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
31struct 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
50static 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
96static int nspire_keypad_open(struct input_dev *input)
97{
98	struct nspire_keypad *keypad = input_get_drvdata(input);
99	unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
100	int error;
101
102	error = clk_prepare_enable(keypad->clk);
103	if (error)
104		return error;
105
106	cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
107	if (cycles_per_us == 0)
108		cycles_per_us = 1;
109
110	delay_cycles = cycles_per_us * keypad->scan_interval;
111	WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
112	delay_cycles &= 0xffff;
113
114	row_delay_cycles = cycles_per_us * keypad->row_delay;
115	WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
116	row_delay_cycles &= 0x3fff;
117
118	val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
119	val |= row_delay_cycles << 2; /* Delay between scanning each row */
120	val |= delay_cycles << 16; /* Delay between scans */
121	writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
122
123	val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
124	writel(val, keypad->reg_base + KEYPAD_CNTL);
125
126	/* Enable interrupts */
127	keypad->int_mask = 1 << 1;
128	writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK);
129
130	return 0;
131}
132
133static void nspire_keypad_close(struct input_dev *input)
134{
135	struct nspire_keypad *keypad = input_get_drvdata(input);
136
137	/* Disable interrupts */
138	writel(0, keypad->reg_base + KEYPAD_INTMSK);
139	/* Acknowledge existing interrupts */
140	writel(~0, keypad->reg_base + KEYPAD_INT);
141
142	clk_disable_unprepare(keypad->clk);
143}
144
145static int nspire_keypad_probe(struct platform_device *pdev)
146{
147	const struct device_node *of_node = pdev->dev.of_node;
148	struct nspire_keypad *keypad;
149	struct input_dev *input;
150	struct resource *res;
151	int irq;
152	int error;
153
154	irq = platform_get_irq(pdev, 0);
155	if (irq < 0)
156		return -EINVAL;
157
158	keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
159			      GFP_KERNEL);
160	if (!keypad) {
161		dev_err(&pdev->dev, "failed to allocate keypad memory\n");
162		return -ENOMEM;
163	}
164
165	keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
166
167	error = of_property_read_u32(of_node, "scan-interval",
168				     &keypad->scan_interval);
169	if (error) {
170		dev_err(&pdev->dev, "failed to get scan-interval\n");
171		return error;
172	}
173
174	error = of_property_read_u32(of_node, "row-delay",
175				     &keypad->row_delay);
176	if (error) {
177		dev_err(&pdev->dev, "failed to get row-delay\n");
178		return error;
179	}
180
181	keypad->active_low = of_property_read_bool(of_node, "active-low");
182
183	keypad->clk = devm_clk_get(&pdev->dev, NULL);
184	if (IS_ERR(keypad->clk)) {
185		dev_err(&pdev->dev, "unable to get clock\n");
186		return PTR_ERR(keypad->clk);
187	}
188
189	keypad->reg_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
190	if (IS_ERR(keypad->reg_base))
191		return PTR_ERR(keypad->reg_base);
192
193	keypad->input = input = devm_input_allocate_device(&pdev->dev);
194	if (!input) {
195		dev_err(&pdev->dev, "failed to allocate input device\n");
196		return -ENOMEM;
197	}
198
199	error = clk_prepare_enable(keypad->clk);
200	if (error) {
201		dev_err(&pdev->dev, "failed to enable clock\n");
202		return error;
203	}
204
205	/* Disable interrupts */
206	writel(0, keypad->reg_base + KEYPAD_INTMSK);
207	/* Acknowledge existing interrupts */
208	writel(~0, keypad->reg_base + KEYPAD_INT);
209
210	/* Disable GPIO interrupts to prevent hanging on touchpad */
211	/* Possibly used to detect touchpad events */
212	writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
213	/* Acknowledge existing GPIO interrupts */
214	writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
215
216	clk_disable_unprepare(keypad->clk);
217
218	input_set_drvdata(input, keypad);
219
220	input->id.bustype = BUS_HOST;
221	input->name = "nspire-keypad";
222	input->open = nspire_keypad_open;
223	input->close = nspire_keypad_close;
224
225	__set_bit(EV_KEY, input->evbit);
226	__set_bit(EV_REP, input->evbit);
227	input_set_capability(input, EV_MSC, MSC_SCAN);
228
229	error = matrix_keypad_build_keymap(NULL, NULL,
230					   KEYPAD_BITMASK_ROWS,
231					   KEYPAD_BITMASK_COLS,
232					   NULL, input);
233	if (error) {
234		dev_err(&pdev->dev, "building keymap failed\n");
235		return error;
236	}
237
238	error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0,
239				 "nspire_keypad", keypad);
240	if (error) {
241		dev_err(&pdev->dev, "allocate irq %d failed\n", irq);
242		return error;
243	}
244
245	error = input_register_device(input);
246	if (error) {
247		dev_err(&pdev->dev,
248			"unable to register input device: %d\n", error);
249		return error;
250	}
251
252	dev_dbg(&pdev->dev,
253		"TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
254		res, keypad->row_delay, keypad->scan_interval,
255		keypad->active_low ? ", active_low" : "");
256
257	return 0;
258}
259
260static const struct of_device_id nspire_keypad_dt_match[] = {
261	{ .compatible = "ti,nspire-keypad" },
262	{ },
263};
264MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
265
266static struct platform_driver nspire_keypad_driver = {
267	.driver = {
268		.name = "nspire-keypad",
269		.of_match_table = nspire_keypad_dt_match,
270	},
271	.probe = nspire_keypad_probe,
272};
273
274module_platform_driver(nspire_keypad_driver);
275
276MODULE_LICENSE("GPL");
277MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");
278