input/touchscreen/zylonite-wm97xx.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * zylonite-wm97xx.c  --  Zylonite Continuous Touch screen driver
0004  *
0005  * Copyright 2004, 2007, 2008 Wolfson Microelectronics PLC.
0006  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
0007  * Parts Copyright : Ian Molton <spyro@f2s.com>
0008  *                   Andrew Zabolotny <zap@homelink.ru>
0009  *
0010  * Notes:
0011  *     This is a wm97xx extended touch driver supporting interrupt driven
0012  *     and continuous operation on Marvell Zylonite development systems
0013  *     (which have a WM9713 on board).
0014  */
0015
0016 #include <linux/module.h>
0017 #include <linux/moduleparam.h>
0018 #include <linux/kernel.h>
0019 #include <linux/delay.h>
0020 #include <linux/gpio/consumer.h>
0021 #include <linux/irq.h>
0022 #include <linux/interrupt.h>
0023 #include <linux/io.h>
0024 #include <linux/soc/pxa/cpu.h>
0025 #include <linux/wm97xx.h>
0026
0027 #include <sound/pxa2xx-lib.h>
0028
0029 struct continuous {
0030     u16 id;    /* codec id */
0031     u8 code;   /* continuous code */
0032     u8 reads;  /* number of coord reads per read cycle */
0033     u32 speed; /* number of coords per second */
0034 };
0035
0036 #define WM_READS(sp) ((sp / HZ) + 1)
0037
0038 static const struct continuous cinfo[] = {
0039     { WM9713_ID2, 0, WM_READS(94),  94  },
0040     { WM9713_ID2, 1, WM_READS(120), 120 },
0041     { WM9713_ID2, 2, WM_READS(154), 154 },
0042     { WM9713_ID2, 3, WM_READS(188), 188 },
0043 };
0044
0045 /* continuous speed index */
0046 static int sp_idx;
0047
0048 /*
0049  * Pen sampling frequency (Hz) in continuous mode.
0050  */
0051 static int cont_rate = 200;
0052 module_param(cont_rate, int, 0);
0053 MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
0054
0055 /*
0056  * Pressure readback.
0057  *
0058  * Set to 1 to read back pen down pressure
0059  */
0060 static int pressure;
0061 module_param(pressure, int, 0);
0062 MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
0063
0064 /*
0065  * AC97 touch data slot.
0066  *
0067  * Touch screen readback data ac97 slot
0068  */
0069 static int ac97_touch_slot = 5;
0070 module_param(ac97_touch_slot, int, 0);
0071 MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
0072
0073
0074 /* flush AC97 slot 5 FIFO machines */
0075 static void wm97xx_acc_pen_up(struct wm97xx *wm)
0076 {
0077     int i;
0078
0079     msleep(1);
0080
0081     for (i = 0; i < 16; i++)
0082         pxa2xx_ac97_read_modr();
0083 }
0084
0085 static int wm97xx_acc_pen_down(struct wm97xx *wm)
0086 {
0087     u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
0088     int reads = 0;
0089     static u16 last, tries;
0090
0091     /* When the AC97 queue has been drained we need to allow time
0092      * to buffer up samples otherwise we end up spinning polling
0093      * for samples.  The controller can't have a suitably low
0094      * threshold set to use the notifications it gives.
0095      */
0096     msleep(1);
0097
0098     if (tries > 5) {
0099         tries = 0;
0100         return RC_PENUP;
0101     }
0102
0103     x = pxa2xx_ac97_read_modr();
0104     if (x == last) {
0105         tries++;
0106         return RC_AGAIN;
0107     }
0108     last = x;
0109     do {
0110         if (reads)
0111             x = pxa2xx_ac97_read_modr();
0112         y = pxa2xx_ac97_read_modr();
0113         if (pressure)
0114             p = pxa2xx_ac97_read_modr();
0115
0116         dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
0117             x, y, p);
0118
0119         /* are samples valid */
0120         if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
0121             (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
0122             (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
0123             goto up;
0124
0125         /* coordinate is good */
0126         tries = 0;
0127         input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
0128         input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
0129         input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
0130         input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
0131         input_sync(wm->input_dev);
0132         reads++;
0133     } while (reads < cinfo[sp_idx].reads);
0134 up:
0135     return RC_PENDOWN | RC_AGAIN;
0136 }
0137
0138 static int wm97xx_acc_startup(struct wm97xx *wm)
0139 {
0140     int idx;
0141
0142     /* check we have a codec */
0143     if (wm->ac97 == NULL)
0144         return -ENODEV;
0145
0146     /* Go you big red fire engine */
0147     for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
0148         if (wm->id != cinfo[idx].id)
0149             continue;
0150         sp_idx = idx;
0151         if (cont_rate <= cinfo[idx].speed)
0152             break;
0153     }
0154     wm->acc_rate = cinfo[sp_idx].code;
0155     wm->acc_slot = ac97_touch_slot;
0156     dev_info(wm->dev,
0157          "zylonite accelerated touchscreen driver, %d samples/sec\n",
0158          cinfo[sp_idx].speed);
0159
0160     return 0;
0161 }
0162
0163 static struct wm97xx_mach_ops zylonite_mach_ops = {
0164     .acc_enabled    = 1,
0165     .acc_pen_up = wm97xx_acc_pen_up,
0166     .acc_pen_down   = wm97xx_acc_pen_down,
0167     .acc_startup    = wm97xx_acc_startup,
0168     .irq_gpio   = WM97XX_GPIO_2,
0169 };
0170
0171 static int zylonite_wm97xx_probe(struct platform_device *pdev)
0172 {
0173     struct wm97xx *wm = platform_get_drvdata(pdev);
0174     struct gpio_desc *gpio_touch_irq;
0175     int err;
0176
0177     gpio_touch_irq = devm_gpiod_get(&pdev->dev, "touch", GPIOD_IN);
0178     err = PTR_ERR_OR_ZERO(gpio_touch_irq);
0179     if (err) {
0180         dev_err(&pdev->dev, "Cannot get irq gpio: %d\n", err);
0181         return err;
0182     }
0183
0184     wm->pen_irq = gpiod_to_irq(gpio_touch_irq);
0185     irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
0186
0187     wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
0188                WM97XX_GPIO_POL_HIGH,
0189                WM97XX_GPIO_STICKY,
0190                WM97XX_GPIO_WAKE);
0191     wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
0192                WM97XX_GPIO_POL_HIGH,
0193                WM97XX_GPIO_NOTSTICKY,
0194                WM97XX_GPIO_NOWAKE);
0195
0196     return wm97xx_register_mach_ops(wm, &zylonite_mach_ops);
0197 }
0198
0199 static int zylonite_wm97xx_remove(struct platform_device *pdev)
0200 {
0201     struct wm97xx *wm = platform_get_drvdata(pdev);
0202
0203     wm97xx_unregister_mach_ops(wm);
0204
0205     return 0;
0206 }
0207
0208 static struct platform_driver zylonite_wm97xx_driver = {
0209     .probe  = zylonite_wm97xx_probe,
0210     .remove = zylonite_wm97xx_remove,
0211     .driver = {
0212         .name   = "wm97xx-touch",
0213     },
0214 };
0215 module_platform_driver(zylonite_wm97xx_driver);
0216
0217 /* Module information */
0218 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
0219 MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
0220 MODULE_LICENSE("GPL");