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 */
wm97xx_acc_pen_up(struct wm97xx * wm)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 
wm97xx_acc_pen_down(struct wm97xx * wm)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 
wm97xx_acc_startup(struct wm97xx * wm)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 
wm97xx_acc_shutdown(struct wm97xx * wm)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 
mainstone_wm97xx_probe(struct platform_device * pdev)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 
mainstone_wm97xx_remove(struct platform_device * pdev)255 static int 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 	return 0;
262 }
263 
264 static struct platform_driver mainstone_wm97xx_driver = {
265 	.probe	= mainstone_wm97xx_probe,
266 	.remove	= mainstone_wm97xx_remove,
267 	.driver	= {
268 		.name	= "wm97xx-touch",
269 	},
270 };
271 module_platform_driver(mainstone_wm97xx_driver);
272 
273 /* Module information */
274 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
275 MODULE_DESCRIPTION("wm97xx continuous touch driver for mainstone");
276 MODULE_LICENSE("GPL");
277