drivers/input/keyboard/lpc32xx-keys.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * NXP LPC32xx SoC Key Scan Interface
   4  *
   5  * Authors:
   6  *    Kevin Wells <kevin.wells@nxp.com>
   7  *    Roland Stigge <stigge@antcom.de>
   8  *
   9  * Copyright (C) 2010 NXP Semiconductors
  10  * Copyright (C) 2012 Roland Stigge
  11  *
  12  * This controller supports square key matrices from 1x1 up to 8x8
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/slab.h>
  18 #include <linux/irq.h>
  19 #include <linux/pm.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/input.h>
  22 #include <linux/clk.h>
  23 #include <linux/io.h>
  24 #include <linux/of.h>
  25 #include <linux/input/matrix_keypad.h>
  26
  27 #define DRV_NAME                                "lpc32xx_keys"
  28
  29 /*
  30  * Key scanner register offsets
  31  */
  32 #define LPC32XX_KS_DEB(x)                       ((x) + 0x00)
  33 #define LPC32XX_KS_STATE_COND(x)                ((x) + 0x04)
  34 #define LPC32XX_KS_IRQ(x)                       ((x) + 0x08)
  35 #define LPC32XX_KS_SCAN_CTL(x)                  ((x) + 0x0C)
  36 #define LPC32XX_KS_FAST_TST(x)                  ((x) + 0x10)
  37 #define LPC32XX_KS_MATRIX_DIM(x)                ((x) + 0x14) /* 1..8 */
  38 #define LPC32XX_KS_DATA(x, y)                   ((x) + 0x40 + ((y) << 2))
  39
  40 #define LPC32XX_KSCAN_DEB_NUM_DEB_PASS(n)       ((n) & 0xFF)
  41
  42 #define LPC32XX_KSCAN_SCOND_IN_IDLE             0x0
  43 #define LPC32XX_KSCAN_SCOND_IN_SCANONCE         0x1
  44 #define LPC32XX_KSCAN_SCOND_IN_IRQGEN           0x2
  45 #define LPC32XX_KSCAN_SCOND_IN_SCAN_MATRIX      0x3
  46
  47 #define LPC32XX_KSCAN_IRQ_PENDING_CLR           0x1
  48
  49 #define LPC32XX_KSCAN_SCTRL_SCAN_DELAY(n)       ((n) & 0xFF)
  50
  51 #define LPC32XX_KSCAN_FTST_FORCESCANONCE        0x1
  52 #define LPC32XX_KSCAN_FTST_USE32K_CLK           0x2
  53
  54 #define LPC32XX_KSCAN_MSEL_SELECT(n)            ((n) & 0xF)
  55
  56 struct lpc32xx_kscan_drv {
  57         struct input_dev *input;
  58         struct clk *clk;
  59         void __iomem *kscan_base;
  60         unsigned int irq;
  61
  62         u32 matrix_sz;          /* Size of matrix in XxY, ie. 3 = 3x3 */
  63         u32 deb_clks;           /* Debounce clocks (based on 32KHz clock) */
  64         u32 scan_delay;         /* Scan delay (based on 32KHz clock) */
  65
  66         unsigned short *keymap; /* Pointer to key map for the scan matrix */
  67         unsigned int row_shift;
  68
  69         u8 lastkeystates[8];
  70 };
  71
  72 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
  73 {
  74         struct input_dev *input = kscandat->input;
  75         unsigned row, changed, scancode, keycode;
  76         u8 key;
  77
  78         key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
  79         changed = key ^ kscandat->lastkeystates[col];
  80         kscandat->lastkeystates[col] = key;
  81
  82         for (row = 0; changed; row++, changed >>= 1) {
  83                 if (changed & 1) {
  84                         /* Key state changed, signal an event */
  85                         scancode = MATRIX_SCAN_CODE(row, col,
  86                                                     kscandat->row_shift);
  87                         keycode = kscandat->keymap[scancode];
  88                         input_event(input, EV_MSC, MSC_SCAN, scancode);
  89                         input_report_key(input, keycode, key & (1 << row));
  90                 }
  91         }
  92 }
  93
  94 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
  95 {
  96         struct lpc32xx_kscan_drv *kscandat = dev_id;
  97         int i;
  98
  99         for (i = 0; i < kscandat->matrix_sz; i++)
 100                 lpc32xx_mod_states(kscandat, i);
 101
 102         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 103
 104         input_sync(kscandat->input);
 105
 106         return IRQ_HANDLED;
 107 }
 108
 109 static int lpc32xx_kscan_open(struct input_dev *dev)
 110 {
 111         struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
 112         int error;
 113
 114         error = clk_prepare_enable(kscandat->clk);
 115         if (error)
 116                 return error;
 117
 118         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 119
 120         return 0;
 121 }
 122
 123 static void lpc32xx_kscan_close(struct input_dev *dev)
 124 {
 125         struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
 126
 127         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 128         clk_disable_unprepare(kscandat->clk);
 129 }
 130
 131 static int lpc32xx_parse_dt(struct device *dev,
 132                                       struct lpc32xx_kscan_drv *kscandat)
 133 {
 134         struct device_node *np = dev->of_node;
 135         u32 rows = 0, columns = 0;
 136         int err;
 137
 138         err = matrix_keypad_parse_properties(dev, &rows, &columns);
 139         if (err)
 140                 return err;
 141         if (rows != columns) {
 142                 dev_err(dev, "rows and columns must be equal!\n");
 143                 return -EINVAL;
 144         }
 145
 146         kscandat->matrix_sz = rows;
 147         kscandat->row_shift = get_count_order(columns);
 148
 149         of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
 150         of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
 151         if (!kscandat->deb_clks || !kscandat->scan_delay) {
 152                 dev_err(dev, "debounce or scan delay not specified\n");
 153                 return -EINVAL;
 154         }
 155
 156         return 0;
 157 }
 158
 159 static int lpc32xx_kscan_probe(struct platform_device *pdev)
 160 {
 161         struct lpc32xx_kscan_drv *kscandat;
 162         struct input_dev *input;
 163         size_t keymap_size;
 164         int error;
 165         int irq;
 166
 167         irq = platform_get_irq(pdev, 0);
 168         if (irq < 0)
 169                 return -EINVAL;
 170
 171         kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
 172                                 GFP_KERNEL);
 173         if (!kscandat)
 174                 return -ENOMEM;
 175
 176         error = lpc32xx_parse_dt(&pdev->dev, kscandat);
 177         if (error) {
 178                 dev_err(&pdev->dev, "failed to parse device tree\n");
 179                 return error;
 180         }
 181
 182         keymap_size = sizeof(kscandat->keymap[0]) *
 183                                 (kscandat->matrix_sz << kscandat->row_shift);
 184         kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
 185         if (!kscandat->keymap)
 186                 return -ENOMEM;
 187
 188         kscandat->input = input = devm_input_allocate_device(&pdev->dev);
 189         if (!input) {
 190                 dev_err(&pdev->dev, "failed to allocate input device\n");
 191                 return -ENOMEM;
 192         }
 193
 194         /* Setup key input */
 195         input->name             = pdev->name;
 196         input->phys             = "lpc32xx/input0";
 197         input->id.vendor        = 0x0001;
 198         input->id.product       = 0x0001;
 199         input->id.version       = 0x0100;
 200         input->open             = lpc32xx_kscan_open;
 201         input->close            = lpc32xx_kscan_close;
 202         input->dev.parent       = &pdev->dev;
 203
 204         input_set_capability(input, EV_MSC, MSC_SCAN);
 205
 206         error = matrix_keypad_build_keymap(NULL, NULL,
 207                                            kscandat->matrix_sz,
 208                                            kscandat->matrix_sz,
 209                                            kscandat->keymap, kscandat->input);
 210         if (error) {
 211                 dev_err(&pdev->dev, "failed to build keymap\n");
 212                 return error;
 213         }
 214
 215         input_set_drvdata(kscandat->input, kscandat);
 216
 217         kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
 218         if (IS_ERR(kscandat->kscan_base))
 219                 return PTR_ERR(kscandat->kscan_base);
 220
 221         /* Get the key scanner clock */
 222         kscandat->clk = devm_clk_get(&pdev->dev, NULL);
 223         if (IS_ERR(kscandat->clk)) {
 224                 dev_err(&pdev->dev, "failed to get clock\n");
 225                 return PTR_ERR(kscandat->clk);
 226         }
 227
 228         /* Configure the key scanner */
 229         error = clk_prepare_enable(kscandat->clk);
 230         if (error)
 231                 return error;
 232
 233         writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
 234         writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
 235         writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
 236                LPC32XX_KS_FAST_TST(kscandat->kscan_base));
 237         writel(kscandat->matrix_sz,
 238                LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
 239         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 240         clk_disable_unprepare(kscandat->clk);
 241
 242         error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
 243                                  pdev->name, kscandat);
 244         if (error) {
 245                 dev_err(&pdev->dev, "failed to request irq\n");
 246                 return error;
 247         }
 248
 249         error = input_register_device(kscandat->input);
 250         if (error) {
 251                 dev_err(&pdev->dev, "failed to register input device\n");
 252                 return error;
 253         }
 254
 255         platform_set_drvdata(pdev, kscandat);
 256
 257         return 0;
 258 }
 259
 260 static int lpc32xx_kscan_suspend(struct device *dev)
 261 {
 262         struct platform_device *pdev = to_platform_device(dev);
 263         struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
 264         struct input_dev *input = kscandat->input;
 265
 266         mutex_lock(&input->mutex);
 267
 268         if (input_device_enabled(input)) {
 269                 /* Clear IRQ and disable clock */
 270                 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 271                 clk_disable_unprepare(kscandat->clk);
 272         }
 273
 274         mutex_unlock(&input->mutex);
 275         return 0;
 276 }
 277
 278 static int lpc32xx_kscan_resume(struct device *dev)
 279 {
 280         struct platform_device *pdev = to_platform_device(dev);
 281         struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
 282         struct input_dev *input = kscandat->input;
 283         int retval = 0;
 284
 285         mutex_lock(&input->mutex);
 286
 287         if (input_device_enabled(input)) {
 288                 /* Enable clock and clear IRQ */
 289                 retval = clk_prepare_enable(kscandat->clk);
 290                 if (retval == 0)
 291                         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 292         }
 293
 294         mutex_unlock(&input->mutex);
 295         return retval;
 296 }
 297
 298 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
 299                                 lpc32xx_kscan_resume);
 300
 301 static const struct of_device_id lpc32xx_kscan_match[] = {
 302         { .compatible = "nxp,lpc3220-key" },
 303         {},
 304 };
 305 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
 306
 307 static struct platform_driver lpc32xx_kscan_driver = {
 308         .probe          = lpc32xx_kscan_probe,
 309         .driver         = {
 310                 .name   = DRV_NAME,
 311                 .pm     = pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
 312                 .of_match_table = lpc32xx_kscan_match,
 313         }
 314 };
 315
 316 module_platform_driver(lpc32xx_kscan_driver);
 317
 318 MODULE_LICENSE("GPL");
 319 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com>");
 320 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 321 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");