Date:	Sun, 09 Dec 2012 13:55:30 +0100
From:	Lars-Peter Clausen <lars@...afoo.de>
To:	Alexander Holler <holler@...oftware.de>
CC:	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
	Jonathan Cameron <jic23@....ac.uk>, rtc-linux@...glegroups.com,
	Alessandro Zummo <a.zummo@...ertech.it>,
	srinivas pandruvada <srinivas.pandruvada@...el.com>
Subject: Re: [PATCH 3/3] iio: add rtc-driver for HID sensors of type time

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@...oftware.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@...oftware.de>");
> +MODULE_LICENSE("GPL");

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