1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Driver for cros-ec proximity sensor exposed through MKBP switch
4  *
5  * Copyright 2021 Google LLC.
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/mutex.h>
11 #include <linux/notifier.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 
17 #include <linux/platform_data/cros_ec_commands.h>
18 #include <linux/platform_data/cros_ec_proto.h>
19 
20 #include <linux/iio/events.h>
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 
24 #include <asm/unaligned.h>
25 
26 struct cros_ec_mkbp_proximity_data {
27 	struct cros_ec_device *ec;
28 	struct iio_dev *indio_dev;
29 	struct mutex lock;
30 	struct notifier_block notifier;
31 	int last_proximity;
32 	bool enabled;
33 };
34 
35 static const struct iio_event_spec cros_ec_mkbp_proximity_events[] = {
36 	{
37 		.type = IIO_EV_TYPE_THRESH,
38 		.dir = IIO_EV_DIR_EITHER,
39 		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
40 	},
41 };
42 
43 static const struct iio_chan_spec cros_ec_mkbp_proximity_chan_spec[] = {
44 	{
45 		.type = IIO_PROXIMITY,
46 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
47 		.event_spec = cros_ec_mkbp_proximity_events,
48 		.num_event_specs = ARRAY_SIZE(cros_ec_mkbp_proximity_events),
49 	},
50 };
51 
52 static int cros_ec_mkbp_proximity_parse_state(const void *data)
53 {
54 	u32 switches = get_unaligned_le32(data);
55 
56 	return !!(switches & BIT(EC_MKBP_FRONT_PROXIMITY));
57 }
58 
59 static int cros_ec_mkbp_proximity_query(struct cros_ec_device *ec_dev,
60 					int *state)
61 {
62 	struct {
63 		struct cros_ec_command msg;
64 		union {
65 			struct ec_params_mkbp_info params;
66 			u32 switches;
67 		};
68 	} __packed buf = { };
69 	struct ec_params_mkbp_info *params = &buf.params;
70 	struct cros_ec_command *msg = &buf.msg;
71 	u32 *switches = &buf.switches;
72 	size_t insize = sizeof(*switches);
73 	int ret;
74 
75 	msg->command = EC_CMD_MKBP_INFO;
76 	msg->version = 1;
77 	msg->outsize = sizeof(*params);
78 	msg->insize = insize;
79 
80 	params->info_type = EC_MKBP_INFO_CURRENT;
81 	params->event_type = EC_MKBP_EVENT_SWITCH;
82 
83 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
84 	if (ret < 0)
85 		return ret;
86 
87 	if (ret != insize) {
88 		dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n", ret,
89 			 insize);
90 		return -EPROTO;
91 	}
92 
93 	*state = cros_ec_mkbp_proximity_parse_state(switches);
94 	return IIO_VAL_INT;
95 }
96 
97 static void cros_ec_mkbp_proximity_push_event(struct cros_ec_mkbp_proximity_data *data, int state)
98 {
99 	s64 timestamp;
100 	u64 ev;
101 	int dir;
102 	struct iio_dev *indio_dev = data->indio_dev;
103 	struct cros_ec_device *ec = data->ec;
104 
105 	mutex_lock(&data->lock);
106 	if (state != data->last_proximity) {
107 		if (data->enabled) {
108 			timestamp = ktime_to_ns(ec->last_event_time);
109 			if (iio_device_get_clock(indio_dev) != CLOCK_BOOTTIME)
110 				timestamp = iio_get_time_ns(indio_dev);
111 
112 			dir = state ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
113 			ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
114 						  IIO_EV_TYPE_THRESH, dir);
115 			iio_push_event(indio_dev, ev, timestamp);
116 		}
117 		data->last_proximity = state;
118 	}
119 	mutex_unlock(&data->lock);
120 }
121 
122 static int cros_ec_mkbp_proximity_notify(struct notifier_block *nb,
123 					 unsigned long queued_during_suspend,
124 					 void *_ec)
125 {
126 	struct cros_ec_mkbp_proximity_data *data;
127 	struct cros_ec_device *ec = _ec;
128 	u8 event_type = ec->event_data.event_type & EC_MKBP_EVENT_TYPE_MASK;
129 	void *switches;
130 	int state;
131 
132 	if (event_type == EC_MKBP_EVENT_SWITCH) {
133 		data = container_of(nb, struct cros_ec_mkbp_proximity_data,
134 				    notifier);
135 
136 		switches = &ec->event_data.data.switches;
137 		state = cros_ec_mkbp_proximity_parse_state(switches);
138 		cros_ec_mkbp_proximity_push_event(data, state);
139 	}
140 
141 	return NOTIFY_OK;
142 }
143 
144 static int cros_ec_mkbp_proximity_read_raw(struct iio_dev *indio_dev,
145 			   const struct iio_chan_spec *chan, int *val,
146 			   int *val2, long mask)
147 {
148 	struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
149 	struct cros_ec_device *ec = data->ec;
150 
151 	if (chan->type == IIO_PROXIMITY && mask == IIO_CHAN_INFO_RAW)
152 		return cros_ec_mkbp_proximity_query(ec, val);
153 
154 	return -EINVAL;
155 }
156 
157 static int cros_ec_mkbp_proximity_read_event_config(struct iio_dev *indio_dev,
158 				    const struct iio_chan_spec *chan,
159 				    enum iio_event_type type,
160 				    enum iio_event_direction dir)
161 {
162 	struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
163 
164 	return data->enabled;
165 }
166 
167 static int cros_ec_mkbp_proximity_write_event_config(struct iio_dev *indio_dev,
168 				     const struct iio_chan_spec *chan,
169 				     enum iio_event_type type,
170 				     enum iio_event_direction dir, int state)
171 {
172 	struct cros_ec_mkbp_proximity_data *data = iio_priv(indio_dev);
173 
174 	mutex_lock(&data->lock);
175 	data->enabled = state;
176 	mutex_unlock(&data->lock);
177 
178 	return 0;
179 }
180 
181 static const struct iio_info cros_ec_mkbp_proximity_info = {
182 	.read_raw = cros_ec_mkbp_proximity_read_raw,
183 	.read_event_config = cros_ec_mkbp_proximity_read_event_config,
184 	.write_event_config = cros_ec_mkbp_proximity_write_event_config,
185 };
186 
187 static __maybe_unused int cros_ec_mkbp_proximity_resume(struct device *dev)
188 {
189 	struct cros_ec_mkbp_proximity_data *data = dev_get_drvdata(dev);
190 	struct cros_ec_device *ec = data->ec;
191 	int ret, state;
192 
193 	ret = cros_ec_mkbp_proximity_query(ec, &state);
194 	if (ret < 0) {
195 		dev_warn(dev, "failed to fetch proximity state on resume: %d\n",
196 			 ret);
197 	} else {
198 		cros_ec_mkbp_proximity_push_event(data, state);
199 	}
200 
201 	return 0;
202 }
203 
204 static SIMPLE_DEV_PM_OPS(cros_ec_mkbp_proximity_pm_ops, NULL,
205 			 cros_ec_mkbp_proximity_resume);
206 
207 static int cros_ec_mkbp_proximity_probe(struct platform_device *pdev)
208 {
209 	struct device *dev = &pdev->dev;
210 	struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
211 	struct iio_dev *indio_dev;
212 	struct cros_ec_mkbp_proximity_data *data;
213 	int ret;
214 
215 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
216 	if (!indio_dev)
217 		return -ENOMEM;
218 
219 	data = iio_priv(indio_dev);
220 	data->ec = ec;
221 	data->indio_dev = indio_dev;
222 	data->last_proximity = -1; /* Unknown to start */
223 	mutex_init(&data->lock);
224 	platform_set_drvdata(pdev, data);
225 
226 	indio_dev->name = dev->driver->name;
227 	indio_dev->info = &cros_ec_mkbp_proximity_info;
228 	indio_dev->modes = INDIO_DIRECT_MODE;
229 	indio_dev->channels = cros_ec_mkbp_proximity_chan_spec;
230 	indio_dev->num_channels = ARRAY_SIZE(cros_ec_mkbp_proximity_chan_spec);
231 
232 	ret = devm_iio_device_register(dev, indio_dev);
233 	if (ret)
234 		return ret;
235 
236 	data->notifier.notifier_call = cros_ec_mkbp_proximity_notify;
237 	blocking_notifier_chain_register(&ec->event_notifier, &data->notifier);
238 
239 	return 0;
240 }
241 
242 static int cros_ec_mkbp_proximity_remove(struct platform_device *pdev)
243 {
244 	struct cros_ec_mkbp_proximity_data *data = platform_get_drvdata(pdev);
245 	struct cros_ec_device *ec = data->ec;
246 
247 	blocking_notifier_chain_unregister(&ec->event_notifier,
248 					   &data->notifier);
249 
250 	return 0;
251 }
252 
253 static const struct of_device_id cros_ec_mkbp_proximity_of_match[] = {
254 	{ .compatible = "google,cros-ec-mkbp-proximity" },
255 	{}
256 };
257 MODULE_DEVICE_TABLE(of, cros_ec_mkbp_proximity_of_match);
258 
259 static struct platform_driver cros_ec_mkbp_proximity_driver = {
260 	.driver = {
261 		.name = "cros-ec-mkbp-proximity",
262 		.of_match_table = cros_ec_mkbp_proximity_of_match,
263 		.pm = &cros_ec_mkbp_proximity_pm_ops,
264 	},
265 	.probe = cros_ec_mkbp_proximity_probe,
266 	.remove = cros_ec_mkbp_proximity_remove,
267 };
268 module_platform_driver(cros_ec_mkbp_proximity_driver);
269 
270 MODULE_LICENSE("GPL v2");
271 MODULE_DESCRIPTION("ChromeOS EC MKBP proximity sensor driver");
272