62e5147568
The workqueue "workqueue" has a single workitem(&priv->work) and hence doesn't require ordering. Also, it is not being used on a memory reclaim path. Hence, the singlethreaded workqueue has been replaced with the use of system_wq. System workqueues have been able to handle high level of concurrency for a long time now and hence it's not required to have a singlethreaded workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue created with create_singlethread_workqueue(), system_wq allows multiple work items to overlap executions even on the same CPU; however, a per-cpu workqueue doesn't have any CPU locality or global ordering guarantee unless the target CPU is explicitly specified and thus the increase of local concurrency shouldn't make any difference. Workitem is sync cancelled in mc13783_ts_remove() to ensure that there are no workitems pending when the driver is disconnected. Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
246 lines
6.3 KiB
C
246 lines
6.3 KiB
C
/*
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* Driver for the Freescale Semiconductor MC13783 touchscreen.
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*
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* Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
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* Copyright (C) 2009 Sascha Hauer, Pengutronix
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*
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* Initial development of this code was funded by
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* Phytec Messtechnik GmbH, http://www.phytec.de/
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/platform_device.h>
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#include <linux/mfd/mc13783.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/input.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#define MC13783_TS_NAME "mc13783-ts"
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#define DEFAULT_SAMPLE_TOLERANCE 300
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static unsigned int sample_tolerance = DEFAULT_SAMPLE_TOLERANCE;
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module_param(sample_tolerance, uint, S_IRUGO | S_IWUSR);
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MODULE_PARM_DESC(sample_tolerance,
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"If the minimal and maximal value read out for one axis (out "
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"of three) differ by this value (default: "
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__stringify(DEFAULT_SAMPLE_TOLERANCE) ") or more, the reading "
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"is supposed to be wrong and is discarded. Set to 0 to "
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"disable this check.");
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struct mc13783_ts_priv {
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struct input_dev *idev;
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struct mc13xxx *mc13xxx;
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struct delayed_work work;
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unsigned int sample[4];
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struct mc13xxx_ts_platform_data *touch;
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};
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static irqreturn_t mc13783_ts_handler(int irq, void *data)
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{
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struct mc13783_ts_priv *priv = data;
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mc13xxx_irq_ack(priv->mc13xxx, irq);
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/*
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* Kick off reading coordinates. Note that if work happens already
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* be queued for future execution (it rearms itself) it will not
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* be rescheduled for immediate execution here. However the rearm
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* delay is HZ / 50 which is acceptable.
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*/
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schedule_delayed_work(&priv->work, 0);
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return IRQ_HANDLED;
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}
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#define sort3(a0, a1, a2) ({ \
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if (a0 > a1) \
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swap(a0, a1); \
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if (a1 > a2) \
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swap(a1, a2); \
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if (a0 > a1) \
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swap(a0, a1); \
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})
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static void mc13783_ts_report_sample(struct mc13783_ts_priv *priv)
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{
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struct input_dev *idev = priv->idev;
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int x0, x1, x2, y0, y1, y2;
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int cr0, cr1;
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/*
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* the values are 10-bit wide only, but the two least significant
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* bits are for future 12 bit use and reading yields 0
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*/
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x0 = priv->sample[0] & 0xfff;
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x1 = priv->sample[1] & 0xfff;
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x2 = priv->sample[2] & 0xfff;
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y0 = priv->sample[3] & 0xfff;
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y1 = (priv->sample[0] >> 12) & 0xfff;
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y2 = (priv->sample[1] >> 12) & 0xfff;
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cr0 = (priv->sample[2] >> 12) & 0xfff;
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cr1 = (priv->sample[3] >> 12) & 0xfff;
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dev_dbg(&idev->dev,
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"x: (% 4d,% 4d,% 4d) y: (% 4d, % 4d,% 4d) cr: (% 4d, % 4d)\n",
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x0, x1, x2, y0, y1, y2, cr0, cr1);
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sort3(x0, x1, x2);
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sort3(y0, y1, y2);
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cr0 = (cr0 + cr1) / 2;
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if (!cr0 || !sample_tolerance ||
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(x2 - x0 < sample_tolerance &&
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y2 - y0 < sample_tolerance)) {
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/* report the median coordinate and average pressure */
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if (cr0) {
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input_report_abs(idev, ABS_X, x1);
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input_report_abs(idev, ABS_Y, y1);
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dev_dbg(&idev->dev, "report (%d, %d, %d)\n",
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x1, y1, 0x1000 - cr0);
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schedule_delayed_work(&priv->work, HZ / 50);
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} else {
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dev_dbg(&idev->dev, "report release\n");
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}
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input_report_abs(idev, ABS_PRESSURE,
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cr0 ? 0x1000 - cr0 : cr0);
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input_report_key(idev, BTN_TOUCH, cr0);
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input_sync(idev);
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} else {
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dev_dbg(&idev->dev, "discard event\n");
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}
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}
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static void mc13783_ts_work(struct work_struct *work)
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{
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struct mc13783_ts_priv *priv =
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container_of(work, struct mc13783_ts_priv, work.work);
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unsigned int mode = MC13XXX_ADC_MODE_TS;
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unsigned int channel = 12;
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if (mc13xxx_adc_do_conversion(priv->mc13xxx,
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mode, channel,
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priv->touch->ato, priv->touch->atox,
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priv->sample) == 0)
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mc13783_ts_report_sample(priv);
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}
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static int mc13783_ts_open(struct input_dev *dev)
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{
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struct mc13783_ts_priv *priv = input_get_drvdata(dev);
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int ret;
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mc13xxx_lock(priv->mc13xxx);
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mc13xxx_irq_ack(priv->mc13xxx, MC13XXX_IRQ_TS);
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ret = mc13xxx_irq_request(priv->mc13xxx, MC13XXX_IRQ_TS,
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mc13783_ts_handler, MC13783_TS_NAME, priv);
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if (ret)
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goto out;
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ret = mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
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MC13XXX_ADC0_TSMOD_MASK, MC13XXX_ADC0_TSMOD0);
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if (ret)
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mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
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out:
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mc13xxx_unlock(priv->mc13xxx);
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return ret;
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}
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static void mc13783_ts_close(struct input_dev *dev)
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{
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struct mc13783_ts_priv *priv = input_get_drvdata(dev);
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mc13xxx_lock(priv->mc13xxx);
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mc13xxx_reg_rmw(priv->mc13xxx, MC13XXX_ADC0,
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MC13XXX_ADC0_TSMOD_MASK, 0);
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mc13xxx_irq_free(priv->mc13xxx, MC13XXX_IRQ_TS, priv);
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mc13xxx_unlock(priv->mc13xxx);
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cancel_delayed_work_sync(&priv->work);
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}
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static int __init mc13783_ts_probe(struct platform_device *pdev)
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{
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struct mc13783_ts_priv *priv;
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struct input_dev *idev;
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int ret = -ENOMEM;
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priv = kzalloc(sizeof(*priv), GFP_KERNEL);
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idev = input_allocate_device();
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if (!priv || !idev)
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goto err_free_mem;
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INIT_DELAYED_WORK(&priv->work, mc13783_ts_work);
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priv->mc13xxx = dev_get_drvdata(pdev->dev.parent);
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priv->idev = idev;
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priv->touch = dev_get_platdata(&pdev->dev);
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if (!priv->touch) {
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dev_err(&pdev->dev, "missing platform data\n");
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ret = -ENODEV;
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goto err_free_mem;
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}
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idev->name = MC13783_TS_NAME;
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idev->dev.parent = &pdev->dev;
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idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
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idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
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input_set_abs_params(idev, ABS_X, 0, 0xfff, 0, 0);
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input_set_abs_params(idev, ABS_Y, 0, 0xfff, 0, 0);
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input_set_abs_params(idev, ABS_PRESSURE, 0, 0xfff, 0, 0);
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idev->open = mc13783_ts_open;
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idev->close = mc13783_ts_close;
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input_set_drvdata(idev, priv);
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ret = input_register_device(priv->idev);
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if (ret) {
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dev_err(&pdev->dev,
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"register input device failed with %d\n", ret);
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goto err_free_mem;
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}
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platform_set_drvdata(pdev, priv);
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return 0;
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err_free_mem:
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input_free_device(idev);
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kfree(priv);
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return ret;
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}
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static int mc13783_ts_remove(struct platform_device *pdev)
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{
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struct mc13783_ts_priv *priv = platform_get_drvdata(pdev);
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input_unregister_device(priv->idev);
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kfree(priv);
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return 0;
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}
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static struct platform_driver mc13783_ts_driver = {
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.remove = mc13783_ts_remove,
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.driver = {
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.name = MC13783_TS_NAME,
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},
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};
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module_platform_driver_probe(mc13783_ts_driver, mc13783_ts_probe);
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MODULE_DESCRIPTION("MC13783 input touchscreen driver");
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MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" MC13783_TS_NAME);
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