drivers/input/touchscreen/zylonite-wm97xx.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
   4  *
   5  * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  * Parts Copyright : Ian Molton <spyro@f2s.com>
   8  *                   Andrew Zabolotny <zap@homelink.ru>
   9  *
  10  * Notes:
  11  *     This is a wm97xx extended touch driver supporting interrupt driven
  12  *     and continuous operation on Marvell Zylonite development systems
  13  *     (which have a WM9713 on board).
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/kernel.h>
  19 #include <linux/delay.h>
  20 #include <linux/gpio/consumer.h>
  21 #include <linux/irq.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/io.h>
  24 #include <linux/soc/pxa/cpu.h>
  25 #include <linux/wm97xx.h>
  26
  27 #include <sound/pxa2xx-lib.h>
  28
  29 struct continuous {
  30         u16 id;    /* codec id */
  31         u8 code;   /* continuous code */
  32         u8 reads;  /* number of coord reads per read cycle */
  33         u32 speed; /* number of coords per second */
  34 };
  35
  36 #define WM_READS(sp) ((sp / HZ) + 1)
  37
  38 static const struct continuous cinfo[] = {
  39         { WM9713_ID2, 0, WM_READS(94),  94  },
  40         { WM9713_ID2, 1, WM_READS(120), 120 },
  41         { WM9713_ID2, 2, WM_READS(154), 154 },
  42         { WM9713_ID2, 3, WM_READS(188), 188 },
  43 };
  44
  45 /* continuous speed index */
  46 static int sp_idx;
  47
  48 /*
  49  * Pen sampling frequency (Hz) in continuous mode.
  50  */
  51 static int cont_rate = 200;
  52 module_param(cont_rate, int, 0);
  53 MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
  54
  55 /*
  56  * Pressure readback.
  57  *
  58  * Set to 1 to read back pen down pressure
  59  */
  60 static int pressure;
  61 module_param(pressure, int, 0);
  62 MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
  63
  64 /*
  65  * AC97 touch data slot.
  66  *
  67  * Touch screen readback data ac97 slot
  68  */
  69 static int ac97_touch_slot = 5;
  70 module_param(ac97_touch_slot, int, 0);
  71 MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
  72
  73
  74 /* flush AC97 slot 5 FIFO machines */
  75 static void wm97xx_acc_pen_up(struct wm97xx *wm)
  76 {
  77         int i;
  78
  79         msleep(1);
  80
  81         for (i = 0; i < 16; i++)
  82                 pxa2xx_ac97_read_modr();
  83 }
  84
  85 static int wm97xx_acc_pen_down(struct wm97xx *wm)
  86 {
  87         u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
  88         int reads = 0;
  89         static u16 last, tries;
  90
  91         /* When the AC97 queue has been drained we need to allow time
  92          * to buffer up samples otherwise we end up spinning polling
  93          * for samples.  The controller can't have a suitably low
  94          * threshold set to use the notifications it gives.
  95          */
  96         msleep(1);
  97
  98         if (tries > 5) {
  99                 tries = 0;
 100                 return RC_PENUP;
 101         }
 102
 103         x = pxa2xx_ac97_read_modr();
 104         if (x == last) {
 105                 tries++;
 106                 return RC_AGAIN;
 107         }
 108         last = x;
 109         do {
 110                 if (reads)
 111                         x = pxa2xx_ac97_read_modr();
 112                 y = pxa2xx_ac97_read_modr();
 113                 if (pressure)
 114                         p = pxa2xx_ac97_read_modr();
 115
 116                 dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
 117                         x, y, p);
 118
 119                 /* are samples valid */
 120                 if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
 121                     (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
 122                     (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
 123                         goto up;
 124
 125                 /* coordinate is good */
 126                 tries = 0;
 127                 input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
 128                 input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
 129                 input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
 130                 input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
 131                 input_sync(wm->input_dev);
 132                 reads++;
 133         } while (reads < cinfo[sp_idx].reads);
 134 up:
 135         return RC_PENDOWN | RC_AGAIN;
 136 }
 137
 138 static int wm97xx_acc_startup(struct wm97xx *wm)
 139 {
 140         int idx;
 141
 142         /* check we have a codec */
 143         if (wm->ac97 == NULL)
 144                 return -ENODEV;
 145
 146         /* Go you big red fire engine */
 147         for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
 148                 if (wm->id != cinfo[idx].id)
 149                         continue;
 150                 sp_idx = idx;
 151                 if (cont_rate <= cinfo[idx].speed)
 152                         break;
 153         }
 154         wm->acc_rate = cinfo[sp_idx].code;
 155         wm->acc_slot = ac97_touch_slot;
 156         dev_info(wm->dev,
 157                  "zylonite accelerated touchscreen driver, %d samples/sec\n",
 158                  cinfo[sp_idx].speed);
 159
 160         return 0;
 161 }
 162
 163 static struct wm97xx_mach_ops zylonite_mach_ops = {
 164         .acc_enabled    = 1,
 165         .acc_pen_up     = wm97xx_acc_pen_up,
 166         .acc_pen_down   = wm97xx_acc_pen_down,
 167         .acc_startup    = wm97xx_acc_startup,
 168         .irq_gpio       = WM97XX_GPIO_2,
 169 };
 170
 171 static int zylonite_wm97xx_probe(struct platform_device *pdev)
 172 {
 173         struct wm97xx *wm = platform_get_drvdata(pdev);
 174         struct gpio_desc *gpio_touch_irq;
 175         int err;
 176
 177         gpio_touch_irq = devm_gpiod_get(&pdev->dev, "touch", GPIOD_IN);
 178         err = PTR_ERR_OR_ZERO(gpio_touch_irq);
 179         if (err) {
 180                 dev_err(&pdev->dev, "Cannot get irq gpio: %d\n", err);
 181                 return err;
 182         }
 183
 184         wm->pen_irq = gpiod_to_irq(gpio_touch_irq);
 185         irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
 186
 187         wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
 188                            WM97XX_GPIO_POL_HIGH,
 189                            WM97XX_GPIO_STICKY,
 190                            WM97XX_GPIO_WAKE);
 191         wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
 192                            WM97XX_GPIO_POL_HIGH,
 193                            WM97XX_GPIO_NOTSTICKY,
 194                            WM97XX_GPIO_NOWAKE);
 195
 196         return wm97xx_register_mach_ops(wm, &zylonite_mach_ops);
 197 }
 198
 199 static int zylonite_wm97xx_remove(struct platform_device *pdev)
 200 {
 201         struct wm97xx *wm = platform_get_drvdata(pdev);
 202
 203         wm97xx_unregister_mach_ops(wm);
 204
 205         return 0;
 206 }
 207
 208 static struct platform_driver zylonite_wm97xx_driver = {
 209         .probe  = zylonite_wm97xx_probe,
 210         .remove = zylonite_wm97xx_remove,
 211         .driver = {
 212                 .name   = "wm97xx-touch",
 213         },
 214 };
 215 module_platform_driver(zylonite_wm97xx_driver);
 216
 217 /* Module information */
 218 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 219 MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
 220 MODULE_LICENSE("GPL");