drivers/input/keyboard/nspire-keypad.c

   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
  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
  96 static int nspire_keypad_chip_init(struct nspire_keypad *keypad)
  97 {
  98         unsigned long val = 0, cycles_per_us, delay_cycles, row_delay_cycles;
  99
 100         cycles_per_us = (clk_get_rate(keypad->clk) / 1000000);
 101         if (cycles_per_us == 0)
 102                 cycles_per_us = 1;
 103
 104         delay_cycles = cycles_per_us * keypad->scan_interval;
 105         WARN_ON(delay_cycles >= (1 << 16)); /* Overflow */
 106         delay_cycles &= 0xffff;
 107
 108         row_delay_cycles = cycles_per_us * keypad->row_delay;
 109         WARN_ON(row_delay_cycles >= (1 << 14)); /* Overflow */
 110         row_delay_cycles &= 0x3fff;
 111
 112         val |= 3 << 0; /* Set scan mode to 3 (continuous scan) */
 113         val |= row_delay_cycles << 2; /* Delay between scanning each row */
 114         val |= delay_cycles << 16; /* Delay between scans */
 115         writel(val, keypad->reg_base + KEYPAD_SCAN_MODE);
 116
 117         val = (KEYPAD_BITMASK_ROWS & 0xff) | (KEYPAD_BITMASK_COLS & 0xff)<<8;
 118         writel(val, keypad->reg_base + KEYPAD_CNTL);
 119
 120         /* Enable interrupts */
 121         keypad->int_mask = 1 << 1;
 122         writel(keypad->int_mask, keypad->reg_base + KEYPAD_INTMSK);
 123
 124         /* Disable GPIO interrupts to prevent hanging on touchpad */
 125         /* Possibly used to detect touchpad events */
 126         writel(0, keypad->reg_base + KEYPAD_UNKNOWN_INT);
 127         /* Acknowledge existing interrupts */
 128         writel(~0, keypad->reg_base + KEYPAD_UNKNOWN_INT_STS);
 129
 130         return 0;
 131 }
 132
 133 static int nspire_keypad_open(struct input_dev *input)
 134 {
 135         struct nspire_keypad *keypad = input_get_drvdata(input);
 136         int error;
 137
 138         error = clk_prepare_enable(keypad->clk);
 139         if (error)
 140                 return error;
 141
 142         error = nspire_keypad_chip_init(keypad);
 143         if (error) {
 144                 clk_disable_unprepare(keypad->clk);
 145                 return error;
 146         }
 147
 148         return 0;
 149 }
 150
 151 static void nspire_keypad_close(struct input_dev *input)
 152 {
 153         struct nspire_keypad *keypad = input_get_drvdata(input);
 154
 155         clk_disable_unprepare(keypad->clk);
 156 }
 157
 158 static int nspire_keypad_probe(struct platform_device *pdev)
 159 {
 160         const struct device_node *of_node = pdev->dev.of_node;
 161         struct nspire_keypad *keypad;
 162         struct input_dev *input;
 163         struct resource *res;
 164         int irq;
 165         int error;
 166
 167         irq = platform_get_irq(pdev, 0);
 168         if (irq < 0)
 169                 return -EINVAL;
 170
 171         keypad = devm_kzalloc(&pdev->dev, sizeof(struct nspire_keypad),
 172                               GFP_KERNEL);
 173         if (!keypad) {
 174                 dev_err(&pdev->dev, "failed to allocate keypad memory\n");
 175                 return -ENOMEM;
 176         }
 177
 178         keypad->row_shift = get_count_order(KEYPAD_BITMASK_COLS);
 179
 180         error = of_property_read_u32(of_node, "scan-interval",
 181                                      &keypad->scan_interval);
 182         if (error) {
 183                 dev_err(&pdev->dev, "failed to get scan-interval\n");
 184                 return error;
 185         }
 186
 187         error = of_property_read_u32(of_node, "row-delay",
 188                                      &keypad->row_delay);
 189         if (error) {
 190                 dev_err(&pdev->dev, "failed to get row-delay\n");
 191                 return error;
 192         }
 193
 194         keypad->active_low = of_property_read_bool(of_node, "active-low");
 195
 196         keypad->clk = devm_clk_get(&pdev->dev, NULL);
 197         if (IS_ERR(keypad->clk)) {
 198                 dev_err(&pdev->dev, "unable to get clock\n");
 199                 return PTR_ERR(keypad->clk);
 200         }
 201
 202         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 203         keypad->reg_base = devm_ioremap_resource(&pdev->dev, res);
 204         if (IS_ERR(keypad->reg_base))
 205                 return PTR_ERR(keypad->reg_base);
 206
 207         keypad->input = input = devm_input_allocate_device(&pdev->dev);
 208         if (!input) {
 209                 dev_err(&pdev->dev, "failed to allocate input device\n");
 210                 return -ENOMEM;
 211         }
 212
 213         input_set_drvdata(input, keypad);
 214
 215         input->id.bustype = BUS_HOST;
 216         input->name = "nspire-keypad";
 217         input->open = nspire_keypad_open;
 218         input->close = nspire_keypad_close;
 219
 220         __set_bit(EV_KEY, input->evbit);
 221         __set_bit(EV_REP, input->evbit);
 222         input_set_capability(input, EV_MSC, MSC_SCAN);
 223
 224         error = matrix_keypad_build_keymap(NULL, NULL,
 225                                            KEYPAD_BITMASK_ROWS,
 226                                            KEYPAD_BITMASK_COLS,
 227                                            NULL, input);
 228         if (error) {
 229                 dev_err(&pdev->dev, "building keymap failed\n");
 230                 return error;
 231         }
 232
 233         error = devm_request_irq(&pdev->dev, irq, nspire_keypad_irq, 0,
 234                                  "nspire_keypad", keypad);
 235         if (error) {
 236                 dev_err(&pdev->dev, "allocate irq %d failed\n", irq);
 237                 return error;
 238         }
 239
 240         error = input_register_device(input);
 241         if (error) {
 242                 dev_err(&pdev->dev,
 243                         "unable to register input device: %d\n", error);
 244                 return error;
 245         }
 246
 247         dev_dbg(&pdev->dev,
 248                 "TI-NSPIRE keypad at %pR (scan_interval=%uus, row_delay=%uus%s)\n",
 249                 res, keypad->row_delay, keypad->scan_interval,
 250                 keypad->active_low ? ", active_low" : "");
 251
 252         return 0;
 253 }
 254
 255 static const struct of_device_id nspire_keypad_dt_match[] = {
 256         { .compatible = "ti,nspire-keypad" },
 257         { },
 258 };
 259 MODULE_DEVICE_TABLE(of, nspire_keypad_dt_match);
 260
 261 static struct platform_driver nspire_keypad_driver = {
 262         .driver = {
 263                 .name = "nspire-keypad",
 264                 .of_match_table = nspire_keypad_dt_match,
 265         },
 266         .probe = nspire_keypad_probe,
 267 };
 268
 269 module_platform_driver(nspire_keypad_driver);
 270
 271 MODULE_LICENSE("GPL");
 272 MODULE_DESCRIPTION("TI-NSPIRE Keypad Driver");