1/*
2 * Driver for the Freescale Semiconductor MC13783 touchscreen.
3 *
4 * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
5 * Copyright (C) 2009 Sascha Hauer, Pengutronix
6 *
7 * Initial development of this code was funded by
8 * Phytec Messtechnik GmbH, http://www.phytec.de/
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 version 2 as published by
12 * the Free Software Foundation.
13 */
14#include <linux/platform_device.h>
15#include <linux/mfd/mc13783.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/input.h>
19#include <linux/sched.h>
20#include <linux/slab.h>
21#include <linux/init.h>
22
23#define MC13783_TS_NAME	"mc13783-ts"
24
25#define DEFAULT_SAMPLE_TOLERANCE 300
26
27static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
28module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
29MODULE_PARM_DESC(sample_tolerance,
30		"If the minimal and maximal value read out for one axis (out "
31		"of three) differ by this value (default: "
32		__stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
33		"is supposed to be wrong and is discarded.  Set to 0 to "
34		"disable this check.");
35
36struct mc13783_ts_priv {
37	struct input_dev *idev;
38	struct mc13xxx *mc13xxx;
39	struct delayed_work work;
40	struct workqueue_struct *workq;
41	unsigned int sample[4];
42	struct mc13xxx_ts_platform_data *touch;
43};
44
45static irqreturn_t mc13783_ts_handler(int irq, void *data)
46{
47	struct mc13783_ts_priv *priv = data;
48
49	mc13xxx_irq_ack(priv->mc13xxx, irq);
50
51	/*
52	 * Kick off reading coordinates. Note that if work happens already
53	 * be queued for future execution (it rearms itself) it will not
54	 * be rescheduled for immediate execution here. However the rearm
55	 * delay is HZ / 50 which is acceptable.
56	 */
57	queue_delayed_work(priv->workq, &priv->work, 0);
58
59	return IRQ_HANDLED;
60}
61
62#define sort3(a0, a1, a2) ({						\
63		if (a0 > a1)						\
64			swap(a0, a1);					\
65		if (a1 > a2)						\
66			swap(a1, a2);					\
67		if (a0 > a1)						\
68			swap(a0, a1);					\
69		})
70
71static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
72{
73	struct input_dev *idev = priv->idev;
74	int x0, x1, x2, y0, y1, y2;
75	int cr0, cr1;
76
77	/*
78	 * the values are 10-bit wide only, but the two least significant
79	 * bits are for future 12 bit use and reading yields 0
80	 */
81	x0 = priv->sample[0] & 0xfff;
82	x1 = priv->sample[1] & 0xfff;
83	x2 = priv->sample[2] & 0xfff;
84	y0 = priv->sample[3] & 0xfff;
85	y1 = (priv->sample[0] >> 12) & 0xfff;
86	y2 = (priv->sample[1] >> 12) & 0xfff;
87	cr0 = (priv->sample[2] >> 12) & 0xfff;
88	cr1 = (priv->sample[3] >> 12) & 0xfff;
89
90	dev_dbg(&idev->dev,
91		"x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
92		x0, x1, x2, y0, y1, y2, cr0, cr1);
93
94	sort3(x0, x1, x2);
95	sort3(y0, y1, y2);
96
97	cr0 = (cr0 + cr1) / 2;
98
99	if (!cr0 || !sample_tolerance ||
100			(x2 - x0 < sample_tolerance &&
101			 y2 - y0 < sample_tolerance)) {
102		/* report the median coordinate and average pressure */
103		if (cr0) {
104			input_report_abs(idev, ABS_X, x1);
105			input_report_abs(idev, ABS_Y, y1);
106
107			dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
108					x1, y1, 0x1000 - cr0);
109			queue_delayed_work(priv->workq, &priv->work, HZ / 50);
110		} else
111			dev_dbg(&idev->dev, "report release\n");
112
113		input_report_abs(idev, ABS_PRESSURE,
114				cr0 ? 0x1000 - cr0 : cr0);
115		input_report_key(idev, BTN_TOUCH, cr0);
116		input_sync(idev);
117	} else
118		dev_dbg(&idev->dev, "discard event\n");
119}
120
121static void mc13783_ts_work(struct work_struct *work)
122{
123	struct mc13783_ts_priv *priv =
124		container_of(work, struct mc13783_ts_priv, work.work);
125	unsigned int mode = MC13XXX_ADC_MODE_TS;
126	unsigned int channel = 12;
127
128	if (mc13xxx_adc_do_conversion(priv->mc13xxx,
129				mode, channel,
130				priv->touch->ato, priv->touch->atox,
131				priv->sample) == 0)
132		mc13783_ts_report_sample(priv);
133}
134
135static int mc13783_ts_open(struct input_dev *dev)
136{
137	struct mc13783_ts_priv *priv = input_get_drvdata(dev);
138	int ret;
139
140	mc13xxx_lock(priv->mc13xxx);
141
142	mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
143
144	ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
145		mc13783_ts_handler, MC13783_TS_NAME, priv);
146	if (ret)
147		goto out;
148
149	ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
150			MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
151	if (ret)
152		mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
153out:
154	mc13xxx_unlock(priv->mc13xxx);
155	return ret;
156}
157
158static void mc13783_ts_close(struct input_dev *dev)
159{
160	struct mc13783_ts_priv *priv = input_get_drvdata(dev);
161
162	mc13xxx_lock(priv->mc13xxx);
163	mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
164			MC13XXX_ADC0_TSMOD_MASK, 0);
165	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
166	mc13xxx_unlock(priv->mc13xxx);
167
168	cancel_delayed_work_sync(&priv->work);
169}
170
171static int __init mc13783_ts_probe(struct platform_device *pdev)
172{
173	struct mc13783_ts_priv *priv;
174	struct input_dev *idev;
175	int ret = -ENOMEM;
176
177	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
178	idev = input_allocate_device();
179	if (!priv || !idev)
180		goto err_free_mem;
181
182	INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
183	priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
184	priv->idev = idev;
185	priv->touch = dev_get_platdata(&pdev->dev);
186	if (!priv->touch) {
187		dev_err(&pdev->dev, "missing platform data\n");
188		ret = -ENODEV;
189		goto err_free_mem;
190	}
191
192	/*
193	 * We need separate workqueue because mc13783_adc_do_conversion
194	 * uses keventd and thus would deadlock.
195	 */
196	priv->workq = create_singlethread_workqueue("mc13783_ts");
197	if (!priv->workq)
198		goto err_free_mem;
199
200	idev->name = MC13783_TS_NAME;
201	idev->dev.parent = &pdev->dev;
202
203	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
204	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
205	input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
206	input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
207	input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
208
209	idev->open = mc13783_ts_open;
210	idev->close = mc13783_ts_close;
211
212	input_set_drvdata(idev, priv);
213
214	ret = input_register_device(priv->idev);
215	if (ret) {
216		dev_err(&pdev->dev,
217			"register input device failed with %d\n", ret);
218		goto err_destroy_wq;
219	}
220
221	platform_set_drvdata(pdev, priv);
222	return 0;
223
224err_destroy_wq:
225	destroy_workqueue(priv->workq);
226err_free_mem:
227	input_free_device(idev);
228	kfree(priv);
229	return ret;
230}
231
232static int mc13783_ts_remove(struct platform_device *pdev)
233{
234	struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
235
236	destroy_workqueue(priv->workq);
237	input_unregister_device(priv->idev);
238	kfree(priv);
239
240	return 0;
241}
242
243static struct platform_driver mc13783_ts_driver = {
244	.remove		= mc13783_ts_remove,
245	.driver		= {
246		.name	= MC13783_TS_NAME,
247	},
248};
249
250module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
251
252MODULE_DESCRIPTION("MC13783 input touchscreen driver");
253MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
254MODULE_LICENSE("GPL v2");
255MODULE_ALIAS("platform:" MC13783_TS_NAME);
256