1/*
2 * HID Sensor Time Driver
3 * Copyright (c) 2012, Alexander Holler.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12 * more details.
13 *
14 * You should have received a copy of the GNU General Public License along with
15 * this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 */
19#include <linux/device.h>
20#include <linux/platform_device.h>
21#include <linux/module.h>
22#include <linux/hid-sensor-hub.h>
23#include <linux/iio/iio.h>
24#include <linux/rtc.h>
25
26enum hid_time_channel {
27	CHANNEL_SCAN_INDEX_YEAR,
28	CHANNEL_SCAN_INDEX_MONTH,
29	CHANNEL_SCAN_INDEX_DAY,
30	CHANNEL_SCAN_INDEX_HOUR,
31	CHANNEL_SCAN_INDEX_MINUTE,
32	CHANNEL_SCAN_INDEX_SECOND,
33	TIME_RTC_CHANNEL_MAX,
34};
35
36struct hid_time_state {
37	struct hid_sensor_hub_callbacks callbacks;
38	struct hid_sensor_common common_attributes;
39	struct hid_sensor_hub_attribute_info info[TIME_RTC_CHANNEL_MAX];
40	struct rtc_time last_time;
41	spinlock_t lock_last_time;
42	struct completion comp_last_time;
43	struct rtc_time time_buf;
44	struct rtc_device *rtc;
45};
46
47static const u32 hid_time_addresses[TIME_RTC_CHANNEL_MAX] = {
48	HID_USAGE_SENSOR_TIME_YEAR,
49	HID_USAGE_SENSOR_TIME_MONTH,
50	HID_USAGE_SENSOR_TIME_DAY,
51	HID_USAGE_SENSOR_TIME_HOUR,
52	HID_USAGE_SENSOR_TIME_MINUTE,
53	HID_USAGE_SENSOR_TIME_SECOND,
54};
55
56/* Channel names for verbose error messages */
57static const char * const hid_time_channel_names[TIME_RTC_CHANNEL_MAX] = {
58	"year", "month", "day", "hour", "minute", "second",
59};
60
61/* Callback handler to send event after all samples are received and captured */
62static int hid_time_proc_event(struct hid_sensor_hub_device *hsdev,
63				unsigned usage_id, void *priv)
64{
65	unsigned long flags;
66	struct hid_time_state *time_state = platform_get_drvdata(priv);
67
68	spin_lock_irqsave(&time_state->lock_last_time, flags);
69	time_state->last_time = time_state->time_buf;
70	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
71	complete(&time_state->comp_last_time);
72	return 0;
73}
74
75static u32 hid_time_value(size_t raw_len, char *raw_data)
76{
77	switch (raw_len) {
78	case 1:
79		return *(u8 *)raw_data;
80	case 2:
81		return *(u16 *)raw_data;
82	case 4:
83		return *(u32 *)raw_data;
84	default:
85		return (u32)(~0U); /* 0xff... or -1 to denote an error */
86	}
87}
88
89static int hid_time_capture_sample(struct hid_sensor_hub_device *hsdev,
90				unsigned usage_id, size_t raw_len,
91				char *raw_data, void *priv)
92{
93	struct hid_time_state *time_state = platform_get_drvdata(priv);
94	struct rtc_time *time_buf = &time_state->time_buf;
95
96	switch (usage_id) {
97	case HID_USAGE_SENSOR_TIME_YEAR:
98		/*
99		 * The draft for HID-sensors (HUTRR39) currently doesn't define
100		 * the range for the year attribute. Therefor we support
101		 * 8 bit (0-99) and 16 or 32 bits (full) as size for the year.
102		 */
103		if (raw_len == 1) {
104			time_buf->tm_year = *(u8 *)raw_data;
105			if (time_buf->tm_year < 70)
106				/* assume we are in 1970...2069 */
107				time_buf->tm_year += 100;
108		} else
109			time_buf->tm_year =
110				(int)hid_time_value(raw_len, raw_data)-1900;
111		break;
112	case HID_USAGE_SENSOR_TIME_MONTH:
113		/* sensors are sending the month as 1-12, we need 0-11 */
114		time_buf->tm_mon = (int)hid_time_value(raw_len, raw_data)-1;
115		break;
116	case HID_USAGE_SENSOR_TIME_DAY:
117		time_buf->tm_mday = (int)hid_time_value(raw_len, raw_data);
118		break;
119	case HID_USAGE_SENSOR_TIME_HOUR:
120		time_buf->tm_hour = (int)hid_time_value(raw_len, raw_data);
121		break;
122	case HID_USAGE_SENSOR_TIME_MINUTE:
123		time_buf->tm_min = (int)hid_time_value(raw_len, raw_data);
124		break;
125	case HID_USAGE_SENSOR_TIME_SECOND:
126		time_buf->tm_sec = (int)hid_time_value(raw_len, raw_data);
127		break;
128	default:
129		return -EINVAL;
130	}
131	return 0;
132}
133
134/* small helper, haven't found any other way */
135static const char *hid_time_attrib_name(u32 attrib_id)
136{
137	static const char unknown[] = "unknown";
138	unsigned i;
139
140	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
141		if (hid_time_addresses[i] == attrib_id)
142			return hid_time_channel_names[i];
143	}
144	return unknown; /* should never happen */
145}
146
147static int hid_time_parse_report(struct platform_device *pdev,
148				struct hid_sensor_hub_device *hsdev,
149				unsigned usage_id,
150				struct hid_time_state *time_state)
151{
152	int report_id, i;
153
154	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i)
155		if (sensor_hub_input_get_attribute_info(hsdev,
156				HID_INPUT_REPORT, usage_id,
157				hid_time_addresses[i],
158				&time_state->info[i]) < 0)
159			return -EINVAL;
160	/* Check the (needed) attributes for sanity */
161	report_id = time_state->info[0].report_id;
162	if (report_id < 0) {
163		dev_err(&pdev->dev, "bad report ID!\n");
164		return -EINVAL;
165	}
166	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
167		if (time_state->info[i].report_id != report_id) {
168			dev_err(&pdev->dev,
169				"not all needed attributes inside the same report!\n");
170			return -EINVAL;
171		}
172		if (time_state->info[i].size == 3 ||
173				time_state->info[i].size > 4) {
174			dev_err(&pdev->dev,
175				"attribute '%s' not 8, 16 or 32 bits wide!\n",
176				hid_time_attrib_name(
177					time_state->info[i].attrib_id));
178			return -EINVAL;
179		}
180		if (time_state->info[i].units !=
181				HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED &&
182				/* allow attribute seconds with unit seconds */
183				!(time_state->info[i].attrib_id ==
184				HID_USAGE_SENSOR_TIME_SECOND &&
185				time_state->info[i].units ==
186				HID_USAGE_SENSOR_UNITS_SECOND)) {
187			dev_err(&pdev->dev,
188				"attribute '%s' hasn't a unit of type 'none'!\n",
189				hid_time_attrib_name(
190					time_state->info[i].attrib_id));
191			return -EINVAL;
192		}
193		if (time_state->info[i].unit_expo) {
194			dev_err(&pdev->dev,
195				"attribute '%s' hasn't a unit exponent of 1!\n",
196				hid_time_attrib_name(
197					time_state->info[i].attrib_id));
198			return -EINVAL;
199		}
200	}
201
202	return 0;
203}
204
205static int hid_rtc_read_time(struct device *dev, struct rtc_time *tm)
206{
207	unsigned long flags;
208	struct hid_time_state *time_state =
209		platform_get_drvdata(to_platform_device(dev));
210	int ret;
211
212	reinit_completion(&time_state->comp_last_time);
213	/* get a report with all values through requesting one value */
214	sensor_hub_input_attr_get_raw_value(time_state->common_attributes.hsdev,
215			HID_USAGE_SENSOR_TIME, hid_time_addresses[0],
216			time_state->info[0].report_id, SENSOR_HUB_SYNC);
217	/* wait for all values (event) */
218	ret = wait_for_completion_killable_timeout(
219			&time_state->comp_last_time, HZ*6);
220	if (ret > 0) {
221		/* no error */
222		spin_lock_irqsave(&time_state->lock_last_time, flags);
223		*tm = time_state->last_time;
224		spin_unlock_irqrestore(&time_state->lock_last_time, flags);
225		return 0;
226	}
227	if (!ret)
228		return -EIO; /* timeouted */
229	return ret; /* killed (-ERESTARTSYS) */
230}
231
232static const struct rtc_class_ops hid_time_rtc_ops = {
233	.read_time = hid_rtc_read_time,
234};
235
236static int hid_time_probe(struct platform_device *pdev)
237{
238	int ret = 0;
239	struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);
240	struct hid_time_state *time_state = devm_kzalloc(&pdev->dev,
241		sizeof(struct hid_time_state), GFP_KERNEL);
242
243	if (time_state == NULL)
244		return -ENOMEM;
245
246	platform_set_drvdata(pdev, time_state);
247
248	spin_lock_init(&time_state->lock_last_time);
249	init_completion(&time_state->comp_last_time);
250	time_state->common_attributes.hsdev = hsdev;
251	time_state->common_attributes.pdev = pdev;
252
253	ret = hid_sensor_parse_common_attributes(hsdev,
254				HID_USAGE_SENSOR_TIME,
255				&time_state->common_attributes);
256	if (ret) {
257		dev_err(&pdev->dev, "failed to setup common attributes!\n");
258		return ret;
259	}
260
261	ret = hid_time_parse_report(pdev, hsdev, HID_USAGE_SENSOR_TIME,
262					time_state);
263	if (ret) {
264		dev_err(&pdev->dev, "failed to setup attributes!\n");
265		return ret;
266	}
267
268	time_state->callbacks.send_event = hid_time_proc_event;
269	time_state->callbacks.capture_sample = hid_time_capture_sample;
270	time_state->callbacks.pdev = pdev;
271	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_TIME,
272					&time_state->callbacks);
273	if (ret < 0) {
274		dev_err(&pdev->dev, "register callback failed!\n");
275		return ret;
276	}
277
278	ret = sensor_hub_device_open(hsdev);
279	if (ret) {
280		dev_err(&pdev->dev, "failed to open sensor hub device!\n");
281		goto err_open;
282	}
283
284	/*
285	 * Enable HID input processing early in order to be able to read the
286	 * clock already in devm_rtc_device_register().
287	 */
288	hid_device_io_start(hsdev->hdev);
289
290	time_state->rtc = devm_rtc_device_register(&pdev->dev,
291					"hid-sensor-time", &hid_time_rtc_ops,
292					THIS_MODULE);
293
294	if (IS_ERR_OR_NULL(time_state->rtc)) {
295		hid_device_io_stop(hsdev->hdev);
296		ret = time_state->rtc ? PTR_ERR(time_state->rtc) : -ENODEV;
297		time_state->rtc = NULL;
298		dev_err(&pdev->dev, "rtc device register failed!\n");
299		goto err_rtc;
300	}
301
302	return ret;
303
304err_rtc:
305	sensor_hub_device_close(hsdev);
306err_open:
307	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
308	return ret;
309}
310
311static int hid_time_remove(struct platform_device *pdev)
312{
313	struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);
314
315	sensor_hub_device_close(hsdev);
316	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
317
318	return 0;
319}
320
321static struct platform_device_id hid_time_ids[] = {
322	{
323		/* Format: HID-SENSOR-usage_id_in_hex_lowercase */
324		.name = "HID-SENSOR-2000a0",
325	},
326	{ /* sentinel */ }
327};
328MODULE_DEVICE_TABLE(platform, hid_time_ids);
329
330static struct platform_driver hid_time_platform_driver = {
331	.id_table = hid_time_ids,
332	.driver = {
333		.name	= KBUILD_MODNAME,
334	},
335	.probe		= hid_time_probe,
336	.remove		= hid_time_remove,
337};
338module_platform_driver(hid_time_platform_driver);
339
340MODULE_DESCRIPTION("HID Sensor Time");
341MODULE_AUTHOR("Alexander Holler <holler@ahsoftware.de>");
342MODULE_LICENSE("GPL");
343