Re: [PATCH 4/5] iio: mechanical: new HID sensor boolean switch

[Lars-Peter Clausen <lars@metafoo.de>]

On 06/11/2013 04:52 PM, Alexandre Relange wrote:
> Implements the Boolean Switch sensor from the USB sensor usage tables
> http://www.usb.org/developers/hidpage/HUTRR39b.pdf
> 
> This code is based on drivers/iio/light/hid-sensor-als.c
> 
> Signed-off-by: Alexandre Relange <alexandre@relange.org>

I'm wondering, how is this different from a GPIO (or GPI for that matter)?

> ---
>  drivers/iio/mechanical/Kconfig             |  14 ++
>  drivers/iio/mechanical/Makefile            |   1 +
>  drivers/iio/mechanical/hid-sensor-switch.c | 359 +++++++++++++++++++++++++++++
>  include/linux/hid-sensor-ids.h             |   4 +
>  4 files changed, 378 insertions(+)
>  create mode 100644 drivers/iio/mechanical/hid-sensor-switch.c
> 
> diff --git a/drivers/iio/mechanical/Kconfig b/drivers/iio/mechanical/Kconfig
> index b536fa2..e449588 100644
> --- a/drivers/iio/mechanical/Kconfig
> +++ b/drivers/iio/mechanical/Kconfig
> @@ -3,4 +3,18 @@
>  #
>  menu "Mechanical sensors"
>  
> +config HID_SENSOR_SWITCH
> +	depends on HID_SENSOR_HUB
> +	select IIO_BUFFER
> +	select IIO_TRIGGERED_BUFFER
> +	select HID_SENSOR_IIO_COMMON
> +	select HID_SENSOR_IIO_TRIGGER
> +	tristate "HID Boolean Switch"
> +	help
> +	  Say yes here to build support for the HID SENSOR
> +	  Boolean Switch sensor.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called hid-sensor-switch.
> +
>  endmenu
> diff --git a/drivers/iio/mechanical/Makefile b/drivers/iio/mechanical/Makefile
> index 716098f..30931c5 100644
> --- a/drivers/iio/mechanical/Makefile
> +++ b/drivers/iio/mechanical/Makefile
> @@ -1,3 +1,4 @@
>  #
>  # Makefile for IIO Mechanical sensors
>  #
> +obj-$(CONFIG_HID_SENSOR_SWITCH)	+= hid-sensor-switch.o
> diff --git a/drivers/iio/mechanical/hid-sensor-switch.c b/drivers/iio/mechanical/hid-sensor-switch.c
> new file mode 100644
> index 0000000..7027305
> --- /dev/null
> +++ b/drivers/iio/mechanical/hid-sensor-switch.c
> @@ -0,0 +1,359 @@
> +/*
> + * HID Sensors Driver
> + * Copyright (c) 2012, Intel Corporation.
> + * Copyright (c) 2013, Alexandre Relange
> + *
> + * 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; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
> + *
> + */
> +#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/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"
> +
> +/*Format: HID-SENSOR-usage_id_in_hex*/
> +/*Usage ID from spec for Boolean-Switch: 0x200061*/
> +#define DRIVER_NAME "HID-SENSOR-200061"
> +
> +#define CHANNEL_SCAN_INDEX_SWITCH 0
> +
> +struct switch_state {
> +	struct hid_sensor_hub_callbacks callbacks;
> +	struct hid_sensor_common common_attributes;
> +	struct hid_sensor_hub_attribute_info switch_attr;
> +	u32 value;
> +};
> +
> +/* Channel definitions */
> +static const struct iio_chan_spec switch_channels[] = {
> +	{
> +		.type = IIO_STATE,
> +		.info_mask_shared_by_type =
> +			BIT(IIO_CHAN_INFO_SAMP_FREQ) |
> +			BIT(IIO_CHAN_INFO_HYSTERESIS),
> +		.scan_index = CHANNEL_SCAN_INDEX_SWITCH,
> +	}
> +};
> +
> +/* Adjust channel real bits based on report descriptor */
> +static void switch_adjust_channel_bit_mask(struct iio_chan_spec *channels,
> +					int channel, int size)
> +{
> +	channels[channel].scan_type.sign = 'u';
> +	/* 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 switch_read_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int *val, int *val2,
> +			      long mask)
> +{
> +	struct switch_state *switch_state = iio_priv(indio_dev);
> +	int report_id = -1;
> +	u32 address;
> +	int ret;
> +	int ret_type;
> +
> +	*val = 0;
> +	*val2 = 0;
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->scan_index) {
> +		case  CHANNEL_SCAN_INDEX_SWITCH:
> +			report_id = switch_state->switch_attr.report_id;
> +			address =
> +			HID_USAGE_SENSOR_MECHA_BOOL_SWITCH_STATE;
> +			break;
> +		default:
> +			report_id = -1;
> +			break;
> +		}
> +		if (report_id >= 0)
> +			*val = sensor_hub_input_attr_get_raw_value(
> +				switch_state->common_attributes.hsdev,
> +				HID_USAGE_SENSOR_MECHA_BOOL_SWITCH, address,
> +				report_id);
> +		else {
> +			*val = 0;
> +			return -EINVAL;
> +		}
> +		ret_type = IIO_VAL_INT;
> +		break;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		ret = hid_sensor_read_samp_freq_value(
> +				&switch_state->common_attributes, val, val2);
> +		ret_type = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	case IIO_CHAN_INFO_HYSTERESIS:
> +		ret = hid_sensor_read_raw_hyst_value(
> +				&switch_state->common_attributes, val, val2);
> +		ret_type = IIO_VAL_INT_PLUS_MICRO;
> +		break;
> +	default:
> +		ret_type = -EINVAL;
> +		break;
> +	}
> +
> +	return ret_type;
> +}
> +
> +/* Channel write_raw handler */
> +static int switch_write_raw(struct iio_dev *indio_dev,
> +			       struct iio_chan_spec const *chan,
> +			       int val,
> +			       int val2,
> +			       long mask)
> +{
> +	struct switch_state *switch_state = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		ret = hid_sensor_write_samp_freq_value(
> +				&switch_state->common_attributes, val, val2);
> +		break;
> +	case IIO_CHAN_INFO_HYSTERESIS:
> +		ret = hid_sensor_write_raw_hyst_value(
> +				&switch_state->common_attributes, val, val2);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int switch_write_raw_get_fmt(struct iio_dev *indio_dev,
> +			       struct iio_chan_spec const *chan,
> +			       long mask)
> +{
> +	return IIO_VAL_INT_PLUS_MICRO;
> +}
> +
> +static const struct iio_info switch_info = {
> +	.driver_module = THIS_MODULE,
> +	.read_raw = &switch_read_raw,
> +	.write_raw = &switch_write_raw,
> +	.write_raw_get_fmt = &switch_write_raw_get_fmt,
> +};
> +
> +/* Function to push data to buffer */
> +static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
> +{
> +	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
> +	iio_push_to_buffers(indio_dev, (u8 *)data);
> +}
> +
> +/* Callback handler to send event after all samples are received and captured */
> +static int switch_proc_event(struct hid_sensor_hub_device *hsdev,
> +				unsigned usage_id,
> +				void *priv)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(priv);
> +	struct switch_state *switch_state = iio_priv(indio_dev);
> +
> +	dev_dbg(&indio_dev->dev, "switch_proc_event [%d]\n",
> +				switch_state->common_attributes.data_ready);
> +	if (switch_state->common_attributes.data_ready)
> +		hid_sensor_push_data(indio_dev,
> +				(u8 *)&switch_state->value,
> +				sizeof(switch_state->value));
> +
> +	return 0;
> +}
> +
> +/* Capture samples in local storage */
> +static int switch_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 switch_state *switch_state = iio_priv(indio_dev);
> +	int ret = -EINVAL;
> +
> +	switch (usage_id) {
> +	case HID_USAGE_SENSOR_MECHA_BOOL_SWITCH_STATE:
> +		switch_state->value = *(u32 *)raw_data;
> +		ret = 0;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +/* Parse report which is specific to an usage id*/
> +static int switch_parse_report(struct platform_device *pdev,
> +				struct hid_sensor_hub_device *hsdev,
> +				struct iio_chan_spec *channels,
> +				unsigned usage_id,
> +				struct switch_state *st)
> +{
> +	int ret;
> +
> +	ret = sensor_hub_input_get_attribute_info(hsdev, HID_INPUT_REPORT,
> +			usage_id,
> +			HID_USAGE_SENSOR_MECHA_BOOL_SWITCH_STATE,
> +			&st->switch_attr);
> +	if (ret < 0)
> +		return ret;
> +	switch_adjust_channel_bit_mask(channels, CHANNEL_SCAN_INDEX_SWITCH,
> +					st->switch_attr.size);
> +
> +	dev_dbg(&pdev->dev, "switch %x:%x\n", st->switch_attr.index,
> +			st->switch_attr.report_id);
> +
> +	return ret;
> +}
> +
> +/* Function to initialize the processing for usage id */
> +static int hid_switch_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;
> +	static const char *name = "switch";
> +	struct iio_dev *indio_dev;
> +	struct switch_state *switch_state;
> +	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> +	struct iio_chan_spec *channels;
> +
> +	indio_dev = iio_device_alloc(sizeof(struct switch_state));
> +	if (indio_dev == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	switch_state = iio_priv(indio_dev);
> +	switch_state->common_attributes.hsdev = hsdev;
> +	switch_state->common_attributes.pdev = pdev;
> +
> +	ret = hid_sensor_parse_common_attributes(hsdev, HID_USAGE_SENSOR_MECHA_BOOL_SWITCH,
> +					&switch_state->common_attributes);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to setup common attributes\n");
> +		goto error_free_dev;
> +	}
> +
> +	channels = kmemdup(switch_channels, sizeof(switch_channels), GFP_KERNEL);
> +	if (!channels) {
> +		ret = -ENOMEM;
> +		dev_err(&pdev->dev, "failed to duplicate channels\n");
> +		goto error_free_dev;
> +	}
> +
> +	ret = switch_parse_report(pdev, hsdev, channels,
> +				HID_USAGE_SENSOR_MECHA_BOOL_SWITCH, switch_state);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to setup attributes\n");
> +		goto error_free_dev_mem;
> +	}
> +
> +	indio_dev->channels = channels;
> +	indio_dev->num_channels =
> +				ARRAY_SIZE(switch_channels);
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->info = &switch_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;
> +	}
> +	switch_state->common_attributes.data_ready = false;
> +	ret = hid_sensor_setup_trigger(indio_dev, name,
> +				&switch_state->common_attributes);
> +	if (ret < 0) {
> +		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;
> +	}
> +
> +	switch_state->callbacks.send_event = switch_proc_event;
> +	switch_state->callbacks.capture_sample = switch_capture_sample;
> +	switch_state->callbacks.pdev = pdev;
> +	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_MECHA_BOOL_SWITCH,
> +					&switch_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(indio_dev);
> +error_unreg_buffer_funcs:
> +	iio_triggered_buffer_cleanup(indio_dev);
> +error_free_dev_mem:
> +	kfree(indio_dev->channels);
> +error_free_dev:
> +	iio_device_free(indio_dev);
> +error_ret:
> +	return ret;
> +}
> +
> +/* Function to deinitialize the processing for usage id */
> +static int hid_switch_remove(struct platform_device *pdev)
> +{
> +	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> +	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_MECHA_BOOL_SWITCH);
> +	iio_device_unregister(indio_dev);
> +	hid_sensor_remove_trigger(indio_dev);
> +	iio_triggered_buffer_cleanup(indio_dev);
> +	kfree(indio_dev->channels);
> +	iio_device_free(indio_dev);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver hid_switch_platform_driver = {
> +	.driver = {
> +		.name	= DRIVER_NAME,
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= hid_switch_probe,
> +	.remove		= hid_switch_remove,
> +};
> +module_platform_driver(hid_switch_platform_driver);
> +
> +MODULE_DESCRIPTION("HID Sensor Boolean Switch");
> +MODULE_AUTHOR("Alexandre Relange <alexandre@relange.org>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> index 6f24446..e469078 100644
> --- a/include/linux/hid-sensor-ids.h
> +++ b/include/linux/hid-sensor-ids.h
> @@ -31,6 +31,10 @@
>  #define HID_USAGE_SENSOR_ALS					0x200041
>  #define HID_USAGE_SENSOR_LIGHT_ILLUM				0x2004d1
>  
> +/* MECHANICAL: Boolean Switch: (200061) */
> +#define HID_USAGE_SENSOR_MECHA_BOOL_SWITCH			0x200061
> +#define HID_USAGE_SENSOR_MECHA_BOOL_SWITCH_STATE		0x200491
> +
>  /* Gyro 3D: (200076) */
>  #define HID_USAGE_SENSOR_GYRO_3D				0x200076
>  #define HID_USAGE_SENSOR_ANGL_VELOCITY_X_AXIS			0x200457