drivers/input/touchscreen/lpc32xx_ts.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * LPC32xx built-in touchscreen driver
   4  *
   5  * Copyright (C) 2010 NXP Semiconductors
   6  */
   7
   8 #include <linux/platform_device.h>
   9 #include <linux/input.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12 #include <linux/clk.h>
  13 #include <linux/io.h>
  14 #include <linux/slab.h>
  15 #include <linux/of.h>
  16
  17 /*
  18  * Touchscreen controller register offsets
  19  */
  20 #define LPC32XX_TSC_STAT                        0x00
  21 #define LPC32XX_TSC_SEL                         0x04
  22 #define LPC32XX_TSC_CON                         0x08
  23 #define LPC32XX_TSC_FIFO                        0x0C
  24 #define LPC32XX_TSC_DTR                         0x10
  25 #define LPC32XX_TSC_RTR                         0x14
  26 #define LPC32XX_TSC_UTR                         0x18
  27 #define LPC32XX_TSC_TTR                         0x1C
  28 #define LPC32XX_TSC_DXP                         0x20
  29 #define LPC32XX_TSC_MIN_X                       0x24
  30 #define LPC32XX_TSC_MAX_X                       0x28
  31 #define LPC32XX_TSC_MIN_Y                       0x2C
  32 #define LPC32XX_TSC_MAX_Y                       0x30
  33 #define LPC32XX_TSC_AUX_UTR                     0x34
  34 #define LPC32XX_TSC_AUX_MIN                     0x38
  35 #define LPC32XX_TSC_AUX_MAX                     0x3C
  36
  37 #define LPC32XX_TSC_STAT_FIFO_OVRRN             BIT(8)
  38 #define LPC32XX_TSC_STAT_FIFO_EMPTY             BIT(7)
  39
  40 #define LPC32XX_TSC_SEL_DEFVAL                  0x0284
  41
  42 #define LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4        (0x1 << 11)
  43 #define LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(s)     ((10 - (s)) << 7)
  44 #define LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(s)     ((10 - (s)) << 4)
  45 #define LPC32XX_TSC_ADCCON_POWER_UP             BIT(2)
  46 #define LPC32XX_TSC_ADCCON_AUTO_EN              BIT(0)
  47
  48 #define LPC32XX_TSC_FIFO_TS_P_LEVEL             BIT(31)
  49 #define LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(x)     (((x) & 0x03FF0000) >> 16)
  50 #define LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(y)     ((y) & 0x000003FF)
  51
  52 #define LPC32XX_TSC_ADCDAT_VALUE_MASK           0x000003FF
  53
  54 #define LPC32XX_TSC_MIN_XY_VAL                  0x0
  55 #define LPC32XX_TSC_MAX_XY_VAL                  0x3FF
  56
  57 #define MOD_NAME "ts-lpc32xx"
  58
  59 #define tsc_readl(dev, reg) \
  60         __raw_readl((dev)->tsc_base + (reg))
  61 #define tsc_writel(dev, reg, val) \
  62         __raw_writel((val), (dev)->tsc_base + (reg))
  63
  64 struct lpc32xx_tsc {
  65         struct input_dev *dev;
  66         void __iomem *tsc_base;
  67         int irq;
  68         struct clk *clk;
  69 };
  70
  71 static void lpc32xx_fifo_clear(struct lpc32xx_tsc *tsc)
  72 {
  73         while (!(tsc_readl(tsc, LPC32XX_TSC_STAT) &
  74                         LPC32XX_TSC_STAT_FIFO_EMPTY))
  75                 tsc_readl(tsc, LPC32XX_TSC_FIFO);
  76 }
  77
  78 static irqreturn_t lpc32xx_ts_interrupt(int irq, void *dev_id)
  79 {
  80         u32 tmp, rv[4], xs[4], ys[4];
  81         int idx;
  82         struct lpc32xx_tsc *tsc = dev_id;
  83         struct input_dev *input = tsc->dev;
  84
  85         tmp = tsc_readl(tsc, LPC32XX_TSC_STAT);
  86
  87         if (tmp & LPC32XX_TSC_STAT_FIFO_OVRRN) {
  88                 /* FIFO overflow - throw away samples */
  89                 lpc32xx_fifo_clear(tsc);
  90                 return IRQ_HANDLED;
  91         }
  92
  93         /*
  94          * Gather and normalize 4 samples. Pen-up events may have less
  95          * than 4 samples, but its ok to pop 4 and let the last sample
  96          * pen status check drop the samples.
  97          */
  98         idx = 0;
  99         while (idx < 4 &&
 100                !(tsc_readl(tsc, LPC32XX_TSC_STAT) &
 101                         LPC32XX_TSC_STAT_FIFO_EMPTY)) {
 102                 tmp = tsc_readl(tsc, LPC32XX_TSC_FIFO);
 103                 xs[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
 104                         LPC32XX_TSC_FIFO_NORMALIZE_X_VAL(tmp);
 105                 ys[idx] = LPC32XX_TSC_ADCDAT_VALUE_MASK -
 106                         LPC32XX_TSC_FIFO_NORMALIZE_Y_VAL(tmp);
 107                 rv[idx] = tmp;
 108                 idx++;
 109         }
 110
 111         /* Data is only valid if pen is still down in last sample */
 112         if (!(rv[3] & LPC32XX_TSC_FIFO_TS_P_LEVEL) && idx == 4) {
 113                 /* Use average of 2nd and 3rd sample for position */
 114                 input_report_abs(input, ABS_X, (xs[1] + xs[2]) / 2);
 115                 input_report_abs(input, ABS_Y, (ys[1] + ys[2]) / 2);
 116                 input_report_key(input, BTN_TOUCH, 1);
 117         } else {
 118                 input_report_key(input, BTN_TOUCH, 0);
 119         }
 120
 121         input_sync(input);
 122
 123         return IRQ_HANDLED;
 124 }
 125
 126 static void lpc32xx_stop_tsc(struct lpc32xx_tsc *tsc)
 127 {
 128         /* Disable auto mode */
 129         tsc_writel(tsc, LPC32XX_TSC_CON,
 130                    tsc_readl(tsc, LPC32XX_TSC_CON) &
 131                              ~LPC32XX_TSC_ADCCON_AUTO_EN);
 132
 133         clk_disable_unprepare(tsc->clk);
 134 }
 135
 136 static int lpc32xx_setup_tsc(struct lpc32xx_tsc *tsc)
 137 {
 138         u32 tmp;
 139         int err;
 140
 141         err = clk_prepare_enable(tsc->clk);
 142         if (err)
 143                 return err;
 144
 145         tmp = tsc_readl(tsc, LPC32XX_TSC_CON) & ~LPC32XX_TSC_ADCCON_POWER_UP;
 146
 147         /* Set the TSC FIFO depth to 4 samples @ 10-bits per sample (max) */
 148         tmp = LPC32XX_TSC_ADCCON_IRQ_TO_FIFO_4 |
 149               LPC32XX_TSC_ADCCON_X_SAMPLE_SIZE(10) |
 150               LPC32XX_TSC_ADCCON_Y_SAMPLE_SIZE(10);
 151         tsc_writel(tsc, LPC32XX_TSC_CON, tmp);
 152
 153         /* These values are all preset */
 154         tsc_writel(tsc, LPC32XX_TSC_SEL, LPC32XX_TSC_SEL_DEFVAL);
 155         tsc_writel(tsc, LPC32XX_TSC_MIN_X, LPC32XX_TSC_MIN_XY_VAL);
 156         tsc_writel(tsc, LPC32XX_TSC_MAX_X, LPC32XX_TSC_MAX_XY_VAL);
 157         tsc_writel(tsc, LPC32XX_TSC_MIN_Y, LPC32XX_TSC_MIN_XY_VAL);
 158         tsc_writel(tsc, LPC32XX_TSC_MAX_Y, LPC32XX_TSC_MAX_XY_VAL);
 159
 160         /* Aux support is not used */
 161         tsc_writel(tsc, LPC32XX_TSC_AUX_UTR, 0);
 162         tsc_writel(tsc, LPC32XX_TSC_AUX_MIN, 0);
 163         tsc_writel(tsc, LPC32XX_TSC_AUX_MAX, 0);
 164
 165         /*
 166          * Set sample rate to about 240Hz per X/Y pair. A single measurement
 167          * consists of 4 pairs which gives about a 60Hz sample rate based on
 168          * a stable 32768Hz clock source. Values are in clocks.
 169          * Rate is (32768 / (RTR + XCONV + RTR + YCONV + DXP + TTR + UTR) / 4
 170          */
 171         tsc_writel(tsc, LPC32XX_TSC_RTR, 0x2);
 172         tsc_writel(tsc, LPC32XX_TSC_DTR, 0x2);
 173         tsc_writel(tsc, LPC32XX_TSC_TTR, 0x10);
 174         tsc_writel(tsc, LPC32XX_TSC_DXP, 0x4);
 175         tsc_writel(tsc, LPC32XX_TSC_UTR, 88);
 176
 177         lpc32xx_fifo_clear(tsc);
 178
 179         /* Enable automatic ts event capture */
 180         tsc_writel(tsc, LPC32XX_TSC_CON, tmp | LPC32XX_TSC_ADCCON_AUTO_EN);
 181
 182         return 0;
 183 }
 184
 185 static int lpc32xx_ts_open(struct input_dev *dev)
 186 {
 187         struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
 188
 189         return lpc32xx_setup_tsc(tsc);
 190 }
 191
 192 static void lpc32xx_ts_close(struct input_dev *dev)
 193 {
 194         struct lpc32xx_tsc *tsc = input_get_drvdata(dev);
 195
 196         lpc32xx_stop_tsc(tsc);
 197 }
 198
 199 static int lpc32xx_ts_probe(struct platform_device *pdev)
 200 {
 201         struct device *dev = &pdev->dev;
 202         struct lpc32xx_tsc *tsc;
 203         struct input_dev *input;
 204         int irq;
 205         int error;
 206
 207         irq = platform_get_irq(pdev, 0);
 208         if (irq < 0)
 209                 return irq;
 210
 211         tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL);
 212         if (!tsc)
 213                 return -ENOMEM;
 214
 215         tsc->irq = irq;
 216
 217         tsc->tsc_base = devm_platform_ioremap_resource(pdev, 0);
 218         if (IS_ERR(tsc->tsc_base))
 219                 return PTR_ERR(tsc->tsc_base);
 220
 221         tsc->clk = devm_clk_get(dev, NULL);
 222         if (IS_ERR(tsc->clk)) {
 223                 dev_err(&pdev->dev, "failed getting clock\n");
 224                 return PTR_ERR(tsc->clk);
 225         }
 226
 227         input = devm_input_allocate_device(dev);
 228         if (!input) {
 229                 dev_err(&pdev->dev, "failed allocating input device\n");
 230                 return -ENOMEM;
 231         }
 232
 233         input->name = MOD_NAME;
 234         input->phys = "lpc32xx/input0";
 235         input->id.bustype = BUS_HOST;
 236         input->id.vendor = 0x0001;
 237         input->id.product = 0x0002;
 238         input->id.version = 0x0100;
 239         input->open = lpc32xx_ts_open;
 240         input->close = lpc32xx_ts_close;
 241
 242         input_set_capability(input, EV_KEY, BTN_TOUCH);
 243         input_set_abs_params(input, ABS_X, LPC32XX_TSC_MIN_XY_VAL,
 244                              LPC32XX_TSC_MAX_XY_VAL, 0, 0);
 245         input_set_abs_params(input, ABS_Y, LPC32XX_TSC_MIN_XY_VAL,
 246                              LPC32XX_TSC_MAX_XY_VAL, 0, 0);
 247
 248         input_set_drvdata(input, tsc);
 249         tsc->dev = input;
 250
 251         error = devm_request_irq(dev, tsc->irq, lpc32xx_ts_interrupt,
 252                                  0, pdev->name, tsc);
 253         if (error) {
 254                 dev_err(&pdev->dev, "failed requesting interrupt\n");
 255                 return error;
 256         }
 257
 258         error = input_register_device(input);
 259         if (error) {
 260                 dev_err(&pdev->dev, "failed registering input device\n");
 261                 return error;
 262         }
 263
 264         platform_set_drvdata(pdev, tsc);
 265         device_init_wakeup(&pdev->dev, true);
 266
 267         return 0;
 268 }
 269
 270 #ifdef CONFIG_PM
 271 static int lpc32xx_ts_suspend(struct device *dev)
 272 {
 273         struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
 274         struct input_dev *input = tsc->dev;
 275
 276         /*
 277          * Suspend and resume can be called when the device hasn't been
 278          * enabled. If there are no users that have the device open, then
 279          * avoid calling the TSC stop and start functions as the TSC
 280          * isn't yet clocked.
 281          */
 282         mutex_lock(&input->mutex);
 283
 284         if (input_device_enabled(input)) {
 285                 if (device_may_wakeup(dev))
 286                         enable_irq_wake(tsc->irq);
 287                 else
 288                         lpc32xx_stop_tsc(tsc);
 289         }
 290
 291         mutex_unlock(&input->mutex);
 292
 293         return 0;
 294 }
 295
 296 static int lpc32xx_ts_resume(struct device *dev)
 297 {
 298         struct lpc32xx_tsc *tsc = dev_get_drvdata(dev);
 299         struct input_dev *input = tsc->dev;
 300
 301         mutex_lock(&input->mutex);
 302
 303         if (input_device_enabled(input)) {
 304                 if (device_may_wakeup(dev))
 305                         disable_irq_wake(tsc->irq);
 306                 else
 307                         lpc32xx_setup_tsc(tsc);
 308         }
 309
 310         mutex_unlock(&input->mutex);
 311
 312         return 0;
 313 }
 314
 315 static const struct dev_pm_ops lpc32xx_ts_pm_ops = {
 316         .suspend        = lpc32xx_ts_suspend,
 317         .resume         = lpc32xx_ts_resume,
 318 };
 319 #define LPC32XX_TS_PM_OPS (&lpc32xx_ts_pm_ops)
 320 #else
 321 #define LPC32XX_TS_PM_OPS NULL
 322 #endif
 323
 324 #ifdef CONFIG_OF
 325 static const struct of_device_id lpc32xx_tsc_of_match[] = {
 326         { .compatible = "nxp,lpc3220-tsc", },
 327         { },
 328 };
 329 MODULE_DEVICE_TABLE(of, lpc32xx_tsc_of_match);
 330 #endif
 331
 332 static struct platform_driver lpc32xx_ts_driver = {
 333         .probe          = lpc32xx_ts_probe,
 334         .driver         = {
 335                 .name   = MOD_NAME,
 336                 .pm     = LPC32XX_TS_PM_OPS,
 337                 .of_match_table = of_match_ptr(lpc32xx_tsc_of_match),
 338         },
 339 };
 340 module_platform_driver(lpc32xx_ts_driver);
 341
 342 MODULE_AUTHOR("Kevin Wells <kevin.wells@nxp.com");
 343 MODULE_DESCRIPTION("LPC32XX TSC Driver");
 344 MODULE_LICENSE("GPL");
 345 MODULE_ALIAS("platform:lpc32xx_ts");