Patchwork [3/3] iio: add rtc-driver for HID sensors of type time

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Submitter Alexander Holler
Date Dec. 9, 2012, 12:21 p.m.
Message ID <1355055699-2965-4-git-send-email-holler@ahsoftware.de>
Download mbox | patch
Permalink /patch/204697/
State New
Headers show

Comments

Alexander Holler - Dec. 9, 2012, 12:21 p.m.
This driver makes the time from HID sensors (hubs) which are offering
such available like any other RTC does.

Currently the time can only be read. Setting the time must be done
through sending a report, which currently isn't supported by
hid-sensor-hub.

It is necessary that all values like year, month etc, are send as
8bit values (1 byte each) and all of them in 1 report. Also the
spec HUTRR39b doesn't define the range of the year field, we
tread it as 0 - 99 because that's what most RTCs I know about are
offering.

Signed-off-by: Alexander Holler <holler@ahsoftware.de>
---
 drivers/iio/Kconfig                |    1 +
 drivers/iio/Makefile               |    1 +
 drivers/iio/time/Kconfig           |   14 ++
 drivers/iio/time/Makefile          |    5 +
 drivers/iio/time/hid-sensor-time.c |  397 ++++++++++++++++++++++++++++++++++++
 5 files changed, 418 insertions(+), 0 deletions(-)
 create mode 100644 drivers/iio/time/Kconfig
 create mode 100644 drivers/iio/time/Makefile
 create mode 100644 drivers/iio/time/hid-sensor-time.c
Lars-Peter Clausen - Dec. 9, 2012, 12:55 p.m.
On 12/09/2012 01:21 PM, Alexander Holler wrote:
> This driver makes the time from HID sensors (hubs) which are offering
> such available like any other RTC does.
> 
> Currently the time can only be read. Setting the time must be done
> through sending a report, which currently isn't supported by
> hid-sensor-hub.
> 
> It is necessary that all values like year, month etc, are send as
> 8bit values (1 byte each) and all of them in 1 report. Also the
> spec HUTRR39b doesn't define the range of the year field, we
> tread it as 0 - 99 because that's what most RTCs I know about are
> offering.

I don't think we should register a IIO device for this. Just an RTC device
should be fully sufficient.

> 
> Signed-off-by: Alexander Holler <holler@ahsoftware.de>
> ---
>  drivers/iio/Kconfig                |    1 +
>  drivers/iio/Makefile               |    1 +
>  drivers/iio/time/Kconfig           |   14 ++
>  drivers/iio/time/Makefile          |    5 +
>  drivers/iio/time/hid-sensor-time.c |  397 ++++++++++++++++++++++++++++++++++++
>  5 files changed, 418 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/iio/time/Kconfig
>  create mode 100644 drivers/iio/time/Makefile
>  create mode 100644 drivers/iio/time/hid-sensor-time.c
> 
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index fc937ac..78fa3ff 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -63,5 +63,6 @@ source "drivers/iio/dac/Kconfig"
>  source "drivers/iio/common/Kconfig"
>  source "drivers/iio/gyro/Kconfig"
>  source "drivers/iio/magnetometer/Kconfig"
> +source "drivers/iio/time/Kconfig"
>  
>  endif # IIO
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index 761f2b6..6a6da31 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -19,3 +19,4 @@ obj-y += dac/
>  obj-y += common/
>  obj-y += gyro/
>  obj-y += magnetometer/
> +obj-y += time/
> diff --git a/drivers/iio/time/Kconfig b/drivers/iio/time/Kconfig
> new file mode 100644
> index 0000000..0ca4682
> --- /dev/null
> +++ b/drivers/iio/time/Kconfig
> @@ -0,0 +1,14 @@
> +#
> +# Time sensors
> +#
> +menu "Time sensors"
> +
> +config HID_SENSOR_TIME
> +	depends on HID_SENSOR_HUB
> +	select HID_SENSOR_IIO_COMMON
> +	tristate "HID Time"
> +	help
> +	  Say yes here to build support for the HID SENSOR Time.
> +	  This drivers makes such sensors available as RTCs.
> +
> +endmenu
> diff --git a/drivers/iio/time/Makefile b/drivers/iio/time/Makefile
> new file mode 100644
> index 0000000..705fe0d
> --- /dev/null
> +++ b/drivers/iio/time/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for industrial I/O Time sensor driver
> +#
> +
> +obj-$(CONFIG_HID_SENSOR_TIME) += hid-sensor-time.o
> diff --git a/drivers/iio/time/hid-sensor-time.c b/drivers/iio/time/hid-sensor-time.c
> new file mode 100644
> index 0000000..a5993d6
> --- /dev/null
> +++ b/drivers/iio/time/hid-sensor-time.c
> @@ -0,0 +1,397 @@
> +/*
> + * HID Sensor Time Driver
> + * Copyright (c) 2012, Alexander Holler.
> + *
> + * 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/hid-sensor-hub.h>
> +#include <linux/iio/iio.h>
> +#include <linux/rtc.h>
> +#include "../common/hid-sensors/hid-sensor-attributes.h"
> +
> +/* Format: HID-SENSOR-usage_id_in_hex */
> +/* Usage ID from spec for Time: 0x2000A0 */
> +#define DRIVER_NAME "HID-SENSOR-2000a0" /* must be lowercase */
> +
> +enum hid_time_channel {
> +	CHANNEL_SCAN_INDEX_YEAR,
> +	CHANNEL_SCAN_INDEX_MONTH,
> +	CHANNEL_SCAN_INDEX_DAY,
> +	CHANNEL_SCAN_INDEX_HOUR,
> +	CHANNEL_SCAN_INDEX_MINUTE,
> +	CHANNEL_SCAN_INDEX_SECOND,
> +	TIME_RTC_CHANNEL_MAX,
> +};
> +
> +struct hid_time_state {
> +	struct hid_sensor_hub_callbacks callbacks;
> +	struct hid_sensor_iio_common common_attributes;
> +	struct hid_sensor_hub_attribute_info info[TIME_RTC_CHANNEL_MAX];
> +	struct rtc_time last_time;
> +	spinlock_t lock_last_time;
> +	struct completion comp_last_time;
> +	struct rtc_time time_buf;
> +	struct rtc_device *rtc;
> +};
> +
> +static const u32 hid_time_addresses[TIME_RTC_CHANNEL_MAX] = {
> +	HID_USAGE_SENSOR_TIME_YEAR,
> +	HID_USAGE_SENSOR_TIME_MONTH,
> +	HID_USAGE_SENSOR_TIME_DAY,
> +	HID_USAGE_SENSOR_TIME_HOUR,
> +	HID_USAGE_SENSOR_TIME_MINUTE,
> +	HID_USAGE_SENSOR_TIME_SECOND,
> +};
> +
> +/* Channel definitions */
> +static const struct iio_chan_spec hid_time_channels[TIME_RTC_CHANNEL_MAX] = {
> +	{
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_YEAR,
> +		.extend_name = "year",
> +	}, {
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_MONTH,
> +		.extend_name = "month",
> +	}, {
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_DAY,
> +		.extend_name = "day",
> +	}, {
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_HOUR,
> +		.extend_name = "hour",
> +	}, {
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_MINUTE,
> +		.extend_name = "minute",
> +	}, {
> +		.info_mask = IIO_CHAN_INFO_RAW,
> +		.scan_index = CHANNEL_SCAN_INDEX_SECOND,
> +		.extend_name = "second",
> +	}
> +};
> +
> +/* Adjust channel real bits based on report descriptor */
> +static void hid_time_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 u8 */
> +	channels[channel].scan_type.storagebits = sizeof(u8) * 8;
> +}
> +
> +static int hid_time_read_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int *val, int *val2,
> +			      long mask)
> +{
> +	struct hid_time_state *time_state = iio_priv(indio_dev);
> +	int report_id;
> +	u32 address;
> +
> +	*val = 0;
> +	*val2 = 0;
> +	if(mask)
> +		return -EINVAL;
> +	report_id = time_state->info[chan->scan_index].report_id;
> +	address = hid_time_addresses[chan->scan_index];
> +	if (report_id >= 0) {
> +		*val = sensor_hub_input_attr_get_raw_value(
> +			time_state->common_attributes.hsdev,
> +			HID_USAGE_SENSOR_TIME, address, report_id);
> +		return IIO_VAL_INT;
> +	}
> +	*val = 0;
> +	return -EINVAL;
> +}
> +
> +/* Callback handler to send event after all samples are received and captured */
> +static int hid_time_proc_event(struct hid_sensor_hub_device *hsdev,
> +				unsigned usage_id, void *priv)
> +{
> +	unsigned long flags;
> +	struct iio_dev *indio_dev = platform_get_drvdata(priv);
> +	struct hid_time_state *time_state = iio_priv(indio_dev);
> +
> +	spin_lock_irqsave(&time_state->lock_last_time, flags);
> +	time_state->last_time = time_state->time_buf;
> +	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
> +	complete(&time_state->comp_last_time);
> +	return 0;
> +}
> +
> +static int hid_time_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 hid_time_state *time_state = iio_priv(indio_dev);
> +	struct rtc_time *time_buf = &time_state->time_buf;
> +
> +	switch (usage_id) {
> +	case HID_USAGE_SENSOR_TIME_YEAR:
> +		time_buf->tm_year = *(u8 *)raw_data;
> +		if (time_buf->tm_year < 70)
> +			/* assume we are in 1970...2069 */
> +			time_buf->tm_year += 100;
> +		break;
> +	case HID_USAGE_SENSOR_TIME_MONTH:
> +		time_buf->tm_mon = --*(u8 *)raw_data;
> +		break;
> +	case HID_USAGE_SENSOR_TIME_DAY:
> +		time_buf->tm_mday = *(u8 *)raw_data;
> +		break;
> +	case HID_USAGE_SENSOR_TIME_HOUR:
> +		time_buf->tm_hour = *(u8 *)raw_data;
> +		break;
> +	case HID_USAGE_SENSOR_TIME_MINUTE:
> +		time_buf->tm_min = *(u8 *)raw_data;
> +		break;
> +	case HID_USAGE_SENSOR_TIME_SECOND:
> +		time_buf->tm_sec = *(u8 *)raw_data;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	return 0;
> +}
> +
> +static int hid_time_parse_report(struct platform_device *pdev,
> +				struct hid_sensor_hub_device *hsdev,
> +				struct iio_chan_spec *channels,
> +				unsigned usage_id, struct hid_time_state *st)
> +{
> +	int ret, i=0;
> +
> +	for (; i < TIME_RTC_CHANNEL_MAX; ++i) {
> +		ret = sensor_hub_input_get_attribute_info(hsdev,
> +				HID_INPUT_REPORT, usage_id,
> +				hid_time_addresses[i], &st->info[i]);
> +		if (ret < 0)
> +			return ret;
> +		hid_time_adjust_channel_bit_mask(channels, i,
> +				st->info[i].size);
> +	}
> +
> +	return ret;
> +}
> +
> +static int hid_rtc_read_time(struct device *dev,
> +	struct rtc_time *tm)
> +{
> +	int val;
> +	unsigned long flags;
> +	struct iio_dev *indio_dev =
> +		platform_get_drvdata(to_platform_device(dev));
> +	struct hid_time_state *time_state = iio_priv(indio_dev);
> +
> +	init_completion(&time_state->comp_last_time);
> +	/* start a read */
> +	if (hid_time_read_raw(indio_dev,
> +			&hid_time_channels[0], &val, &val, 0) == -EINVAL) {
> +		dev_err(dev, "unable to read time!\n");
> +		return -EIO;
> +	}
> +	/* wait for all values (event) */
> +	wait_for_completion_interruptible_timeout(&time_state->comp_last_time,
> +							HZ*6);
> +	spin_lock_irqsave(&time_state->lock_last_time, flags);
> +	*tm = time_state->last_time;
> +	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
> +
> +	return 0;
> +}
> +
> +/* small helper, haven't found any other way */
> +static const char *attrib_name(u32 attrib_id)
> +{
> +	unsigned i=0;
> +	static const char unknown[] = "unknown";
> +
> +	for(; i< TIME_RTC_CHANNEL_MAX; ++i) {
> +		if(hid_time_addresses[i] == attrib_id)
> +			return hid_time_channels[i].extend_name;
> +	}
> +	return unknown; /* should never happen */
> +}
> +
> +static const struct iio_info hid_time_info = {
> +	.driver_module = THIS_MODULE,
> +	.read_raw = &hid_time_read_raw,
> +};
> +
> +static const struct rtc_class_ops rtc_ops = {
> +	.read_time = hid_rtc_read_time,
> +};
> +
> +static int __devinit hid_time_probe(struct platform_device *pdev)
> +{
> +	int temp, ret = 0;
> +	static char *name = "hid_time";
> +	struct hid_time_state *time_state;
> +	struct iio_chan_spec *channels;
> +	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
> +	struct iio_dev *indio_dev = iio_device_alloc(sizeof(struct hid_time_state));
> +
> +	if (indio_dev == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	time_state = iio_priv(indio_dev);
> +	time_state->common_attributes.hsdev = hsdev;
> +	time_state->common_attributes.pdev = pdev;
> +
> +	ret = hid_sensor_parse_common_attributes(hsdev,
> +				HID_USAGE_SENSOR_TIME,
> +				&time_state->common_attributes);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to setup common attributes!\n");
> +		goto error_free_dev;
> +	}
> +
> +	channels = kmemdup(hid_time_channels,
> +					sizeof(hid_time_channels),
> +					GFP_KERNEL);
> +	if (!channels) {
> +		dev_err(&pdev->dev, "failed to duplicate channels!\n");
> +		goto error_free_dev;
> +	}
> +
> +	ret = hid_time_parse_report(pdev, hsdev, channels,
> +				HID_USAGE_SENSOR_TIME, time_state);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to setup attributes!\n");
> +		goto error_free_dev_mem;
> +	}
> +
> +	/* Check the attributes we need for sanity */
> +	temp = time_state->info[ret].report_id;
> +	if (temp<0) {
> +		dev_err(&pdev->dev, "bad report ID!\n");
> +		goto error_free_dev_mem;
> +	}
> +	for (ret = 0; ret< TIME_RTC_CHANNEL_MAX; ++ret) {
> +		if (time_state->info[ret].report_id != temp) {
> +			dev_err(&pdev->dev,
> +				"not all needed attributes inside the same report!\n");
> +			goto error_free_dev_mem;
> +		}
> +		if (time_state->info[ret].size != 1) {
> +			dev_err(&pdev->dev,
> +				"attribute '%s' not 8 bits wide!\n",
> +				attrib_name(time_state->info[ret].attrib_id));
> +			goto error_free_dev_mem;
> +		}
> +		if (time_state->info[ret].units !=
> +				HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED &&
> +				/* allow attribute seconds with unit seconds */
> +				!(time_state->info[ret].attrib_id ==
> +				HID_USAGE_SENSOR_TIME_SECOND &&
> +				time_state->info[ret].units ==
> +				HID_USAGE_SENSOR_UNITS_SECOND)) {
> +			dev_err(&pdev->dev,
> +				"attribute '%s' hasn't a unit of type 'none'!\n",
> +				attrib_name(time_state->info[ret].attrib_id));
> +			goto error_free_dev_mem;
> +		}
> +		if (time_state->info[ret].unit_expo) {
> +			dev_err(&pdev->dev,
> +				"attribute '%s' hasn't a unit exponent of 1!\n",
> +				attrib_name(time_state->info[ret].attrib_id));
> +			goto error_free_dev_mem;
> +		}
> +	}
> +
> +	indio_dev->channels = channels;
> +	indio_dev->num_channels = ARRAY_SIZE(hid_time_channels);
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->info = &hid_time_info;
> +	indio_dev->name = name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = iio_device_register(indio_dev);
> +	if (ret) {
> +		dev_err(&pdev->dev, "device register failed!\n");
> +		goto error_free_dev_mem;
> +	}
> +
> +	time_state->callbacks.send_event = hid_time_proc_event;
> +	time_state->callbacks.capture_sample = hid_time_capture_sample;
> +	time_state->callbacks.pdev = pdev;
> +	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_TIME,
> +					&time_state->callbacks);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "register callback failed!\n");
> +		goto error_iio_unreg;
> +	}
> +
> +	time_state->rtc = rtc_device_register("hid-sensor-time",
> +				&pdev->dev, &rtc_ops, THIS_MODULE);
> +
> +	if (IS_ERR(time_state->rtc)) {
> +		ret = PTR_ERR(time_state->rtc);
> +		dev_err(&pdev->dev, "rtc device register failed!\n");
> +		goto error_iio_unreg;
> +	}
> +
> +	return ret;
> +
> +error_iio_unreg:
> +	iio_device_unregister(indio_dev);
> +error_free_dev_mem:
> +	kfree(indio_dev->channels);
> +error_free_dev:
> +	iio_device_free(indio_dev);
> +error_ret:
> +	return ret;
> +}
> +
> +static int __devinit hid_time_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 hid_time_state *time_state = iio_priv(indio_dev);
> +
> +	if (!IS_ERR(time_state->rtc))
> +		rtc_device_unregister(time_state->rtc);
> +	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
> +	iio_device_unregister(indio_dev);
> +	kfree(indio_dev->channels);
> +	iio_device_free(indio_dev);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver hid_time_platform_driver = {
> +	.driver = {
> +		.name	= DRIVER_NAME,
> +		.owner	= THIS_MODULE,
> +	},
> +	.probe		= hid_time_probe,
> +	.remove		= hid_time_remove,
> +};
> +module_platform_driver(hid_time_platform_driver);
> +
> +MODULE_DESCRIPTION("HID Sensor Time");
> +MODULE_AUTHOR("Alexander Holler <holler@ahsoftware.de>");
> +MODULE_LICENSE("GPL");
Alexander Holler - Dec. 9, 2012, 4:40 p.m.
Am 09.12.2012 13:55, schrieb Lars-Peter Clausen:
> On 12/09/2012 01:21 PM, Alexander Holler wrote:
>> This driver makes the time from HID sensors (hubs) which are offering
>> such available like any other RTC does.
>>
>> Currently the time can only be read. Setting the time must be done
>> through sending a report, which currently isn't supported by
>> hid-sensor-hub.
>>
>> It is necessary that all values like year, month etc, are send as
>> 8bit values (1 byte each) and all of them in 1 report. Also the
>> spec HUTRR39b doesn't define the range of the year field, we
>> tread it as 0 - 99 because that's what most RTCs I know about are
>> offering.
>
> I don't think we should register a IIO device for this. Just an RTC device
> should be fully sufficient.
>

You would have to implement all the used services hid-sensor-hub offers 
in the rtc-driver again.

Regards,

Alexander
Alexander Holler - Dec. 9, 2012, 6:16 p.m.
Am 09.12.2012 17:40, schrieb Alexander Holler:
> Am 09.12.2012 13:55, schrieb Lars-Peter Clausen:
>> On 12/09/2012 01:21 PM, Alexander Holler wrote:
>>> This driver makes the time from HID sensors (hubs) which are offering
>>> such available like any other RTC does.
>>>
>>> Currently the time can only be read. Setting the time must be done
>>> through sending a report, which currently isn't supported by
>>> hid-sensor-hub.
>>>
>>> It is necessary that all values like year, month etc, are send as
>>> 8bit values (1 byte each) and all of them in 1 report. Also the
>>> spec HUTRR39b doesn't define the range of the year field, we
>>> tread it as 0 - 99 because that's what most RTCs I know about are
>>> offering.
>>
>> I don't think we should register a IIO device for this. Just an RTC
>> device
>> should be fully sufficient.
>>
>
> You would have to implement all the used services hid-sensor-hub offers
> in the rtc-driver again.

Besides that, time is part of the spec for HID sensors, which makes 
sense. Making that available as a RTC to read/set the time is imho the 
best to way support that. If you want a driver which doesn't use the HID 
sensor hub framework (or iio), you would either have to define your own 
standard or make sure it is interoperable with the HID sensor hub 
framework, which might not be trivial.

Regards,

Alexander
Lars-Peter Clausen - Dec. 9, 2012, 7:20 p.m.
On 12/09/2012 07:16 PM, Alexander Holler wrote:
> Am 09.12.2012 17:40, schrieb Alexander Holler:
>> Am 09.12.2012 13:55, schrieb Lars-Peter Clausen:
>>> On 12/09/2012 01:21 PM, Alexander Holler wrote:
>>>> This driver makes the time from HID sensors (hubs) which are offering
>>>> such available like any other RTC does.
>>>>
>>>> Currently the time can only be read. Setting the time must be done
>>>> through sending a report, which currently isn't supported by
>>>> hid-sensor-hub.
>>>>
>>>> It is necessary that all values like year, month etc, are send as
>>>> 8bit values (1 byte each) and all of them in 1 report. Also the
>>>> spec HUTRR39b doesn't define the range of the year field, we
>>>> tread it as 0 - 99 because that's what most RTCs I know about are
>>>> offering.
>>>
>>> I don't think we should register a IIO device for this. Just an RTC
>>> device
>>> should be fully sufficient.
>>>
>>
>> You would have to implement all the used services hid-sensor-hub offers
>> in the rtc-driver again.
> 
> Besides that, time is part of the spec for HID sensors, which makes
> sense. Making that available as a RTC to read/set the time is imho the
> best to way support that. If you want a driver which doesn't use the HID
> sensor hub framework (or iio), you would either have to define your own
> standard or make sure it is interoperable with the HID sensor hub
> framework, which might not be trivial.

I agree with what you wrote above. It just doesn't make sense to register a IIO
device for a RTC type device. Just rip out all the IIO related bits from the
driver and it will be fine.

- Lars
Alexander Holler - Dec. 10, 2012, 1:12 p.m.
Am 09.12.2012 20:20, schrieb Lars-Peter Clausen:

> I agree with what you wrote above. It just doesn't make sense to register a IIO
> device for a RTC type device. Just rip out all the IIO related bits from the
> driver and it will be fine.

Ah, I misunderstood you. Yes, you are right. As I already have removed 
the buffer, trigger and the exposure of attributes in sysfs (the driver 
started as a copy from one of the other hid sensor drivers), the IIO 
device itself doesn't make sense anymore.

I will remove it.

Regards,

Alexander

Patch

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index fc937ac..78fa3ff 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -63,5 +63,6 @@  source "drivers/iio/dac/Kconfig"
 source "drivers/iio/common/Kconfig"
 source "drivers/iio/gyro/Kconfig"
 source "drivers/iio/magnetometer/Kconfig"
+source "drivers/iio/time/Kconfig"
 
 endif # IIO
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 761f2b6..6a6da31 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -19,3 +19,4 @@  obj-y += dac/
 obj-y += common/
 obj-y += gyro/
 obj-y += magnetometer/
+obj-y += time/
diff --git a/drivers/iio/time/Kconfig b/drivers/iio/time/Kconfig
new file mode 100644
index 0000000..0ca4682
--- /dev/null
+++ b/drivers/iio/time/Kconfig
@@ -0,0 +1,14 @@ 
+#
+# Time sensors
+#
+menu "Time sensors"
+
+config HID_SENSOR_TIME
+	depends on HID_SENSOR_HUB
+	select HID_SENSOR_IIO_COMMON
+	tristate "HID Time"
+	help
+	  Say yes here to build support for the HID SENSOR Time.
+	  This drivers makes such sensors available as RTCs.
+
+endmenu
diff --git a/drivers/iio/time/Makefile b/drivers/iio/time/Makefile
new file mode 100644
index 0000000..705fe0d
--- /dev/null
+++ b/drivers/iio/time/Makefile
@@ -0,0 +1,5 @@ 
+#
+# Makefile for industrial I/O Time sensor driver
+#
+
+obj-$(CONFIG_HID_SENSOR_TIME) += hid-sensor-time.o
diff --git a/drivers/iio/time/hid-sensor-time.c b/drivers/iio/time/hid-sensor-time.c
new file mode 100644
index 0000000..a5993d6
--- /dev/null
+++ b/drivers/iio/time/hid-sensor-time.c
@@ -0,0 +1,397 @@ 
+/*
+ * HID Sensor Time Driver
+ * Copyright (c) 2012, Alexander Holler.
+ *
+ * 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/hid-sensor-hub.h>
+#include <linux/iio/iio.h>
+#include <linux/rtc.h>
+#include "../common/hid-sensors/hid-sensor-attributes.h"
+
+/* Format: HID-SENSOR-usage_id_in_hex */
+/* Usage ID from spec for Time: 0x2000A0 */
+#define DRIVER_NAME "HID-SENSOR-2000a0" /* must be lowercase */
+
+enum hid_time_channel {
+	CHANNEL_SCAN_INDEX_YEAR,
+	CHANNEL_SCAN_INDEX_MONTH,
+	CHANNEL_SCAN_INDEX_DAY,
+	CHANNEL_SCAN_INDEX_HOUR,
+	CHANNEL_SCAN_INDEX_MINUTE,
+	CHANNEL_SCAN_INDEX_SECOND,
+	TIME_RTC_CHANNEL_MAX,
+};
+
+struct hid_time_state {
+	struct hid_sensor_hub_callbacks callbacks;
+	struct hid_sensor_iio_common common_attributes;
+	struct hid_sensor_hub_attribute_info info[TIME_RTC_CHANNEL_MAX];
+	struct rtc_time last_time;
+	spinlock_t lock_last_time;
+	struct completion comp_last_time;
+	struct rtc_time time_buf;
+	struct rtc_device *rtc;
+};
+
+static const u32 hid_time_addresses[TIME_RTC_CHANNEL_MAX] = {
+	HID_USAGE_SENSOR_TIME_YEAR,
+	HID_USAGE_SENSOR_TIME_MONTH,
+	HID_USAGE_SENSOR_TIME_DAY,
+	HID_USAGE_SENSOR_TIME_HOUR,
+	HID_USAGE_SENSOR_TIME_MINUTE,
+	HID_USAGE_SENSOR_TIME_SECOND,
+};
+
+/* Channel definitions */
+static const struct iio_chan_spec hid_time_channels[TIME_RTC_CHANNEL_MAX] = {
+	{
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_YEAR,
+		.extend_name = "year",
+	}, {
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_MONTH,
+		.extend_name = "month",
+	}, {
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_DAY,
+		.extend_name = "day",
+	}, {
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_HOUR,
+		.extend_name = "hour",
+	}, {
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_MINUTE,
+		.extend_name = "minute",
+	}, {
+		.info_mask = IIO_CHAN_INFO_RAW,
+		.scan_index = CHANNEL_SCAN_INDEX_SECOND,
+		.extend_name = "second",
+	}
+};
+
+/* Adjust channel real bits based on report descriptor */
+static void hid_time_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 u8 */
+	channels[channel].scan_type.storagebits = sizeof(u8) * 8;
+}
+
+static int hid_time_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val, int *val2,
+			      long mask)
+{
+	struct hid_time_state *time_state = iio_priv(indio_dev);
+	int report_id;
+	u32 address;
+
+	*val = 0;
+	*val2 = 0;
+	if(mask)
+		return -EINVAL;
+	report_id = time_state->info[chan->scan_index].report_id;
+	address = hid_time_addresses[chan->scan_index];
+	if (report_id >= 0) {
+		*val = sensor_hub_input_attr_get_raw_value(
+			time_state->common_attributes.hsdev,
+			HID_USAGE_SENSOR_TIME, address, report_id);
+		return IIO_VAL_INT;
+	}
+	*val = 0;
+	return -EINVAL;
+}
+
+/* Callback handler to send event after all samples are received and captured */
+static int hid_time_proc_event(struct hid_sensor_hub_device *hsdev,
+				unsigned usage_id, void *priv)
+{
+	unsigned long flags;
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct hid_time_state *time_state = iio_priv(indio_dev);
+
+	spin_lock_irqsave(&time_state->lock_last_time, flags);
+	time_state->last_time = time_state->time_buf;
+	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
+	complete(&time_state->comp_last_time);
+	return 0;
+}
+
+static int hid_time_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 hid_time_state *time_state = iio_priv(indio_dev);
+	struct rtc_time *time_buf = &time_state->time_buf;
+
+	switch (usage_id) {
+	case HID_USAGE_SENSOR_TIME_YEAR:
+		time_buf->tm_year = *(u8 *)raw_data;
+		if (time_buf->tm_year < 70)
+			/* assume we are in 1970...2069 */
+			time_buf->tm_year += 100;
+		break;
+	case HID_USAGE_SENSOR_TIME_MONTH:
+		time_buf->tm_mon = --*(u8 *)raw_data;
+		break;
+	case HID_USAGE_SENSOR_TIME_DAY:
+		time_buf->tm_mday = *(u8 *)raw_data;
+		break;
+	case HID_USAGE_SENSOR_TIME_HOUR:
+		time_buf->tm_hour = *(u8 *)raw_data;
+		break;
+	case HID_USAGE_SENSOR_TIME_MINUTE:
+		time_buf->tm_min = *(u8 *)raw_data;
+		break;
+	case HID_USAGE_SENSOR_TIME_SECOND:
+		time_buf->tm_sec = *(u8 *)raw_data;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int hid_time_parse_report(struct platform_device *pdev,
+				struct hid_sensor_hub_device *hsdev,
+				struct iio_chan_spec *channels,
+				unsigned usage_id, struct hid_time_state *st)
+{
+	int ret, i=0;
+
+	for (; i < TIME_RTC_CHANNEL_MAX; ++i) {
+		ret = sensor_hub_input_get_attribute_info(hsdev,
+				HID_INPUT_REPORT, usage_id,
+				hid_time_addresses[i], &st->info[i]);
+		if (ret < 0)
+			return ret;
+		hid_time_adjust_channel_bit_mask(channels, i,
+				st->info[i].size);
+	}
+
+	return ret;
+}
+
+static int hid_rtc_read_time(struct device *dev,
+	struct rtc_time *tm)
+{
+	int val;
+	unsigned long flags;
+	struct iio_dev *indio_dev =
+		platform_get_drvdata(to_platform_device(dev));
+	struct hid_time_state *time_state = iio_priv(indio_dev);
+
+	init_completion(&time_state->comp_last_time);
+	/* start a read */
+	if (hid_time_read_raw(indio_dev,
+			&hid_time_channels[0], &val, &val, 0) == -EINVAL) {
+		dev_err(dev, "unable to read time!\n");
+		return -EIO;
+	}
+	/* wait for all values (event) */
+	wait_for_completion_interruptible_timeout(&time_state->comp_last_time,
+							HZ*6);
+	spin_lock_irqsave(&time_state->lock_last_time, flags);
+	*tm = time_state->last_time;
+	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
+
+	return 0;
+}
+
+/* small helper, haven't found any other way */
+static const char *attrib_name(u32 attrib_id)
+{
+	unsigned i=0;
+	static const char unknown[] = "unknown";
+
+	for(; i< TIME_RTC_CHANNEL_MAX; ++i) {
+		if(hid_time_addresses[i] == attrib_id)
+			return hid_time_channels[i].extend_name;
+	}
+	return unknown; /* should never happen */
+}
+
+static const struct iio_info hid_time_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw = &hid_time_read_raw,
+};
+
+static const struct rtc_class_ops rtc_ops = {
+	.read_time = hid_rtc_read_time,
+};
+
+static int __devinit hid_time_probe(struct platform_device *pdev)
+{
+	int temp, ret = 0;
+	static char *name = "hid_time";
+	struct hid_time_state *time_state;
+	struct iio_chan_spec *channels;
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	struct iio_dev *indio_dev = iio_device_alloc(sizeof(struct hid_time_state));
+
+	if (indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+	platform_set_drvdata(pdev, indio_dev);
+
+	time_state = iio_priv(indio_dev);
+	time_state->common_attributes.hsdev = hsdev;
+	time_state->common_attributes.pdev = pdev;
+
+	ret = hid_sensor_parse_common_attributes(hsdev,
+				HID_USAGE_SENSOR_TIME,
+				&time_state->common_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup common attributes!\n");
+		goto error_free_dev;
+	}
+
+	channels = kmemdup(hid_time_channels,
+					sizeof(hid_time_channels),
+					GFP_KERNEL);
+	if (!channels) {
+		dev_err(&pdev->dev, "failed to duplicate channels!\n");
+		goto error_free_dev;
+	}
+
+	ret = hid_time_parse_report(pdev, hsdev, channels,
+				HID_USAGE_SENSOR_TIME, time_state);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup attributes!\n");
+		goto error_free_dev_mem;
+	}
+
+	/* Check the attributes we need for sanity */
+	temp = time_state->info[ret].report_id;
+	if (temp<0) {
+		dev_err(&pdev->dev, "bad report ID!\n");
+		goto error_free_dev_mem;
+	}
+	for (ret = 0; ret< TIME_RTC_CHANNEL_MAX; ++ret) {
+		if (time_state->info[ret].report_id != temp) {
+			dev_err(&pdev->dev,
+				"not all needed attributes inside the same report!\n");
+			goto error_free_dev_mem;
+		}
+		if (time_state->info[ret].size != 1) {
+			dev_err(&pdev->dev,
+				"attribute '%s' not 8 bits wide!\n",
+				attrib_name(time_state->info[ret].attrib_id));
+			goto error_free_dev_mem;
+		}
+		if (time_state->info[ret].units !=
+				HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED &&
+				/* allow attribute seconds with unit seconds */
+				!(time_state->info[ret].attrib_id ==
+				HID_USAGE_SENSOR_TIME_SECOND &&
+				time_state->info[ret].units ==
+				HID_USAGE_SENSOR_UNITS_SECOND)) {
+			dev_err(&pdev->dev,
+				"attribute '%s' hasn't a unit of type 'none'!\n",
+				attrib_name(time_state->info[ret].attrib_id));
+			goto error_free_dev_mem;
+		}
+		if (time_state->info[ret].unit_expo) {
+			dev_err(&pdev->dev,
+				"attribute '%s' hasn't a unit exponent of 1!\n",
+				attrib_name(time_state->info[ret].attrib_id));
+			goto error_free_dev_mem;
+		}
+	}
+
+	indio_dev->channels = channels;
+	indio_dev->num_channels = ARRAY_SIZE(hid_time_channels);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &hid_time_info;
+	indio_dev->name = name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed!\n");
+		goto error_free_dev_mem;
+	}
+
+	time_state->callbacks.send_event = hid_time_proc_event;
+	time_state->callbacks.capture_sample = hid_time_capture_sample;
+	time_state->callbacks.pdev = pdev;
+	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_TIME,
+					&time_state->callbacks);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "register callback failed!\n");
+		goto error_iio_unreg;
+	}
+
+	time_state->rtc = rtc_device_register("hid-sensor-time",
+				&pdev->dev, &rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(time_state->rtc)) {
+		ret = PTR_ERR(time_state->rtc);
+		dev_err(&pdev->dev, "rtc device register failed!\n");
+		goto error_iio_unreg;
+	}
+
+	return ret;
+
+error_iio_unreg:
+	iio_device_unregister(indio_dev);
+error_free_dev_mem:
+	kfree(indio_dev->channels);
+error_free_dev:
+	iio_device_free(indio_dev);
+error_ret:
+	return ret;
+}
+
+static int __devinit hid_time_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 hid_time_state *time_state = iio_priv(indio_dev);
+
+	if (!IS_ERR(time_state->rtc))
+		rtc_device_unregister(time_state->rtc);
+	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
+	iio_device_unregister(indio_dev);
+	kfree(indio_dev->channels);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+static struct platform_driver hid_time_platform_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= hid_time_probe,
+	.remove		= hid_time_remove,
+};
+module_platform_driver(hid_time_platform_driver);
+
+MODULE_DESCRIPTION("HID Sensor Time");
+MODULE_AUTHOR("Alexander Holler <holler@ahsoftware.de>");
+MODULE_LICENSE("GPL");