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
19enum {
20	IQS62X_SW_HALL_N,
21	IQS62X_SW_HALL_S,
22};
23
24static const char * const iqs62x_switch_names[] = {
25	[IQS62X_SW_HALL_N] = "hall-switch-north",
26	[IQS62X_SW_HALL_S] = "hall-switch-south",
27};
28
29struct iqs62x_switch_desc {
30	enum iqs62x_event_flag flag;
31	unsigned int code;
32	bool enabled;
33};
34
35struct 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
45static 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
101static 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
187static 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
250static 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
313static void 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
324static struct platform_driver iqs62x_keys_platform_driver = {
325	.driver = {
326		.name = "iqs62x-keys",
327	},
328	.probe = iqs62x_keys_probe,
329	.remove_new = iqs62x_keys_remove,
330};
331module_platform_driver(iqs62x_keys_platform_driver);
332
333MODULE_AUTHOR("Jeff LaBundy <jeff@labundy.com>");
334MODULE_DESCRIPTION("Azoteq IQS620A/621/622/624/625 Keys and Switches");
335MODULE_LICENSE("GPL");
336MODULE_ALIAS("platform:iqs62x-keys");
337