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 			return ret;
81 		}
82 		iqs62x_keys->switches[i].code = val;
83 		iqs62x_keys->switches[i].enabled = true;
84 
85 		if (fwnode_property_present(child, "azoteq,use-prox"))
86 			iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
87 							 IQS62X_EVENT_HALL_N_P :
88 							 IQS62X_EVENT_HALL_S_P);
89 		else
90 			iqs62x_keys->switches[i].flag = (i == IQS62X_SW_HALL_N ?
91 							 IQS62X_EVENT_HALL_N_T :
92 							 IQS62X_EVENT_HALL_S_T);
93 	}
94 
95 	return 0;
96 }
97 
98 static int iqs62x_keys_init(struct iqs62x_keys_private *iqs62x_keys)
99 {
100 	struct iqs62x_core *iqs62x = iqs62x_keys->iqs62x;
101 	enum iqs62x_event_flag flag;
102 	unsigned int event_reg, val;
103 	unsigned int event_mask = 0;
104 	int ret, i;
105 
106 	switch (iqs62x->dev_desc->prod_num) {
107 	case IQS620_PROD_NUM:
108 	case IQS621_PROD_NUM:
109 	case IQS622_PROD_NUM:
110 		event_reg = IQS620_GLBL_EVENT_MASK;
111 
112 		/*
113 		 * Discreet button, hysteresis and SAR UI flags represent keys
114 		 * and are unmasked if mapped to a valid keycode.
115 		 */
116 		for (i = 0; i < iqs62x_keys->keycodemax; i++) {
117 			if (iqs62x_keys->keycode[i] == KEY_RESERVED)
118 				continue;
119 
120 			if (iqs62x_events[i].reg == IQS62X_EVENT_PROX)
121 				event_mask |= iqs62x->dev_desc->prox_mask;
122 			else if (iqs62x_events[i].reg == IQS62X_EVENT_HYST)
123 				event_mask |= (iqs62x->dev_desc->hyst_mask |
124 					       iqs62x->dev_desc->sar_mask);
125 		}
126 
127 		ret = regmap_read(iqs62x->regmap, iqs62x->dev_desc->hall_flags,
128 				  &val);
129 		if (ret)
130 			return ret;
131 
132 		/*
133 		 * Hall UI flags represent switches and are unmasked if their
134 		 * corresponding child nodes are present.
135 		 */
136 		for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++) {
137 			if (!(iqs62x_keys->switches[i].enabled))
138 				continue;
139 
140 			flag = iqs62x_keys->switches[i].flag;
141 
142 			if (iqs62x_events[flag].reg != IQS62X_EVENT_HALL)
143 				continue;
144 
145 			event_mask |= iqs62x->dev_desc->hall_mask;
146 
147 			input_report_switch(iqs62x_keys->input,
148 					    iqs62x_keys->switches[i].code,
149 					    (val & iqs62x_events[flag].mask) ==
150 					    iqs62x_events[flag].val);
151 		}
152 
153 		input_sync(iqs62x_keys->input);
154 		break;
155 
156 	case IQS624_PROD_NUM:
157 		event_reg = IQS624_HALL_UI;
158 
159 		/*
160 		 * Interval change events represent keys and are unmasked if
161 		 * either wheel movement flag is mapped to a valid keycode.
162 		 */
163 		if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP] != KEY_RESERVED)
164 			event_mask |= IQS624_HALL_UI_INT_EVENT;
165 
166 		if (iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN] != KEY_RESERVED)
167 			event_mask |= IQS624_HALL_UI_INT_EVENT;
168 
169 		ret = regmap_read(iqs62x->regmap, iqs62x->dev_desc->interval,
170 				  &val);
171 		if (ret)
172 			return ret;
173 
174 		iqs62x_keys->interval = val;
175 		break;
176 
177 	default:
178 		return 0;
179 	}
180 
181 	return regmap_update_bits(iqs62x->regmap, event_reg, event_mask, 0);
182 }
183 
184 static int iqs62x_keys_notifier(struct notifier_block *notifier,
185 				unsigned long event_flags, void *context)
186 {
187 	struct iqs62x_event_data *event_data = context;
188 	struct iqs62x_keys_private *iqs62x_keys;
189 	int ret, i;
190 
191 	iqs62x_keys = container_of(notifier, struct iqs62x_keys_private,
192 				   notifier);
193 
194 	if (event_flags & BIT(IQS62X_EVENT_SYS_RESET)) {
195 		ret = iqs62x_keys_init(iqs62x_keys);
196 		if (ret) {
197 			dev_err(iqs62x_keys->input->dev.parent,
198 				"Failed to re-initialize device: %d\n", ret);
199 			return NOTIFY_BAD;
200 		}
201 
202 		return NOTIFY_OK;
203 	}
204 
205 	for (i = 0; i < iqs62x_keys->keycodemax; i++) {
206 		if (iqs62x_events[i].reg == IQS62X_EVENT_WHEEL &&
207 		    event_data->interval == iqs62x_keys->interval)
208 			continue;
209 
210 		input_report_key(iqs62x_keys->input, iqs62x_keys->keycode[i],
211 				 event_flags & BIT(i));
212 	}
213 
214 	for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
215 		if (iqs62x_keys->switches[i].enabled)
216 			input_report_switch(iqs62x_keys->input,
217 					    iqs62x_keys->switches[i].code,
218 					    event_flags &
219 					    BIT(iqs62x_keys->switches[i].flag));
220 
221 	input_sync(iqs62x_keys->input);
222 
223 	if (event_data->interval == iqs62x_keys->interval)
224 		return NOTIFY_OK;
225 
226 	/*
227 	 * Each frame contains at most one wheel event (up or down), in which
228 	 * case a complementary release cycle is emulated.
229 	 */
230 	if (event_flags & BIT(IQS62X_EVENT_WHEEL_UP)) {
231 		input_report_key(iqs62x_keys->input,
232 				 iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_UP],
233 				 0);
234 		input_sync(iqs62x_keys->input);
235 	} else if (event_flags & BIT(IQS62X_EVENT_WHEEL_DN)) {
236 		input_report_key(iqs62x_keys->input,
237 				 iqs62x_keys->keycode[IQS62X_EVENT_WHEEL_DN],
238 				 0);
239 		input_sync(iqs62x_keys->input);
240 	}
241 
242 	iqs62x_keys->interval = event_data->interval;
243 
244 	return NOTIFY_OK;
245 }
246 
247 static int iqs62x_keys_probe(struct platform_device *pdev)
248 {
249 	struct iqs62x_core *iqs62x = dev_get_drvdata(pdev->dev.parent);
250 	struct iqs62x_keys_private *iqs62x_keys;
251 	struct input_dev *input;
252 	int ret, i;
253 
254 	iqs62x_keys = devm_kzalloc(&pdev->dev, sizeof(*iqs62x_keys),
255 				   GFP_KERNEL);
256 	if (!iqs62x_keys)
257 		return -ENOMEM;
258 
259 	platform_set_drvdata(pdev, iqs62x_keys);
260 
261 	ret = iqs62x_keys_parse_prop(pdev, iqs62x_keys);
262 	if (ret)
263 		return ret;
264 
265 	input = devm_input_allocate_device(&pdev->dev);
266 	if (!input)
267 		return -ENOMEM;
268 
269 	input->keycodemax = iqs62x_keys->keycodemax;
270 	input->keycode = iqs62x_keys->keycode;
271 	input->keycodesize = sizeof(*iqs62x_keys->keycode);
272 
273 	input->name = iqs62x->dev_desc->dev_name;
274 	input->id.bustype = BUS_I2C;
275 
276 	for (i = 0; i < iqs62x_keys->keycodemax; i++)
277 		if (iqs62x_keys->keycode[i] != KEY_RESERVED)
278 			input_set_capability(input, EV_KEY,
279 					     iqs62x_keys->keycode[i]);
280 
281 	for (i = 0; i < ARRAY_SIZE(iqs62x_keys->switches); i++)
282 		if (iqs62x_keys->switches[i].enabled)
283 			input_set_capability(input, EV_SW,
284 					     iqs62x_keys->switches[i].code);
285 
286 	iqs62x_keys->iqs62x = iqs62x;
287 	iqs62x_keys->input = input;
288 
289 	ret = iqs62x_keys_init(iqs62x_keys);
290 	if (ret) {
291 		dev_err(&pdev->dev, "Failed to initialize device: %d\n", ret);
292 		return ret;
293 	}
294 
295 	ret = input_register_device(iqs62x_keys->input);
296 	if (ret) {
297 		dev_err(&pdev->dev, "Failed to register device: %d\n", ret);
298 		return ret;
299 	}
300 
301 	iqs62x_keys->notifier.notifier_call = iqs62x_keys_notifier;
302 	ret = blocking_notifier_chain_register(&iqs62x_keys->iqs62x->nh,
303 					       &iqs62x_keys->notifier);
304 	if (ret)
305 		dev_err(&pdev->dev, "Failed to register notifier: %d\n", ret);
306 
307 	return ret;
308 }
309 
310 static int iqs62x_keys_remove(struct platform_device *pdev)
311 {
312 	struct iqs62x_keys_private *iqs62x_keys = platform_get_drvdata(pdev);
313 	int ret;
314 
315 	ret = blocking_notifier_chain_unregister(&iqs62x_keys->iqs62x->nh,
316 						 &iqs62x_keys->notifier);
317 	if (ret)
318 		dev_err(&pdev->dev, "Failed to unregister notifier: %d\n", ret);
319 
320 	return ret;
321 }
322 
323 static struct platform_driver iqs62x_keys_platform_driver = {
324 	.driver = {
325 		.name = "iqs62x-keys",
326 	},
327 	.probe = iqs62x_keys_probe,
328 	.remove = iqs62x_keys_remove,
329 };
330 module_platform_driver(iqs62x_keys_platform_driver);
331 
332 MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
333 MODULE_DESCRIPTION("Azoteq IQS620A/621/622/624/625 Keys and Switches");
334 MODULE_LICENSE("GPL");
335 MODULE_ALIAS("platform:iqs62x-keys");
336