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