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 
26 enum 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 
36 struct 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 
47 static 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 */
57 static 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 */
62 static 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 
75 static 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 
89 static 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 */
135 static 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 
147 static 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 
205 static 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 	INIT_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);
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 
232 static const struct rtc_class_ops hid_time_rtc_ops = {
233 	.read_time = hid_rtc_read_time,
234 };
235 
236 static int hid_time_probe(struct platform_device *pdev)
237 {
238 	int ret = 0;
239 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
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 	time_state->rtc = devm_rtc_device_register(&pdev->dev,
279 					"hid-sensor-time", &hid_time_rtc_ops,
280 					THIS_MODULE);
281 
282 	if (IS_ERR_OR_NULL(time_state->rtc)) {
283 		ret = time_state->rtc ? PTR_ERR(time_state->rtc) : -ENODEV;
284 		time_state->rtc = NULL;
285 		sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
286 		dev_err(&pdev->dev, "rtc device register failed!\n");
287 	}
288 
289 	return ret;
290 }
291 
292 static int hid_time_remove(struct platform_device *pdev)
293 {
294 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
295 
296 	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
297 
298 	return 0;
299 }
300 
301 static struct platform_device_id hid_time_ids[] = {
302 	{
303 		/* Format: HID-SENSOR-usage_id_in_hex_lowercase */
304 		.name = "HID-SENSOR-2000a0",
305 	},
306 	{ /* sentinel */ }
307 };
308 MODULE_DEVICE_TABLE(platform, hid_time_ids);
309 
310 static struct platform_driver hid_time_platform_driver = {
311 	.id_table = hid_time_ids,
312 	.driver = {
313 		.name	= KBUILD_MODNAME,
314 		.owner	= THIS_MODULE,
315 	},
316 	.probe		= hid_time_probe,
317 	.remove		= hid_time_remove,
318 };
319 module_platform_driver(hid_time_platform_driver);
320 
321 MODULE_DESCRIPTION("HID Sensor Time");
322 MODULE_AUTHOR("Alexander Holler <holler@ahsoftware.de>");
323 MODULE_LICENSE("GPL");
324