1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2022 MediaTek Inc.
4  * Author Fengping Yu <fengping.yu@mediatek.com>
5  */
6 #include <linux/bitops.h>
7 #include <linux/clk.h>
8 #include <linux/input.h>
9 #include <linux/input/matrix_keypad.h>
10 #include <linux/interrupt.h>
11 #include <linux/module.h>
12 #include <linux/property.h>
13 #include <linux/platform_device.h>
14 #include <linux/regmap.h>
15 
16 #define MTK_KPD_NAME		"mt6779-keypad"
17 #define MTK_KPD_MEM		0x0004
18 #define MTK_KPD_DEBOUNCE	0x0018
19 #define MTK_KPD_DEBOUNCE_MASK	GENMASK(13, 0)
20 #define MTK_KPD_DEBOUNCE_MAX_MS	256
21 #define MTK_KPD_SEL		0x0020
22 #define MTK_KPD_SEL_DOUBLE_KP_MODE	BIT(0)
23 #define MTK_KPD_SEL_COL	GENMASK(15, 10)
24 #define MTK_KPD_SEL_ROW	GENMASK(9, 4)
25 #define MTK_KPD_SEL_COLMASK(c)	GENMASK((c) + 9, 10)
26 #define MTK_KPD_SEL_ROWMASK(r)	GENMASK((r) + 3, 4)
27 #define MTK_KPD_NUM_MEMS	5
28 #define MTK_KPD_NUM_BITS	136	/* 4*32+8 MEM5 only use 8 BITS */
29 
30 struct mt6779_keypad {
31 	struct regmap *regmap;
32 	struct input_dev *input_dev;
33 	struct clk *clk;
34 	u32 n_rows;
35 	u32 n_cols;
36 	void (*calc_row_col)(unsigned int key,
37 			     unsigned int *row, unsigned int *col);
38 	DECLARE_BITMAP(keymap_state, MTK_KPD_NUM_BITS);
39 };
40 
41 static const struct regmap_config mt6779_keypad_regmap_cfg = {
42 	.reg_bits = 32,
43 	.val_bits = 32,
44 	.reg_stride = sizeof(u32),
45 	.max_register = 36,
46 };
47 
48 static irqreturn_t mt6779_keypad_irq_handler(int irq, void *dev_id)
49 {
50 	struct mt6779_keypad *keypad = dev_id;
51 	const unsigned short *keycode = keypad->input_dev->keycode;
52 	DECLARE_BITMAP(new_state, MTK_KPD_NUM_BITS);
53 	DECLARE_BITMAP(change, MTK_KPD_NUM_BITS);
54 	unsigned int bit_nr, key;
55 	unsigned int row, col;
56 	unsigned int scancode;
57 	unsigned int row_shift = get_count_order(keypad->n_cols);
58 	bool pressed;
59 
60 	regmap_bulk_read(keypad->regmap, MTK_KPD_MEM,
61 			 new_state, MTK_KPD_NUM_MEMS);
62 
63 	bitmap_xor(change, new_state, keypad->keymap_state, MTK_KPD_NUM_BITS);
64 
65 	for_each_set_bit(bit_nr, change, MTK_KPD_NUM_BITS) {
66 		/*
67 		 * Registers are 32bits, but only bits [15:0] are used to
68 		 * indicate key status.
69 		 */
70 		if (bit_nr % 32 >= 16)
71 			continue;
72 
73 		key = bit_nr / 32 * 16 + bit_nr % 32;
74 		keypad->calc_row_col(key, &row, &col);
75 
76 		scancode = MATRIX_SCAN_CODE(row, col, row_shift);
77 		/* 1: not pressed, 0: pressed */
78 		pressed = !test_bit(bit_nr, new_state);
79 		dev_dbg(&keypad->input_dev->dev, "%s",
80 			pressed ? "pressed" : "released");
81 
82 		input_event(keypad->input_dev, EV_MSC, MSC_SCAN, scancode);
83 		input_report_key(keypad->input_dev, keycode[scancode], pressed);
84 		input_sync(keypad->input_dev);
85 
86 		dev_dbg(&keypad->input_dev->dev,
87 			"report Linux keycode = %d\n", keycode[scancode]);
88 	}
89 
90 	bitmap_copy(keypad->keymap_state, new_state, MTK_KPD_NUM_BITS);
91 
92 	return IRQ_HANDLED;
93 }
94 
95 static void mt6779_keypad_clk_disable(void *data)
96 {
97 	clk_disable_unprepare(data);
98 }
99 
100 static void mt6779_keypad_calc_row_col_single(unsigned int key,
101 					      unsigned int *row,
102 					      unsigned int *col)
103 {
104 	*row = key / 9;
105 	*col = key % 9;
106 }
107 
108 static void mt6779_keypad_calc_row_col_double(unsigned int key,
109 					      unsigned int *row,
110 					      unsigned int *col)
111 {
112 	*row = key / 13;
113 	*col = (key % 13) / 2;
114 }
115 
116 static int mt6779_keypad_pdrv_probe(struct platform_device *pdev)
117 {
118 	struct mt6779_keypad *keypad;
119 	void __iomem *base;
120 	int irq;
121 	u32 debounce;
122 	u32 keys_per_group;
123 	bool wakeup;
124 	int error;
125 
126 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
127 	if (!keypad)
128 		return -ENOMEM;
129 
130 	base = devm_platform_ioremap_resource(pdev, 0);
131 	if (IS_ERR(base))
132 		return PTR_ERR(base);
133 
134 	keypad->regmap = devm_regmap_init_mmio(&pdev->dev, base,
135 					       &mt6779_keypad_regmap_cfg);
136 	if (IS_ERR(keypad->regmap)) {
137 		dev_err(&pdev->dev,
138 			"regmap init failed:%pe\n", keypad->regmap);
139 		return PTR_ERR(keypad->regmap);
140 	}
141 
142 	bitmap_fill(keypad->keymap_state, MTK_KPD_NUM_BITS);
143 
144 	keypad->input_dev = devm_input_allocate_device(&pdev->dev);
145 	if (!keypad->input_dev) {
146 		dev_err(&pdev->dev, "Failed to allocate input dev\n");
147 		return -ENOMEM;
148 	}
149 
150 	keypad->input_dev->name = MTK_KPD_NAME;
151 	keypad->input_dev->id.bustype = BUS_HOST;
152 
153 	error = matrix_keypad_parse_properties(&pdev->dev, &keypad->n_rows,
154 					       &keypad->n_cols);
155 	if (error) {
156 		dev_err(&pdev->dev, "Failed to parse keypad params\n");
157 		return error;
158 	}
159 
160 	if (device_property_read_u32(&pdev->dev, "debounce-delay-ms",
161 				     &debounce))
162 		debounce = 16;
163 
164 	if (debounce > MTK_KPD_DEBOUNCE_MAX_MS) {
165 		dev_err(&pdev->dev,
166 			"Debounce time exceeds the maximum allowed time %dms\n",
167 			MTK_KPD_DEBOUNCE_MAX_MS);
168 		return -EINVAL;
169 	}
170 
171 	if (device_property_read_u32(&pdev->dev, "mediatek,keys-per-group",
172 				     &keys_per_group))
173 		keys_per_group = 1;
174 
175 	switch (keys_per_group) {
176 	case 1:
177 		keypad->calc_row_col = mt6779_keypad_calc_row_col_single;
178 		break;
179 	case 2:
180 		keypad->calc_row_col = mt6779_keypad_calc_row_col_double;
181 		break;
182 	default:
183 		dev_err(&pdev->dev,
184 			"Invalid keys-per-group: %d\n", keys_per_group);
185 		return -EINVAL;
186 	}
187 
188 	wakeup = device_property_read_bool(&pdev->dev, "wakeup-source");
189 
190 	dev_dbg(&pdev->dev, "n_row=%d n_col=%d debounce=%d\n",
191 		keypad->n_rows, keypad->n_cols, debounce);
192 
193 	error = matrix_keypad_build_keymap(NULL, NULL,
194 					   keypad->n_rows, keypad->n_cols,
195 					   NULL, keypad->input_dev);
196 	if (error) {
197 		dev_err(&pdev->dev, "Failed to build keymap\n");
198 		return error;
199 	}
200 
201 	input_set_capability(keypad->input_dev, EV_MSC, MSC_SCAN);
202 
203 	regmap_write(keypad->regmap, MTK_KPD_DEBOUNCE,
204 		     (debounce * (1 << 5)) & MTK_KPD_DEBOUNCE_MASK);
205 
206 	if (keys_per_group == 2)
207 		regmap_update_bits(keypad->regmap, MTK_KPD_SEL,
208 				   MTK_KPD_SEL_DOUBLE_KP_MODE,
209 				   MTK_KPD_SEL_DOUBLE_KP_MODE);
210 
211 	regmap_update_bits(keypad->regmap, MTK_KPD_SEL, MTK_KPD_SEL_ROW,
212 			   MTK_KPD_SEL_ROWMASK(keypad->n_rows));
213 	regmap_update_bits(keypad->regmap, MTK_KPD_SEL, MTK_KPD_SEL_COL,
214 			   MTK_KPD_SEL_COLMASK(keypad->n_cols));
215 
216 	keypad->clk = devm_clk_get(&pdev->dev, "kpd");
217 	if (IS_ERR(keypad->clk))
218 		return PTR_ERR(keypad->clk);
219 
220 	error = clk_prepare_enable(keypad->clk);
221 	if (error) {
222 		dev_err(&pdev->dev, "cannot prepare/enable keypad clock\n");
223 		return error;
224 	}
225 
226 	error = devm_add_action_or_reset(&pdev->dev, mt6779_keypad_clk_disable,
227 					 keypad->clk);
228 	if (error)
229 		return error;
230 
231 	irq = platform_get_irq(pdev, 0);
232 	if (irq < 0)
233 		return irq;
234 
235 	error = devm_request_threaded_irq(&pdev->dev, irq,
236 					  NULL, mt6779_keypad_irq_handler,
237 					  IRQF_ONESHOT, MTK_KPD_NAME, keypad);
238 	if (error) {
239 		dev_err(&pdev->dev, "Failed to request IRQ#%d: %d\n",
240 			irq, error);
241 		return error;
242 	}
243 
244 	error = input_register_device(keypad->input_dev);
245 	if (error) {
246 		dev_err(&pdev->dev, "Failed to register device\n");
247 		return error;
248 	}
249 
250 	error = device_init_wakeup(&pdev->dev, wakeup);
251 	if (error)
252 		dev_warn(&pdev->dev, "device_init_wakeup() failed: %d\n",
253 			 error);
254 
255 	return 0;
256 }
257 
258 static const struct of_device_id mt6779_keypad_of_match[] = {
259 	{ .compatible = "mediatek,mt6779-keypad" },
260 	{ .compatible = "mediatek,mt6873-keypad" },
261 	{ /* sentinel */ }
262 };
263 
264 static struct platform_driver mt6779_keypad_pdrv = {
265 	.probe = mt6779_keypad_pdrv_probe,
266 	.driver = {
267 		   .name = MTK_KPD_NAME,
268 		   .of_match_table = mt6779_keypad_of_match,
269 	},
270 };
271 module_platform_driver(mt6779_keypad_pdrv);
272 
273 MODULE_AUTHOR("Mediatek Corporation");
274 MODULE_DESCRIPTION("MTK Keypad (KPD) Driver");
275 MODULE_LICENSE("GPL");
276