Sascha Hauer | d201fd5 | 2009-12-15 08:48:57 -0800 | [diff] [blame] | 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/init.h> |
| 21 | |
| 22 | #define MC13783_TS_NAME "mc13783-ts" |
| 23 | |
| 24 | #define DEFAULT_SAMPLE_TOLERANCE 300 |
| 25 | |
| 26 | static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE; |
| 27 | module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR); |
| 28 | MODULE_PARM_DESC(sample_tolerance, |
| 29 | "If the minimal and maximal value read out for one axis (out " |
| 30 | "of three) differ by this value (default: " |
| 31 | __stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading " |
| 32 | "is supposed to be wrong and is discarded. Set to 0 to " |
| 33 | "disable this check."); |
| 34 | |
| 35 | struct mc13783_ts_priv { |
| 36 | struct input_dev *idev; |
| 37 | struct mc13783 *mc13783; |
| 38 | struct delayed_work work; |
| 39 | struct workqueue_struct *workq; |
| 40 | unsigned int sample[4]; |
| 41 | }; |
| 42 | |
| 43 | static irqreturn_t mc13783_ts_handler(int irq, void *data) |
| 44 | { |
| 45 | struct mc13783_ts_priv *priv = data; |
| 46 | |
Uwe Kleine-König | 2a833191 | 2010-03-05 13:44:26 -0800 | [diff] [blame^] | 47 | mc13783_irq_ack(priv->mc13783, irq); |
Sascha Hauer | d201fd5 | 2009-12-15 08:48:57 -0800 | [diff] [blame] | 48 | |
| 49 | /* |
| 50 | * Kick off reading coordinates. Note that if work happens already |
| 51 | * be queued for future execution (it rearms itself) it will not |
| 52 | * be rescheduled for immediate execution here. However the rearm |
| 53 | * delay is HZ / 50 which is acceptable. |
| 54 | */ |
| 55 | queue_delayed_work(priv->workq, &priv->work, 0); |
| 56 | |
| 57 | return IRQ_HANDLED; |
| 58 | } |
| 59 | |
| 60 | #define sort3(a0, a1, a2) ({ \ |
| 61 | if (a0 > a1) \ |
| 62 | swap(a0, a1); \ |
| 63 | if (a1 > a2) \ |
| 64 | swap(a1, a2); \ |
| 65 | if (a0 > a1) \ |
| 66 | swap(a0, a1); \ |
| 67 | }) |
| 68 | |
| 69 | static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv) |
| 70 | { |
| 71 | struct input_dev *idev = priv->idev; |
| 72 | int x0, x1, x2, y0, y1, y2; |
| 73 | int cr0, cr1; |
| 74 | |
| 75 | /* |
| 76 | * the values are 10-bit wide only, but the two least significant |
| 77 | * bits are for future 12 bit use and reading yields 0 |
| 78 | */ |
| 79 | x0 = priv->sample[0] & 0xfff; |
| 80 | x1 = priv->sample[1] & 0xfff; |
| 81 | x2 = priv->sample[2] & 0xfff; |
| 82 | y0 = priv->sample[3] & 0xfff; |
| 83 | y1 = (priv->sample[0] >> 12) & 0xfff; |
| 84 | y2 = (priv->sample[1] >> 12) & 0xfff; |
| 85 | cr0 = (priv->sample[2] >> 12) & 0xfff; |
| 86 | cr1 = (priv->sample[3] >> 12) & 0xfff; |
| 87 | |
| 88 | dev_dbg(&idev->dev, |
| 89 | "x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n", |
| 90 | x0, x1, x2, y0, y1, y2, cr0, cr1); |
| 91 | |
| 92 | sort3(x0, x1, x2); |
| 93 | sort3(y0, y1, y2); |
| 94 | |
| 95 | cr0 = (cr0 + cr1) / 2; |
| 96 | |
| 97 | if (!cr0 || !sample_tolerance || |
| 98 | (x2 - x0 < sample_tolerance && |
| 99 | y2 - y0 < sample_tolerance)) { |
| 100 | /* report the median coordinate and average pressure */ |
| 101 | if (cr0) { |
| 102 | input_report_abs(idev, ABS_X, x1); |
| 103 | input_report_abs(idev, ABS_Y, y1); |
| 104 | |
| 105 | dev_dbg(&idev->dev, "report (%d, %d, %d)\n", |
| 106 | x1, y1, 0x1000 - cr0); |
| 107 | queue_delayed_work(priv->workq, &priv->work, HZ / 50); |
| 108 | } else |
| 109 | dev_dbg(&idev->dev, "report release\n"); |
| 110 | |
| 111 | input_report_abs(idev, ABS_PRESSURE, |
| 112 | cr0 ? 0x1000 - cr0 : cr0); |
| 113 | input_report_key(idev, BTN_TOUCH, cr0); |
| 114 | input_sync(idev); |
| 115 | } else |
| 116 | dev_dbg(&idev->dev, "discard event\n"); |
| 117 | } |
| 118 | |
| 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 = MC13783_ADC_MODE_TS; |
| 124 | unsigned int channel = 12; |
| 125 | |
| 126 | if (mc13783_adc_do_conversion(priv->mc13783, |
| 127 | mode, channel, priv->sample) == 0) |
| 128 | mc13783_ts_report_sample(priv); |
| 129 | } |
| 130 | |
| 131 | static int mc13783_ts_open(struct input_dev *dev) |
| 132 | { |
| 133 | struct mc13783_ts_priv *priv = input_get_drvdata(dev); |
| 134 | int ret; |
| 135 | |
| 136 | mc13783_lock(priv->mc13783); |
| 137 | |
Uwe Kleine-König | 2a833191 | 2010-03-05 13:44:26 -0800 | [diff] [blame^] | 138 | mc13783_irq_ack(priv->mc13783, MC13783_IRQ_TS); |
Sascha Hauer | d201fd5 | 2009-12-15 08:48:57 -0800 | [diff] [blame] | 139 | |
| 140 | ret = mc13783_irq_request(priv->mc13783, MC13783_IRQ_TS, |
| 141 | mc13783_ts_handler, MC13783_TS_NAME, priv); |
| 142 | if (ret) |
| 143 | goto out; |
| 144 | |
| 145 | ret = mc13783_reg_rmw(priv->mc13783, MC13783_ADC0, |
| 146 | MC13783_ADC0_TSMOD_MASK, MC13783_ADC0_TSMOD0); |
| 147 | if (ret) |
| 148 | mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv); |
| 149 | out: |
| 150 | mc13783_unlock(priv->mc13783); |
| 151 | return ret; |
| 152 | } |
| 153 | |
| 154 | static void mc13783_ts_close(struct input_dev *dev) |
| 155 | { |
| 156 | struct mc13783_ts_priv *priv = input_get_drvdata(dev); |
| 157 | |
| 158 | mc13783_lock(priv->mc13783); |
| 159 | mc13783_reg_rmw(priv->mc13783, MC13783_ADC0, |
| 160 | MC13783_ADC0_TSMOD_MASK, 0); |
| 161 | mc13783_irq_free(priv->mc13783, MC13783_IRQ_TS, priv); |
| 162 | mc13783_unlock(priv->mc13783); |
| 163 | |
| 164 | cancel_delayed_work_sync(&priv->work); |
| 165 | } |
| 166 | |
| 167 | static int __init mc13783_ts_probe(struct platform_device *pdev) |
| 168 | { |
| 169 | struct mc13783_ts_priv *priv; |
| 170 | struct input_dev *idev; |
| 171 | int ret = -ENOMEM; |
| 172 | |
| 173 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
| 174 | idev = input_allocate_device(); |
| 175 | if (!priv || !idev) |
| 176 | goto err_free_mem; |
| 177 | |
| 178 | INIT_DELAYED_WORK(&priv->work, mc13783_ts_work); |
| 179 | priv->mc13783 = dev_get_drvdata(pdev->dev.parent); |
| 180 | priv->idev = idev; |
| 181 | |
| 182 | /* |
| 183 | * We need separate workqueue because mc13783_adc_do_conversion |
| 184 | * uses keventd and thus would deadlock. |
| 185 | */ |
| 186 | priv->workq = create_singlethread_workqueue("mc13783_ts"); |
| 187 | if (!priv->workq) |
| 188 | goto err_free_mem; |
| 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_destroy_wq; |
| 209 | } |
| 210 | |
| 211 | platform_set_drvdata(pdev, priv); |
| 212 | return 0; |
| 213 | |
| 214 | err_destroy_wq: |
| 215 | destroy_workqueue(priv->workq); |
| 216 | err_free_mem: |
| 217 | input_free_device(idev); |
| 218 | kfree(priv); |
| 219 | return ret; |
| 220 | } |
| 221 | |
| 222 | static int __devexit mc13783_ts_remove(struct platform_device *pdev) |
| 223 | { |
| 224 | struct mc13783_ts_priv *priv = platform_get_drvdata(pdev); |
| 225 | |
| 226 | platform_set_drvdata(pdev, NULL); |
| 227 | |
| 228 | destroy_workqueue(priv->workq); |
| 229 | input_unregister_device(priv->idev); |
| 230 | kfree(priv); |
| 231 | |
| 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | static struct platform_driver mc13783_ts_driver = { |
| 236 | .remove = __devexit_p(mc13783_ts_remove), |
| 237 | .driver = { |
| 238 | .owner = THIS_MODULE, |
| 239 | .name = MC13783_TS_NAME, |
| 240 | }, |
| 241 | }; |
| 242 | |
| 243 | static int __init mc13783_ts_init(void) |
| 244 | { |
| 245 | return platform_driver_probe(&mc13783_ts_driver, &mc13783_ts_probe); |
| 246 | } |
| 247 | module_init(mc13783_ts_init); |
| 248 | |
| 249 | static void __exit mc13783_ts_exit(void) |
| 250 | { |
| 251 | platform_driver_unregister(&mc13783_ts_driver); |
| 252 | } |
| 253 | module_exit(mc13783_ts_exit); |
| 254 | |
| 255 | MODULE_DESCRIPTION("MC13783 input touchscreen driver"); |
| 256 | MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>"); |
| 257 | MODULE_LICENSE("GPL v2"); |
| 258 | MODULE_ALIAS("platform:" MC13783_TS_NAME); |