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
34 struct 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
nspire_keypad_irq(int irq,void * dev_id)53 static 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
nspire_keypad_chip_init(struct nspire_keypad * keypad)99 static 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
nspire_keypad_open(struct input_dev * input)136 static 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
nspire_keypad_close(struct input_dev * input)154 static 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
nspire_keypad_probe(struct platform_device * pdev)161 static 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 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
260 static const struct of_device_id nspire_keypad_dt_match[] = {
261 { .compatible = "ti,nspire-keypad" },
262 { },
263 };
264 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
265
266 static 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
274 module_platform_driver(nspire_keypad_driver);
275
276 MODULE_LICENSE("GPL");
277 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");
278
