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 */
wm97xx_acc_pen_up(struct wm97xx * wm)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
wm97xx_acc_pen_down(struct wm97xx * wm)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
wm97xx_acc_startup(struct wm97xx * wm)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
zylonite_wm97xx_probe(struct platform_device * pdev)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
zylonite_wm97xx_remove(struct platform_device * pdev)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");
221