1/*
2 * Atmel AT91 and AVR32 continuous touch screen driver for Wolfson WM97xx AC97
3 * codecs.
4 *
5 * Copyright (C) 2008 - 2009 Atmel Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
10 */
11#include <linux/module.h>
12#include <linux/moduleparam.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/delay.h>
16#include <linux/irq.h>
17#include <linux/interrupt.h>
18#include <linux/wm97xx.h>
19#include <linux/timer.h>
20#include <linux/gpio.h>
21#include <linux/io.h>
22#include <linux/slab.h>
23
24#define AC97C_ICA		0x10
25#define AC97C_CBRHR		0x30
26#define AC97C_CBSR		0x38
27#define AC97C_CBMR		0x3c
28#define AC97C_IER		0x54
29#define AC97C_IDR		0x58
30
31#define AC97C_RXRDY		(1 << 4)
32#define AC97C_OVRUN		(1 << 5)
33
34#define AC97C_CMR_SIZE_20	(0 << 16)
35#define AC97C_CMR_SIZE_18	(1 << 16)
36#define AC97C_CMR_SIZE_16	(2 << 16)
37#define AC97C_CMR_SIZE_10	(3 << 16)
38#define AC97C_CMR_CEM_LITTLE	(1 << 18)
39#define AC97C_CMR_CEM_BIG	(0 << 18)
40#define AC97C_CMR_CENA		(1 << 21)
41
42#define AC97C_INT_CBEVT		(1 << 4)
43
44#define AC97C_SR_CAEVT		(1 << 3)
45
46#define AC97C_CH_MASK(slot)						\
47	(0x7 << (3 * (slot - 3)))
48#define AC97C_CH_ASSIGN(slot, channel)					\
49	(AC97C_CHANNEL_##channel << (3 * (slot - 3)))
50#define AC97C_CHANNEL_NONE	0x0
51#define AC97C_CHANNEL_B		0x2
52
53#define ac97c_writel(chip, reg, val)			\
54	__raw_writel((val), (chip)->regs + AC97C_##reg)
55#define ac97c_readl(chip, reg)				\
56	__raw_readl((chip)->regs + AC97C_##reg)
57
58#ifdef CONFIG_CPU_AT32AP700X
59#define ATMEL_WM97XX_AC97C_IOMEM	(0xfff02800)
60#define ATMEL_WM97XX_AC97C_IRQ		(29)
61#define ATMEL_WM97XX_GPIO_DEFAULT	(32+16) /* Pin 16 on port B. */
62#else
63#error Unknown CPU, this driver only supports AT32AP700X CPUs.
64#endif
65
66struct continuous {
67	u16 id;    /* codec id */
68	u8 code;   /* continuous code */
69	u8 reads;  /* number of coord reads per read cycle */
70	u32 speed; /* number of coords per second */
71};
72
73#define WM_READS(sp) ((sp / HZ) + 1)
74
75static const struct continuous cinfo[] = {
76	{WM9705_ID2, 0, WM_READS(94), 94},
77	{WM9705_ID2, 1, WM_READS(188), 188},
78	{WM9705_ID2, 2, WM_READS(375), 375},
79	{WM9705_ID2, 3, WM_READS(750), 750},
80	{WM9712_ID2, 0, WM_READS(94), 94},
81	{WM9712_ID2, 1, WM_READS(188), 188},
82	{WM9712_ID2, 2, WM_READS(375), 375},
83	{WM9712_ID2, 3, WM_READS(750), 750},
84	{WM9713_ID2, 0, WM_READS(94), 94},
85	{WM9713_ID2, 1, WM_READS(120), 120},
86	{WM9713_ID2, 2, WM_READS(154), 154},
87	{WM9713_ID2, 3, WM_READS(188), 188},
88};
89
90/* Continuous speed index. */
91static int sp_idx;
92
93/*
94 * Pen sampling frequency (Hz) in continuous mode.
95 */
96static int cont_rate = 188;
97module_param(cont_rate, int, 0);
98MODULE_PARM_DESC(cont_rate, "Sampling rate in continuous mode (Hz)");
99
100/*
101 * Pen down detection.
102 *
103 * This driver can either poll or use an interrupt to indicate a pen down
104 * event. If the irq request fails then it will fall back to polling mode.
105 */
106static int pen_int = 1;
107module_param(pen_int, int, 0);
108MODULE_PARM_DESC(pen_int, "Pen down detection (1 = interrupt, 0 = polling)");
109
110/*
111 * Pressure readback.
112 *
113 * Set to 1 to read back pen down pressure.
114 */
115static int pressure;
116module_param(pressure, int, 0);
117MODULE_PARM_DESC(pressure, "Pressure readback (1 = pressure, 0 = no pressure)");
118
119/*
120 * AC97 touch data slot.
121 *
122 * Touch screen readback data ac97 slot.
123 */
124static int ac97_touch_slot = 5;
125module_param(ac97_touch_slot, int, 0);
126MODULE_PARM_DESC(ac97_touch_slot, "Touch screen data slot AC97 number");
127
128/*
129 * GPIO line number.
130 *
131 * Set to GPIO number where the signal from the WM97xx device is hooked up.
132 */
133static int atmel_gpio_line = ATMEL_WM97XX_GPIO_DEFAULT;
134module_param(atmel_gpio_line, int, 0);
135MODULE_PARM_DESC(atmel_gpio_line, "GPIO line number connected to WM97xx");
136
137struct atmel_wm97xx {
138	struct wm97xx		*wm;
139	struct timer_list	pen_timer;
140	void __iomem		*regs;
141	unsigned long		ac97c_irq;
142	unsigned long		gpio_pen;
143	unsigned long		gpio_irq;
144	unsigned short		x;
145	unsigned short		y;
146};
147
148static irqreturn_t atmel_wm97xx_channel_b_interrupt(int irq, void *dev_id)
149{
150	struct atmel_wm97xx *atmel_wm97xx = dev_id;
151	struct wm97xx *wm = atmel_wm97xx->wm;
152	int status = ac97c_readl(atmel_wm97xx, CBSR);
153	irqreturn_t retval = IRQ_NONE;
154
155	if (status & AC97C_OVRUN) {
156		dev_dbg(&wm->touch_dev->dev, "AC97C overrun\n");
157		ac97c_readl(atmel_wm97xx, CBRHR);
158		retval = IRQ_HANDLED;
159	} else if (status & AC97C_RXRDY) {
160		u16 data;
161		u16 value;
162		u16 source;
163		u16 pen_down;
164
165		data = ac97c_readl(atmel_wm97xx, CBRHR);
166		value = data & 0x0fff;
167		source = data & WM97XX_ADCSEL_MASK;
168		pen_down = (data & WM97XX_PEN_DOWN) >> 8;
169
170		if (source == WM97XX_ADCSEL_X)
171			atmel_wm97xx->x = value;
172		if (source == WM97XX_ADCSEL_Y)
173			atmel_wm97xx->y = value;
174
175		if (!pressure && source == WM97XX_ADCSEL_Y) {
176			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
177			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
178			input_report_key(wm->input_dev, BTN_TOUCH, pen_down);
179			input_sync(wm->input_dev);
180		} else if (pressure && source == WM97XX_ADCSEL_PRES) {
181			input_report_abs(wm->input_dev, ABS_X, atmel_wm97xx->x);
182			input_report_abs(wm->input_dev, ABS_Y, atmel_wm97xx->y);
183			input_report_abs(wm->input_dev, ABS_PRESSURE, value);
184			input_report_key(wm->input_dev, BTN_TOUCH, value);
185			input_sync(wm->input_dev);
186		}
187
188		retval = IRQ_HANDLED;
189	}
190
191	return retval;
192}
193
194static void atmel_wm97xx_acc_pen_up(struct wm97xx *wm)
195{
196	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
197	struct input_dev *input_dev = wm->input_dev;
198	int pen_down = gpio_get_value(atmel_wm97xx->gpio_pen);
199
200	if (pen_down != 0) {
201		mod_timer(&atmel_wm97xx->pen_timer,
202			  jiffies + msecs_to_jiffies(1));
203	} else {
204		if (pressure)
205			input_report_abs(input_dev, ABS_PRESSURE, 0);
206		input_report_key(input_dev, BTN_TOUCH, 0);
207		input_sync(input_dev);
208	}
209}
210
211static void atmel_wm97xx_pen_timer(unsigned long data)
212{
213	atmel_wm97xx_acc_pen_up((struct wm97xx *)data);
214}
215
216static int atmel_wm97xx_acc_startup(struct wm97xx *wm)
217{
218	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(wm->touch_dev);
219	int idx = 0;
220
221	if (wm->ac97 == NULL)
222		return -ENODEV;
223
224	for (idx = 0; idx < ARRAY_SIZE(cinfo); idx++) {
225		if (wm->id != cinfo[idx].id)
226			continue;
227
228		sp_idx = idx;
229
230		if (cont_rate <= cinfo[idx].speed)
231			break;
232	}
233
234	wm->acc_rate = cinfo[sp_idx].code;
235	wm->acc_slot = ac97_touch_slot;
236	dev_info(&wm->touch_dev->dev, "atmel accelerated touchscreen driver, "
237			"%d samples/sec\n", cinfo[sp_idx].speed);
238
239	if (pen_int) {
240		unsigned long reg;
241
242		wm->pen_irq = atmel_wm97xx->gpio_irq;
243
244		switch (wm->id) {
245		case WM9712_ID2: /* Fall through. */
246		case WM9713_ID2:
247			/*
248			 * Use GPIO 13 (PEN_DOWN) to assert GPIO line 3
249			 * (PENDOWN).
250			 */
251			wm97xx_config_gpio(wm, WM97XX_GPIO_13, WM97XX_GPIO_IN,
252					WM97XX_GPIO_POL_HIGH,
253					WM97XX_GPIO_STICKY,
254					WM97XX_GPIO_WAKE);
255			wm97xx_config_gpio(wm, WM97XX_GPIO_3, WM97XX_GPIO_OUT,
256					WM97XX_GPIO_POL_HIGH,
257					WM97XX_GPIO_NOTSTICKY,
258					WM97XX_GPIO_NOWAKE);
259		case WM9705_ID2: /* Fall through. */
260			/*
261			 * Enable touch data slot in AC97 controller channel B.
262			 */
263			reg = ac97c_readl(atmel_wm97xx, ICA);
264			reg &= ~AC97C_CH_MASK(wm->acc_slot);
265			reg |= AC97C_CH_ASSIGN(wm->acc_slot, B);
266			ac97c_writel(atmel_wm97xx, ICA, reg);
267
268			/*
269			 * Enable channel and interrupt for RXRDY and OVERRUN.
270			 */
271			ac97c_writel(atmel_wm97xx, CBMR, AC97C_CMR_CENA
272					| AC97C_CMR_CEM_BIG
273					| AC97C_CMR_SIZE_16
274					| AC97C_OVRUN
275					| AC97C_RXRDY);
276			/* Dummy read to empty RXRHR. */
277			ac97c_readl(atmel_wm97xx, CBRHR);
278			/*
279			 * Enable interrupt for channel B in the AC97
280			 * controller.
281			 */
282			ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
283			break;
284		default:
285			dev_err(&wm->touch_dev->dev, "pen down irq not "
286					"supported on this device\n");
287			pen_int = 0;
288			break;
289		}
290	}
291
292	return 0;
293}
294
295static void atmel_wm97xx_acc_shutdown(struct wm97xx *wm)
296{
297	if (pen_int) {
298		struct atmel_wm97xx *atmel_wm97xx =
299			platform_get_drvdata(wm->touch_dev);
300		unsigned long ica;
301
302		switch (wm->id & 0xffff) {
303		case WM9705_ID2: /* Fall through. */
304		case WM9712_ID2: /* Fall through. */
305		case WM9713_ID2:
306			/* Disable slot and turn off channel B interrupts. */
307			ica = ac97c_readl(atmel_wm97xx, ICA);
308			ica &= ~AC97C_CH_MASK(wm->acc_slot);
309			ac97c_writel(atmel_wm97xx, ICA, ica);
310			ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
311			ac97c_writel(atmel_wm97xx, CBMR, 0);
312			wm->pen_irq = 0;
313			break;
314		default:
315			dev_err(&wm->touch_dev->dev, "unknown codec\n");
316			break;
317		}
318	}
319}
320
321static void atmel_wm97xx_irq_enable(struct wm97xx *wm, int enable)
322{
323	/* Intentionally left empty. */
324}
325
326static struct wm97xx_mach_ops atmel_mach_ops = {
327	.acc_enabled	= 1,
328	.acc_pen_up	= atmel_wm97xx_acc_pen_up,
329	.acc_startup	= atmel_wm97xx_acc_startup,
330	.acc_shutdown	= atmel_wm97xx_acc_shutdown,
331	.irq_enable	= atmel_wm97xx_irq_enable,
332	.irq_gpio	= WM97XX_GPIO_3,
333};
334
335static int __init atmel_wm97xx_probe(struct platform_device *pdev)
336{
337	struct wm97xx *wm = platform_get_drvdata(pdev);
338	struct atmel_wm97xx *atmel_wm97xx;
339	int ret;
340
341	atmel_wm97xx = kzalloc(sizeof(struct atmel_wm97xx), GFP_KERNEL);
342	if (!atmel_wm97xx) {
343		dev_dbg(&pdev->dev, "out of memory\n");
344		return -ENOMEM;
345	}
346
347	atmel_wm97xx->wm	= wm;
348	atmel_wm97xx->regs	= (void *)ATMEL_WM97XX_AC97C_IOMEM;
349	atmel_wm97xx->ac97c_irq	= ATMEL_WM97XX_AC97C_IRQ;
350	atmel_wm97xx->gpio_pen	= atmel_gpio_line;
351	atmel_wm97xx->gpio_irq	= gpio_to_irq(atmel_wm97xx->gpio_pen);
352
353	setup_timer(&atmel_wm97xx->pen_timer, atmel_wm97xx_pen_timer,
354			(unsigned long)wm);
355
356	ret = request_irq(atmel_wm97xx->ac97c_irq,
357			  atmel_wm97xx_channel_b_interrupt,
358			  IRQF_SHARED, "atmel-wm97xx-ch-b", atmel_wm97xx);
359	if (ret) {
360		dev_dbg(&pdev->dev, "could not request ac97c irq\n");
361		goto err;
362	}
363
364	platform_set_drvdata(pdev, atmel_wm97xx);
365
366	ret = wm97xx_register_mach_ops(wm, &atmel_mach_ops);
367	if (ret)
368		goto err_irq;
369
370	return ret;
371
372err_irq:
373	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
374err:
375	kfree(atmel_wm97xx);
376	return ret;
377}
378
379static int __exit atmel_wm97xx_remove(struct platform_device *pdev)
380{
381	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
382	struct wm97xx *wm = atmel_wm97xx->wm;
383
384	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
385	free_irq(atmel_wm97xx->ac97c_irq, atmel_wm97xx);
386	del_timer_sync(&atmel_wm97xx->pen_timer);
387	wm97xx_unregister_mach_ops(wm);
388	kfree(atmel_wm97xx);
389
390	return 0;
391}
392
393#ifdef CONFIG_PM_SLEEP
394static int atmel_wm97xx_suspend(struct device *dev)
395{
396	struct platform_device *pdev = to_platform_device(dev);
397	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
398
399	ac97c_writel(atmel_wm97xx, IDR, AC97C_INT_CBEVT);
400	disable_irq(atmel_wm97xx->gpio_irq);
401	del_timer_sync(&atmel_wm97xx->pen_timer);
402
403	return 0;
404}
405
406static int atmel_wm97xx_resume(struct device *dev)
407{
408	struct platform_device *pdev = to_platform_device(dev);
409	struct atmel_wm97xx *atmel_wm97xx = platform_get_drvdata(pdev);
410	struct wm97xx *wm = atmel_wm97xx->wm;
411
412	if (wm->input_dev->users) {
413		enable_irq(atmel_wm97xx->gpio_irq);
414		ac97c_writel(atmel_wm97xx, IER, AC97C_INT_CBEVT);
415	}
416
417	return 0;
418}
419#endif
420
421static SIMPLE_DEV_PM_OPS(atmel_wm97xx_pm_ops,
422			 atmel_wm97xx_suspend, atmel_wm97xx_resume);
423
424static struct platform_driver atmel_wm97xx_driver = {
425	.remove		= __exit_p(atmel_wm97xx_remove),
426	.driver		= {
427		.name	= "wm97xx-touch",
428		.pm	= &atmel_wm97xx_pm_ops,
429	},
430};
431
432module_platform_driver_probe(atmel_wm97xx_driver, atmel_wm97xx_probe);
433
434MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
435MODULE_DESCRIPTION("wm97xx continuous touch driver for Atmel AT91 and AVR32");
436MODULE_LICENSE("GPL");
437