Version:  2.0.40 2.2.26 2.4.37 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Linux/drivers/input/keyboard/nspire-keypad.c

  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 
 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 
 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 
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 
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 
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         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 
262 static const struct of_device_id nspire_keypad_dt_match[] = {
263         { .compatible = "ti,nspire-keypad" },
264         { },
265 };
266 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
267 
268 static struct platform_driver nspire_keypad_driver = {
269         .driver = {
270                 .name = "nspire-keypad",
271                 .owner = THIS_MODULE,
272                 .of_match_table = nspire_keypad_dt_match,
273         },
274         .probe = nspire_keypad_probe,
275 };
276 
277 module_platform_driver(nspire_keypad_driver);
278 
279 MODULE_LICENSE("GPL");
280 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");
281 

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