1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
4  *
5  *  Copyright (C) 2006 Harald Welte <laforge@openezx.org>
6  *  Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
7  */
8 
9 #include <linux/module.h>
10 #include <linux/fs.h>
11 #include <linux/string.h>
12 #include <linux/slab.h>
13 #include <linux/pm.h>
14 #include <linux/timer.h>
15 #include <linux/interrupt.h>
16 #include <linux/platform_device.h>
17 #include <linux/input.h>
18 #include <linux/mfd/ezx-pcap.h>
19 
20 struct pcap_ts {
21 	struct pcap_chip *pcap;
22 	struct input_dev *input;
23 	struct delayed_work work;
24 	u16 x, y;
25 	u16 pressure;
26 	u8 read_state;
27 };
28 
29 #define SAMPLE_DELAY	20 /* msecs */
30 
31 #define X_AXIS_MIN	0
32 #define X_AXIS_MAX	1023
33 #define Y_AXIS_MAX	X_AXIS_MAX
34 #define Y_AXIS_MIN	X_AXIS_MIN
35 #define PRESSURE_MAX	X_AXIS_MAX
36 #define PRESSURE_MIN	X_AXIS_MIN
37 
pcap_ts_read_xy(void * data,u16 res[2])38 static void pcap_ts_read_xy(void *data, u16 res[2])
39 {
40 	struct pcap_ts *pcap_ts = data;
41 
42 	switch (pcap_ts->read_state) {
43 	case PCAP_ADC_TS_M_PRESSURE:
44 		/* pressure reading is unreliable */
45 		if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
46 			pcap_ts->pressure = res[0];
47 		pcap_ts->read_state = PCAP_ADC_TS_M_XY;
48 		schedule_delayed_work(&pcap_ts->work, 0);
49 		break;
50 	case PCAP_ADC_TS_M_XY:
51 		pcap_ts->y = res[0];
52 		pcap_ts->x = res[1];
53 		if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
54 		    pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
55 			/* pen has been released */
56 			input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
57 			input_report_key(pcap_ts->input, BTN_TOUCH, 0);
58 
59 			pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
60 			schedule_delayed_work(&pcap_ts->work, 0);
61 		} else {
62 			/* pen is touching the screen */
63 			input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
64 			input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
65 			input_report_key(pcap_ts->input, BTN_TOUCH, 1);
66 			input_report_abs(pcap_ts->input, ABS_PRESSURE,
67 						pcap_ts->pressure);
68 
69 			/* switch back to pressure read mode */
70 			pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
71 			schedule_delayed_work(&pcap_ts->work,
72 					msecs_to_jiffies(SAMPLE_DELAY));
73 		}
74 		input_sync(pcap_ts->input);
75 		break;
76 	default:
77 		dev_warn(&pcap_ts->input->dev,
78 				"pcap_ts: Warning, unhandled read_state %d\n",
79 				pcap_ts->read_state);
80 		break;
81 	}
82 }
83 
pcap_ts_work(struct work_struct * work)84 static void pcap_ts_work(struct work_struct *work)
85 {
86 	struct delayed_work *dw = to_delayed_work(work);
87 	struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
88 	u8 ch[2];
89 
90 	pcap_set_ts_bits(pcap_ts->pcap,
91 			pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
92 
93 	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
94 		return;
95 
96 	/* start adc conversion */
97 	ch[0] = PCAP_ADC_CH_TS_X1;
98 	ch[1] = PCAP_ADC_CH_TS_Y1;
99 	pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
100 						pcap_ts_read_xy, pcap_ts);
101 }
102 
pcap_ts_event_touch(int pirq,void * data)103 static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
104 {
105 	struct pcap_ts *pcap_ts = data;
106 
107 	if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
108 		pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
109 		schedule_delayed_work(&pcap_ts->work, 0);
110 	}
111 	return IRQ_HANDLED;
112 }
113 
pcap_ts_open(struct input_dev * dev)114 static int pcap_ts_open(struct input_dev *dev)
115 {
116 	struct pcap_ts *pcap_ts = input_get_drvdata(dev);
117 
118 	pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
119 	schedule_delayed_work(&pcap_ts->work, 0);
120 
121 	return 0;
122 }
123 
pcap_ts_close(struct input_dev * dev)124 static void pcap_ts_close(struct input_dev *dev)
125 {
126 	struct pcap_ts *pcap_ts = input_get_drvdata(dev);
127 
128 	cancel_delayed_work_sync(&pcap_ts->work);
129 
130 	pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
131 	pcap_set_ts_bits(pcap_ts->pcap,
132 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
133 }
134 
pcap_ts_probe(struct platform_device * pdev)135 static int pcap_ts_probe(struct platform_device *pdev)
136 {
137 	struct input_dev *input_dev;
138 	struct pcap_ts *pcap_ts;
139 	int err = -ENOMEM;
140 
141 	pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
142 	if (!pcap_ts)
143 		return err;
144 
145 	pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
146 	platform_set_drvdata(pdev, pcap_ts);
147 
148 	input_dev = input_allocate_device();
149 	if (!input_dev)
150 		goto fail;
151 
152 	INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);
153 
154 	pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
155 	pcap_set_ts_bits(pcap_ts->pcap,
156 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
157 
158 	pcap_ts->input = input_dev;
159 	input_set_drvdata(input_dev, pcap_ts);
160 
161 	input_dev->name = "pcap-touchscreen";
162 	input_dev->phys = "pcap_ts/input0";
163 	input_dev->id.bustype = BUS_HOST;
164 	input_dev->id.vendor = 0x0001;
165 	input_dev->id.product = 0x0002;
166 	input_dev->id.version = 0x0100;
167 	input_dev->dev.parent = &pdev->dev;
168 	input_dev->open = pcap_ts_open;
169 	input_dev->close = pcap_ts_close;
170 
171 	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
172 	input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
173 	input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
174 	input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
175 	input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
176 			     PRESSURE_MAX, 0, 0);
177 
178 	err = input_register_device(pcap_ts->input);
179 	if (err)
180 		goto fail_allocate;
181 
182 	err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
183 			pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
184 	if (err)
185 		goto fail_register;
186 
187 	return 0;
188 
189 fail_register:
190 	input_unregister_device(input_dev);
191 	goto fail;
192 fail_allocate:
193 	input_free_device(input_dev);
194 fail:
195 	kfree(pcap_ts);
196 
197 	return err;
198 }
199 
pcap_ts_remove(struct platform_device * pdev)200 static int pcap_ts_remove(struct platform_device *pdev)
201 {
202 	struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);
203 
204 	free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
205 	cancel_delayed_work_sync(&pcap_ts->work);
206 
207 	input_unregister_device(pcap_ts->input);
208 
209 	kfree(pcap_ts);
210 
211 	return 0;
212 }
213 
214 #ifdef CONFIG_PM
pcap_ts_suspend(struct device * dev)215 static int pcap_ts_suspend(struct device *dev)
216 {
217 	struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
218 
219 	pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
220 	return 0;
221 }
222 
pcap_ts_resume(struct device * dev)223 static int pcap_ts_resume(struct device *dev)
224 {
225 	struct pcap_ts *pcap_ts = dev_get_drvdata(dev);
226 
227 	pcap_set_ts_bits(pcap_ts->pcap,
228 				pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
229 	return 0;
230 }
231 
232 static const struct dev_pm_ops pcap_ts_pm_ops = {
233 	.suspend	= pcap_ts_suspend,
234 	.resume		= pcap_ts_resume,
235 };
236 #define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
237 #else
238 #define PCAP_TS_PM_OPS NULL
239 #endif
240 
241 static struct platform_driver pcap_ts_driver = {
242 	.probe		= pcap_ts_probe,
243 	.remove		= pcap_ts_remove,
244 	.driver		= {
245 		.name	= "pcap-ts",
246 		.pm	= PCAP_TS_PM_OPS,
247 	},
248 };
249 module_platform_driver(pcap_ts_driver);
250 
251 MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
252 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
253 MODULE_LICENSE("GPL");
254 MODULE_ALIAS("platform:pcap_ts");
255