Re: [PATCH v5 02/18] platform: cros_ec: Add cros_ec_sensor_hub driver

[Jonathan Cameron]

On Fri, 15 Nov 2019 01:33:56 -0800
Gwendal Grignou <gwendal@xxxxxxxxxxxx> 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>
Looks good to me!

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>

> ---
> Changes in v5:
> - Use devm_add_action_or_reset() to free children devices.
>   In consequence, remove array and define not use for house keeping in
>   .h file, remove .remove entry point.
> - Use PTR_ERR() when needed.
> - Use demv_kzalloc for device memory allocation.
> 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   | 197 ++++++++++++++++++
>  .../linux/platform_data/cros_ec_sensorhub.h   |  22 ++
>  5 files changed, 233 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..884ac9a287f2 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
> +	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..85e3d3f25786
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_sensorhub.c
> @@ -0,0 +1,197 @@
> +// 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 void cros_ec_sensorhub_free_single_sensor(void *arg)
> +{
> +	struct platform_device *pdev = arg;
> +
> +	platform_device_unregister(pdev);
> +}
> +
> +static int cros_ec_sensorhub_allocate_single_sensor(struct device *parent,
> +						    char *sensor_name,
> +						    int sensor_num)
> +{
> +	struct platform_device *pdev;
> +	struct cros_ec_sensor_platform sensor_platforms = {
> +		.sensor_num = sensor_num,
> +	};
> +
> +	pdev = platform_device_register_data(parent, sensor_name,
> +					     PLATFORM_DEVID_AUTO,
> +					     &sensor_platforms,
> +					     sizeof(sensor_platforms));
> +	if (IS_ERR(pdev))
> +		return PTR_ERR(pdev);
> +
> +	return devm_add_action_or_reset(parent,
> +			cros_ec_sensorhub_free_single_sensor, pdev);
> +}
> +
> +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;
> +	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;
> +		}
> +		ret = cros_ec_sensorhub_allocate_single_sensor(dev, name, i);
> +		if (ret)
> +			goto error;
> +
> +		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)) {
> +		ret = cros_ec_sensorhub_allocate_single_sensor(dev,
> +							"cros-ec-lid-angle", 0);
> +		if (ret)
> +			goto error;
> +	}
> +	kfree(msg);
> +	return 0;
> +
> +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 cros_ec_sensorhub *data =
> +		devm_kzalloc(dev, 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);
> +			return ret;
> +		}
> +	} 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++) {
> +			ret = cros_ec_sensorhub_allocate_single_sensor(dev,
> +						"cros-ec-accel-legacy", i);
> +			if (ret) {
> +				dev_err(dev, "Legacy %d failed %d\n", i, ret);
> +				return ret;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +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..63c8dafb87e8
> --- /dev/null
> +++ b/include/linux/platform_data/cros_ec_sensorhub.h
> @@ -0,0 +1,22 @@
> +/* 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.
> + *
> + * @ec:           Embedded Controller where the hub is located.
> + */
> +struct cros_ec_sensorhub {
> +	struct cros_ec_dev *ec;
> +};
> +
> +#endif   /* __LINUX_PLATFORM_DATA_CROS_EC_SENSORHUB_H */