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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         struct workqueue_struct *workq;
 41         unsigned int sample[4];
 42         struct mc13xxx_ts_platform_data *touch;
 43 };
 44 
 45 static 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 
 71 static 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 
121 static 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 
135 static 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);
153 out:
154         mc13xxx_unlock(priv->mc13xxx);
155         return ret;
156 }
157 
158 static 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 
171 static 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 
224 err_destroy_wq:
225         destroy_workqueue(priv->workq);
226 err_free_mem:
227         input_free_device(idev);
228         kfree(priv);
229         return ret;
230 }
231 
232 static 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 
243 static struct platform_driver mc13783_ts_driver = {
244         .remove         = mc13783_ts_remove,
245         .driver         = {
246                 .owner  = THIS_MODULE,
247                 .name   = MC13783_TS_NAME,
248         },
249 };
250 
251 module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
252 
253 MODULE_DESCRIPTION("MC13783 input touchscreen driver");
254 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
255 MODULE_LICENSE("GPL v2");
256 MODULE_ALIAS("platform:" MC13783_TS_NAME);
257 

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