1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
4  */
5 
6 #include <linux/input/matrix_keypad.h>
7 #include <linux/platform_device.h>
8 #include <linux/interrupt.h>
9 #include <linux/io.h>
10 #include <linux/delay.h>
11 #include <linux/input.h>
12 #include <linux/slab.h>
13 #include <linux/clk.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 
17 #define KEYPAD_SCAN_MODE	0x00
18 #define KEYPAD_CNTL		0x04
19 #define KEYPAD_INT		0x08
20 #define KEYPAD_INTMSK		0x0C
21 
22 #define KEYPAD_DATA		0x10
23 #define KEYPAD_GPIO		0x30
24 
25 #define KEYPAD_UNKNOWN_INT	0x40
26 #define KEYPAD_UNKNOWN_INT_STS	0x44
27 
28 #define KEYPAD_BITMASK_COLS	11
29 #define KEYPAD_BITMASK_ROWS	8
30 
31 struct nspire_keypad {
32 	void __iomem *reg_base;
33 	u32 int_mask;
34 
35 	struct input_dev *input;
36 	struct clk *clk;
37 
38 	struct matrix_keymap_data *keymap;
39 	int row_shift;
40 
41 	/* Maximum delay estimated assuming 33MHz APB */
42 	u32 scan_interval;	/* In microseconds (~2000us max) */
43 	u32 row_delay;		/* In microseconds (~500us max) */
44 
45 	u16 state[KEYPAD_BITMASK_ROWS];
46 
47 	bool active_low;
48 };
49 
50 static irqreturn_t nspire_keypad_irq(int irq, void *dev_id)
51 {
52 	struct nspire_keypad *keypad = dev_id;
53 	struct input_dev *input = keypad->input;
54 	unsigned short *keymap = input->keycode;
55 	unsigned int code;
56 	int row, col;
57 	u32 int_sts;
58 	u16 state[8];
59 	u16 bits, changed;
60 
61 	int_sts = readl(keypad->reg_base + KEYPAD_INT) & keypad->int_mask;
62 	if (!int_sts)
63 		return IRQ_NONE;
64 
65 	memcpy_fromio(state, keypad->reg_base + KEYPAD_DATA, sizeof(state));
66 
67 	for (row = 0; row < KEYPAD_BITMASK_ROWS; row++) {
68 		bits = state[row];
69 		if (keypad->active_low)
70 			bits = ~bits;
71 
72 		changed = bits ^ keypad->state[row];
73 		if (!changed)
74 			continue;
75 
76 		keypad->state[row] = bits;
77 
78 		for (col = 0; col < KEYPAD_BITMASK_COLS; col++) {
79 			if (!(changed & (1U << col)))
80 				continue;
81 
82 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
83 			input_event(input, EV_MSC, MSC_SCAN, code);
84 			input_report_key(input, keymap[code],
85 					 bits & (1U << col));
86 		}
87 	}
88 
89 	input_sync(input);
90 
91 	writel(0x3, keypad->reg_base + KEYPAD_INT);
92 
93 	return IRQ_HANDLED;
94 }
95 
96 static int nspire_keypad_chip_init(struct nspire_keypad *keypad)
97 {
98 	unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
99 
100 	cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
101 	if (cycles_per_us == 0)
102 		cycles_per_us = 1;
103 
104 	delay_cycles = cycles_per_us * keypad->scan_interval;
105 	WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
106 	delay_cycles &= 0xffff;
107 
108 	row_delay_cycles = cycles_per_us * keypad->row_delay;
109 	WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
110 	row_delay_cycles &= 0x3fff;
111 
112 	val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
113 	val |= row_delay_cycles << 2; /* Delay between scanning each row */
114 	val |= delay_cycles << 16; /* Delay between scans */
115 	writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
116 
117 	val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
118 	writel(val, keypad->reg_base + KEYPAD_CNTL);
119 
120 	/* Enable interrupts */
121 	keypad->int_mask = 1 << 1;
122 	writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK);
123 
124 	/* Disable GPIO interrupts to prevent hanging on touchpad */
125 	/* Possibly used to detect touchpad events */
126 	writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
127 	/* Acknowledge existing interrupts */
128 	writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
129 
130 	return 0;
131 }
132 
133 static int nspire_keypad_open(struct input_dev *input)
134 {
135 	struct nspire_keypad *keypad = input_get_drvdata(input);
136 	int error;
137 
138 	error = clk_prepare_enable(keypad->clk);
139 	if (error)
140 		return error;
141 
142 	error = nspire_keypad_chip_init(keypad);
143 	if (error) {
144 		clk_disable_unprepare(keypad->clk);
145 		return error;
146 	}
147 
148 	return 0;
149 }
150 
151 static void nspire_keypad_close(struct input_dev *input)
152 {
153 	struct nspire_keypad *keypad = input_get_drvdata(input);
154 
155 	clk_disable_unprepare(keypad->clk);
156 }
157 
158 static int nspire_keypad_probe(struct platform_device *pdev)
159 {
160 	const struct device_node *of_node = pdev->dev.of_node;
161 	struct nspire_keypad *keypad;
162 	struct input_dev *input;
163 	struct resource *res;
164 	int irq;
165 	int error;
166 
167 	irq = platform_get_irq(pdev, 0);
168 	if (irq < 0)
169 		return -EINVAL;
170 
171 	keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
172 			      GFP_KERNEL);
173 	if (!keypad) {
174 		dev_err(&pdev->dev, "failed to allocate keypad memory\n");
175 		return -ENOMEM;
176 	}
177 
178 	keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
179 
180 	error = of_property_read_u32(of_node, "scan-interval",
181 				     &keypad->scan_interval);
182 	if (error) {
183 		dev_err(&pdev->dev, "failed to get scan-interval\n");
184 		return error;
185 	}
186 
187 	error = of_property_read_u32(of_node, "row-delay",
188 				     &keypad->row_delay);
189 	if (error) {
190 		dev_err(&pdev->dev, "failed to get row-delay\n");
191 		return error;
192 	}
193 
194 	keypad->active_low = of_property_read_bool(of_node, "active-low");
195 
196 	keypad->clk = devm_clk_get(&pdev->dev, NULL);
197 	if (IS_ERR(keypad->clk)) {
198 		dev_err(&pdev->dev, "unable to get clock\n");
199 		return PTR_ERR(keypad->clk);
200 	}
201 
202 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
203 	keypad->reg_base = devm_ioremap_resource(&pdev->dev, res);
204 	if (IS_ERR(keypad->reg_base))
205 		return PTR_ERR(keypad->reg_base);
206 
207 	keypad->input = input = devm_input_allocate_device(&pdev->dev);
208 	if (!input) {
209 		dev_err(&pdev->dev, "failed to allocate input device\n");
210 		return -ENOMEM;
211 	}
212 
213 	input_set_drvdata(input, keypad);
214 
215 	input->id.bustype = BUS_HOST;
216 	input->name = "nspire-keypad";
217 	input->open = nspire_keypad_open;
218 	input->close = nspire_keypad_close;
219 
220 	__set_bit(EV_KEY, input->evbit);
221 	__set_bit(EV_REP, input->evbit);
222 	input_set_capability(input, EV_MSC, MSC_SCAN);
223 
224 	error = matrix_keypad_build_keymap(NULL, NULL,
225 					   KEYPAD_BITMASK_ROWS,
226 					   KEYPAD_BITMASK_COLS,
227 					   NULL, input);
228 	if (error) {
229 		dev_err(&pdev->dev, "building keymap failed\n");
230 		return error;
231 	}
232 
233 	error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0,
234 				 "nspire_keypad", keypad);
235 	if (error) {
236 		dev_err(&pdev->dev, "allocate irq %d failed\n", irq);
237 		return error;
238 	}
239 
240 	error = input_register_device(input);
241 	if (error) {
242 		dev_err(&pdev->dev,
243 			"unable to register input device: %d\n", error);
244 		return error;
245 	}
246 
247 	dev_dbg(&pdev->dev,
248 		"TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
249 		res, keypad->row_delay, keypad->scan_interval,
250 		keypad->active_low ? ", active_low" : "");
251 
252 	return 0;
253 }
254 
255 static const struct of_device_id nspire_keypad_dt_match[] = {
256 	{ .compatible = "ti,nspire-keypad" },
257 	{ },
258 };
259 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
260 
261 static struct platform_driver nspire_keypad_driver = {
262 	.driver = {
263 		.name = "nspire-keypad",
264 		.of_match_table = nspire_keypad_dt_match,
265 	},
266 	.probe = nspire_keypad_probe,
267 };
268 
269 module_platform_driver(nspire_keypad_driver);
270 
271 MODULE_LICENSE("GPL");
272 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");
273