drivers/input/touchscreen/mainstone-wm97xx.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * mainstone-wm97xx.c  --  Mainstone Continuous Touch screen driver for
   4  *                         Wolfson WM97xx AC97 Codecs.
   5  *
   6  * Copyright 2004, 2007 Wolfson Microelectronics PLC.
   7  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
   8  * Parts Copyright : Ian Molton <spyro@f2s.com>
   9  *                   Andrew Zabolotny <zap@homelink.ru>
  10  *
  11  * Notes:
  12  *     This is a wm97xx extended touch driver to capture touch
  13  *     data in a continuous manner on the Intel XScale architecture
  14  *
  15  *  Features:
  16  *       - codecs supported:- WM9705, WM9712, WM9713
  17  *       - processors supported:- Intel XScale PXA25x, PXA26x, PXA27x
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/moduleparam.h>
  22 #include <linux/kernel.h>
  23 #include <linux/delay.h>
  24 #include <linux/gpio/consumer.h>
  25 #include <linux/irq.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/io.h>
  28 #include <linux/soc/pxa/cpu.h>
  29 #include <linux/wm97xx.h>
  30
  31 #include <sound/pxa2xx-lib.h>
  32
  33 #include <asm/mach-types.h>
  34
  35 struct continuous {
  36         u16 id;    /* codec id */
  37         u8 code;   /* continuous code */
  38         u8 reads;  /* number of coord reads per read cycle */
  39         u32 speed; /* number of coords per second */
  40 };
  41
  42 #define WM_READS(sp) ((sp / HZ) + 1)
  43
  44 static const struct continuous cinfo[] = {
  45         { WM9705_ID2, 0, WM_READS(94),  94  },
  46         { WM9705_ID2, 1, WM_READS(188), 188 },
  47         { WM9705_ID2, 2, WM_READS(375), 375 },
  48         { WM9705_ID2, 3, WM_READS(750), 750 },
  49         { WM9712_ID2, 0, WM_READS(94),  94  },
  50         { WM9712_ID2, 1, WM_READS(188), 188 },
  51         { WM9712_ID2, 2, WM_READS(375), 375 },
  52         { WM9712_ID2, 3, WM_READS(750), 750 },
  53         { WM9713_ID2, 0, WM_READS(94),  94  },
  54         { WM9713_ID2, 1, WM_READS(120), 120 },
  55         { WM9713_ID2, 2, WM_READS(154), 154 },
  56         { WM9713_ID2, 3, WM_READS(188), 188 },
  57 };
  58
  59 /* continuous speed index */
  60 static int sp_idx;
  61 static struct gpio_desc *gpiod_irq;
  62
  63 /*
  64  * Pen sampling frequency (Hz) in continuous mode.
  65  */
  66 static int cont_rate = 200;
  67 module_param(cont_rate, int, 0);
  68 MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
  69
  70 /*
  71  * Pen down detection.
  72  *
  73  * This driver can either poll or use an interrupt to indicate a pen down
  74  * event. If the irq request fails then it will fall back to polling mode.
  75  */
  76 static int pen_int;
  77 module_param(pen_int, int, 0);
  78 MODULE_PARM_DESC(pen_int, "Pen down detection (1 = interrupt, 0 = polling)");
  79
  80 /*
  81  * Pressure readback.
  82  *
  83  * Set to 1 to read back pen down pressure
  84  */
  85 static int pressure;
  86 module_param(pressure, int, 0);
  87 MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
  88
  89 /*
  90  * AC97 touch data slot.
  91  *
  92  * Touch screen readback data ac97 slot
  93  */
  94 static int ac97_touch_slot = 5;
  95 module_param(ac97_touch_slot, int, 0);
  96 MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
  97
  98
  99 /* flush AC97 slot 5 FIFO on pxa machines */
 100 static void wm97xx_acc_pen_up(struct wm97xx *wm)
 101 {
 102         unsigned int count;
 103
 104         msleep(1);
 105
 106         if (cpu_is_pxa27x()) {
 107                 while (pxa2xx_ac97_read_misr() & (1 << 2))
 108                         pxa2xx_ac97_read_modr();
 109         } else if (cpu_is_pxa3xx()) {
 110                 for (count = 0; count < 16; count++)
 111                         pxa2xx_ac97_read_modr();
 112         }
 113 }
 114
 115 static int wm97xx_acc_pen_down(struct wm97xx *wm)
 116 {
 117         u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
 118         int reads = 0;
 119         static u16 last, tries;
 120
 121         /* When the AC97 queue has been drained we need to allow time
 122          * to buffer up samples otherwise we end up spinning polling
 123          * for samples.  The controller can't have a suitably low
 124          * threshold set to use the notifications it gives.
 125          */
 126         msleep(1);
 127
 128         if (tries > 5) {
 129                 tries = 0;
 130                 return RC_PENUP;
 131         }
 132
 133         x = pxa2xx_ac97_read_modr();
 134         if (x == last) {
 135                 tries++;
 136                 return RC_AGAIN;
 137         }
 138         last = x;
 139         do {
 140                 if (reads)
 141                         x = pxa2xx_ac97_read_modr();
 142                 y = pxa2xx_ac97_read_modr();
 143                 if (pressure)
 144                         p = pxa2xx_ac97_read_modr();
 145
 146                 dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
 147                         x, y, p);
 148
 149                 /* are samples valid */
 150                 if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
 151                     (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
 152                     (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
 153                         goto up;
 154
 155                 /* coordinate is good */
 156                 tries = 0;
 157                 input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
 158                 input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
 159                 input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
 160                 input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
 161                 input_sync(wm->input_dev);
 162                 reads++;
 163         } while (reads < cinfo[sp_idx].reads);
 164 up:
 165         return RC_PENDOWN | RC_AGAIN;
 166 }
 167
 168 static int wm97xx_acc_startup(struct wm97xx *wm)
 169 {
 170         int idx = 0, ret = 0;
 171
 172         /* check we have a codec */
 173         if (wm->ac97 == NULL)
 174                 return -ENODEV;
 175
 176         /* Go you big red fire engine */
 177         for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
 178                 if (wm->id != cinfo[idx].id)
 179                         continue;
 180                 sp_idx = idx;
 181                 if (cont_rate <= cinfo[idx].speed)
 182                         break;
 183         }
 184         wm->acc_rate = cinfo[sp_idx].code;
 185         wm->acc_slot = ac97_touch_slot;
 186         dev_info(wm->dev,
 187                  "mainstone accelerated touchscreen driver, %d samples/sec\n",
 188                  cinfo[sp_idx].speed);
 189
 190         if (pen_int) {
 191                 gpiod_irq = gpiod_get(wm->dev, "touch", GPIOD_IN);
 192                 if (IS_ERR(gpiod_irq))
 193                         pen_int = 0;
 194         }
 195
 196         if (pen_int) {
 197                 wm->pen_irq = gpiod_to_irq(gpiod_irq);
 198                 irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
 199         }
 200
 201         /* codec specific irq config */
 202         if (pen_int) {
 203                 switch (wm->id) {
 204                 case WM9705_ID2:
 205                         break;
 206                 case WM9712_ID2:
 207                 case WM9713_ID2:
 208                         /* use PEN_DOWN GPIO 13 to assert IRQ on GPIO line 2 */
 209                         wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
 210                                            WM97XX_GPIO_POL_HIGH,
 211                                            WM97XX_GPIO_STICKY,
 212                                            WM97XX_GPIO_WAKE);
 213                         wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
 214                                            WM97XX_GPIO_POL_HIGH,
 215                                            WM97XX_GPIO_NOTSTICKY,
 216                                            WM97XX_GPIO_NOWAKE);
 217                         break;
 218                 default:
 219                         dev_err(wm->dev,
 220                                 "pen down irq not supported on this device\n");
 221                         pen_int = 0;
 222                         break;
 223                 }
 224         }
 225
 226         return ret;
 227 }
 228
 229 static void wm97xx_acc_shutdown(struct wm97xx *wm)
 230 {
 231         /* codec specific deconfig */
 232         if (pen_int) {
 233                 if (gpiod_irq)
 234                         gpiod_put(gpiod_irq);
 235                 wm->pen_irq = 0;
 236         }
 237 }
 238
 239 static struct wm97xx_mach_ops mainstone_mach_ops = {
 240         .acc_enabled    = 1,
 241         .acc_pen_up     = wm97xx_acc_pen_up,
 242         .acc_pen_down   = wm97xx_acc_pen_down,
 243         .acc_startup    = wm97xx_acc_startup,
 244         .acc_shutdown   = wm97xx_acc_shutdown,
 245         .irq_gpio       = WM97XX_GPIO_2,
 246 };
 247
 248 static int mainstone_wm97xx_probe(struct platform_device *pdev)
 249 {
 250         struct wm97xx *wm = platform_get_drvdata(pdev);
 251
 252         return wm97xx_register_mach_ops(wm, &mainstone_mach_ops);
 253 }
 254
 255 static void mainstone_wm97xx_remove(struct platform_device *pdev)
 256 {
 257         struct wm97xx *wm = platform_get_drvdata(pdev);
 258
 259         wm97xx_unregister_mach_ops(wm);
 260 }
 261
 262 static struct platform_driver mainstone_wm97xx_driver = {
 263         .probe  = mainstone_wm97xx_probe,
 264         .remove_new = mainstone_wm97xx_remove,
 265         .driver = {
 266                 .name   = "wm97xx-touch",
 267         },
 268 };
 269 module_platform_driver(mainstone_wm97xx_driver);
 270
 271 /* Module information */
 272 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 273 MODULE_DESCRIPTION("wm97xx continuous touch driver for mainstone");
 274 MODULE_LICENSE("GPL");