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 <[email protected]>
   7  *    Roland Stigge <[email protected]>
   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
  61         u32 matrix_sz;          /* Size of matrix in XxY, ie. 3 = 3x3 */
  62         u32 deb_clks;           /* Debounce clocks (based on 32KHz clock) */
  63         u32 scan_delay;         /* Scan delay (based on 32KHz clock) */
  64
  65         unsigned int row_shift;
  66         unsigned short *keymap; /* Pointer to key map for the scan matrix */
  67
  68         u8 lastkeystates[8];
  69 };
  70
  71 static void lpc32xx_mod_states(struct lpc32xx_kscan_drv *kscandat, int col)
  72 {
  73         struct input_dev *input = kscandat->input;
  74         unsigned row, changed, scancode, keycode;
  75         u8 key;
  76
  77         key = readl(LPC32XX_KS_DATA(kscandat->kscan_base, col));
  78         changed = key ^ kscandat->lastkeystates[col];
  79         kscandat->lastkeystates[col] = key;
  80
  81         for (row = 0; changed; row++, changed >>= 1) {
  82                 if (changed & 1) {
  83                         /* Key state changed, signal an event */
  84                         scancode = MATRIX_SCAN_CODE(row, col,
  85                                                     kscandat->row_shift);
  86                         keycode = kscandat->keymap[scancode];
  87                         input_event(input, EV_MSC, MSC_SCAN, scancode);
  88                         input_report_key(input, keycode, key & (1 << row));
  89                 }
  90         }
  91 }
  92
  93 static irqreturn_t lpc32xx_kscan_irq(int irq, void *dev_id)
  94 {
  95         struct lpc32xx_kscan_drv *kscandat = dev_id;
  96         int i;
  97
  98         for (i = 0; i < kscandat->matrix_sz; i++)
  99                 lpc32xx_mod_states(kscandat, i);
 100
 101         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 102
 103         input_sync(kscandat->input);
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 static int lpc32xx_kscan_open(struct input_dev *dev)
 109 {
 110         struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
 111         int error;
 112
 113         error = clk_prepare_enable(kscandat->clk);
 114         if (error)
 115                 return error;
 116
 117         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 118
 119         return 0;
 120 }
 121
 122 static void lpc32xx_kscan_close(struct input_dev *dev)
 123 {
 124         struct lpc32xx_kscan_drv *kscandat = input_get_drvdata(dev);
 125
 126         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 127         clk_disable_unprepare(kscandat->clk);
 128 }
 129
 130 static int lpc32xx_parse_dt(struct device *dev,
 131                                       struct lpc32xx_kscan_drv *kscandat)
 132 {
 133         struct device_node *np = dev->of_node;
 134         u32 rows = 0, columns = 0;
 135         int err;
 136
 137         err = matrix_keypad_parse_properties(dev, &rows, &columns);
 138         if (err)
 139                 return err;
 140         if (rows != columns) {
 141                 dev_err(dev, "rows and columns must be equal!\n");
 142                 return -EINVAL;
 143         }
 144
 145         kscandat->matrix_sz = rows;
 146         kscandat->row_shift = get_count_order(columns);
 147
 148         of_property_read_u32(np, "nxp,debounce-delay-ms", &kscandat->deb_clks);
 149         of_property_read_u32(np, "nxp,scan-delay-ms", &kscandat->scan_delay);
 150         if (!kscandat->deb_clks || !kscandat->scan_delay) {
 151                 dev_err(dev, "debounce or scan delay not specified\n");
 152                 return -EINVAL;
 153         }
 154
 155         return 0;
 156 }
 157
 158 static int lpc32xx_kscan_probe(struct platform_device *pdev)
 159 {
 160         struct lpc32xx_kscan_drv *kscandat;
 161         struct input_dev *input;
 162         size_t keymap_size;
 163         int error;
 164         int irq;
 165
 166         irq = platform_get_irq(pdev, 0);
 167         if (irq < 0)
 168                 return -EINVAL;
 169
 170         kscandat = devm_kzalloc(&pdev->dev, sizeof(*kscandat),
 171                                 GFP_KERNEL);
 172         if (!kscandat)
 173                 return -ENOMEM;
 174
 175         error = lpc32xx_parse_dt(&pdev->dev, kscandat);
 176         if (error) {
 177                 dev_err(&pdev->dev, "failed to parse device tree\n");
 178                 return error;
 179         }
 180
 181         keymap_size = sizeof(kscandat->keymap[0]) *
 182                                 (kscandat->matrix_sz << kscandat->row_shift);
 183         kscandat->keymap = devm_kzalloc(&pdev->dev, keymap_size, GFP_KERNEL);
 184         if (!kscandat->keymap)
 185                 return -ENOMEM;
 186
 187         kscandat->input = input = devm_input_allocate_device(&pdev->dev);
 188         if (!input) {
 189                 dev_err(&pdev->dev, "failed to allocate input device\n");
 190                 return -ENOMEM;
 191         }
 192
 193         /* Setup key input */
 194         input->name             = pdev->name;
 195         input->phys             = "lpc32xx/input0";
 196         input->id.vendor        = 0x0001;
 197         input->id.product       = 0x0001;
 198         input->id.version       = 0x0100;
 199         input->open             = lpc32xx_kscan_open;
 200         input->close            = lpc32xx_kscan_close;
 201         input->dev.parent       = &pdev->dev;
 202
 203         input_set_capability(input, EV_MSC, MSC_SCAN);
 204
 205         error = matrix_keypad_build_keymap(NULL, NULL,
 206                                            kscandat->matrix_sz,
 207                                            kscandat->matrix_sz,
 208                                            kscandat->keymap, kscandat->input);
 209         if (error) {
 210                 dev_err(&pdev->dev, "failed to build keymap\n");
 211                 return error;
 212         }
 213
 214         input_set_drvdata(kscandat->input, kscandat);
 215
 216         kscandat->kscan_base = devm_platform_ioremap_resource(pdev, 0);
 217         if (IS_ERR(kscandat->kscan_base))
 218                 return PTR_ERR(kscandat->kscan_base);
 219
 220         /* Get the key scanner clock */
 221         kscandat->clk = devm_clk_get(&pdev->dev, NULL);
 222         if (IS_ERR(kscandat->clk)) {
 223                 dev_err(&pdev->dev, "failed to get clock\n");
 224                 return PTR_ERR(kscandat->clk);
 225         }
 226
 227         /* Configure the key scanner */
 228         error = clk_prepare_enable(kscandat->clk);
 229         if (error)
 230                 return error;
 231
 232         writel(kscandat->deb_clks, LPC32XX_KS_DEB(kscandat->kscan_base));
 233         writel(kscandat->scan_delay, LPC32XX_KS_SCAN_CTL(kscandat->kscan_base));
 234         writel(LPC32XX_KSCAN_FTST_USE32K_CLK,
 235                LPC32XX_KS_FAST_TST(kscandat->kscan_base));
 236         writel(kscandat->matrix_sz,
 237                LPC32XX_KS_MATRIX_DIM(kscandat->kscan_base));
 238         writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 239         clk_disable_unprepare(kscandat->clk);
 240
 241         error = devm_request_irq(&pdev->dev, irq, lpc32xx_kscan_irq, 0,
 242                                  pdev->name, kscandat);
 243         if (error) {
 244                 dev_err(&pdev->dev, "failed to request irq\n");
 245                 return error;
 246         }
 247
 248         error = input_register_device(kscandat->input);
 249         if (error) {
 250                 dev_err(&pdev->dev, "failed to register input device\n");
 251                 return error;
 252         }
 253
 254         platform_set_drvdata(pdev, kscandat);
 255
 256         return 0;
 257 }
 258
 259 static int lpc32xx_kscan_suspend(struct device *dev)
 260 {
 261         struct platform_device *pdev = to_platform_device(dev);
 262         struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
 263         struct input_dev *input = kscandat->input;
 264
 265         guard(mutex)(&input->mutex);
 266
 267         if (input_device_enabled(input)) {
 268                 /* Clear IRQ and disable clock */
 269                 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 270                 clk_disable_unprepare(kscandat->clk);
 271         }
 272
 273         return 0;
 274 }
 275
 276 static int lpc32xx_kscan_resume(struct device *dev)
 277 {
 278         struct platform_device *pdev = to_platform_device(dev);
 279         struct lpc32xx_kscan_drv *kscandat = platform_get_drvdata(pdev);
 280         struct input_dev *input = kscandat->input;
 281         int error;
 282
 283         guard(mutex)(&input->mutex);
 284
 285         if (input_device_enabled(input)) {
 286                 /* Enable clock and clear IRQ */
 287                 error = clk_prepare_enable(kscandat->clk);
 288                 if (error)
 289                         return error;
 290
 291                 writel(1, LPC32XX_KS_IRQ(kscandat->kscan_base));
 292         }
 293
 294         return 0;
 295 }
 296
 297 static DEFINE_SIMPLE_DEV_PM_OPS(lpc32xx_kscan_pm_ops, lpc32xx_kscan_suspend,
 298                                 lpc32xx_kscan_resume);
 299
 300 static const struct of_device_id lpc32xx_kscan_match[] = {
 301         { .compatible = "nxp,lpc3220-key" },
 302         {},
 303 };
 304 MODULE_DEVICE_TABLE(of, lpc32xx_kscan_match);
 305
 306 static struct platform_driver lpc32xx_kscan_driver = {
 307         .probe          = lpc32xx_kscan_probe,
 308         .driver         = {
 309                 .name   = DRV_NAME,
 310                 .pm     = pm_sleep_ptr(&lpc32xx_kscan_pm_ops),
 311                 .of_match_table = lpc32xx_kscan_match,
 312         }
 313 };
 314
 315 module_platform_driver(lpc32xx_kscan_driver);
 316
 317 MODULE_LICENSE("GPL");
 318 MODULE_AUTHOR("Kevin Wells <[email protected]>");
 319 MODULE_AUTHOR("Roland Stigge <[email protected]>");
 320 MODULE_DESCRIPTION("Key scanner driver for LPC32XX devices");