1. 根目录:
2. drivers
3. iio
4. pressure
5. hid-sensor-press.c

/*
 * HID Sensors Driver
 * Copyright (c) 2014, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.
 *
 */
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/hid-sensor-hub.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include "../common/hid-sensors/hid-sensor-trigger.h"

#define CHANNEL_SCAN_INDEX_PRESSURE 0

struct press_state {
	struct hid_sensor_hub_callbacks callbacks;
	struct hid_sensor_common common_attributes;
	struct hid_sensor_hub_attribute_info press_attr;
	u32 press_data;
	int scale_pre_decml;
	int scale_post_decml;
	int scale_precision;
	int value_offset;
};

/* Channel definitions */
static const struct iio_chan_spec press_channels[] = {
	{
		.type = IIO_PRESSURE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
		BIT(IIO_CHAN_INFO_SCALE) |
		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
		BIT(IIO_CHAN_INFO_HYSTERESIS),
		.scan_index = CHANNEL_SCAN_INDEX_PRESSURE,
	}
};

/* Adjust channel real bits based on report descriptor */
static void press_adjust_channel_bit_mask(struct iio_chan_spec *channels,
					int channel, int size)
{
	channels[channel].scan_type.sign = 's';
	/* Real storage bits will change based on the report desc. */
	channels[channel].scan_type.realbits = size * 8;
	/* Maximum size of a sample to capture is u32 */
	channels[channel].scan_type.storagebits = sizeof(u32) * 8;
}

/* Channel read_raw handler */
static int press_read_raw(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      int *val, int *val2,
			      long mask)
{
	struct press_state *press_state = iio_priv(indio_dev);
	int report_id = -1;
	u32 address;
	int ret_type;

	*val = 0;
	*val2 = 0;
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		switch (chan->scan_index) {
		case  CHANNEL_SCAN_INDEX_PRESSURE:
			report_id = press_state->press_attr.report_id;
			address =
			HID_USAGE_SENSOR_ATMOSPHERIC_PRESSURE;
			break;
		default:
			report_id = -1;
			break;
		}
		if (report_id >= 0) {
			hid_sensor_power_state(&press_state->common_attributes,
						true);
			*val = sensor_hub_input_attr_get_raw_value(
				press_state->common_attributes.hsdev,
				HID_USAGE_SENSOR_PRESSURE, address,
				report_id,
				SENSOR_HUB_SYNC);
			hid_sensor_power_state(&press_state->common_attributes,
						false);
		} else {
			*val = 0;
			return -EINVAL;
		}
		ret_type = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_SCALE:
		*val = press_state->scale_pre_decml;
		*val2 = press_state->scale_post_decml;
		ret_type = press_state->scale_precision;
		break;
	case IIO_CHAN_INFO_OFFSET:
		*val = press_state->value_offset;
		ret_type = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_SAMP_FREQ:
		ret_type = hid_sensor_read_samp_freq_value(
				&press_state->common_attributes, val, val2);
		break;
	case IIO_CHAN_INFO_HYSTERESIS:
		ret_type = hid_sensor_read_raw_hyst_value(
				&press_state->common_attributes, val, val2);
		break;
	default:
		ret_type = -EINVAL;
		break;
	}

	return ret_type;
}

/* Channel write_raw handler */
static int press_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val,
			       int val2,
			       long mask)
{
	struct press_state *press_state = iio_priv(indio_dev);
	int ret = 0;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		ret = hid_sensor_write_samp_freq_value(
				&press_state->common_attributes, val, val2);
		break;
	case IIO_CHAN_INFO_HYSTERESIS:
		ret = hid_sensor_write_raw_hyst_value(
				&press_state->common_attributes, val, val2);
		break;
	default:
		ret = -EINVAL;
	}

	return ret;
}

static const struct iio_info press_info = {
	.driver_module = THIS_MODULE,
	.read_raw = &press_read_raw,
	.write_raw = &press_write_raw,
};

/* Function to push data to buffer */
static void hid_sensor_push_data(struct iio_dev *indio_dev, const void *data,
					int len)
{
	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
	iio_push_to_buffers(indio_dev, data);
}

/* Callback handler to send event after all samples are received and captured */
static int press_proc_event(struct hid_sensor_hub_device *hsdev,
				unsigned usage_id,
				void *priv)
{
	struct iio_dev *indio_dev = platform_get_drvdata(priv);
	struct press_state *press_state = iio_priv(indio_dev);

	dev_dbg(&indio_dev->dev, "press_proc_event\n");
	if (atomic_read(&press_state->common_attributes.data_ready))
		hid_sensor_push_data(indio_dev,
				&press_state->press_data,
				sizeof(press_state->press_data));

	return 0;
}

/* Capture samples in local storage */
static int press_capture_sample(struct hid_sensor_hub_device *hsdev,
				unsigned usage_id,
				size_t raw_len, char *raw_data,
				void *priv)
{
	struct iio_dev *indio_dev = platform_get_drvdata(priv);
	struct press_state *press_state = iio_priv(indio_dev);
	int ret = -EINVAL;

	switch (usage_id) {
	case HID_USAGE_SENSOR_ATMOSPHERIC_PRESSURE:
		press_state->press_data = *(u32 *)raw_data;
		ret = 0;
		break;
	default:
		break;
	}

	return ret;
}

/* Parse report which is specific to an usage id*/
static int press_parse_report(struct platform_device *pdev,
				struct hid_sensor_hub_device *hsdev,
				struct iio_chan_spec *channels,
				unsigned usage_id,
				struct press_state *st)
{
	int ret;

	ret = sensor_hub_input_get_attribute_info(hsdev, HID_INPUT_REPORT,
			usage_id,
			HID_USAGE_SENSOR_ATMOSPHERIC_PRESSURE,
			&st->press_attr);
	if (ret < 0)
		return ret;
	press_adjust_channel_bit_mask(channels, CHANNEL_SCAN_INDEX_PRESSURE,
					st->press_attr.size);

	dev_dbg(&pdev->dev, "press %x:%x\n", st->press_attr.index,
			st->press_attr.report_id);

	st->scale_precision = hid_sensor_format_scale(
				HID_USAGE_SENSOR_PRESSURE,
				&st->press_attr,
				&st->scale_pre_decml, &st->scale_post_decml);

	/* Set Sensitivity field ids, when there is no individual modifier */
	if (st->common_attributes.sensitivity.index < 0) {
		sensor_hub_input_get_attribute_info(hsdev,
			HID_FEATURE_REPORT, usage_id,
			HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS |
			HID_USAGE_SENSOR_DATA_ATMOSPHERIC_PRESSURE,
			&st->common_attributes.sensitivity);
		dev_dbg(&pdev->dev, "Sensitivity index:report %d:%d\n",
			st->common_attributes.sensitivity.index,
			st->common_attributes.sensitivity.report_id);
	}
	return ret;
}

/* Function to initialize the processing for usage id */
static int hid_press_probe(struct platform_device *pdev)
{
	int ret = 0;
	static const char *name = "press";
	struct iio_dev *indio_dev;
	struct press_state *press_state;
	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;

	indio_dev = devm_iio_device_alloc(&pdev->dev,
				sizeof(struct press_state));
	if (!indio_dev)
		return -ENOMEM;
	platform_set_drvdata(pdev, indio_dev);

	press_state = iio_priv(indio_dev);
	press_state->common_attributes.hsdev = hsdev;
	press_state->common_attributes.pdev = pdev;

	ret = hid_sensor_parse_common_attributes(hsdev,
					HID_USAGE_SENSOR_PRESSURE,
					&press_state->common_attributes);
	if (ret) {
		dev_err(&pdev->dev, "failed to setup common attributes\n");
		return ret;
	}

	indio_dev->channels = kmemdup(press_channels, sizeof(press_channels),
				      GFP_KERNEL);
	if (!indio_dev->channels) {
		dev_err(&pdev->dev, "failed to duplicate channels\n");
		return -ENOMEM;
	}

	ret = press_parse_report(pdev, hsdev,
				 (struct iio_chan_spec *)indio_dev->channels,
				 HID_USAGE_SENSOR_PRESSURE, press_state);
	if (ret) {
		dev_err(&pdev->dev, "failed to setup attributes\n");
		goto error_free_dev_mem;
	}

	indio_dev->num_channels =
				ARRAY_SIZE(press_channels);
	indio_dev->dev.parent = &pdev->dev;
	indio_dev->info = &press_info;
	indio_dev->name = name;
	indio_dev->modes = INDIO_DIRECT_MODE;

	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
		NULL, NULL);
	if (ret) {
		dev_err(&pdev->dev, "failed to initialize trigger buffer\n");
		goto error_free_dev_mem;
	}
	atomic_set(&press_state->common_attributes.data_ready, 0);
	ret = hid_sensor_setup_trigger(indio_dev, name,
				&press_state->common_attributes);
	if (ret) {
		dev_err(&pdev->dev, "trigger setup failed\n");
		goto error_unreg_buffer_funcs;
	}

	ret = iio_device_register(indio_dev);
	if (ret) {
		dev_err(&pdev->dev, "device register failed\n");
		goto error_remove_trigger;
	}

	press_state->callbacks.send_event = press_proc_event;
	press_state->callbacks.capture_sample = press_capture_sample;
	press_state->callbacks.pdev = pdev;
	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_PRESSURE,
					&press_state->callbacks);
	if (ret < 0) {
		dev_err(&pdev->dev, "callback reg failed\n");
		goto error_iio_unreg;
	}

	return ret;

error_iio_unreg:
	iio_device_unregister(indio_dev);
error_remove_trigger:
	hid_sensor_remove_trigger(&press_state->common_attributes);
error_unreg_buffer_funcs:
	iio_triggered_buffer_cleanup(indio_dev);
error_free_dev_mem:
	kfree(indio_dev->channels);
	return ret;
}

/* Function to deinitialize the processing for usage id */
static int hid_press_remove(struct platform_device *pdev)
{
	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct press_state *press_state = iio_priv(indio_dev);

	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_PRESSURE);
	iio_device_unregister(indio_dev);
	hid_sensor_remove_trigger(&press_state->common_attributes);
	iio_triggered_buffer_cleanup(indio_dev);
	kfree(indio_dev->channels);

	return 0;
}

static const struct platform_device_id hid_press_ids[] = {
	{
		/* Format: HID-SENSOR-usage_id_in_hex_lowercase */
		.name = "HID-SENSOR-200031",
	},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, hid_press_ids);

static struct platform_driver hid_press_platform_driver = {
	.id_table = hid_press_ids,
	.driver = {
		.name	= KBUILD_MODNAME,
		.pm	= &hid_sensor_pm_ops,
	},
	.probe		= hid_press_probe,
	.remove		= hid_press_remove,
};
module_platform_driver(hid_press_platform_driver);

MODULE_DESCRIPTION("HID Sensor Pressure");
MODULE_AUTHOR("Archana Patni <archana.patni@intel.com>");
MODULE_LICENSE("GPL");