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 27static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE; 28module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR); 29MODULE_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 36struct mc13783_ts_priv { 37 struct input_dev *idev; 38 struct mc13783 *mc13783; 39 struct delayed_work work; 40 struct workqueue_struct *workq; 41 unsigned int sample[4]; 42}; 43 44static irqreturn_t mc13783_ts_handler(int irq, void *data) 45{ 46 struct mc13783_ts_priv *priv = data; 47 48 mc13783_irq_ack(priv->mc13783, 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 queue_delayed_work(priv->workq, &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 70static 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 queue_delayed_work(priv->workq, &priv->work, HZ / 50); 109 } else 110 dev_dbg(&idev->dev, "report release\n"); 111 112 input_report_abs(idev, ABS_PRESSURE, 113 cr0 ? 0x1000 - cr0 : cr0); 114 input_report_key(idev, BTN_TOUCH, cr0); 115 input_sync(idev); 116 } else 117 dev_dbg(&idev->dev, "discard event\n"); 118} 119 120static void mc13783_ts_work(struct work_struct *work) 121{ 122 struct mc13783_ts_priv *priv = 123 container_of(work, struct mc13783_ts_priv, work.work); 124 unsigned int mode = MC13783_ADC_MODE_TS; 125 unsigned int channel = 12; 126 127 if (mc13783_adc_do_conversion(priv->mc13783, 128 mode, channel, priv->sample) == 0) 129 mc13783_ts_report_sample(priv); 130} 131 132static int mc13783_ts_open(struct input_dev *dev) 133{ 134 struct mc13783_ts_priv *priv = input_get_drvdata(dev); 135 int ret; 136 137 mc13783_lock(priv->mc13783); 138 139 mc13783_irq_ack(priv->mc13783, MC13783_IRQ_TS); 140 141 ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_TS, 142 mc13783_ts_handler, MC13783_TS_NAME, priv); 143 if (ret) 144 goto out; 145 146 ret = mc13783_reg_rmw(priv->mc13783, MC13783_ADC0, 147 MC13783_ADC0_TSMOD_MASK, MC13783_ADC0_TSMOD0); 148 if (ret) 149 mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv); 150out: 151 mc13783_unlock(priv->mc13783); 152 return ret; 153} 154 155static void mc13783_ts_close(struct input_dev *dev) 156{ 157 struct mc13783_ts_priv *priv = input_get_drvdata(dev); 158 159 mc13783_lock(priv->mc13783); 160 mc13783_reg_rmw(priv->mc13783, MC13783_ADC0, 161 MC13783_ADC0_TSMOD_MASK, 0); 162 mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv); 163 mc13783_unlock(priv->mc13783); 164 165 cancel_delayed_work_sync(&priv->work); 166} 167 168static int __init mc13783_ts_probe(struct platform_device *pdev) 169{ 170 struct mc13783_ts_priv *priv; 171 struct input_dev *idev; 172 int ret = -ENOMEM; 173 174 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 175 idev = input_allocate_device(); 176 if (!priv || !idev) 177 goto err_free_mem; 178 179 INIT_DELAYED_WORK(&priv->work, mc13783_ts_work); 180 priv->mc13783 = dev_get_drvdata(pdev->dev.parent); 181 priv->idev = idev; 182 183 /* 184 * We need separate workqueue because mc13783_adc_do_conversion 185 * uses keventd and thus would deadlock. 186 */ 187 priv->workq = create_singlethread_workqueue("mc13783_ts"); 188 if (!priv->workq) 189 goto err_free_mem; 190 191 idev->name = MC13783_TS_NAME; 192 idev->dev.parent = &pdev->dev; 193 194 idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 195 idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 196 input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0); 197 input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0); 198 input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0); 199 200 idev->open = mc13783_ts_open; 201 idev->close = mc13783_ts_close; 202 203 input_set_drvdata(idev, priv); 204 205 ret = input_register_device(priv->idev); 206 if (ret) { 207 dev_err(&pdev->dev, 208 "register input device failed with %d\n", ret); 209 goto err_destroy_wq; 210 } 211 212 platform_set_drvdata(pdev, priv); 213 return 0; 214 215err_destroy_wq: 216 destroy_workqueue(priv->workq); 217err_free_mem: 218 input_free_device(idev); 219 kfree(priv); 220 return ret; 221} 222 223static int __devexit mc13783_ts_remove(struct platform_device *pdev) 224{ 225 struct mc13783_ts_priv *priv = platform_get_drvdata(pdev); 226 227 platform_set_drvdata(pdev, NULL); 228 229 destroy_workqueue(priv->workq); 230 input_unregister_device(priv->idev); 231 kfree(priv); 232 233 return 0; 234} 235 236static struct platform_driver mc13783_ts_driver = { 237 .remove = __devexit_p(mc13783_ts_remove), 238 .driver = { 239 .owner = THIS_MODULE, 240 .name = MC13783_TS_NAME, 241 }, 242}; 243 244static int __init mc13783_ts_init(void) 245{ 246 return platform_driver_probe(&mc13783_ts_driver, &mc13783_ts_probe); 247} 248module_init(mc13783_ts_init); 249 250static void __exit mc13783_ts_exit(void) 251{ 252 platform_driver_unregister(&mc13783_ts_driver); 253} 254module_exit(mc13783_ts_exit); 255 256MODULE_DESCRIPTION("MC13783 input touchscreen driver"); 257MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); 258MODULE_LICENSE("GPL v2"); 259MODULE_ALIAS("platform:" MC13783_TS_NAME); 260