Re: [PATCH 02/13] platform: cros_ec: Add cros_ec_sensor_hub driver

Jonathan Cameron
2019-10-05T15:36:50Z

On Sat, 5 Oct 2019 16:35:05 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> On Sun, 22 Sep 2019 10:50:10 -0700
> Gwendal Grignou <gwendal@chromium.org> wrote:
>
> > 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>
>
> Minor bits inline.
>
> My assumption for this sensor hub is it just acts as a
> combiner of data and doesn't guarantee that the sample
> rates are the same or anything like that? If it does
> it would be much nicer to support as a single sensor, but
> if not this approach is the best way.
Ah. I'd missed the point. This is really a bit rework of
existing functionality, not a new device type. Ignore me ;)
>
> > ---
> > drivers/iio/common/cros_ec_sensors/Kconfig | 2 +-
> > drivers/platform/chrome/Kconfig | 18 +-
> > drivers/platform/chrome/Makefile | 1 +
> > drivers/platform/chrome/cros_ec_sensorhub.c | 211 ++++++++++++++++++
> > .../linux/platform_data/cros_ec_sensorhub.h | 21 ++
> > 5 files changed, 249 insertions(+), 4 deletions(-)
> > 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..add967236cfb 100644
> > --- a/drivers/platform/chrome/Kconfig
> > +++ b/drivers/platform/chrome/Kconfig
> > @@ -132,9 +132,9 @@ config CROS_EC_LPC
> > module will be called cros_ec_lpcs.
> >
> > config CROS_EC_PROTO
> > - bool
> > - help
> > - ChromeOS EC communication protocol helpers.
> > + bool
> > + help
> > + ChromeOS EC communication protocol helpers.
> As already pointed out. Not relevant.
> >
> > config CROS_KBD_LED_BACKLIGHT
> > tristate "Backlight LED support for Chrome OS keyboards"
> > @@ -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 Senosr 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 sensorr
> > + 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..80688018ef66
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_ec_sensorhub.c
> > @@ -0,0 +1,211 @@
> > +// 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/fs.h>
> > +#include <linux/miscdevice.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/core.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_device.h>
> > +#include <linux/poll.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +#include <linux/uaccess.h>
> > +
> > +#include <linux/platform_data/cros_ec_sensorhub.h>
> > +
> > +#define DRV_NAME "cros-ec-sensorhub"
> > +
> > +static int cros_ec_sensors_register(struct device *dev,
> > + struct cros_ec_dev *ec)
> > +{
> > + int ret, i, id, sensor_num;
> > + struct mfd_cell *sensor_cells;
> > + struct cros_ec_sensor_platform *sensor_platforms;
> > + int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
> > + struct ec_params_motion_sense *params;
> > + struct ec_response_motion_sense *resp;
> > + struct cros_ec_command *msg;
> > +
> > + 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;
> > + }
> > +
> > + /*
> > + * Build an array of sensors driver and register them all.
>
> Single line comment syntax.
>
> > + */
> > + msg = kzalloc(sizeof(struct cros_ec_command) +
> > + max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
> > + if (msg == NULL) {
> > + ret = -ENOMEM;
> > + goto error;
> > + }
> > +
> > + 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;
> > +
> > + /*
> > + * Allocate 1 extra sensor if lid angle sensor is needed.
>
> Single line comment is enough.
>
> > + */
> > + sensor_cells = kcalloc(sensor_num + 1, sizeof(struct mfd_cell),
> > + GFP_KERNEL);
> > + if (sensor_cells == NULL) {
> > + ret = -ENOMEM;
> > + goto error;
> > + }
> > +
> > + sensor_platforms = kcalloc(sensor_num,
> > + sizeof(struct cros_ec_sensor_platform),
> > + GFP_KERNEL);
> > + if (sensor_platforms == NULL) {
> > + ret = -ENOMEM;
> > + goto error_platforms;
> > + }
> > +
> > + 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:
> > + sensor_cells[id].name = "cros-ec-accel";
> > + break;
> > + case MOTIONSENSE_TYPE_BARO:
> > + sensor_cells[id].name = "cros-ec-baro";
> > + break;
> > + case MOTIONSENSE_TYPE_GYRO:
> > + sensor_cells[id].name = "cros-ec-gyro";
> > + break;
> > + case MOTIONSENSE_TYPE_MAG:
> > + sensor_cells[id].name = "cros-ec-mag";
> > + break;
> > + case MOTIONSENSE_TYPE_PROX:
> > + sensor_cells[id].name = "cros-ec-prox";
> > + break;
> > + case MOTIONSENSE_TYPE_LIGHT:
> > + sensor_cells[id].name = "cros-ec-light";
> > + break;
> > + case MOTIONSENSE_TYPE_ACTIVITY:
> > + sensor_cells[id].name = "cros-ec-activity";
> > + break;
> > + default:
> > + dev_warn(dev, "unknown type %d\n", resp->info.type);
> > + continue;
> > + }
> > + sensor_platforms[id].sensor_num = i;
> > + sensor_cells[id].platform_data = &sensor_platforms[id];
> > + sensor_cells[id].pdata_size =
> > + sizeof(struct cros_ec_sensor_platform);
> > +
> > + sensor_type[resp->info.type]++;
> > + id++;
> > + }
> > +
> > + 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)) {
> > + sensor_cells[id].name = "cros-ec-lid-angle";
> > + id++;
> > + }
> > +
> > + ret = mfd_add_hotplug_devices(dev, sensor_cells, id);
> > + kfree(sensor_platforms);
> > +error_platforms:
> > + kfree(sensor_cells);
> > +error:
> > + kfree(msg);
> > + return ret;
> > +}
> > +
> > +static struct cros_ec_sensor_platform sensor_platforms[] = {
> > + { .sensor_num = 0 },
> > + { .sensor_num = 1 }
> > +};
> > +
> > +static const struct mfd_cell cros_ec_accel_legacy_cells[] = {
> > + {
> > + .name = "cros-ec-accel-legacy",
> > + .platform_data = &sensor_platforms[0],
> > + .pdata_size = sizeof(struct cros_ec_sensor_platform),
> > + },
> > + {
> > + .name = "cros-ec-accel-legacy",
> > + .platform_data = &sensor_platforms[1],
> > + .pdata_size = sizeof(struct cros_ec_sensor_platform),
> > + }
> > +};
> > +
> one line is normally enough ;)
> > +
> > +
> > +static int cros_ec_sensorhub_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct cros_ec_dev *ec = dev_get_drvdata(dev->parent);
> > + int ret;
> > + 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_sensors_register(dev, ec);
> > + } else {
> > + /* Workaroud for older EC firmware */
> > + ret = mfd_add_hotplug_devices(dev,
> > + cros_ec_accel_legacy_cells,
> > + ARRAY_SIZE(cros_ec_accel_legacy_cells));
> > + }
> > + if (ret)
> > + dev_err(dev, "failed to add EC sensors: error %d\n", ret);
> > + return ret;
> > +}
> > +
> > +static struct platform_driver cros_ec_sensorhub_driver = {
> > + .driver = {
> > + .name = DRV_NAME,
> > + },
> > + .probe = cros_ec_sensorhub_probe,
> > +};
> > +
> > +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..a8b64ecf5b9b
> > --- /dev/null
> > +++ b/include/linux/platform_data/cros_ec_sensorhub.h
> > @@ -0,0 +1,21 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * cros_ec_sensorhub- Chrome OS EC MEMS Sensor Hub driver.
> > + *
> > + * Copyright (C) 2019 Google, Inc
>
> My favourite moan of the day. what's the point of this blank line?
>
> > + *
> > + */
> > +
> > +#ifndef __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
> > +#define __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H
> > +
> > +#include <linux/platform_data/cros_ec_commands.h>
> > +
> > +/**
> > + * struct cros_ec_sensorhub - Sensor Hub device data.
>
> If it's kernel-doc should be complete (include the elements).
>
> > + */
> > +struct cros_ec_sensorhub {
> > + struct cros_ec_dev *ec;
> > +};
> > +
> > +#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
>