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

From: Enric Balletbo i Serra
Date: Tue Oct 01 2019 - 06:32:04 EST

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Hi Gwendal,

Some comments below.

On 22/9/19 19:50, Gwendal Grignou 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@xxxxxxxxxxxx>
> ---
> 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.
>

That change is unrelated to the patch.

> 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"

Typo: s/Senosr/Sensor/

> + 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

Typo : s/sensorr/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..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.
> + */
> + 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.
> + */
> + 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);

That's problematic.

In general using mfd_* in a !MFD driver is considered a hack. I know that the
Intel Sensor Hub and few other drivers does this but it's not correct and I know
Lee won't be happy with this change.

I think we should be using the platform_device_add() API here.

Thanks,
Enric

> + 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),
> + }
> +};
> +
> +
> +
> +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@xxxxxxxxxxxx>");
> +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
> + *
> + */
> +
> +#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.
> + */
> +struct cros_ec_sensorhub {
> + struct cros_ec_dev *ec;
> +};
> +
> +#endif /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */
>

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