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* Atmel Touch Screen Driver
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* Copyright (c) 2008 ATMEL
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* Copyright (c) 2008 Dan Liang
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* Copyright (c) 2008 TimeSys Corporation
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* Copyright (c) 2008 Justin Waters
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* Based on touchscreen code from Atmel Corporation.
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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#include <linux/init.h>
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#include <linux/err.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/slab.h>
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#include <linux/interrupt.h>
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#include <linux/clk.h>
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#include <linux/platform_device.h>
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#include <mach/board.h>
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/* Register definitions based on AT91SAM9RL64 preliminary draft datasheet */
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#define ATMEL_TSADCC_CR 0x00 /* Control register */
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#define ATMEL_TSADCC_SWRST (1 << 0) /* Software Reset*/
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#define ATMEL_TSADCC_START (1 << 1) /* Start conversion */
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#define ATMEL_TSADCC_MR 0x04 /* Mode register */
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#define ATMEL_TSADCC_TSAMOD (3 << 0) /* ADC mode */
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#define ATMEL_TSADCC_TSAMOD_ADC_ONLY_MODE (0x0) /* ADC Mode */
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#define ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE (0x1) /* Touch Screen Only Mode */
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#define ATMEL_TSADCC_LOWRES (1 << 4) /* Resolution selection */
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#define ATMEL_TSADCC_SLEEP (1 << 5) /* Sleep mode */
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#define ATMEL_TSADCC_PENDET (1 << 6) /* Pen Detect selection */
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#define ATMEL_TSADCC_PRES (1 << 7) /* Pressure Measurement Selection */
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#define ATMEL_TSADCC_PRESCAL (0x3f << 8) /* Prescalar Rate Selection */
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#define ATMEL_TSADCC_EPRESCAL (0xff << 8) /* Prescalar Rate Selection (Extended) */
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#define ATMEL_TSADCC_STARTUP (0x7f << 16) /* Start Up time */
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#define ATMEL_TSADCC_SHTIM (0xf << 24) /* Sample & Hold time */
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#define ATMEL_TSADCC_PENDBC (0xf << 28) /* Pen Detect debouncing time */
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#define ATMEL_TSADCC_TRGR 0x08 /* Trigger register */
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#define ATMEL_TSADCC_TRGMOD (7 << 0) /* Trigger mode */
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#define ATMEL_TSADCC_TRGMOD_NONE (0 << 0)
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#define ATMEL_TSADCC_TRGMOD_EXT_RISING (1 << 0)
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#define ATMEL_TSADCC_TRGMOD_EXT_FALLING (2 << 0)
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#define ATMEL_TSADCC_TRGMOD_EXT_ANY (3 << 0)
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#define ATMEL_TSADCC_TRGMOD_PENDET (4 << 0)
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#define ATMEL_TSADCC_TRGMOD_PERIOD (5 << 0)
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#define ATMEL_TSADCC_TRGMOD_CONTINUOUS (6 << 0)
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#define ATMEL_TSADCC_TRGPER (0xffff << 16) /* Trigger period */
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#define ATMEL_TSADCC_TSR 0x0C /* Touch Screen register */
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#define ATMEL_TSADCC_TSFREQ (0xf << 0) /* TS Frequency in Interleaved mode */
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#define ATMEL_TSADCC_TSSHTIM (0xf << 24) /* Sample & Hold time */
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#define ATMEL_TSADCC_CHER 0x10 /* Channel Enable register */
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#define ATMEL_TSADCC_CHDR 0x14 /* Channel Disable register */
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#define ATMEL_TSADCC_CHSR 0x18 /* Channel Status register */
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#define ATMEL_TSADCC_CH(n) (1 << (n)) /* Channel number */
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#define ATMEL_TSADCC_SR 0x1C /* Status register */
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#define ATMEL_TSADCC_EOC(n) (1 << ((n)+0)) /* End of conversion for channel N */
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#define ATMEL_TSADCC_OVRE(n) (1 << ((n)+8)) /* Overrun error for channel N */
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#define ATMEL_TSADCC_DRDY (1 << 16) /* Data Ready */
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#define ATMEL_TSADCC_GOVRE (1 << 17) /* General Overrun Error */
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#define ATMEL_TSADCC_ENDRX (1 << 18) /* End of RX Buffer */
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#define ATMEL_TSADCC_RXBUFF (1 << 19) /* TX Buffer full */
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#define ATMEL_TSADCC_PENCNT (1 << 20) /* Pen contact */
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#define ATMEL_TSADCC_NOCNT (1 << 21) /* No contact */
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#define ATMEL_TSADCC_LCDR 0x20 /* Last Converted Data register */
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#define ATMEL_TSADCC_DATA (0x3ff << 0) /* Channel data */
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#define ATMEL_TSADCC_IER 0x24 /* Interrupt Enable register */
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#define ATMEL_TSADCC_IDR 0x28 /* Interrupt Disable register */
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#define ATMEL_TSADCC_IMR 0x2C /* Interrupt Mask register */
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#define ATMEL_TSADCC_CDR0 0x30 /* Channel Data 0 */
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#define ATMEL_TSADCC_CDR1 0x34 /* Channel Data 1 */
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#define ATMEL_TSADCC_CDR2 0x38 /* Channel Data 2 */
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#define ATMEL_TSADCC_CDR3 0x3C /* Channel Data 3 */
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#define ATMEL_TSADCC_CDR4 0x40 /* Channel Data 4 */
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#define ATMEL_TSADCC_CDR5 0x44 /* Channel Data 5 */
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#define ATMEL_TSADCC_XPOS 0x50
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#define ATMEL_TSADCC_Z1DAT 0x54
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#define ATMEL_TSADCC_Z2DAT 0x58
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#define PRESCALER_VAL(x) ((x) >> 8)
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#define ADC_DEFAULT_CLOCK 100000
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struct input_dev *input;
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unsigned int prev_absx;
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unsigned int prev_absy;
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unsigned char bufferedmeasure;
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static void __iomem *tsc_base;
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#define atmel_tsadcc_read(reg) __raw_readl(tsc_base + (reg))
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#define atmel_tsadcc_write(reg, val) __raw_writel((val), tsc_base + (reg))
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static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
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struct atmel_tsadcc *ts_dev = (struct atmel_tsadcc *)dev;
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struct input_dev *input_dev = ts_dev->input;
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status = atmel_tsadcc_read(ATMEL_TSADCC_SR);
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status &= atmel_tsadcc_read(ATMEL_TSADCC_IMR);
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if (status & ATMEL_TSADCC_NOCNT) {
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reg = atmel_tsadcc_read(ATMEL_TSADCC_MR) | ATMEL_TSADCC_PENDBC;
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atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
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atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
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atmel_tsadcc_write(ATMEL_TSADCC_IDR,
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ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
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atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
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input_report_key(input_dev, BTN_TOUCH, 0);
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ts_dev->bufferedmeasure = 0;
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input_sync(input_dev);
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} else if (status & ATMEL_TSADCC_PENCNT) {
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reg = atmel_tsadcc_read(ATMEL_TSADCC_MR);
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reg &= ~ATMEL_TSADCC_PENDBC;
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atmel_tsadcc_write(ATMEL_TSADCC_IDR, ATMEL_TSADCC_PENCNT);
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atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
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atmel_tsadcc_write(ATMEL_TSADCC_IER,
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ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
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atmel_tsadcc_write(ATMEL_TSADCC_TRGR,
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ATMEL_TSADCC_TRGMOD_PERIOD | (0x0FFF << 16));
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} else if (status & ATMEL_TSADCC_EOC(3)) {
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/* Conversion finished */
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if (ts_dev->bufferedmeasure) {
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/* Last measurement is always discarded, since it can
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* Always report previous measurement */
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input_report_abs(input_dev, ABS_X, ts_dev->prev_absx);
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input_report_abs(input_dev, ABS_Y, ts_dev->prev_absy);
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input_report_key(input_dev, BTN_TOUCH, 1);
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input_sync(input_dev);
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ts_dev->bufferedmeasure = 1;
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/* Now make new measurement */
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ts_dev->prev_absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
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ts_dev->prev_absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);
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ts_dev->prev_absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
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ts_dev->prev_absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
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* The functions for inserting/removing us as a module.
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static int __devinit atmel_tsadcc_probe(struct platform_device *pdev)
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struct atmel_tsadcc *ts_dev;
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struct input_dev *input_dev;
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struct resource *res;
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struct at91_tsadcc_data *pdata = pdev->dev.platform_data;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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dev_err(&pdev->dev, "no mmio resource defined.\n");
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/* Allocate memory for device */
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ts_dev = kzalloc(sizeof(struct atmel_tsadcc), GFP_KERNEL);
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dev_err(&pdev->dev, "failed to allocate memory.\n");
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platform_set_drvdata(pdev, ts_dev);
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input_dev = input_allocate_device();
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dev_err(&pdev->dev, "failed to allocate input device.\n");
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ts_dev->irq = platform_get_irq(pdev, 0);
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if (ts_dev->irq < 0) {
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dev_err(&pdev->dev, "no irq ID is designated.\n");
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if (!request_mem_region(res->start, resource_size(res),
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"atmel tsadcc regs")) {
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dev_err(&pdev->dev, "resources is unavailable.\n");
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tsc_base = ioremap(res->start, resource_size(res));
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dev_err(&pdev->dev, "failed to map registers.\n");
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goto err_release_mem;
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err = request_irq(ts_dev->irq, atmel_tsadcc_interrupt, 0,
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pdev->dev.driver->name, ts_dev);
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dev_err(&pdev->dev, "failed to allocate irq.\n");
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ts_dev->clk = clk_get(&pdev->dev, "tsc_clk");
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if (IS_ERR(ts_dev->clk)) {
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dev_err(&pdev->dev, "failed to get ts_clk\n");
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err = PTR_ERR(ts_dev->clk);
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ts_dev->input = input_dev;
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ts_dev->bufferedmeasure = 0;
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snprintf(ts_dev->phys, sizeof(ts_dev->phys),
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"%s/input0", dev_name(&pdev->dev));
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input_dev->name = "atmel touch screen controller";
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input_dev->phys = ts_dev->phys;
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input_dev->dev.parent = &pdev->dev;
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__set_bit(EV_ABS, input_dev->evbit);
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input_set_abs_params(input_dev, ABS_X, 0, 0x3FF, 0, 0);
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input_set_abs_params(input_dev, ABS_Y, 0, 0x3FF, 0, 0);
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input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
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/* clk_enable() always returns 0, no need to check it */
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clk_enable(ts_dev->clk);
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prsc = clk_get_rate(ts_dev->clk);
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dev_info(&pdev->dev, "Master clock is set at: %d Hz\n", prsc);
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if (!pdata->adc_clock)
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pdata->adc_clock = ADC_DEFAULT_CLOCK;
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prsc = (prsc / (2 * pdata->adc_clock)) - 1;
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/* saturate if this value is too high */
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if (cpu_is_at91sam9rl()) {
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if (prsc > PRESCALER_VAL(ATMEL_TSADCC_PRESCAL))
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prsc = PRESCALER_VAL(ATMEL_TSADCC_PRESCAL);
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if (prsc > PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL))
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prsc = PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL);
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dev_info(&pdev->dev, "Prescaler is set at: %d\n", prsc);
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reg = ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE |
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((0x00 << 5) & ATMEL_TSADCC_SLEEP) | /* Normal Mode */
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((0x01 << 6) & ATMEL_TSADCC_PENDET) | /* Enable Pen Detect */
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((0x26 << 16) & ATMEL_TSADCC_STARTUP) |
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((pdata->pendet_debounce << 28) & ATMEL_TSADCC_PENDBC);
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atmel_tsadcc_write(ATMEL_TSADCC_CR, ATMEL_TSADCC_SWRST);
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atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
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atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
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atmel_tsadcc_write(ATMEL_TSADCC_TSR,
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(pdata->ts_sample_hold_time << 24) & ATMEL_TSADCC_TSSHTIM);
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atmel_tsadcc_read(ATMEL_TSADCC_SR);
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atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
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/* All went ok, so register to the input system */
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err = input_register_device(input_dev);
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clk_disable(ts_dev->clk);
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clk_put(ts_dev->clk);
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free_irq(ts_dev->irq, ts_dev);
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release_mem_region(res->start, resource_size(res));
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input_free_device(input_dev);
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static int __devexit atmel_tsadcc_remove(struct platform_device *pdev)
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struct atmel_tsadcc *ts_dev = dev_get_drvdata(&pdev->dev);
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struct resource *res;
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free_irq(ts_dev->irq, ts_dev);
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input_unregister_device(ts_dev->input);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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release_mem_region(res->start, resource_size(res));
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clk_disable(ts_dev->clk);
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clk_put(ts_dev->clk);
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static struct platform_driver atmel_tsadcc_driver = {
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.probe = atmel_tsadcc_probe,
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.remove = __devexit_p(atmel_tsadcc_remove),
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.name = "atmel_tsadcc",
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static int __init atmel_tsadcc_init(void)
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return platform_driver_register(&atmel_tsadcc_driver);
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static void __exit atmel_tsadcc_exit(void)
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platform_driver_unregister(&atmel_tsadcc_driver);
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module_init(atmel_tsadcc_init);
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module_exit(atmel_tsadcc_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Atmel TouchScreen Driver");
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MODULE_AUTHOR("Dan Liang <dan.liang@atmel.com>");