1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for the Freescale Semiconductor MC13783 touchscreen.
4  *
5  * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
6  * Copyright (C) 2009 Sascha Hauer, Pengutronix
7  *
8  * Initial development of this code was funded by
9  * Phytec Messtechnik GmbH, http://www.phytec.de/
10  */
11 #include <linux/platform_device.h>
12 #include <linux/mfd/mc13783.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/input.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 
20 #define MC13783_TS_NAME	"mc13783-ts"
21 
22 #define DEFAULT_SAMPLE_TOLERANCE 300
23 
24 static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
25 module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
26 MODULE_PARM_DESC(sample_tolerance,
27 		"If the minimal and maximal value read out for one axis (out "
28 		"of three) differ by this value (default: "
29 		__stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
30 		"is supposed to be wrong and is discarded.  Set to 0 to "
31 		"disable this check.");
32 
33 struct mc13783_ts_priv {
34 	struct input_dev *idev;
35 	struct mc13xxx *mc13xxx;
36 	struct delayed_work work;
37 	unsigned int sample[4];
38 	struct mc13xxx_ts_platform_data *touch;
39 };
40 
mc13783_ts_handler(int irq,void * data)41 static irqreturn_t mc13783_ts_handler(int irq, void *data)
42 {
43 	struct mc13783_ts_priv *priv = data;
44 
45 	mc13xxx_irq_ack(priv->mc13xxx, irq);
46 
47 	/*
48 	 * Kick off reading coordinates. Note that if work happens already
49 	 * be queued for future execution (it rearms itself) it will not
50 	 * be rescheduled for immediate execution here. However the rearm
51 	 * delay is HZ / 50 which is acceptable.
52 	 */
53 	schedule_delayed_work(&priv->work, 0);
54 
55 	return IRQ_HANDLED;
56 }
57 
58 #define sort3(a0, a1, a2) ({						\
59 		if (a0 > a1)						\
60 			swap(a0, a1);					\
61 		if (a1 > a2)						\
62 			swap(a1, a2);					\
63 		if (a0 > a1)						\
64 			swap(a0, a1);					\
65 		})
66 
mc13783_ts_report_sample(struct mc13783_ts_priv * priv)67 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
68 {
69 	struct input_dev *idev = priv->idev;
70 	int x0, x1, x2, y0, y1, y2;
71 	int cr0, cr1;
72 
73 	/*
74 	 * the values are 10-bit wide only, but the two least significant
75 	 * bits are for future 12 bit use and reading yields 0
76 	 */
77 	x0 = priv->sample[0] & 0xfff;
78 	x1 = priv->sample[1] & 0xfff;
79 	x2 = priv->sample[2] & 0xfff;
80 	y0 = priv->sample[3] & 0xfff;
81 	y1 = (priv->sample[0] >> 12) & 0xfff;
82 	y2 = (priv->sample[1] >> 12) & 0xfff;
83 	cr0 = (priv->sample[2] >> 12) & 0xfff;
84 	cr1 = (priv->sample[3] >> 12) & 0xfff;
85 
86 	dev_dbg(&idev->dev,
87 		"x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
88 		x0, x1, x2, y0, y1, y2, cr0, cr1);
89 
90 	sort3(x0, x1, x2);
91 	sort3(y0, y1, y2);
92 
93 	cr0 = (cr0 + cr1) / 2;
94 
95 	if (!cr0 || !sample_tolerance ||
96 			(x2 - x0 < sample_tolerance &&
97 			 y2 - y0 < sample_tolerance)) {
98 		/* report the median coordinate and average pressure */
99 		if (cr0) {
100 			input_report_abs(idev, ABS_X, x1);
101 			input_report_abs(idev, ABS_Y, y1);
102 
103 			dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
104 					x1, y1, 0x1000 - cr0);
105 			schedule_delayed_work(&priv->work, HZ / 50);
106 		} else {
107 			dev_dbg(&idev->dev, "report release\n");
108 		}
109 
110 		input_report_abs(idev, ABS_PRESSURE,
111 				cr0 ? 0x1000 - cr0 : cr0);
112 		input_report_key(idev, BTN_TOUCH, cr0);
113 		input_sync(idev);
114 	} else {
115 		dev_dbg(&idev->dev, "discard event\n");
116 	}
117 }
118 
mc13783_ts_work(struct work_struct * work)119 static void mc13783_ts_work(struct work_struct *work)
120 {
121 	struct mc13783_ts_priv *priv =
122 		container_of(work, struct mc13783_ts_priv, work.work);
123 	unsigned int mode = MC13XXX_ADC_MODE_TS;
124 	unsigned int channel = 12;
125 
126 	if (mc13xxx_adc_do_conversion(priv->mc13xxx,
127 				mode, channel,
128 				priv->touch->ato, priv->touch->atox,
129 				priv->sample) == 0)
130 		mc13783_ts_report_sample(priv);
131 }
132 
mc13783_ts_open(struct input_dev * dev)133 static int mc13783_ts_open(struct input_dev *dev)
134 {
135 	struct mc13783_ts_priv *priv = input_get_drvdata(dev);
136 	int ret;
137 
138 	mc13xxx_lock(priv->mc13xxx);
139 
140 	mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
141 
142 	ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
143 		mc13783_ts_handler, MC13783_TS_NAME, priv);
144 	if (ret)
145 		goto out;
146 
147 	ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
148 			MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
149 	if (ret)
150 		mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
151 out:
152 	mc13xxx_unlock(priv->mc13xxx);
153 	return ret;
154 }
155 
mc13783_ts_close(struct input_dev * dev)156 static void mc13783_ts_close(struct input_dev *dev)
157 {
158 	struct mc13783_ts_priv *priv = input_get_drvdata(dev);
159 
160 	mc13xxx_lock(priv->mc13xxx);
161 	mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
162 			MC13XXX_ADC0_TSMOD_MASK, 0);
163 	mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
164 	mc13xxx_unlock(priv->mc13xxx);
165 
166 	cancel_delayed_work_sync(&priv->work);
167 }
168 
mc13783_ts_probe(struct platform_device * pdev)169 static int __init mc13783_ts_probe(struct platform_device *pdev)
170 {
171 	struct mc13783_ts_priv *priv;
172 	struct input_dev *idev;
173 	int ret = -ENOMEM;
174 
175 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
176 	idev = input_allocate_device();
177 	if (!priv || !idev)
178 		goto err_free_mem;
179 
180 	INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
181 	priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
182 	priv->idev = idev;
183 	priv->touch = dev_get_platdata(&pdev->dev);
184 	if (!priv->touch) {
185 		dev_err(&pdev->dev, "missing platform data\n");
186 		ret = -ENODEV;
187 		goto err_free_mem;
188 	}
189 
190 	idev->name = MC13783_TS_NAME;
191 	idev->dev.parent = &pdev->dev;
192 
193 	idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
194 	idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
195 	input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
196 	input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
197 	input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
198 
199 	idev->open = mc13783_ts_open;
200 	idev->close = mc13783_ts_close;
201 
202 	input_set_drvdata(idev, priv);
203 
204 	ret = input_register_device(priv->idev);
205 	if (ret) {
206 		dev_err(&pdev->dev,
207 			"register input device failed with %d\n", ret);
208 		goto err_free_mem;
209 	}
210 
211 	platform_set_drvdata(pdev, priv);
212 	return 0;
213 
214 err_free_mem:
215 	input_free_device(idev);
216 	kfree(priv);
217 	return ret;
218 }
219 
mc13783_ts_remove(struct platform_device * pdev)220 static int mc13783_ts_remove(struct platform_device *pdev)
221 {
222 	struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
223 
224 	input_unregister_device(priv->idev);
225 	kfree(priv);
226 
227 	return 0;
228 }
229 
230 static struct platform_driver mc13783_ts_driver = {
231 	.remove		= mc13783_ts_remove,
232 	.driver		= {
233 		.name	= MC13783_TS_NAME,
234 	},
235 };
236 
237 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
238 
239 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
240 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
241 MODULE_LICENSE("GPL v2");
242 MODULE_ALIAS("platform:" MC13783_TS_NAME);
243