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/irq.h>
25 #include <linux/interrupt.h>
26 #include <linux/wm97xx.h>
27 #include <linux/io.h>
28 #include <linux/gpio.h>
29 
30 #include <mach/regs-ac97.h>
31 
32 #include <asm/mach-types.h>
33 
34 struct continuous {
35 	u16 id;    /* codec id */
36 	u8 code;   /* continuous code */
37 	u8 reads;  /* number of coord reads per read cycle */
38 	u32 speed; /* number of coords per second */
39 };
40 
41 #define WM_READS(sp) ((sp / HZ) + 1)
42 
43 static const struct continuous cinfo[] = {
44 	{WM9705_ID2, 0, WM_READS(94), 94},
45 	{WM9705_ID2, 1, WM_READS(188), 188},
46 	{WM9705_ID2, 2, WM_READS(375), 375},
47 	{WM9705_ID2, 3, WM_READS(750), 750},
48 	{WM9712_ID2, 0, WM_READS(94), 94},
49 	{WM9712_ID2, 1, WM_READS(188), 188},
50 	{WM9712_ID2, 2, WM_READS(375), 375},
51 	{WM9712_ID2, 3, WM_READS(750), 750},
52 	{WM9713_ID2, 0, WM_READS(94), 94},
53 	{WM9713_ID2, 1, WM_READS(120), 120},
54 	{WM9713_ID2, 2, WM_READS(154), 154},
55 	{WM9713_ID2, 3, WM_READS(188), 188},
56 };
57 
58 /* continuous speed index */
59 static int sp_idx;
60 static u16 last, tries;
61 static int 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 */
100 #ifdef CONFIG_PXA27x
101 static void wm97xx_acc_pen_up(struct wm97xx *wm)
102 {
103 	schedule_timeout_uninterruptible(1);
104 
105 	while (MISR & (1 << 2))
106 		MODR;
107 }
108 #else
109 static void wm97xx_acc_pen_up(struct wm97xx *wm)
110 {
111 	unsigned int count;
112 
113 	schedule_timeout_uninterruptible(1);
114 
115 	for (count = 0; count < 16; count++)
116 		MODR;
117 }
118 #endif
119 
120 static int wm97xx_acc_pen_down(struct wm97xx *wm)
121 {
122 	u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
123 	int reads = 0;
124 
125 	/* When the AC97 queue has been drained we need to allow time
126 	 * to buffer up samples otherwise we end up spinning polling
127 	 * for samples.  The controller can't have a suitably low
128 	 * threshold set to use the notifications it gives.
129 	 */
130 	schedule_timeout_uninterruptible(1);
131 
132 	if (tries > 5) {
133 		tries = 0;
134 		return RC_PENUP;
135 	}
136 
137 	x = MODR;
138 	if (x == last) {
139 		tries++;
140 		return RC_AGAIN;
141 	}
142 	last = x;
143 	do {
144 		if (reads)
145 			x = MODR;
146 		y = MODR;
147 		if (pressure)
148 			p = MODR;
149 
150 		dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
151 			x, y, p);
152 
153 		/* are samples valid */
154 		if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
155 		    (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
156 		    (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
157 			goto up;
158 
159 		/* coordinate is good */
160 		tries = 0;
161 		input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
162 		input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
163 		input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
164 		input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
165 		input_sync(wm->input_dev);
166 		reads++;
167 	} while (reads < cinfo[sp_idx].reads);
168 up:
169 	return RC_PENDOWN | RC_AGAIN;
170 }
171 
172 static int wm97xx_acc_startup(struct wm97xx *wm)
173 {
174 	int idx = 0, ret = 0;
175 
176 	/* check we have a codec */
177 	if (wm->ac97 == NULL)
178 		return -ENODEV;
179 
180 	/* Go you big red fire engine */
181 	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
182 		if (wm->id != cinfo[idx].id)
183 			continue;
184 		sp_idx = idx;
185 		if (cont_rate <= cinfo[idx].speed)
186 			break;
187 	}
188 	wm->acc_rate = cinfo[sp_idx].code;
189 	wm->acc_slot = ac97_touch_slot;
190 	dev_info(wm->dev,
191 		 "mainstone accelerated touchscreen driver, %d samples/sec\n",
192 		 cinfo[sp_idx].speed);
193 
194 	/* IRQ driven touchscreen is used on Palm hardware */
195 	if (machine_is_palmt5() || machine_is_palmtx() || machine_is_palmld()) {
196 		pen_int = 1;
197 		irq = 27;
198 		/* There is some obscure mutant of WM9712 interbred with WM9713
199 		 * used on Palm HW */
200 		wm->variant = WM97xx_WM1613;
201 	} else if (machine_is_mainstone() && pen_int)
202 		irq = 4;
203 
204 	if (irq) {
205 		ret = gpio_request(irq, "Touchscreen IRQ");
206 		if (ret)
207 			goto out;
208 
209 		ret = gpio_direction_input(irq);
210 		if (ret) {
211 			gpio_free(irq);
212 			goto out;
213 		}
214 
215 		wm->pen_irq = gpio_to_irq(irq);
216 		irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
217 	} else /* pen irq not supported */
218 		pen_int = 0;
219 
220 	/* codec specific irq config */
221 	if (pen_int) {
222 		switch (wm->id) {
223 		case WM9705_ID2:
224 			break;
225 		case WM9712_ID2:
226 		case WM9713_ID2:
227 			/* use PEN_DOWN GPIO 13 to assert IRQ on GPIO line 2 */
228 			wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
229 					   WM97XX_GPIO_POL_HIGH,
230 					   WM97XX_GPIO_STICKY,
231 					   WM97XX_GPIO_WAKE);
232 			wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
233 					   WM97XX_GPIO_POL_HIGH,
234 					   WM97XX_GPIO_NOTSTICKY,
235 					   WM97XX_GPIO_NOWAKE);
236 			break;
237 		default:
238 			dev_err(wm->dev,
239 				"pen down irq not supported on this device\n");
240 			pen_int = 0;
241 			break;
242 		}
243 	}
244 
245 out:
246 	return ret;
247 }
248 
249 static void wm97xx_acc_shutdown(struct wm97xx *wm)
250 {
251 	/* codec specific deconfig */
252 	if (pen_int) {
253 		if (irq)
254 			gpio_free(irq);
255 		wm->pen_irq = 0;
256 	}
257 }
258 
259 static void wm97xx_irq_enable(struct wm97xx *wm, int enable)
260 {
261 	if (enable)
262 		enable_irq(wm->pen_irq);
263 	else
264 		disable_irq_nosync(wm->pen_irq);
265 }
266 
267 static struct wm97xx_mach_ops mainstone_mach_ops = {
268 	.acc_enabled = 1,
269 	.acc_pen_up = wm97xx_acc_pen_up,
270 	.acc_pen_down = wm97xx_acc_pen_down,
271 	.acc_startup = wm97xx_acc_startup,
272 	.acc_shutdown = wm97xx_acc_shutdown,
273 	.irq_enable = wm97xx_irq_enable,
274 	.irq_gpio = WM97XX_GPIO_2,
275 };
276 
277 static int mainstone_wm97xx_probe(struct platform_device *pdev)
278 {
279 	struct wm97xx *wm = platform_get_drvdata(pdev);
280 
281 	return wm97xx_register_mach_ops(wm, &mainstone_mach_ops);
282 }
283 
284 static int mainstone_wm97xx_remove(struct platform_device *pdev)
285 {
286 	struct wm97xx *wm = platform_get_drvdata(pdev);
287 
288 	wm97xx_unregister_mach_ops(wm);
289 	return 0;
290 }
291 
292 static struct platform_driver mainstone_wm97xx_driver = {
293 	.probe = mainstone_wm97xx_probe,
294 	.remove = mainstone_wm97xx_remove,
295 	.driver = {
296 		.name = "wm97xx-touch",
297 	},
298 };
299 module_platform_driver(mainstone_wm97xx_driver);
300 
301 /* Module information */
302 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
303 MODULE_DESCRIPTION("wm97xx continuous touch driver for mainstone");
304 MODULE_LICENSE("GPL");
305