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         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");