1 /*
2  * mainstone-wm97xx.c  --  Mainstone Continuous Touch screen driver for
3  *                         Wolfson WM97xx AC97 Codecs.
4  *
5  * Copyright 2004, 2007 Wolfson Microelectronics PLC.
6  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
7  * Parts Copyright : Ian Molton <spyro@f2s.com>
8  *                   Andrew Zabolotny <zap@homelink.ru>
9  *
10  *  This program is free software; you can redistribute  it and/or modify it
11  *  under  the terms of  the GNU General  Public License as published by the
12  *  Free Software Foundation;  either version 2 of the  License, or (at your
13  *  option) any later version.
14  *
15  * Notes:
16  *     This is a wm97xx extended touch driver to capture touch
17  *     data in a continuous manner on the Intel XScale architecture
18  *
19  *  Features:
20  *       - codecs supported:- WM9705, WM9712, WM9713
21  *       - processors supported:- Intel XScale PXA25x, PXA26x, PXA27x
22  *
23  */
24 
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/kernel.h>
28 #include <linux/delay.h>
29 #include <linux/irq.h>
30 #include <linux/interrupt.h>
31 #include <linux/wm97xx.h>
32 #include <linux/io.h>
33 #include <linux/gpio.h>
34 
35 #include <mach/regs-ac97.h>
36 
37 #include <asm/mach-types.h>
38 
39 struct continuous {
40 	u16 id;    /* codec id */
41 	u8 code;   /* continuous code */
42 	u8 reads;  /* number of coord reads per read cycle */
43 	u32 speed; /* number of coords per second */
44 };
45 
46 #define WM_READS(sp) ((sp / HZ) + 1)
47 
48 static const struct continuous cinfo[] = {
49 	{WM9705_ID2, 0, WM_READS(94), 94},
50 	{WM9705_ID2, 1, WM_READS(188), 188},
51 	{WM9705_ID2, 2, WM_READS(375), 375},
52 	{WM9705_ID2, 3, WM_READS(750), 750},
53 	{WM9712_ID2, 0, WM_READS(94), 94},
54 	{WM9712_ID2, 1, WM_READS(188), 188},
55 	{WM9712_ID2, 2, WM_READS(375), 375},
56 	{WM9712_ID2, 3, WM_READS(750), 750},
57 	{WM9713_ID2, 0, WM_READS(94), 94},
58 	{WM9713_ID2, 1, WM_READS(120), 120},
59 	{WM9713_ID2, 2, WM_READS(154), 154},
60 	{WM9713_ID2, 3, WM_READS(188), 188},
61 };
62 
63 /* continuous speed index */
64 static int sp_idx;
65 static u16 last, tries;
66 static int irq;
67 
68 /*
69  * Pen sampling frequency (Hz) in continuous mode.
70  */
71 static int cont_rate = 200;
72 module_param(cont_rate, int, 0);
73 MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
74 
75 /*
76  * Pen down detection.
77  *
78  * This driver can either poll or use an interrupt to indicate a pen down
79  * event. If the irq request fails then it will fall back to polling mode.
80  */
81 static int pen_int;
82 module_param(pen_int, int, 0);
83 MODULE_PARM_DESC(pen_int, "Pen down detection (1 = interrupt, 0 = polling)");
84 
85 /*
86  * Pressure readback.
87  *
88  * Set to 1 to read back pen down pressure
89  */
90 static int pressure;
91 module_param(pressure, int, 0);
92 MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
93 
94 /*
95  * AC97 touch data slot.
96  *
97  * Touch screen readback data ac97 slot
98  */
99 static int ac97_touch_slot = 5;
100 module_param(ac97_touch_slot, int, 0);
101 MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
102 
103 
104 /* flush AC97 slot 5 FIFO on pxa machines */
105 #ifdef CONFIG_PXA27x
106 static void wm97xx_acc_pen_up(struct wm97xx *wm)
107 {
108 	schedule_timeout_uninterruptible(1);
109 
110 	while (MISR & (1 << 2))
111 		MODR;
112 }
113 #else
114 static void wm97xx_acc_pen_up(struct wm97xx *wm)
115 {
116 	unsigned int count;
117 
118 	schedule_timeout_uninterruptible(1);
119 
120 	for (count = 0; count < 16; count++)
121 		MODR;
122 }
123 #endif
124 
125 static int wm97xx_acc_pen_down(struct wm97xx *wm)
126 {
127 	u16 x, y, p = 0x100 | WM97XX_ADCSEL_PRES;
128 	int reads = 0;
129 
130 	/* When the AC97 queue has been drained we need to allow time
131 	 * to buffer up samples otherwise we end up spinning polling
132 	 * for samples.  The controller can't have a suitably low
133 	 * threshold set to use the notifications it gives.
134 	 */
135 	schedule_timeout_uninterruptible(1);
136 
137 	if (tries > 5) {
138 		tries = 0;
139 		return RC_PENUP;
140 	}
141 
142 	x = MODR;
143 	if (x == last) {
144 		tries++;
145 		return RC_AGAIN;
146 	}
147 	last = x;
148 	do {
149 		if (reads)
150 			x = MODR;
151 		y = MODR;
152 		if (pressure)
153 			p = MODR;
154 
155 		dev_dbg(wm->dev, "Raw coordinates: x=%x, y=%x, p=%x\n",
156 			x, y, p);
157 
158 		/* are samples valid */
159 		if ((x & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_X ||
160 		    (y & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_Y ||
161 		    (p & WM97XX_ADCSEL_MASK) != WM97XX_ADCSEL_PRES)
162 			goto up;
163 
164 		/* coordinate is good */
165 		tries = 0;
166 		input_report_abs(wm->input_dev, ABS_X, x & 0xfff);
167 		input_report_abs(wm->input_dev, ABS_Y, y & 0xfff);
168 		input_report_abs(wm->input_dev, ABS_PRESSURE, p & 0xfff);
169 		input_report_key(wm->input_dev, BTN_TOUCH, (p != 0));
170 		input_sync(wm->input_dev);
171 		reads++;
172 	} while (reads < cinfo[sp_idx].reads);
173 up:
174 	return RC_PENDOWN | RC_AGAIN;
175 }
176 
177 static int wm97xx_acc_startup(struct wm97xx *wm)
178 {
179 	int idx = 0, ret = 0;
180 
181 	/* check we have a codec */
182 	if (wm->ac97 == NULL)
183 		return -ENODEV;
184 
185 	/* Go you big red fire engine */
186 	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
187 		if (wm->id != cinfo[idx].id)
188 			continue;
189 		sp_idx = idx;
190 		if (cont_rate <= cinfo[idx].speed)
191 			break;
192 	}
193 	wm->acc_rate = cinfo[sp_idx].code;
194 	wm->acc_slot = ac97_touch_slot;
195 	dev_info(wm->dev,
196 		 "mainstone accelerated touchscreen driver, %d samples/sec\n",
197 		 cinfo[sp_idx].speed);
198 
199 	/* IRQ driven touchscreen is used on Palm hardware */
200 	if (machine_is_palmt5() || machine_is_palmtx() || machine_is_palmld()) {
201 		pen_int = 1;
202 		irq = 27;
203 		/* There is some obscure mutant of WM9712 interbred with WM9713
204 		 * used on Palm HW */
205 		wm->variant = WM97xx_WM1613;
206 	} else if (machine_is_mainstone() && pen_int)
207 		irq = 4;
208 
209 	if (irq) {
210 		ret = gpio_request(irq, "Touchscreen IRQ");
211 		if (ret)
212 			goto out;
213 
214 		ret = gpio_direction_input(irq);
215 		if (ret) {
216 			gpio_free(irq);
217 			goto out;
218 		}
219 
220 		wm->pen_irq = gpio_to_irq(irq);
221 		irq_set_irq_type(wm->pen_irq, IRQ_TYPE_EDGE_BOTH);
222 	} else /* pen irq not supported */
223 		pen_int = 0;
224 
225 	/* codec specific irq config */
226 	if (pen_int) {
227 		switch (wm->id) {
228 		case WM9705_ID2:
229 			break;
230 		case WM9712_ID2:
231 		case WM9713_ID2:
232 			/* use PEN_DOWN GPIO 13 to assert IRQ on GPIO line 2 */
233 			wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
234 					   WM97XX_GPIO_POL_HIGH,
235 					   WM97XX_GPIO_STICKY,
236 					   WM97XX_GPIO_WAKE);
237 			wm97xx_config_gpio(wm, WM97XX_GPIO_2, WM97XX_GPIO_OUT,
238 					   WM97XX_GPIO_POL_HIGH,
239 					   WM97XX_GPIO_NOTSTICKY,
240 					   WM97XX_GPIO_NOWAKE);
241 			break;
242 		default:
243 			dev_err(wm->dev,
244 				"pen down irq not supported on this device\n");
245 			pen_int = 0;
246 			break;
247 		}
248 	}
249 
250 out:
251 	return ret;
252 }
253 
254 static void wm97xx_acc_shutdown(struct wm97xx *wm)
255 {
256 	/* codec specific deconfig */
257 	if (pen_int) {
258 		if (irq)
259 			gpio_free(irq);
260 		wm->pen_irq = 0;
261 	}
262 }
263 
264 static void wm97xx_irq_enable(struct wm97xx *wm, int enable)
265 {
266 	if (enable)
267 		enable_irq(wm->pen_irq);
268 	else
269 		disable_irq_nosync(wm->pen_irq);
270 }
271 
272 static struct wm97xx_mach_ops mainstone_mach_ops = {
273 	.acc_enabled = 1,
274 	.acc_pen_up = wm97xx_acc_pen_up,
275 	.acc_pen_down = wm97xx_acc_pen_down,
276 	.acc_startup = wm97xx_acc_startup,
277 	.acc_shutdown = wm97xx_acc_shutdown,
278 	.irq_enable = wm97xx_irq_enable,
279 	.irq_gpio = WM97XX_GPIO_2,
280 };
281 
282 static int mainstone_wm97xx_probe(struct platform_device *pdev)
283 {
284 	struct wm97xx *wm = platform_get_drvdata(pdev);
285 
286 	return wm97xx_register_mach_ops(wm, &mainstone_mach_ops);
287 }
288 
289 static int mainstone_wm97xx_remove(struct platform_device *pdev)
290 {
291 	struct wm97xx *wm = platform_get_drvdata(pdev);
292 
293 	wm97xx_unregister_mach_ops(wm);
294 	return 0;
295 }
296 
297 static struct platform_driver mainstone_wm97xx_driver = {
298 	.probe = mainstone_wm97xx_probe,
299 	.remove = mainstone_wm97xx_remove,
300 	.driver = {
301 		.name = "wm97xx-touch",
302 	},
303 };
304 module_platform_driver(mainstone_wm97xx_driver);
305 
306 /* Module information */
307 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
308 MODULE_DESCRIPTION("wm97xx continuous touch driver for mainstone");
309 MODULE_LICENSE("GPL");
310