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
 29struct 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
 38static 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 */
 46static int sp_idx;
 47
 48/*
 49 * Pen sampling frequency (Hz) in continuous mode.
 50 */
 51static int cont_rate = 200;
 52module_param(cont_rate, int, 0);
 53MODULE_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 */
 60static int pressure;
 61module_param(pressure, int, 0);
 62MODULE_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 */
 69static int ac97_touch_slot = 5;
 70module_param(ac97_touch_slot, int, 0);
 71MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
 72
 73
 74/* flush AC97 slot 5 FIFO machines */
 75static 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
 85static 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);
134up:
135	return RC_PENDOWN | RC_AGAIN;
136}
137
138static 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
163static 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
171static 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
199static 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
208static struct platform_driver zylonite_wm97xx_driver = {
209	.probe	= zylonite_wm97xx_probe,
210	.remove	= zylonite_wm97xx_remove,
211	.driver	= {
212		.name	= "wm97xx-touch",
213	},
214};
215module_platform_driver(zylonite_wm97xx_driver);
216
217/* Module information */
218MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
219MODULE_DESCRIPTION("wm97xx continuous touch driver for Zylonite");
220MODULE_LICENSE("GPL");