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Linux/drivers/input/touchscreen/mc13783_ts.c

  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 
 27 static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
 28 module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
 29 MODULE_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 
 36 struct mc13783_ts_priv {
 37         struct input_dev *idev;
 38         struct mc13xxx *mc13xxx;
 39         struct delayed_work work;
 40         unsigned int sample[4];
 41         struct mc13xxx_ts_platform_data *touch;
 42 };
 43 
 44 static irqreturn_t mc13783_ts_handler(int irq, void *data)
 45 {
 46         struct mc13783_ts_priv *priv = data;
 47 
 48         mc13xxx_irq_ack(priv->mc13xxx, irq);
 49 
 50         /*
 51          * Kick off reading coordinates. Note that if work happens already
 52          * be queued for future execution (it rearms itself) it will not
 53          * be rescheduled for immediate execution here. However the rearm
 54          * delay is HZ / 50 which is acceptable.
 55          */
 56         schedule_delayed_work(&priv->work, 0);
 57 
 58         return IRQ_HANDLED;
 59 }
 60 
 61 #define sort3(a0, a1, a2) ({                                            \
 62                 if (a0 > a1)                                            \
 63                         swap(a0, a1);                                   \
 64                 if (a1 > a2)                                            \
 65                         swap(a1, a2);                                   \
 66                 if (a0 > a1)                                            \
 67                         swap(a0, a1);                                   \
 68                 })
 69 
 70 static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
 71 {
 72         struct input_dev *idev = priv->idev;
 73         int x0, x1, x2, y0, y1, y2;
 74         int cr0, cr1;
 75 
 76         /*
 77          * the values are 10-bit wide only, but the two least significant
 78          * bits are for future 12 bit use and reading yields 0
 79          */
 80         x0 = priv->sample[0] & 0xfff;
 81         x1 = priv->sample[1] & 0xfff;
 82         x2 = priv->sample[2] & 0xfff;
 83         y0 = priv->sample[3] & 0xfff;
 84         y1 = (priv->sample[0] >> 12) & 0xfff;
 85         y2 = (priv->sample[1] >> 12) & 0xfff;
 86         cr0 = (priv->sample[2] >> 12) & 0xfff;
 87         cr1 = (priv->sample[3] >> 12) & 0xfff;
 88 
 89         dev_dbg(&idev->dev,
 90                 "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
 91                 x0, x1, x2, y0, y1, y2, cr0, cr1);
 92 
 93         sort3(x0, x1, x2);
 94         sort3(y0, y1, y2);
 95 
 96         cr0 = (cr0 + cr1) / 2;
 97 
 98         if (!cr0 || !sample_tolerance ||
 99                         (x2 - x0 < sample_tolerance &&
100                          y2 - y0 < sample_tolerance)) {
101                 /* report the median coordinate and average pressure */
102                 if (cr0) {
103                         input_report_abs(idev, ABS_X, x1);
104                         input_report_abs(idev, ABS_Y, y1);
105 
106                         dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
107                                         x1, y1, 0x1000 - cr0);
108                         schedule_delayed_work(&priv->work, HZ / 50);
109                 } else {
110                         dev_dbg(&idev->dev, "report release\n");
111                 }
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 }
121 
122 static void mc13783_ts_work(struct work_struct *work)
123 {
124         struct mc13783_ts_priv *priv =
125                 container_of(work, struct mc13783_ts_priv, work.work);
126         unsigned int mode = MC13XXX_ADC_MODE_TS;
127         unsigned int channel = 12;
128 
129         if (mc13xxx_adc_do_conversion(priv->mc13xxx,
130                                 mode, channel,
131                                 priv->touch->ato, priv->touch->atox,
132                                 priv->sample) == 0)
133                 mc13783_ts_report_sample(priv);
134 }
135 
136 static int mc13783_ts_open(struct input_dev *dev)
137 {
138         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
139         int ret;
140 
141         mc13xxx_lock(priv->mc13xxx);
142 
143         mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
144 
145         ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
146                 mc13783_ts_handler, MC13783_TS_NAME, priv);
147         if (ret)
148                 goto out;
149 
150         ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
151                         MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
152         if (ret)
153                 mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
154 out:
155         mc13xxx_unlock(priv->mc13xxx);
156         return ret;
157 }
158 
159 static void mc13783_ts_close(struct input_dev *dev)
160 {
161         struct mc13783_ts_priv *priv = input_get_drvdata(dev);
162 
163         mc13xxx_lock(priv->mc13xxx);
164         mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
165                         MC13XXX_ADC0_TSMOD_MASK, 0);
166         mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
167         mc13xxx_unlock(priv->mc13xxx);
168 
169         cancel_delayed_work_sync(&priv->work);
170 }
171 
172 static int __init mc13783_ts_probe(struct platform_device *pdev)
173 {
174         struct mc13783_ts_priv *priv;
175         struct input_dev *idev;
176         int ret = -ENOMEM;
177 
178         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
179         idev = input_allocate_device();
180         if (!priv || !idev)
181                 goto err_free_mem;
182 
183         INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
184         priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
185         priv->idev = idev;
186         priv->touch = dev_get_platdata(&pdev->dev);
187         if (!priv->touch) {
188                 dev_err(&pdev->dev, "missing platform data\n");
189                 ret = -ENODEV;
190                 goto err_free_mem;
191         }
192 
193         idev->name = MC13783_TS_NAME;
194         idev->dev.parent = &pdev->dev;
195 
196         idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
197         idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
198         input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
199         input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
200         input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
201 
202         idev->open = mc13783_ts_open;
203         idev->close = mc13783_ts_close;
204 
205         input_set_drvdata(idev, priv);
206 
207         ret = input_register_device(priv->idev);
208         if (ret) {
209                 dev_err(&pdev->dev,
210                         "register input device failed with %d\n", ret);
211                 goto err_free_mem;
212         }
213 
214         platform_set_drvdata(pdev, priv);
215         return 0;
216 
217 err_free_mem:
218         input_free_device(idev);
219         kfree(priv);
220         return ret;
221 }
222 
223 static int mc13783_ts_remove(struct platform_device *pdev)
224 {
225         struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
226 
227         input_unregister_device(priv->idev);
228         kfree(priv);
229 
230         return 0;
231 }
232 
233 static struct platform_driver mc13783_ts_driver = {
234         .remove         = mc13783_ts_remove,
235         .driver         = {
236                 .name   = MC13783_TS_NAME,
237         },
238 };
239 
240 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
241 
242 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
243 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
244 MODULE_LICENSE("GPL v2");
245 MODULE_ALIAS("platform:" MC13783_TS_NAME);
246 

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