text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Sensor HUB driver that discovers sensors behind a ChromeOS Embedded
   * Controller.
   *
   * Copyright 2019 Google LLC
   */
  
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/module.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>
  #include <linux/types.h>
  
  #define DRV_NAME		"cros-ec-sensorhub"
  
  static void cros_ec_sensorhub_free_sensor(void *arg)
  {
  	struct platform_device *pdev = arg;
  
  	platform_device_unregister(pdev);
  }
  
  static int cros_ec_sensorhub_allocate_sensor(struct device *parent,
  					     char *sensor_name,
  					     int sensor_num)
  {
  	struct cros_ec_sensor_platform sensor_platforms = {
  		.sensor_num = sensor_num,
  	};
  	struct platform_device *pdev;
  
  	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_sensor,
  					pdev);
  }
  
  static int cros_ec_sensorhub_register(struct device *dev,
  				      struct cros_ec_sensorhub *sensorhub)
  {
  	int sensor_type[MOTIONSENSE_TYPE_MAX] = { 0 };
  	struct cros_ec_command *msg = sensorhub->msg;
  	struct cros_ec_dev *ec = sensorhub->ec;
  	int ret, i, sensor_num;
  	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;
  	}
  
  	sensorhub->sensor_num = sensor_num;
  	if (sensor_num == 0) {
  		dev_err(dev, "Zero sensors reported.\n");
  		return -EINVAL;
  	}
  
  	msg->version = 1;
  	msg->insize = sizeof(struct ec_response_motion_sense);
  	msg->outsize = sizeof(struct ec_params_motion_sense);
  
  	for (i = 0; i < sensor_num; i++) {
  		sensorhub->params->cmd = MOTIONSENSE_CMD_INFO;
  		sensorhub->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 (sensorhub->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",
  				 sensorhub->resp->info.type);
  			continue;
  		}
  
  		ret = cros_ec_sensorhub_allocate_sensor(dev, name, i);
  		if (ret)
  			return ret;
  
  		sensor_type[sensorhub->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_sensor(dev,
  							"cros-ec-lid-angle",
  							0);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  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);
  	struct cros_ec_sensorhub *data;
  	struct cros_ec_command *msg;
  	int ret;
  	int i;
  
  	msg = devm_kzalloc(dev, sizeof(struct cros_ec_command) +
  			   max((u16)sizeof(struct ec_params_motion_sense),
  			       ec->ec_dev->max_response), GFP_KERNEL);
  	if (!msg)
  		return -ENOMEM;
  
  	msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
  
  	data = devm_kzalloc(dev, sizeof(struct cros_ec_sensorhub), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	mutex_init(&data->cmd_lock);
  
  	data->dev = dev;
  	data->ec = ec;
  	data->msg = msg;
  	data->params = (struct ec_params_motion_sense *)msg->data;
  	data->resp = (struct ec_response_motion_sense *)msg->data;
  
  	dev_set_drvdata(dev, data);
  
  	/* Check whether this EC is a sensor hub. */
  	if (cros_ec_check_features(data->ec, EC_FEATURE_MOTION_SENSE)) {
  		ret = cros_ec_sensorhub_register(dev, data);
  		if (ret)
  			return ret;
  	} else {
  		/*
  		 * If the device has sensors but does not claim to
  		 * be a sensor hub, we are in legacy mode.
  		 */
  		data->sensor_num = 2;
  		for (i = 0; i < data->sensor_num; i++) {
  			ret = cros_ec_sensorhub_allocate_sensor(dev,
  						"cros-ec-accel-legacy", i);
  			if (ret)
  				return ret;
  		}
  	}
  
  	/*
  	 * If the EC does not have a FIFO, the sensors will query their data
  	 * themselves via sysfs or a software trigger.
  	 */
  	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
  		ret = cros_ec_sensorhub_ring_add(data);
  		if (ret)
  			return ret;
  		/*
  		 * The msg and its data is not under the control of the ring
  		 * handler.
  		 */
  		return devm_add_action_or_reset(dev,
  						cros_ec_sensorhub_ring_remove,
  						data);
  	}
  
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  /*
   * When the EC is suspending, we must stop sending interrupt,
   * we may use the same interrupt line for waking up the device.
   * Tell the EC to stop sending non-interrupt event on the iio ring.
   */
  static int cros_ec_sensorhub_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
  	struct cros_ec_dev *ec = sensorhub->ec;
  
  	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
  		return cros_ec_sensorhub_ring_fifo_enable(sensorhub, false);
  	return 0;
  }
  
  static int cros_ec_sensorhub_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct cros_ec_sensorhub *sensorhub = platform_get_drvdata(pdev);
  	struct cros_ec_dev *ec = sensorhub->ec;
  
  	if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO))
  		return cros_ec_sensorhub_ring_fifo_enable(sensorhub, true);
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(cros_ec_sensorhub_pm_ops,
  		cros_ec_sensorhub_suspend,
  		cros_ec_sensorhub_resume);
  
  static struct platform_driver cros_ec_sensorhub_driver = {
  	.driver = {
  		.name = DRV_NAME,
  		.pm = &cros_ec_sensorhub_pm_ops,
  	},
  	.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");
  