linux/drivers/input/keyboard/bcm-keypad.c
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   1/*
   2 * Copyright (C) 2014 Broadcom Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public License as
   6 * published by the Free Software Foundation version 2.
   7 *
   8 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9 * kind, whether express or implied; without even the implied warranty
  10 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14#include <linux/bitops.h>
  15#include <linux/clk.h>
  16#include <linux/gfp.h>
  17#include <linux/io.h>
  18#include <linux/input.h>
  19#include <linux/input/matrix_keypad.h>
  20#include <linux/interrupt.h>
  21#include <linux/module.h>
  22#include <linux/of.h>
  23#include <linux/platform_device.h>
  24#include <linux/stddef.h>
  25#include <linux/types.h>
  26
  27#define DEFAULT_CLK_HZ                  31250
  28#define MAX_ROWS                        8
  29#define MAX_COLS                        8
  30
  31/* Register/field definitions */
  32#define KPCR_OFFSET                     0x00000080
  33#define KPCR_MODE                       0x00000002
  34#define KPCR_MODE_SHIFT                 1
  35#define KPCR_MODE_MASK                  1
  36#define KPCR_ENABLE                     0x00000001
  37#define KPCR_STATUSFILTERENABLE         0x00008000
  38#define KPCR_STATUSFILTERTYPE_SHIFT     12
  39#define KPCR_COLFILTERENABLE            0x00000800
  40#define KPCR_COLFILTERTYPE_SHIFT        8
  41#define KPCR_ROWWIDTH_SHIFT             20
  42#define KPCR_COLUMNWIDTH_SHIFT          16
  43
  44#define KPIOR_OFFSET                    0x00000084
  45#define KPIOR_ROWOCONTRL_SHIFT          24
  46#define KPIOR_ROWOCONTRL_MASK           0xFF000000
  47#define KPIOR_COLUMNOCONTRL_SHIFT       16
  48#define KPIOR_COLUMNOCONTRL_MASK        0x00FF0000
  49#define KPIOR_COLUMN_IO_DATA_SHIFT      0
  50
  51#define KPEMR0_OFFSET                   0x00000090
  52#define KPEMR1_OFFSET                   0x00000094
  53#define KPEMR2_OFFSET                   0x00000098
  54#define KPEMR3_OFFSET                   0x0000009C
  55#define KPEMR_EDGETYPE_BOTH             3
  56
  57#define KPSSR0_OFFSET                   0x000000A0
  58#define KPSSR1_OFFSET                   0x000000A4
  59#define KPSSRN_OFFSET(reg_n)            (KPSSR0_OFFSET + 4 * (reg_n))
  60#define KPIMR0_OFFSET                   0x000000B0
  61#define KPIMR1_OFFSET                   0x000000B4
  62#define KPICR0_OFFSET                   0x000000B8
  63#define KPICR1_OFFSET                   0x000000BC
  64#define KPICRN_OFFSET(reg_n)            (KPICR0_OFFSET + 4 * (reg_n))
  65#define KPISR0_OFFSET                   0x000000C0
  66#define KPISR1_OFFSET                   0x000000C4
  67
  68#define KPCR_STATUSFILTERTYPE_MAX       7
  69#define KPCR_COLFILTERTYPE_MAX          7
  70
  71/* Macros to determine the row/column from a bit that is set in SSR0/1. */
  72#define BIT_TO_ROW_SSRN(bit_nr, reg_n)  (((bit_nr) >> 3) + 4 * (reg_n))
  73#define BIT_TO_COL(bit_nr)              ((bit_nr) % 8)
  74
  75/* Structure representing various run-time entities */
  76struct bcm_kp {
  77        void __iomem *base;
  78        int irq;
  79        struct clk *clk;
  80        struct input_dev *input_dev;
  81        unsigned long last_state[2];
  82        unsigned int n_rows;
  83        unsigned int n_cols;
  84        u32 kpcr;
  85        u32 kpior;
  86        u32 kpemr;
  87        u32 imr0_val;
  88        u32 imr1_val;
  89};
  90
  91/*
  92 * Returns the keycode from the input device keymap given the row and
  93 * column.
  94 */
  95static int bcm_kp_get_keycode(struct bcm_kp *kp, int row, int col)
  96{
  97        unsigned int row_shift = get_count_order(kp->n_cols);
  98        unsigned short *keymap = kp->input_dev->keycode;
  99
 100        return keymap[MATRIX_SCAN_CODE(row, col, row_shift)];
 101}
 102
 103static void bcm_kp_report_keys(struct bcm_kp *kp, int reg_num, int pull_mode)
 104{
 105        unsigned long state, change;
 106        int bit_nr;
 107        int key_press;
 108        int row, col;
 109        unsigned int keycode;
 110
 111        /* Clear interrupts */
 112        writel(0xFFFFFFFF, kp->base + KPICRN_OFFSET(reg_num));
 113
 114        state = readl(kp->base + KPSSRN_OFFSET(reg_num));
 115        change = kp->last_state[reg_num] ^ state;
 116        kp->last_state[reg_num] = state;
 117
 118        for_each_set_bit(bit_nr, &change, BITS_PER_LONG) {
 119                key_press = state & BIT(bit_nr);
 120                /* The meaning of SSR register depends on pull mode. */
 121                key_press = pull_mode ? !key_press : key_press;
 122                row = BIT_TO_ROW_SSRN(bit_nr, reg_num);
 123                col = BIT_TO_COL(bit_nr);
 124                keycode = bcm_kp_get_keycode(kp, row, col);
 125                input_report_key(kp->input_dev, keycode, key_press);
 126        }
 127}
 128
 129static irqreturn_t bcm_kp_isr_thread(int irq, void *dev_id)
 130{
 131        struct bcm_kp *kp = dev_id;
 132        int pull_mode = (kp->kpcr >> KPCR_MODE_SHIFT) & KPCR_MODE_MASK;
 133        int reg_num;
 134
 135        for (reg_num = 0; reg_num <= 1; reg_num++)
 136                bcm_kp_report_keys(kp, reg_num, pull_mode);
 137
 138        input_sync(kp->input_dev);
 139
 140        return IRQ_HANDLED;
 141}
 142
 143static int bcm_kp_start(struct bcm_kp *kp)
 144{
 145        int error;
 146
 147        if (kp->clk) {
 148                error = clk_prepare_enable(kp->clk);
 149                if (error)
 150                        return error;
 151        }
 152
 153        writel(kp->kpior, kp->base + KPIOR_OFFSET);
 154
 155        writel(kp->imr0_val, kp->base + KPIMR0_OFFSET);
 156        writel(kp->imr1_val, kp->base + KPIMR1_OFFSET);
 157
 158        writel(kp->kpemr, kp->base + KPEMR0_OFFSET);
 159        writel(kp->kpemr, kp->base + KPEMR1_OFFSET);
 160        writel(kp->kpemr, kp->base + KPEMR2_OFFSET);
 161        writel(kp->kpemr, kp->base + KPEMR3_OFFSET);
 162
 163        writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
 164        writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
 165
 166        kp->last_state[0] = readl(kp->base + KPSSR0_OFFSET);
 167        kp->last_state[0] = readl(kp->base + KPSSR1_OFFSET);
 168
 169        writel(kp->kpcr | KPCR_ENABLE, kp->base + KPCR_OFFSET);
 170
 171        return 0;
 172}
 173
 174static void bcm_kp_stop(const struct bcm_kp *kp)
 175{
 176        u32 val;
 177
 178        val = readl(kp->base + KPCR_OFFSET);
 179        val &= ~KPCR_ENABLE;
 180        writel(0, kp->base + KPCR_OFFSET);
 181        writel(0, kp->base + KPIMR0_OFFSET);
 182        writel(0, kp->base + KPIMR1_OFFSET);
 183        writel(0xFFFFFFFF, kp->base + KPICR0_OFFSET);
 184        writel(0xFFFFFFFF, kp->base + KPICR1_OFFSET);
 185
 186        if (kp->clk)
 187                clk_disable_unprepare(kp->clk);
 188}
 189
 190static int bcm_kp_open(struct input_dev *dev)
 191{
 192        struct bcm_kp *kp = input_get_drvdata(dev);
 193
 194        return bcm_kp_start(kp);
 195}
 196
 197static void bcm_kp_close(struct input_dev *dev)
 198{
 199        struct bcm_kp *kp = input_get_drvdata(dev);
 200
 201        bcm_kp_stop(kp);
 202}
 203
 204static int bcm_kp_matrix_key_parse_dt(struct bcm_kp *kp)
 205{
 206        struct device *dev = kp->input_dev->dev.parent;
 207        struct device_node *np = dev->of_node;
 208        int error;
 209        unsigned int dt_val;
 210        unsigned int i;
 211        unsigned int num_rows, col_mask, rows_set;
 212
 213        /* Initialize the KPCR Keypad Configuration Register */
 214        kp->kpcr = KPCR_STATUSFILTERENABLE | KPCR_COLFILTERENABLE;
 215
 216        error = matrix_keypad_parse_properties(dev, &kp->n_rows, &kp->n_cols);
 217        if (error) {
 218                dev_err(dev, "failed to parse kp params\n");
 219                return error;
 220        }
 221
 222        /* Set row width for the ASIC block. */
 223        kp->kpcr |= (kp->n_rows - 1) << KPCR_ROWWIDTH_SHIFT;
 224
 225        /* Set column width for the ASIC block. */
 226        kp->kpcr |= (kp->n_cols - 1) << KPCR_COLUMNWIDTH_SHIFT;
 227
 228        /* Configure the IMR registers */
 229
 230        /*
 231         * IMR registers contain interrupt enable bits for 8x8 matrix
 232         * IMR0 register format: <row3> <row2> <row1> <row0>
 233         * IMR1 register format: <row7> <row6> <row5> <row4>
 234         */
 235        col_mask = (1 << (kp->n_cols)) - 1;
 236        num_rows = kp->n_rows;
 237
 238        /* Set column bits in rows 0 to 3 in IMR0 */
 239        kp->imr0_val = col_mask;
 240
 241        rows_set = 1;
 242        while (--num_rows && rows_set++ < 4)
 243                kp->imr0_val |= kp->imr0_val << MAX_COLS;
 244
 245        /* Set column bits in rows 4 to 7 in IMR1 */
 246        kp->imr1_val = 0;
 247        if (num_rows) {
 248                kp->imr1_val = col_mask;
 249                while (--num_rows)
 250                        kp->imr1_val |= kp->imr1_val << MAX_COLS;
 251        }
 252
 253        /* Initialize the KPEMR Keypress Edge Mode Registers */
 254        /* Trigger on both edges */
 255        kp->kpemr = 0;
 256        for (i = 0; i <= 30; i += 2)
 257                kp->kpemr |= (KPEMR_EDGETYPE_BOTH << i);
 258
 259        /*
 260         * Obtain the Status filter debounce value and verify against the
 261         * possible values specified in the DT binding.
 262         */
 263        of_property_read_u32(np, "status-debounce-filter-period", &dt_val);
 264
 265        if (dt_val > KPCR_STATUSFILTERTYPE_MAX) {
 266                dev_err(dev, "Invalid Status filter debounce value %d\n",
 267                        dt_val);
 268                return -EINVAL;
 269        }
 270
 271        kp->kpcr |= dt_val << KPCR_STATUSFILTERTYPE_SHIFT;
 272
 273        /*
 274         * Obtain the Column filter debounce value and verify against the
 275         * possible values specified in the DT binding.
 276         */
 277        of_property_read_u32(np, "col-debounce-filter-period", &dt_val);
 278
 279        if (dt_val > KPCR_COLFILTERTYPE_MAX) {
 280                dev_err(dev, "Invalid Column filter debounce value %d\n",
 281                        dt_val);
 282                return -EINVAL;
 283        }
 284
 285        kp->kpcr |= dt_val << KPCR_COLFILTERTYPE_SHIFT;
 286
 287        /*
 288         * Determine between the row and column,
 289         * which should be configured as output.
 290         */
 291        if (of_property_read_bool(np, "row-output-enabled")) {
 292                /*
 293                * Set RowOContrl or ColumnOContrl in KPIOR
 294                * to the number of pins to drive as outputs
 295                */
 296                kp->kpior = ((1 << kp->n_rows) - 1) <<
 297                                KPIOR_ROWOCONTRL_SHIFT;
 298        } else {
 299                kp->kpior = ((1 << kp->n_cols) - 1) <<
 300                                KPIOR_COLUMNOCONTRL_SHIFT;
 301        }
 302
 303        /*
 304         * Determine if the scan pull up needs to be enabled
 305         */
 306        if (of_property_read_bool(np, "pull-up-enabled"))
 307                kp->kpcr |= KPCR_MODE;
 308
 309        dev_dbg(dev, "n_rows=%d n_col=%d kpcr=%x kpior=%x kpemr=%x\n",
 310                kp->n_rows, kp->n_cols,
 311                kp->kpcr, kp->kpior, kp->kpemr);
 312
 313        return 0;
 314}
 315
 316
 317static int bcm_kp_probe(struct platform_device *pdev)
 318{
 319        struct bcm_kp *kp;
 320        struct input_dev *input_dev;
 321        struct resource *res;
 322        int error;
 323
 324        kp = devm_kzalloc(&pdev->dev, sizeof(*kp), GFP_KERNEL);
 325        if (!kp)
 326                return -ENOMEM;
 327
 328        input_dev = devm_input_allocate_device(&pdev->dev);
 329        if (!input_dev) {
 330                dev_err(&pdev->dev, "failed to allocate the input device\n");
 331                return -ENOMEM;
 332        }
 333
 334        __set_bit(EV_KEY, input_dev->evbit);
 335
 336        /* Enable auto repeat feature of Linux input subsystem */
 337        if (of_property_read_bool(pdev->dev.of_node, "autorepeat"))
 338                __set_bit(EV_REP, input_dev->evbit);
 339
 340        input_dev->name = pdev->name;
 341        input_dev->phys = "keypad/input0";
 342        input_dev->dev.parent = &pdev->dev;
 343        input_dev->open = bcm_kp_open;
 344        input_dev->close = bcm_kp_close;
 345
 346        input_dev->id.bustype = BUS_HOST;
 347        input_dev->id.vendor = 0x0001;
 348        input_dev->id.product = 0x0001;
 349        input_dev->id.version = 0x0100;
 350
 351        input_set_drvdata(input_dev, kp);
 352
 353        kp->input_dev = input_dev;
 354
 355        error = bcm_kp_matrix_key_parse_dt(kp);
 356        if (error)
 357                return error;
 358
 359        error = matrix_keypad_build_keymap(NULL, NULL,
 360                                           kp->n_rows, kp->n_cols,
 361                                           NULL, input_dev);
 362        if (error) {
 363                dev_err(&pdev->dev, "failed to build keymap\n");
 364                return error;
 365        }
 366
 367        /* Get the KEYPAD base address */
 368        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 369        if (!res) {
 370                dev_err(&pdev->dev, "Missing keypad base address resource\n");
 371                return -ENODEV;
 372        }
 373
 374        kp->base = devm_ioremap_resource(&pdev->dev, res);
 375        if (IS_ERR(kp->base))
 376                return PTR_ERR(kp->base);
 377
 378        /* Enable clock */
 379        kp->clk = devm_clk_get(&pdev->dev, "peri_clk");
 380        if (IS_ERR(kp->clk)) {
 381                error = PTR_ERR(kp->clk);
 382                if (error != -ENOENT) {
 383                        if (error != -EPROBE_DEFER)
 384                                dev_err(&pdev->dev, "Failed to get clock\n");
 385                        return error;
 386                }
 387                dev_dbg(&pdev->dev,
 388                        "No clock specified. Assuming it's enabled\n");
 389                kp->clk = NULL;
 390        } else {
 391                unsigned int desired_rate;
 392                long actual_rate;
 393
 394                error = of_property_read_u32(pdev->dev.of_node,
 395                                             "clock-frequency", &desired_rate);
 396                if (error < 0)
 397                        desired_rate = DEFAULT_CLK_HZ;
 398
 399                actual_rate = clk_round_rate(kp->clk, desired_rate);
 400                if (actual_rate <= 0)
 401                        return -EINVAL;
 402
 403                error = clk_set_rate(kp->clk, actual_rate);
 404                if (error)
 405                        return error;
 406
 407                error = clk_prepare_enable(kp->clk);
 408                if (error)
 409                        return error;
 410        }
 411
 412        /* Put the kp into a known sane state */
 413        bcm_kp_stop(kp);
 414
 415        kp->irq = platform_get_irq(pdev, 0);
 416        if (kp->irq < 0)
 417                return -EINVAL;
 418
 419        error = devm_request_threaded_irq(&pdev->dev, kp->irq,
 420                                          NULL, bcm_kp_isr_thread,
 421                                          IRQF_ONESHOT, pdev->name, kp);
 422        if (error) {
 423                dev_err(&pdev->dev, "failed to request IRQ\n");
 424                return error;
 425        }
 426
 427        error = input_register_device(input_dev);
 428        if (error) {
 429                dev_err(&pdev->dev, "failed to register input device\n");
 430                return error;
 431        }
 432
 433        return 0;
 434}
 435
 436static const struct of_device_id bcm_kp_of_match[] = {
 437        { .compatible = "brcm,bcm-keypad" },
 438        { },
 439};
 440MODULE_DEVICE_TABLE(of, bcm_kp_of_match);
 441
 442static struct platform_driver bcm_kp_device_driver = {
 443        .probe          = bcm_kp_probe,
 444        .driver         = {
 445                .name   = "bcm-keypad",
 446                .of_match_table = of_match_ptr(bcm_kp_of_match),
 447        }
 448};
 449
 450module_platform_driver(bcm_kp_device_driver);
 451
 452MODULE_AUTHOR("Broadcom Corporation");
 453MODULE_DESCRIPTION("BCM Keypad Driver");
 454MODULE_LICENSE("GPL v2");
 455