1/*
2 *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2, as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/input/matrix_keypad.h>
10#include <linux/platform_device.h>
11#include <linux/interrupt.h>
12#include <linux/io.h>
13#include <linux/delay.h>
14#include <linux/input.h>
15#include <linux/slab.h>
16#include <linux/clk.h>
17#include <linux/module.h>
18#include <linux/of.h>
19
20#define KEYPAD_SCAN_MODE	0x00
21#define KEYPAD_CNTL		0x04
22#define KEYPAD_INT		0x08
23#define KEYPAD_INTMSK		0x0C
24
25#define KEYPAD_DATA		0x10
26#define KEYPAD_GPIO		0x30
27
28#define KEYPAD_UNKNOWN_INT	0x40
29#define KEYPAD_UNKNOWN_INT_STS	0x44
30
31#define KEYPAD_BITMASK_COLS	11
32#define KEYPAD_BITMASK_ROWS	8
33
34struct nspire_keypad {
35	void __iomem *reg_base;
36	u32 int_mask;
37
38	struct input_dev *input;
39	struct clk *clk;
40
41	struct matrix_keymap_data *keymap;
42	int row_shift;
43
44	/* Maximum delay estimated assuming 33MHz APB */
45	u32 scan_interval;	/* In microseconds (~2000us max) */
46	u32 row_delay;		/* In microseconds (~500us max) */
47
48	u16 state[KEYPAD_BITMASK_ROWS];
49
50	bool active_low;
51};
52
53static irqreturn_t nspire_keypad_irq(int irq, void *dev_id)
54{
55	struct nspire_keypad *keypad = dev_id;
56	struct input_dev *input = keypad->input;
57	unsigned short *keymap = input->keycode;
58	unsigned int code;
59	int row, col;
60	u32 int_sts;
61	u16 state[8];
62	u16 bits, changed;
63
64	int_sts = readl(keypad->reg_base + KEYPAD_INT) & keypad->int_mask;
65	if (!int_sts)
66		return IRQ_NONE;
67
68	memcpy_fromio(state, keypad->reg_base + KEYPAD_DATA, sizeof(state));
69
70	for (row = 0; row < KEYPAD_BITMASK_ROWS; row++) {
71		bits = state[row];
72		if (keypad->active_low)
73			bits = ~bits;
74
75		changed = bits ^ keypad->state[row];
76		if (!changed)
77			continue;
78
79		keypad->state[row] = bits;
80
81		for (col = 0; col < KEYPAD_BITMASK_COLS; col++) {
82			if (!(changed & (1U << col)))
83				continue;
84
85			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
86			input_event(input, EV_MSC, MSC_SCAN, code);
87			input_report_key(input, keymap[code],
88					 bits & (1U << col));
89		}
90	}
91
92	input_sync(input);
93
94	writel(0x3, keypad->reg_base + KEYPAD_INT);
95
96	return IRQ_HANDLED;
97}
98
99static int nspire_keypad_chip_init(struct nspire_keypad *keypad)
100{
101	unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
102
103	cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
104	if (cycles_per_us == 0)
105		cycles_per_us = 1;
106
107	delay_cycles = cycles_per_us * keypad->scan_interval;
108	WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
109	delay_cycles &= 0xffff;
110
111	row_delay_cycles = cycles_per_us * keypad->row_delay;
112	WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
113	row_delay_cycles &= 0x3fff;
114
115	val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
116	val |= row_delay_cycles << 2; /* Delay between scanning each row */
117	val |= delay_cycles << 16; /* Delay between scans */
118	writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
119
120	val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
121	writel(val, keypad->reg_base + KEYPAD_CNTL);
122
123	/* Enable interrupts */
124	keypad->int_mask = 1 << 1;
125	writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK);
126
127	/* Disable GPIO interrupts to prevent hanging on touchpad */
128	/* Possibly used to detect touchpad events */
129	writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
130	/* Acknowledge existing interrupts */
131	writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
132
133	return 0;
134}
135
136static int nspire_keypad_open(struct input_dev *input)
137{
138	struct nspire_keypad *keypad = input_get_drvdata(input);
139	int error;
140
141	error = clk_prepare_enable(keypad->clk);
142	if (error)
143		return error;
144
145	error = nspire_keypad_chip_init(keypad);
146	if (error) {
147		clk_disable_unprepare(keypad->clk);
148		return error;
149	}
150
151	return 0;
152}
153
154static void nspire_keypad_close(struct input_dev *input)
155{
156	struct nspire_keypad *keypad = input_get_drvdata(input);
157
158	clk_disable_unprepare(keypad->clk);
159}
160
161static int nspire_keypad_probe(struct platform_device *pdev)
162{
163	const struct device_node *of_node = pdev->dev.of_node;
164	struct nspire_keypad *keypad;
165	struct input_dev *input;
166	struct resource *res;
167	int irq;
168	int error;
169
170	irq = platform_get_irq(pdev, 0);
171	if (irq < 0) {
172		dev_err(&pdev->dev, "failed to get keypad irq\n");
173		return -EINVAL;
174	}
175
176	keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
177			      GFP_KERNEL);
178	if (!keypad) {
179		dev_err(&pdev->dev, "failed to allocate keypad memory\n");
180		return -ENOMEM;
181	}
182
183	keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
184
185	error = of_property_read_u32(of_node, "scan-interval",
186				     &keypad->scan_interval);
187	if (error) {
188		dev_err(&pdev->dev, "failed to get scan-interval\n");
189		return error;
190	}
191
192	error = of_property_read_u32(of_node, "row-delay",
193				     &keypad->row_delay);
194	if (error) {
195		dev_err(&pdev->dev, "failed to get row-delay\n");
196		return error;
197	}
198
199	keypad->active_low = of_property_read_bool(of_node, "active-low");
200
201	keypad->clk = devm_clk_get(&pdev->dev, NULL);
202	if (IS_ERR(keypad->clk)) {
203		dev_err(&pdev->dev, "unable to get clock\n");
204		return PTR_ERR(keypad->clk);
205	}
206
207	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
208	keypad->reg_base = devm_ioremap_resource(&pdev->dev, res);
209	if (IS_ERR(keypad->reg_base))
210		return PTR_ERR(keypad->reg_base);
211
212	keypad->input = input = devm_input_allocate_device(&pdev->dev);
213	if (!input) {
214		dev_err(&pdev->dev, "failed to allocate input device\n");
215		return -ENOMEM;
216	}
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	platform_set_drvdata(pdev, keypad);
253
254	dev_dbg(&pdev->dev,
255		"TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
256		res, keypad->row_delay, keypad->scan_interval,
257		keypad->active_low ? ", active_low" : "");
258
259	return 0;
260}
261
262static const struct of_device_id nspire_keypad_dt_match[] = {
263	{ .compatible = "ti,nspire-keypad" },
264	{ },
265};
266MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
267
268static struct platform_driver nspire_keypad_driver = {
269	.driver = {
270		.name = "nspire-keypad",
271		.of_match_table = nspire_keypad_dt_match,
272	},
273	.probe = nspire_keypad_probe,
274};
275
276module_platform_driver(nspire_keypad_driver);
277
278MODULE_LICENSE("GPL");
279MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");
280