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 /* Format: HID-SENSOR-usage_id_in_hex */
27 /* Usage ID from spec for Time: 0x2000A0 */
28 #define DRIVER_NAME "HID-SENSOR-2000a0" /* must be lowercase */
29 
30 enum hid_time_channel {
31 	CHANNEL_SCAN_INDEX_YEAR,
32 	CHANNEL_SCAN_INDEX_MONTH,
33 	CHANNEL_SCAN_INDEX_DAY,
34 	CHANNEL_SCAN_INDEX_HOUR,
35 	CHANNEL_SCAN_INDEX_MINUTE,
36 	CHANNEL_SCAN_INDEX_SECOND,
37 	TIME_RTC_CHANNEL_MAX,
38 };
39 
40 struct hid_time_state {
41 	struct hid_sensor_hub_callbacks callbacks;
42 	struct hid_sensor_common common_attributes;
43 	struct hid_sensor_hub_attribute_info info[TIME_RTC_CHANNEL_MAX];
44 	struct rtc_time last_time;
45 	spinlock_t lock_last_time;
46 	struct completion comp_last_time;
47 	struct rtc_time time_buf;
48 	struct rtc_device *rtc;
49 };
50 
51 static const u32 hid_time_addresses[TIME_RTC_CHANNEL_MAX] = {
52 	HID_USAGE_SENSOR_TIME_YEAR,
53 	HID_USAGE_SENSOR_TIME_MONTH,
54 	HID_USAGE_SENSOR_TIME_DAY,
55 	HID_USAGE_SENSOR_TIME_HOUR,
56 	HID_USAGE_SENSOR_TIME_MINUTE,
57 	HID_USAGE_SENSOR_TIME_SECOND,
58 };
59 
60 /* Channel names for verbose error messages */
61 static const char * const hid_time_channel_names[TIME_RTC_CHANNEL_MAX] = {
62 	"year", "month", "day", "hour", "minute", "second",
63 };
64 
65 /* Callback handler to send event after all samples are received and captured */
66 static int hid_time_proc_event(struct hid_sensor_hub_device *hsdev,
67 				unsigned usage_id, void *priv)
68 {
69 	unsigned long flags;
70 	struct hid_time_state *time_state = platform_get_drvdata(priv);
71 
72 	spin_lock_irqsave(&time_state->lock_last_time, flags);
73 	time_state->last_time = time_state->time_buf;
74 	spin_unlock_irqrestore(&time_state->lock_last_time, flags);
75 	complete(&time_state->comp_last_time);
76 	return 0;
77 }
78 
79 static int hid_time_capture_sample(struct hid_sensor_hub_device *hsdev,
80 				unsigned usage_id, size_t raw_len,
81 				char *raw_data, void *priv)
82 {
83 	struct hid_time_state *time_state = platform_get_drvdata(priv);
84 	struct rtc_time *time_buf = &time_state->time_buf;
85 
86 	switch (usage_id) {
87 	case HID_USAGE_SENSOR_TIME_YEAR:
88 		time_buf->tm_year = *(u8 *)raw_data;
89 		if (time_buf->tm_year < 70)
90 			/* assume we are in 1970...2069 */
91 			time_buf->tm_year += 100;
92 		break;
93 	case HID_USAGE_SENSOR_TIME_MONTH:
94 		/* sensor sending the month as 1-12, we need 0-11 */
95 		time_buf->tm_mon = *(u8 *)raw_data-1;
96 		break;
97 	case HID_USAGE_SENSOR_TIME_DAY:
98 		time_buf->tm_mday = *(u8 *)raw_data;
99 		break;
100 	case HID_USAGE_SENSOR_TIME_HOUR:
101 		time_buf->tm_hour = *(u8 *)raw_data;
102 		break;
103 	case HID_USAGE_SENSOR_TIME_MINUTE:
104 		time_buf->tm_min = *(u8 *)raw_data;
105 		break;
106 	case HID_USAGE_SENSOR_TIME_SECOND:
107 		time_buf->tm_sec = *(u8 *)raw_data;
108 		break;
109 	default:
110 		return -EINVAL;
111 	}
112 	return 0;
113 }
114 
115 /* small helper, haven't found any other way */
116 static const char *hid_time_attrib_name(u32 attrib_id)
117 {
118 	static const char unknown[] = "unknown";
119 	unsigned i;
120 
121 	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
122 		if (hid_time_addresses[i] == attrib_id)
123 			return hid_time_channel_names[i];
124 	}
125 	return unknown; /* should never happen */
126 }
127 
128 static int hid_time_parse_report(struct platform_device *pdev,
129 				struct hid_sensor_hub_device *hsdev,
130 				unsigned usage_id,
131 				struct hid_time_state *time_state)
132 {
133 	int report_id, i;
134 
135 	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i)
136 		if (sensor_hub_input_get_attribute_info(hsdev,
137 				HID_INPUT_REPORT, usage_id,
138 				hid_time_addresses[i],
139 				&time_state->info[i]) < 0)
140 			return -EINVAL;
141 	/* Check the (needed) attributes for sanity */
142 	report_id = time_state->info[0].report_id;
143 	if (report_id < 0) {
144 		dev_err(&pdev->dev, "bad report ID!\n");
145 		return -EINVAL;
146 	}
147 	for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
148 		if (time_state->info[i].report_id != report_id) {
149 			dev_err(&pdev->dev,
150 				"not all needed attributes inside the same report!\n");
151 			return -EINVAL;
152 		}
153 		if (time_state->info[i].size != 1) {
154 			dev_err(&pdev->dev,
155 				"attribute '%s' not 8 bits wide!\n",
156 				hid_time_attrib_name(
157 					time_state->info[i].attrib_id));
158 			return -EINVAL;
159 		}
160 		if (time_state->info[i].units !=
161 				HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED &&
162 				/* allow attribute seconds with unit seconds */
163 				!(time_state->info[i].attrib_id ==
164 				HID_USAGE_SENSOR_TIME_SECOND &&
165 				time_state->info[i].units ==
166 				HID_USAGE_SENSOR_UNITS_SECOND)) {
167 			dev_err(&pdev->dev,
168 				"attribute '%s' hasn't a unit of type 'none'!\n",
169 				hid_time_attrib_name(
170 					time_state->info[i].attrib_id));
171 			return -EINVAL;
172 		}
173 		if (time_state->info[i].unit_expo) {
174 			dev_err(&pdev->dev,
175 				"attribute '%s' hasn't a unit exponent of 1!\n",
176 				hid_time_attrib_name(
177 					time_state->info[i].attrib_id));
178 			return -EINVAL;
179 		}
180 	}
181 
182 	return 0;
183 }
184 
185 static int hid_rtc_read_time(struct device *dev, struct rtc_time *tm)
186 {
187 	unsigned long flags;
188 	struct hid_time_state *time_state =
189 		platform_get_drvdata(to_platform_device(dev));
190 	int ret;
191 
192 	INIT_COMPLETION(time_state->comp_last_time);
193 	/* get a report with all values through requesting one value */
194 	sensor_hub_input_attr_get_raw_value(time_state->common_attributes.hsdev,
195 			HID_USAGE_SENSOR_TIME, hid_time_addresses[0],
196 			time_state->info[0].report_id);
197 	/* wait for all values (event) */
198 	ret = wait_for_completion_killable_timeout(
199 			&time_state->comp_last_time, HZ*6);
200 	if (ret > 0) {
201 		/* no error */
202 		spin_lock_irqsave(&time_state->lock_last_time, flags);
203 		*tm = time_state->last_time;
204 		spin_unlock_irqrestore(&time_state->lock_last_time, flags);
205 		return 0;
206 	}
207 	if (!ret)
208 		return -EIO; /* timeouted */
209 	return ret; /* killed (-ERESTARTSYS) */
210 }
211 
212 static const struct rtc_class_ops hid_time_rtc_ops = {
213 	.read_time = hid_rtc_read_time,
214 };
215 
216 static int hid_time_probe(struct platform_device *pdev)
217 {
218 	int ret = 0;
219 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
220 	struct hid_time_state *time_state = devm_kzalloc(&pdev->dev,
221 		sizeof(struct hid_time_state), GFP_KERNEL);
222 
223 	if (time_state == NULL)
224 		return -ENOMEM;
225 
226 	platform_set_drvdata(pdev, time_state);
227 
228 	spin_lock_init(&time_state->lock_last_time);
229 	init_completion(&time_state->comp_last_time);
230 	time_state->common_attributes.hsdev = hsdev;
231 	time_state->common_attributes.pdev = pdev;
232 
233 	ret = hid_sensor_parse_common_attributes(hsdev,
234 				HID_USAGE_SENSOR_TIME,
235 				&time_state->common_attributes);
236 	if (ret) {
237 		dev_err(&pdev->dev, "failed to setup common attributes!\n");
238 		return ret;
239 	}
240 
241 	ret = hid_time_parse_report(pdev, hsdev, HID_USAGE_SENSOR_TIME,
242 					time_state);
243 	if (ret) {
244 		dev_err(&pdev->dev, "failed to setup attributes!\n");
245 		return ret;
246 	}
247 
248 	time_state->callbacks.send_event = hid_time_proc_event;
249 	time_state->callbacks.capture_sample = hid_time_capture_sample;
250 	time_state->callbacks.pdev = pdev;
251 	ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_TIME,
252 					&time_state->callbacks);
253 	if (ret < 0) {
254 		dev_err(&pdev->dev, "register callback failed!\n");
255 		return ret;
256 	}
257 
258 	time_state->rtc = devm_rtc_device_register(&pdev->dev,
259 					"hid-sensor-time", &hid_time_rtc_ops,
260 					THIS_MODULE);
261 
262 	if (IS_ERR(time_state->rtc)) {
263 		dev_err(&pdev->dev, "rtc device register failed!\n");
264 		return PTR_ERR(time_state->rtc);
265 	}
266 
267 	return ret;
268 }
269 
270 static int hid_time_remove(struct platform_device *pdev)
271 {
272 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
273 
274 	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
275 
276 	return 0;
277 }
278 
279 static struct platform_driver hid_time_platform_driver = {
280 	.driver = {
281 		.name	= DRIVER_NAME,
282 		.owner	= THIS_MODULE,
283 	},
284 	.probe		= hid_time_probe,
285 	.remove		= hid_time_remove,
286 };
287 module_platform_driver(hid_time_platform_driver);
288 
289 MODULE_DESCRIPTION("HID Sensor Time");
290 MODULE_AUTHOR("Alexander Holler <holler@ahsoftware.de>");
291 MODULE_LICENSE("GPL");
292