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
nspire_keypad_irq(int irq,void * dev_id)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
nspire_keypad_open(struct input_dev * input)96 static 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
nspire_keypad_close(struct input_dev * input)133 static 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
nspire_keypad_probe(struct platform_device * pdev)145 static 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
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