1 /*
2  * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
3  *
4  *  Copyright (C) 2006 Harald Welte <laforge@openezx.org>
5  *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License version 2 as
9  *  published by the Free Software Foundation.
10  *
11  */
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/fs.h>
16 #include <linux/string.h>
17 #include <linux/slab.h>
18 #include <linux/pm.h>
19 #include <linux/timer.h>
20 #include <linux/interrupt.h>
21 #include <linux/platform_device.h>
22 #include <linux/input.h>
23 #include <linux/mfd/ezx-pcap.h>
24 
25 struct pcap_ts {
26 	struct pcap_chip *pcap;
27 	struct input_dev *input;
28 	struct delayed_work work;
29 	u16 x, y;
30 	u16 pressure;
31 	u8 read_state;
32 };
33 
34 #define SAMPLE_DELAY	20 /* msecs */
35 
36 #define X_AXIS_MIN	0
37 #define X_AXIS_MAX	1023
38 #define Y_AXIS_MAX	X_AXIS_MAX
39 #define Y_AXIS_MIN	X_AXIS_MIN
40 #define PRESSURE_MAX	X_AXIS_MAX
41 #define PRESSURE_MIN	X_AXIS_MIN
42 
43 static void pcap_ts_read_xy(void *data, u16 res[2])
44 {
45 	struct pcap_ts *pcap_ts = data;
46 
47 	switch (pcap_ts->read_state) {
48 	case PCAP_ADC_TS_M_PRESSURE:
49 		/* pressure reading is unreliable */
50 		if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
51 			pcap_ts->pressure = res[0];
52 		pcap_ts->read_state = PCAP_ADC_TS_M_XY;
53 		schedule_delayed_work(&pcap_ts->work, 0);
54 		break;
55 	case PCAP_ADC_TS_M_XY:
56 		pcap_ts->y = res[0];
57 		pcap_ts->x = res[1];
58 		if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
59 		    pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
60 			/* pen has been released */
61 			input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
62 			input_report_key(pcap_ts->input, BTN_TOUCH, 0);
63 
64 			pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
65 			schedule_delayed_work(&pcap_ts->work, 0);
66 		} else {
67 			/* pen is touching the screen */
68 			input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
69 			input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
70 			input_report_key(pcap_ts->input, BTN_TOUCH, 1);
71 			input_report_abs(pcap_ts->input, ABS_PRESSURE,
72 						pcap_ts->pressure);
73 
74 			/* switch back to pressure read mode */
75 			pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
76 			schedule_delayed_work(&pcap_ts->work,
77 					msecs_to_jiffies(SAMPLE_DELAY));
78 		}
79 		input_sync(pcap_ts->input);
80 		break;
81 	default:
82 		dev_warn(&pcap_ts->input->dev,
83 				"pcap_ts: Warning, unhandled read_state %d\n",
84 				pcap_ts->read_state);
85 		break;
86 	}
87 }
88 
89 static void pcap_ts_work(struct work_struct *work)
90 {
91 	struct delayed_work *dw = container_of(work, struct delayed_work, work);
92 	struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
93 	u8 ch[2];
94 
95 	pcap_set_ts_bits(pcap_ts->pcap,
96 			pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
97 
98 	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
99 		return;
100 
101 	/* start adc conversion */
102 	ch[0] = PCAP_ADC_CH_TS_X1;
103 	ch[1] = PCAP_ADC_CH_TS_Y1;
104 	pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
105 						pcap_ts_read_xy, pcap_ts);
106 }
107 
108 static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
109 {
110 	struct pcap_ts *pcap_ts = data;
111 
112 	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
113 		pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
114 		schedule_delayed_work(&pcap_ts->work, 0);
115 	}
116 	return IRQ_HANDLED;
117 }
118 
119 static int pcap_ts_open(struct input_dev *dev)
120 {
121 	struct pcap_ts *pcap_ts = input_get_drvdata(dev);
122 
123 	pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
124 	schedule_delayed_work(&pcap_ts->work, 0);
125 
126 	return 0;
127 }
128 
129 static void pcap_ts_close(struct input_dev *dev)
130 {
131 	struct pcap_ts *pcap_ts = input_get_drvdata(dev);
132 
133 	cancel_delayed_work_sync(&pcap_ts->work);
134 
135 	pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
136 	pcap_set_ts_bits(pcap_ts->pcap,
137 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
138 }
139 
140 static int pcap_ts_probe(struct platform_device *pdev)
141 {
142 	struct input_dev *input_dev;
143 	struct pcap_ts *pcap_ts;
144 	int err = -ENOMEM;
145 
146 	pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
147 	if (!pcap_ts)
148 		return err;
149 
150 	pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
151 	platform_set_drvdata(pdev, pcap_ts);
152 
153 	input_dev = input_allocate_device();
154 	if (!input_dev)
155 		goto fail;
156 
157 	INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);
158 
159 	pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
160 	pcap_set_ts_bits(pcap_ts->pcap,
161 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
162 
163 	pcap_ts->input = input_dev;
164 	input_set_drvdata(input_dev, pcap_ts);
165 
166 	input_dev->name = "pcap-touchscreen";
167 	input_dev->phys = "pcap_ts/input0";
168 	input_dev->id.bustype = BUS_HOST;
169 	input_dev->id.vendor = 0x0001;
170 	input_dev->id.product = 0x0002;
171 	input_dev->id.version = 0x0100;
172 	input_dev->dev.parent = &pdev->dev;
173 	input_dev->open = pcap_ts_open;
174 	input_dev->close = pcap_ts_close;
175 
176 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
177 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
178 	input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
179 	input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
180 	input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
181 			     PRESSURE_MAX, 0, 0);
182 
183 	err = input_register_device(pcap_ts->input);
184 	if (err)
185 		goto fail_allocate;
186 
187 	err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
188 			pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
189 	if (err)
190 		goto fail_register;
191 
192 	return 0;
193 
194 fail_register:
195 	input_unregister_device(input_dev);
196 	goto fail;
197 fail_allocate:
198 	input_free_device(input_dev);
199 fail:
200 	kfree(pcap_ts);
201 
202 	return err;
203 }
204 
205 static int pcap_ts_remove(struct platform_device *pdev)
206 {
207 	struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
208 
209 	free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
210 	cancel_delayed_work_sync(&pcap_ts->work);
211 
212 	input_unregister_device(pcap_ts->input);
213 
214 	kfree(pcap_ts);
215 
216 	return 0;
217 }
218 
219 #ifdef CONFIG_PM
220 static int pcap_ts_suspend(struct device *dev)
221 {
222 	struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
223 
224 	pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
225 	return 0;
226 }
227 
228 static int pcap_ts_resume(struct device *dev)
229 {
230 	struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
231 
232 	pcap_set_ts_bits(pcap_ts->pcap,
233 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
234 	return 0;
235 }
236 
237 static const struct dev_pm_ops pcap_ts_pm_ops = {
238 	.suspend	= pcap_ts_suspend,
239 	.resume		= pcap_ts_resume,
240 };
241 #define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
242 #else
243 #define PCAP_TS_PM_OPS NULL
244 #endif
245 
246 static struct platform_driver pcap_ts_driver = {
247 	.probe		= pcap_ts_probe,
248 	.remove		= pcap_ts_remove,
249 	.driver		= {
250 		.name	= "pcap-ts",
251 		.owner	= THIS_MODULE,
252 		.pm	= PCAP_TS_PM_OPS,
253 	},
254 };
255 module_platform_driver(pcap_ts_driver);
256 
257 MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
258 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
259 MODULE_LICENSE("GPL");
260 MODULE_ALIAS("platform:pcap_ts");
261