linux/drivers/input/touchscreen/lpc32xx_ts.c
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   1/*
   2 * LPC32xx built-in touchscreen driver
   3 *
   4 * Copyright (C) 2010 NXP Semiconductors
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/platform_device.h>
  18#include <linux/init.h>
  19#include <linux/input.h>
  20#include <linux/interrupt.h>
  21#include <linux/module.h>
  22#include <linux/clk.h>
  23#include <linux/io.h>
  24#include <linux/slab.h>
  25#include <linux/of.h>
  26
  27/*
  28 * Touchscreen controller register offsets
  29 */
  30#define LPC32XX_TSC_STAT                        0x00
  31#define LPC32XX_TSC_SEL                         0x04
  32#define LPC32XX_TSC_CON                         0x08
  33#define LPC32XX_TSC_FIFO                        0x0C
  34#define LPC32XX_TSC_DTR                         0x10
  35#define LPC32XX_TSC_RTR                         0x14
  36#define LPC32XX_TSC_UTR                         0x18
  37#define LPC32XX_TSC_TTR                         0x1C
  38#define LPC32XX_TSC_DXP                         0x20
  39#define LPC32XX_TSC_MIN_X                       0x24
  40#define LPC32XX_TSC_MAX_X                       0x28
  41#define LPC32XX_TSC_MIN_Y                       0x2C
  42#define LPC32XX_TSC_MAX_Y                       0x30
  43#define LPC32XX_TSC_AUX_UTR                     0x34
  44#define LPC32XX_TSC_AUX_MIN                     0x38
  45#define LPC32XX_TSC_AUX_MAX                     0x3C
  46
  47#define LPC32XX_TSC_STAT_FIFO_OVRRN             (1 << 8)
  48#define LPC32XX_TSC_STAT_FIFO_EMPTY             (1 << 7)
  49
  50#define LPC32XX_TSC_SEL_DEFVAL                  0x0284
  51
  52#define LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4        (0x1 << 11)
  53#define LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(s)     ((10 - (s)) << 7)
  54#define LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(s)     ((10 - (s)) << 4)
  55#define LPC32XX_TSC_ADCCON_POWER_UP             (1 << 2)
  56#define LPC32XX_TSC_ADCCON_AUTO_EN              (1 << 0)
  57
  58#define LPC32XX_TSC_FIFO_TS_P_LEVEL             (1 << 31)
  59#define LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(x)     (((x) & 0x03FF0000) >> 16)
  60#define LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(y)     ((y) & 0x000003FF)
  61
  62#define LPC32XX_TSC_ADCDAT_VALUE_MASK           0x000003FF
  63
  64#define LPC32XX_TSC_MIN_XY_VAL                  0x0
  65#define LPC32XX_TSC_MAX_XY_VAL                  0x3FF
  66
  67#define MOD_NAME "ts-lpc32xx"
  68
  69#define tsc_readl(dev, reg) \
  70        __raw_readl((dev)->tsc_base + (reg))
  71#define tsc_writel(dev, reg, val) \
  72        __raw_writel((val), (dev)->tsc_base + (reg))
  73
  74struct lpc32xx_tsc {
  75        struct input_dev *dev;
  76        void __iomem *tsc_base;
  77        int irq;
  78        struct clk *clk;
  79};
  80
  81static void lpc32xx_fifo_clear(struct lpc32xx_tsc *tsc)
  82{
  83        while (!(tsc_readl(tsc, LPC32XX_TSC_STAT) &
  84                        LPC32XX_TSC_STAT_FIFO_EMPTY))
  85                tsc_readl(tsc, LPC32XX_TSC_FIFO);
  86}
  87
  88static irqreturn_t lpc32xx_ts_interrupt(int irq, void *dev_id)
  89{
  90        u32 tmp, rv[4], xs[4], ys[4];
  91        int idx;
  92        struct lpc32xx_tsc *tsc = dev_id;
  93        struct input_dev *input = tsc->dev;
  94
  95        tmp = tsc_readl(tsc, LPC32XX_TSC_STAT);
  96
  97        if (tmp & LPC32XX_TSC_STAT_FIFO_OVRRN) {
  98                /* FIFO overflow - throw away samples */
  99                lpc32xx_fifo_clear(tsc);
 100                return IRQ_HANDLED;
 101        }
 102
 103        /*
 104         * Gather and normalize 4 samples. Pen-up events may have less
 105         * than 4 samples, but its ok to pop 4 and let the last sample
 106         * pen status check drop the samples.
 107         */
 108        idx = 0;
 109        while (idx < 4 &&
 110               !(tsc_readl(tsc, LPC32XX_TSC_STAT) &
 111                        LPC32XX_TSC_STAT_FIFO_EMPTY)) {
 112                tmp = tsc_readl(tsc, LPC32XX_TSC_FIFO);
 113                xs[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
 114                        LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(tmp);
 115                ys[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
 116                        LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(tmp);
 117                rv[idx] = tmp;
 118                idx++;
 119        }
 120
 121        /* Data is only valid if pen is still down in last sample */
 122        if (!(rv[3] & LPC32XX_TSC_FIFO_TS_P_LEVEL) && idx == 4) {
 123                /* Use average of 2nd and 3rd sample for position */
 124                input_report_abs(input, ABS_X, (xs[1] + xs[2]) / 2);
 125                input_report_abs(input, ABS_Y, (ys[1] + ys[2]) / 2);
 126                input_report_key(input, BTN_TOUCH, 1);
 127        } else {
 128                input_report_key(input, BTN_TOUCH, 0);
 129        }
 130
 131        input_sync(input);
 132
 133        return IRQ_HANDLED;
 134}
 135
 136static void lpc32xx_stop_tsc(struct lpc32xx_tsc *tsc)
 137{
 138        /* Disable auto mode */
 139        tsc_writel(tsc, LPC32XX_TSC_CON,
 140                   tsc_readl(tsc, LPC32XX_TSC_CON) &
 141                             ~LPC32XX_TSC_ADCCON_AUTO_EN);
 142
 143        clk_disable(tsc->clk);
 144}
 145
 146static void lpc32xx_setup_tsc(struct lpc32xx_tsc *tsc)
 147{
 148        u32 tmp;
 149
 150        clk_enable(tsc->clk);
 151
 152        tmp = tsc_readl(tsc, LPC32XX_TSC_CON) & ~LPC32XX_TSC_ADCCON_POWER_UP;
 153
 154        /* Set the TSC FIFO depth to 4 samples @ 10-bits per sample (max) */
 155        tmp = LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4 |
 156              LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(10) |
 157              LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(10);
 158        tsc_writel(tsc, LPC32XX_TSC_CON, tmp);
 159
 160        /* These values are all preset */
 161        tsc_writel(tsc, LPC32XX_TSC_SEL, LPC32XX_TSC_SEL_DEFVAL);
 162        tsc_writel(tsc, LPC32XX_TSC_MIN_X, LPC32XX_TSC_MIN_XY_VAL);
 163        tsc_writel(tsc, LPC32XX_TSC_MAX_X, LPC32XX_TSC_MAX_XY_VAL);
 164        tsc_writel(tsc, LPC32XX_TSC_MIN_Y, LPC32XX_TSC_MIN_XY_VAL);
 165        tsc_writel(tsc, LPC32XX_TSC_MAX_Y, LPC32XX_TSC_MAX_XY_VAL);
 166
 167        /* Aux support is not used */
 168        tsc_writel(tsc, LPC32XX_TSC_AUX_UTR, 0);
 169        tsc_writel(tsc, LPC32XX_TSC_AUX_MIN, 0);
 170        tsc_writel(tsc, LPC32XX_TSC_AUX_MAX, 0);
 171
 172        /*
 173         * Set sample rate to about 240Hz per X/Y pair. A single measurement
 174         * consists of 4 pairs which gives about a 60Hz sample rate based on
 175         * a stable 32768Hz clock source. Values are in clocks.
 176         * Rate is (32768 / (RTR + XCONV + RTR + YCONV + DXP + TTR + UTR) / 4
 177         */
 178        tsc_writel(tsc, LPC32XX_TSC_RTR, 0x2);
 179        tsc_writel(tsc, LPC32XX_TSC_DTR, 0x2);
 180        tsc_writel(tsc, LPC32XX_TSC_TTR, 0x10);
 181        tsc_writel(tsc, LPC32XX_TSC_DXP, 0x4);
 182        tsc_writel(tsc, LPC32XX_TSC_UTR, 88);
 183
 184        lpc32xx_fifo_clear(tsc);
 185
 186        /* Enable automatic ts event capture */
 187        tsc_writel(tsc, LPC32XX_TSC_CON, tmp | LPC32XX_TSC_ADCCON_AUTO_EN);
 188}
 189
 190static int lpc32xx_ts_open(struct input_dev *dev)
 191{
 192        struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
 193
 194        lpc32xx_setup_tsc(tsc);
 195
 196        return 0;
 197}
 198
 199static void lpc32xx_ts_close(struct input_dev *dev)
 200{
 201        struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
 202
 203        lpc32xx_stop_tsc(tsc);
 204}
 205
 206static int __devinit lpc32xx_ts_probe(struct platform_device *pdev)
 207{
 208        struct lpc32xx_tsc *tsc;
 209        struct input_dev *input;
 210        struct resource *res;
 211        resource_size_t size;
 212        int irq;
 213        int error;
 214
 215        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 216        if (!res) {
 217                dev_err(&pdev->dev, "Can't get memory resource\n");
 218                return -ENOENT;
 219        }
 220
 221        irq = platform_get_irq(pdev, 0);
 222        if (irq < 0) {
 223                dev_err(&pdev->dev, "Can't get interrupt resource\n");
 224                return irq;
 225        }
 226
 227        tsc = kzalloc(sizeof(*tsc), GFP_KERNEL);
 228        input = input_allocate_device();
 229        if (!tsc || !input) {
 230                dev_err(&pdev->dev, "failed allocating memory\n");
 231                error = -ENOMEM;
 232                goto err_free_mem;
 233        }
 234
 235        tsc->dev = input;
 236        tsc->irq = irq;
 237
 238        size = resource_size(res);
 239
 240        if (!request_mem_region(res->start, size, pdev->name)) {
 241                dev_err(&pdev->dev, "TSC registers are not free\n");
 242                error = -EBUSY;
 243                goto err_free_mem;
 244        }
 245
 246        tsc->tsc_base = ioremap(res->start, size);
 247        if (!tsc->tsc_base) {
 248                dev_err(&pdev->dev, "Can't map memory\n");
 249                error = -ENOMEM;
 250                goto err_release_mem;
 251        }
 252
 253        tsc->clk = clk_get(&pdev->dev, NULL);
 254        if (IS_ERR(tsc->clk)) {
 255                dev_err(&pdev->dev, "failed getting clock\n");
 256                error = PTR_ERR(tsc->clk);
 257                goto err_unmap;
 258        }
 259
 260        input->name = MOD_NAME;
 261        input->phys = "lpc32xx/input0";
 262        input->id.bustype = BUS_HOST;
 263        input->id.vendor = 0x0001;
 264        input->id.product = 0x0002;
 265        input->id.version = 0x0100;
 266        input->dev.parent = &pdev->dev;
 267        input->open = lpc32xx_ts_open;
 268        input->close = lpc32xx_ts_close;
 269
 270        input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 271        input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 272        input_set_abs_params(input, ABS_X, LPC32XX_TSC_MIN_XY_VAL,
 273                             LPC32XX_TSC_MAX_XY_VAL, 0, 0);
 274        input_set_abs_params(input, ABS_Y, LPC32XX_TSC_MIN_XY_VAL,
 275                             LPC32XX_TSC_MAX_XY_VAL, 0, 0);
 276
 277        input_set_drvdata(input, tsc);
 278
 279        error = request_irq(tsc->irq, lpc32xx_ts_interrupt,
 280                            0, pdev->name, tsc);
 281        if (error) {
 282                dev_err(&pdev->dev, "failed requesting interrupt\n");
 283                goto err_put_clock;
 284        }
 285
 286        error = input_register_device(input);
 287        if (error) {
 288                dev_err(&pdev->dev, "failed registering input device\n");
 289                goto err_free_irq;
 290        }
 291
 292        platform_set_drvdata(pdev, tsc);
 293        device_init_wakeup(&pdev->dev, 1);
 294
 295        return 0;
 296
 297err_free_irq:
 298        free_irq(tsc->irq, tsc);
 299err_put_clock:
 300        clk_put(tsc->clk);
 301err_unmap:
 302        iounmap(tsc->tsc_base);
 303err_release_mem:
 304        release_mem_region(res->start, size);
 305err_free_mem:
 306        input_free_device(input);
 307        kfree(tsc);
 308
 309        return error;
 310}
 311
 312static int __devexit lpc32xx_ts_remove(struct platform_device *pdev)
 313{
 314        struct lpc32xx_tsc *tsc = platform_get_drvdata(pdev);
 315        struct resource *res;
 316
 317        device_init_wakeup(&pdev->dev, 0);
 318        free_irq(tsc->irq, tsc);
 319
 320        input_unregister_device(tsc->dev);
 321
 322        clk_put(tsc->clk);
 323
 324        iounmap(tsc->tsc_base);
 325        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 326        release_mem_region(res->start, resource_size(res));
 327
 328        kfree(tsc);
 329
 330        return 0;
 331}
 332
 333#ifdef CONFIG_PM
 334static int lpc32xx_ts_suspend(struct device *dev)
 335{
 336        struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
 337        struct input_dev *input = tsc->dev;
 338
 339        /*
 340         * Suspend and resume can be called when the device hasn't been
 341         * enabled. If there are no users that have the device open, then
 342         * avoid calling the TSC stop and start functions as the TSC
 343         * isn't yet clocked.
 344         */
 345        mutex_lock(&input->mutex);
 346
 347        if (input->users) {
 348                if (device_may_wakeup(dev))
 349                        enable_irq_wake(tsc->irq);
 350                else
 351                        lpc32xx_stop_tsc(tsc);
 352        }
 353
 354        mutex_unlock(&input->mutex);
 355
 356        return 0;
 357}
 358
 359static int lpc32xx_ts_resume(struct device *dev)
 360{
 361        struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
 362        struct input_dev *input = tsc->dev;
 363
 364        mutex_lock(&input->mutex);
 365
 366        if (input->users) {
 367                if (device_may_wakeup(dev))
 368                        disable_irq_wake(tsc->irq);
 369                else
 370                        lpc32xx_setup_tsc(tsc);
 371        }
 372
 373        mutex_unlock(&input->mutex);
 374
 375        return 0;
 376}
 377
 378static const struct dev_pm_ops lpc32xx_ts_pm_ops = {
 379        .suspend        = lpc32xx_ts_suspend,
 380        .resume         = lpc32xx_ts_resume,
 381};
 382#define LPC32XX_TS_PM_OPS (&lpc32xx_ts_pm_ops)
 383#else
 384#define LPC32XX_TS_PM_OPS NULL
 385#endif
 386
 387#ifdef CONFIG_OF
 388static struct of_device_id lpc32xx_tsc_of_match[] = {
 389        { .compatible = "nxp,lpc3220-tsc", },
 390        { },
 391};
 392MODULE_DEVICE_TABLE(of, lpc32xx_tsc_of_match);
 393#endif
 394
 395static struct platform_driver lpc32xx_ts_driver = {
 396        .probe          = lpc32xx_ts_probe,
 397        .remove         = __devexit_p(lpc32xx_ts_remove),
 398        .driver         = {
 399                .name   = MOD_NAME,
 400                .owner  = THIS_MODULE,
 401                .pm     = LPC32XX_TS_PM_OPS,
 402                .of_match_table = of_match_ptr(lpc32xx_tsc_of_match),
 403        },
 404};
 405module_platform_driver(lpc32xx_ts_driver);
 406
 407MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com");
 408MODULE_DESCRIPTION("LPC32XX TSC Driver");
 409MODULE_LICENSE("GPL");
 410MODULE_ALIAS("platform:lpc32xx_ts");
 411