1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Azoteq IQS620A/621/622/624/625 Keys and Switches
4  *
5  * Copyright (C) 2019 Jeff LaBundy <jeff@labundy.com>
6  */
7 
8 #include <linux/device.h>
9 #include <linux/input.h>
10 #include <linux/kernel.h>
11 #include <linux/mfd/iqs62x.h>
12 #include <linux/module.h>
13 #include <linux/notifier.h>
14 #include <linux/platform_device.h>
15 #include <linux/property.h>
16 #include <linux/regmap.h>
17 #include <linux/slab.h>
18 
19 enum {
20 	IQS62X_SW_HALL_N,
21 	IQS62X_SW_HALL_S,
22 };
23 
24 static const char * const iqs62x_switch_names[] = {
25 	[IQS62X_SW_HALL_N] = "hall-switch-north",
26 	[IQS62X_SW_HALL_S] = "hall-switch-south",
27 };
28 
29 struct iqs62x_switch_desc {
30 	enum iqs62x_event_flag flag;
31 	unsigned int code;
32 	bool enabled;
33 };
34 
35 struct iqs62x_keys_private {
36 	struct iqs62x_core *iqs62x;
37 	struct input_dev *input;
38 	struct notifier_block notifier;
39 	struct iqs62x_switch_desc switches[ARRAY_SIZE(iqs62x_switch_names)];
40 	unsigned int keycode[IQS62X_NUM_KEYS];
41 	unsigned int keycodemax;
42 	u8 interval;
43 };
44 
45 static int iqs62x_keys_parse_prop(struct platform_device *pdev,
46 				  struct iqs62x_keys_private *iqs62x_keys)
47 {
48 	struct fwnode_handle *child;
49 	unsigned int val;
50 	int ret, i;
51 
52 	ret = device_property_count_u32(&pdev->dev, "linux,keycodes");
53 	if (ret > IQS62X_NUM_KEYS) {
54 		dev_err(&pdev->dev, "Too many keycodes present\n");
55 		return -EINVAL;
56 	} else if (ret < 0) {
57 		dev_err(&pdev->dev, "Failed to count keycodes: %d\n", ret);
58 		return ret;
59 	}
60 	iqs62x_keys->keycodemax = ret;
61 
62 	ret = device_property_read_u32_array(&pdev->dev, "linux,keycodes",
63 					     iqs62x_keys->keycode,
64 					     iqs62x_keys->keycodemax);
65 	if (ret) {
66 		dev_err(&pdev->dev, "Failed to read keycodes: %d\n", ret);
67 		return ret;
68 	}
69 
70 	for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++) {
71 		child = device_get_named_child_node(&pdev->dev,
72 						    iqs62x_switch_names[i]);
73 		if (!child)
74 			continue;
75 
76 		ret = fwnode_property_read_u32(child, "linux,code", &val);
77 		if (ret) {
78 			dev_err(&pdev->dev, "Failed to read switch code: %d\n",
79 				ret);
80 			fwnode_handle_put(child);
81 			return ret;
82 		}
83 		iqs62x_keys->switches[i].code = val;
84 		iqs62x_keys->switches[i].enabled = true;
85 
86 		if (fwnode_property_present(child, "azoteq,use-prox"))
87 			iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
88 							 IQS62X_EVENT_HALL_N_P :
89 							 IQS62X_EVENT_HALL_S_P);
90 		else
91 			iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
92 							 IQS62X_EVENT_HALL_N_T :
93 							 IQS62X_EVENT_HALL_S_T);
94 
95 		fwnode_handle_put(child);
96 	}
97 
98 	return 0;
99 }
100 
101 static int iqs62x_keys_init(struct iqs62x_keys_private *iqs62x_keys)
102 {
103 	struct iqs62x_core *iqs62x = iqs62x_keys->iqs62x;
104 	enum iqs62x_event_flag flag;
105 	unsigned int event_reg, val;
106 	unsigned int event_mask = 0;
107 	int ret, i;
108 
109 	switch (iqs62x->dev_desc->prod_num) {
110 	case IQS620_PROD_NUM:
111 	case IQS621_PROD_NUM:
112 	case IQS622_PROD_NUM:
113 		event_reg = IQS620_GLBL_EVENT_MASK;
114 
115 		/*
116 		 * Discreet button, hysteresis and SAR UI flags represent keys
117 		 * and are unmasked if mapped to a valid keycode.
118 		 */
119 		for (i = 0; i < iqs62x_keys->keycodemax; i++) {
120 			if (iqs62x_keys->keycode[i] == KEY_RESERVED)
121 				continue;
122 
123 			if (iqs62x_events[i].reg == IQS62X_EVENT_PROX)
124 				event_mask |= iqs62x->dev_desc->prox_mask;
125 			else if (iqs62x_events[i].reg == IQS62X_EVENT_HYST)
126 				event_mask |= (iqs62x->dev_desc->hyst_mask |
127 					       iqs62x->dev_desc->sar_mask);
128 		}
129 
130 		ret = regmap_read(iqs62x->regmap, iqs62x->dev_desc->hall_flags,
131 				  &val);
132 		if (ret)
133 			return ret;
134 
135 		/*
136 		 * Hall UI flags represent switches and are unmasked if their
137 		 * corresponding child nodes are present.
138 		 */
139 		for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++) {
140 			if (!(iqs62x_keys->switches[i].enabled))
141 				continue;
142 
143 			flag = iqs62x_keys->switches[i].flag;
144 
145 			if (iqs62x_events[flag].reg != IQS62X_EVENT_HALL)
146 				continue;
147 
148 			event_mask |= iqs62x->dev_desc->hall_mask;
149 
150 			input_report_switch(iqs62x_keys->input,
151 					    iqs62x_keys->switches[i].code,
152 					    (val & iqs62x_events[flag].mask) ==
153 					    iqs62x_events[flag].val);
154 		}
155 
156 		input_sync(iqs62x_keys->input);
157 		break;
158 
159 	case IQS624_PROD_NUM:
160 		event_reg = IQS624_HALL_UI;
161 
162 		/*
163 		 * Interval change events represent keys and are unmasked if
164 		 * either wheel movement flag is mapped to a valid keycode.
165 		 */
166 		if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP] != KEY_RESERVED)
167 			event_mask |= IQS624_HALL_UI_INT_EVENT;
168 
169 		if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN] != KEY_RESERVED)
170 			event_mask |= IQS624_HALL_UI_INT_EVENT;
171 
172 		ret = regmap_read(iqs62x->regmap, iqs62x->dev_desc->interval,
173 				  &val);
174 		if (ret)
175 			return ret;
176 
177 		iqs62x_keys->interval = val;
178 		break;
179 
180 	default:
181 		return 0;
182 	}
183 
184 	return regmap_update_bits(iqs62x->regmap, event_reg, event_mask, 0);
185 }
186 
187 static int iqs62x_keys_notifier(struct notifier_block *notifier,
188 				unsigned long event_flags, void *context)
189 {
190 	struct iqs62x_event_data *event_data = context;
191 	struct iqs62x_keys_private *iqs62x_keys;
192 	int ret, i;
193 
194 	iqs62x_keys = container_of(notifier, struct iqs62x_keys_private,
195 				   notifier);
196 
197 	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
198 		ret = iqs62x_keys_init(iqs62x_keys);
199 		if (ret) {
200 			dev_err(iqs62x_keys->input->dev.parent,
201 				"Failed to re-initialize device: %d\n", ret);
202 			return NOTIFY_BAD;
203 		}
204 
205 		return NOTIFY_OK;
206 	}
207 
208 	for (i = 0; i < iqs62x_keys->keycodemax; i++) {
209 		if (iqs62x_events[i].reg == IQS62X_EVENT_WHEEL &&
210 		    event_data->interval == iqs62x_keys->interval)
211 			continue;
212 
213 		input_report_key(iqs62x_keys->input, iqs62x_keys->keycode[i],
214 				 event_flags & BIT(i));
215 	}
216 
217 	for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
218 		if (iqs62x_keys->switches[i].enabled)
219 			input_report_switch(iqs62x_keys->input,
220 					    iqs62x_keys->switches[i].code,
221 					    event_flags &
222 					    BIT(iqs62x_keys->switches[i].flag));
223 
224 	input_sync(iqs62x_keys->input);
225 
226 	if (event_data->interval == iqs62x_keys->interval)
227 		return NOTIFY_OK;
228 
229 	/*
230 	 * Each frame contains at most one wheel event (up or down), in which
231 	 * case a complementary release cycle is emulated.
232 	 */
233 	if (event_flags & BIT(IQS62X_EVENT_WHEEL_UP)) {
234 		input_report_key(iqs62x_keys->input,
235 				 iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP],
236 				 0);
237 		input_sync(iqs62x_keys->input);
238 	} else if (event_flags & BIT(IQS62X_EVENT_WHEEL_DN)) {
239 		input_report_key(iqs62x_keys->input,
240 				 iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN],
241 				 0);
242 		input_sync(iqs62x_keys->input);
243 	}
244 
245 	iqs62x_keys->interval = event_data->interval;
246 
247 	return NOTIFY_OK;
248 }
249 
250 static int iqs62x_keys_probe(struct platform_device *pdev)
251 {
252 	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
253 	struct iqs62x_keys_private *iqs62x_keys;
254 	struct input_dev *input;
255 	int ret, i;
256 
257 	iqs62x_keys = devm_kzalloc(&pdev->dev, sizeof(*iqs62x_keys),
258 				   GFP_KERNEL);
259 	if (!iqs62x_keys)
260 		return -ENOMEM;
261 
262 	platform_set_drvdata(pdev, iqs62x_keys);
263 
264 	ret = iqs62x_keys_parse_prop(pdev, iqs62x_keys);
265 	if (ret)
266 		return ret;
267 
268 	input = devm_input_allocate_device(&pdev->dev);
269 	if (!input)
270 		return -ENOMEM;
271 
272 	input->keycodemax = iqs62x_keys->keycodemax;
273 	input->keycode = iqs62x_keys->keycode;
274 	input->keycodesize = sizeof(*iqs62x_keys->keycode);
275 
276 	input->name = iqs62x->dev_desc->dev_name;
277 	input->id.bustype = BUS_I2C;
278 
279 	for (i = 0; i < iqs62x_keys->keycodemax; i++)
280 		if (iqs62x_keys->keycode[i] != KEY_RESERVED)
281 			input_set_capability(input, EV_KEY,
282 					     iqs62x_keys->keycode[i]);
283 
284 	for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
285 		if (iqs62x_keys->switches[i].enabled)
286 			input_set_capability(input, EV_SW,
287 					     iqs62x_keys->switches[i].code);
288 
289 	iqs62x_keys->iqs62x = iqs62x;
290 	iqs62x_keys->input = input;
291 
292 	ret = iqs62x_keys_init(iqs62x_keys);
293 	if (ret) {
294 		dev_err(&pdev->dev, "Failed to initialize device: %d\n", ret);
295 		return ret;
296 	}
297 
298 	ret = input_register_device(iqs62x_keys->input);
299 	if (ret) {
300 		dev_err(&pdev->dev, "Failed to register device: %d\n", ret);
301 		return ret;
302 	}
303 
304 	iqs62x_keys->notifier.notifier_call = iqs62x_keys_notifier;
305 	ret = blocking_notifier_chain_register(&iqs62x_keys->iqs62x->nh,
306 					       &iqs62x_keys->notifier);
307 	if (ret)
308 		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
309 
310 	return ret;
311 }
312 
313 static int iqs62x_keys_remove(struct platform_device *pdev)
314 {
315 	struct iqs62x_keys_private *iqs62x_keys = platform_get_drvdata(pdev);
316 	int ret;
317 
318 	ret = blocking_notifier_chain_unregister(&iqs62x_keys->iqs62x->nh,
319 						 &iqs62x_keys->notifier);
320 	if (ret)
321 		dev_err(&pdev->dev, "Failed to unregister notifier: %d\n", ret);
322 
323 	return ret;
324 }
325 
326 static struct platform_driver iqs62x_keys_platform_driver = {
327 	.driver = {
328 		.name = "iqs62x-keys",
329 	},
330 	.probe = iqs62x_keys_probe,
331 	.remove = iqs62x_keys_remove,
332 };
333 module_platform_driver(iqs62x_keys_platform_driver);
334 
335 MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
336 MODULE_DESCRIPTION("Azoteq IQS620A/621/622/624/625 Keys and Switches");
337 MODULE_LICENSE("GPL");
338 MODULE_ALIAS("platform:iqs62x-keys");
339