dev, name, i);
+ if (IS_ERR(pdev)) {
+ ret = IS_ERR(pdev);
+ goto error;
+ }
+ sensorhub->sensor_pdev[id++] = pdev;
+ sensor_type[resp->info.type]++;
+ }
+
+ if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
+ ec->has_kb_wake_angle = true;
+
+ if (cros_ec_check_features(ec,
+ EC_FEATURE_REFINED_TABLET_MODE_HYSTERESIS)) {
+ pdev = cros_ec_sensorhub_allocate_single_sensor(dev,
+ "cros-ec-lid-angle", 0);
+ if (IS_ERR(pdev)) {
+ ret = IS_ERR(pdev);
+ goto error;
+ }
+ sensorhub->sensor_pdev[id++] = pdev;
+ }
+
+error:
+ kfree(msg);
+ return ret;
+}
+
+static int cros_ec_sensorhub_probe(struct platform_device *sensorhub_pdev)
+{
+ struct device *dev = &sensorhub_pdev->dev;
+ struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
+ int ret, i;
+ struct platform_device *pdev;
+ struct cros_ec_sensorhub *data =
+ kzalloc(sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
+
+ if (!data)
+ return -ENOMEM;
+
+ data->ec = ec;
+ dev_set_drvdata(dev, data);
+
+ /* Check whether this EC is a sensor hub. */
+ if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE)) {
+ ret = cros_ec_sensorhub_register(dev, data);
+ if (ret) {
+ dev_err(dev, "Register failed %d\n", ret);
+ goto unregister_sensors;
+ }
+ } else {
+ /*
+ * If the device has sensors but does not claim to
+ * be a sensor hub, we are in legacy mode.
+ */
+ for (i = 0; i < 2; i++) {
+ pdev = cros_ec_sensorhub_allocate_single_sensor(dev,
+ "cros-ec-accel-legacy", i);
+ if (IS_ERR(pdev)) {
+ ret = IS_ERR(pdev);
+ dev_err(dev, "Legacy %d failed %d\n", i, ret);
+ goto unregister_sensors;
+ } else {
+ data->sensor_pdev[i] = pdev;
+ }
+ }
+ }
+
+ return 0;
+
+unregister_sensors:
+ /*
+ * Given the probe has failed, we need to unregister all the sensors,
+ * not jutst the one that did not work: this device will be
+ * de-allocated.
+ */
+ for (i = 0; i < CROS_EC_SENSOR_PDEV_MAX; i++) {
+ pdev = data->sensor_pdev[i];
+ if (pdev)
+ platform_device_unregister(pdev);
+ }
+ return ret;
+}
+
+static int cros_ec_sensorhub_remove(struct platform_device *sensorhub_pdev)
+{
+ struct cros_ec_sensorhub *sensorhub =
+ platform_get_drvdata(sensorhub_pdev);
+ struct platform_device *pdev;
+ int i;
+
+ for (i = 0; i < CROS_EC_SENSOR_PDEV_MAX; i++) {
+ pdev = sensorhub->sensor_pdev[i];
+ if (pdev)
+ platform_device_unregister(pdev);
+ }
+
+ return 0;
+}
+
+static struct platform_driver cros_ec_sensorhub_driver = {
+ .driver = {
+ .name = DRV_NAME,
+ },
+ .probe = cros_ec_sensorhub_probe,
+ .remove = cros_ec_sensorhub_remove,
+};
+
+module_platform_driver(cros_ec_sensorhub_driver);
+
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
+MODULE_DESCRIPTION("ChromeOS EC MEMS Sensor Hub Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/platform_data/cros_ec_sensorhub.h b/include/linux/platform_data/cros_ec_sensorhub.h
new file mode 100644
index 000000000000..da0ba1d201e4
--- /dev/null
+++ b/include/linux/platform_data/cros_ec_sensorhub.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * cros_ec_sensorhub- Chrome OS EC MEMS Sensor Hub driver.
+ *
+ * Copyright (C) 2019 Google, Inc
+ */
+
+#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
+#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
+
+#include <linux/platform_data/cros_ec_commands.h>
+
+/* Maximal number of sensors supported by the EC. */
+#define CROS_EC_SENSOR_MAX 16
+
+/*
+ * Maximal number of sensors supported by the hub:
+ * We add one for the lid angle inclinometer sensor.
+ */
+#define CROS_EC_SENSOR_PDEV_MAX (CROS_EC_SENSOR_MAX + 1)
+
+/**
+ * struct cros_ec_sensorhub - Sensor Hub device data.
+ *
+ * @ec: Embedded Controller where the hub is located.
+ * @sensor_pdev: Array of platform_device, one per sensor.
+ */
+struct cros_ec_sensorhub {
+ struct cros_ec_dev *ec;
+ struct platform_device *sensor_pdev[CROS_EC_SENSOR_PDEV_MAX];
+};
+
+#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
--
2.24.0.rc1.363.gb1bccd3e3d-goog