455 lines
12 KiB
C
455 lines
12 KiB
C
/*
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* Driver for the IMX keypad port.
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* Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
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* Copyright (C) 2012 Christian Kapeller <christian.kapeller@cmotion.eu>
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*
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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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*
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*/
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/*
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To use the imx keypad driver, you have to define the keys in your platform
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code.
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1. Configure the imx keypad row & column pads used by your board
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2. Define the keys you want to use:
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#define BTN_1 0x101
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#define BTN_2 0x102
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#define BTN_3 0x103
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static uint32_t keypad_codes[] = {
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// specify your keymap with KEY(row, col, keycode)
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KEY(0, 1, BTN_1),
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KEY(1, 0, BTN_2),
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KEY(1, 1, BTN_3),
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};
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static struct matrix_keymap_data keypad_data = {
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.keymap = keypad_codes,
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.keymap_size = ARRAY_SIZE(keypad_codes),
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};
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3. Add the keypad to your platform in your devices init callback:
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imx51_add_kpp(&keypad_data);
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4. Compile , flash, and enjoy
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*/
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#include <common.h>
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#include <errno.h>
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#include <init.h>
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#include <io.h>
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#include <poller.h>
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#include <kfifo.h>
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#include <malloc.h>
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#include <matrix_keypad.h>
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#include <linux/err.h>
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/*
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* Keypad Controller registers (halfword)
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*/
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#define KPCR 0x00 /* Keypad Control Register */
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#define KPSR 0x02 /* Keypad Status Register */
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#define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */
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#define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */
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#define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/
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#define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/
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#define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */
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#define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */
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#define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */
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#define KDDR 0x04 /* Keypad Data Direction Register */
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#define KPDR 0x06 /* Keypad Data Register */
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#define MAX_MATRIX_KEY_ROWS 8
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#define MAX_MATRIX_KEY_COLS 8
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#define MATRIX_ROW_SHIFT 3
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#define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)
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struct imx_keypad {
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struct clk *clk;
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struct device_d *dev;
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struct console_device cdev;
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void __iomem *mmio_base;
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/* optional */
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int fifo_size;
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struct kfifo *recv_fifo;
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struct poller_struct poller;
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/*
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* The matrix is stable only if no changes are detected after
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* IMX_KEYPAD_SCANS_FOR_STABILITY scans
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*/
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#define IMX_KEYPAD_SCANS_FOR_STABILITY 3
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int stable_count;
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/* Masks for enabled rows/cols */
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unsigned short rows_en_mask;
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unsigned short cols_en_mask;
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unsigned short keycodes[MAX_MATRIX_KEY_NUM];
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/*
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* Matrix states:
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* -stable: achieved after a complete debounce process.
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* -unstable: used in the debouncing process.
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*/
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unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS];
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unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS];
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};
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static inline struct imx_keypad *
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poller_to_imx_kp_pdata(struct poller_struct *poller)
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{
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return container_of(poller, struct imx_keypad, poller);
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}
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static inline struct imx_keypad *
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cdev_to_imx_kp_pdata(struct console_device *cdev)
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{
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return container_of(cdev, struct imx_keypad, cdev);
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}
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static int imx_keypad_tstc(struct console_device *cdev)
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{
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struct imx_keypad *kp = cdev_to_imx_kp_pdata(cdev);
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return (kfifo_len(kp->recv_fifo) == 0) ? 0 : 1;
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}
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static int imx_keypad_getc(struct console_device *cdev)
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{
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int code = 0;
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struct imx_keypad *kp = cdev_to_imx_kp_pdata(cdev);
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kfifo_get(kp->recv_fifo, (u_char*)&code, sizeof(int));
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return code;
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}
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/* Scan the matrix and return the new state in *matrix_volatile_state. */
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static void imx_keypad_scan_matrix(struct imx_keypad *keypad,
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unsigned short *matrix_volatile_state)
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{
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int col;
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unsigned short reg_val;
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for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
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if ((keypad->cols_en_mask & (1 << col)) == 0)
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continue;
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/*
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* Discharge keypad capacitance:
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* 2. write 1s on column data.
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* 3. configure columns as totem-pole to discharge capacitance.
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* 4. configure columns as open-drain.
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*/
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reg_val = readw(keypad->mmio_base + KPDR);
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reg_val |= 0xff00;
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writew(reg_val, keypad->mmio_base + KPDR);
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reg_val = readw(keypad->mmio_base + KPCR);
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reg_val &= ~((keypad->cols_en_mask & 0xff) << 8);
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writew(reg_val, keypad->mmio_base + KPCR);
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udelay(2);
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reg_val = readw(keypad->mmio_base + KPCR);
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reg_val |= (keypad->cols_en_mask & 0xff) << 8;
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writew(reg_val, keypad->mmio_base + KPCR);
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/*
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* 5. Write a single column to 0, others to 1.
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* 6. Sample row inputs and save data.
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* 7. Repeat steps 2 - 6 for remaining columns.
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*/
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reg_val = readw(keypad->mmio_base + KPDR);
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reg_val &= ~(1 << (8 + col));
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writew(reg_val, keypad->mmio_base + KPDR);
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/*
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* Delay added to avoid propagating the 0 from column to row
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* when scanning.
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*/
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udelay(5);
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/*
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* 1s in matrix_volatile_state[col] means key pressures
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* throw data from non enabled rows.
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*/
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reg_val = readw(keypad->mmio_base + KPDR);
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matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
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}
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/*
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* Return in standby mode:
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* 9. write 0s to columns
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*/
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reg_val = readw(keypad->mmio_base + KPDR);
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reg_val &= 0x00ff;
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writew(reg_val, keypad->mmio_base + KPDR);
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}
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/*
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* Compare the new matrix state (volatile) with the stable one stored in
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* keypad->matrix_stable_state and fire events if changes are detected.
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*/
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static void imx_keypad_fire_events(struct imx_keypad *keypad,
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unsigned short *matrix_volatile_state)
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{
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int row, col;
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for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
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unsigned short bits_changed;
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int code;
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if ((keypad->cols_en_mask & (1 << col)) == 0)
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continue; /* Column is not enabled */
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bits_changed = keypad->matrix_stable_state[col] ^
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matrix_volatile_state[col];
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if (bits_changed == 0)
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continue; /* Column does not contain changes */
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for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
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if ((keypad->rows_en_mask & (1 << row)) == 0)
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continue; /* Row is not enabled */
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if ((bits_changed & (1 << row)) == 0)
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continue; /* Row does not contain changes */
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code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
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kfifo_put(keypad->recv_fifo, (u_char*)(&keypad->keycodes[code]), sizeof(int));
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pr_debug("Event code: %d, val: %d",
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keypad->keycodes[code],
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matrix_volatile_state[col] & (1 << row));
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}
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}
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}
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/*
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* imx_keypad_check_for_events is the timer handler.
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*/
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static void imx_keypad_check_for_events(struct poller_struct *poller)
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{
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struct imx_keypad *keypad = (struct imx_keypad *) poller_to_imx_kp_pdata(poller);
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unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS];
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unsigned short reg_val;
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bool state_changed, is_zero_matrix;
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int i;
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memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));
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imx_keypad_scan_matrix(keypad, matrix_volatile_state);
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state_changed = false;
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for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
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if ((keypad->cols_en_mask & (1 << i)) == 0)
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continue;
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if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
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state_changed = true;
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break;
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}
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}
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/*
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* If the matrix state is changed from the previous scan
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* (Re)Begin the debouncing process, saving the new state in
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* keypad->matrix_unstable_state.
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* else
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* Increase the count of number of scans with a stable state.
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*/
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if (state_changed) {
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memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
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sizeof(matrix_volatile_state));
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keypad->stable_count = 0;
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} else
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keypad->stable_count++;
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/*
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* If the matrix is not as stable as we want reschedule scan
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* in the near future.
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*/
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if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
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return;
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}
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/*
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* If the matrix state is stable, fire the events and save the new
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* stable state. Note, if the matrix is kept stable for longer
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* (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all
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* events have already been generated.
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*/
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if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
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imx_keypad_fire_events(keypad, matrix_volatile_state);
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memcpy(keypad->matrix_stable_state, matrix_volatile_state,
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sizeof(matrix_volatile_state));
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}
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is_zero_matrix = true;
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for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
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if (matrix_volatile_state[i] != 0) {
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is_zero_matrix = false;
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break;
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}
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}
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if (is_zero_matrix) {
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/*
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* All keys have been released. Enable only the KDI
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* interrupt for future key presses (clear the KDI
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* status bit and its sync chain before that).
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*/
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC;
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writew(reg_val, keypad->mmio_base + KPSR);
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val |= KBD_STAT_KDIE;
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reg_val &= ~KBD_STAT_KRIE;
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writew(reg_val, keypad->mmio_base + KPSR);
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} else {
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/*
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* Some keys are still pressed. Schedule a rescan in
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* attempt to detect multiple key presses and enable
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* the KRI interrupt to react quickly to key release
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* event.
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*/
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS;
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writew(reg_val, keypad->mmio_base + KPSR);
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val |= KBD_STAT_KRIE;
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reg_val &= ~KBD_STAT_KDIE;
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writew(reg_val, keypad->mmio_base + KPSR);
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}
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}
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static void imx_keypad_config(struct imx_keypad *keypad)
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{
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unsigned short reg_val;
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/*
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* Include enabled rows in interrupt generation (KPCR[7:0])
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* Configure keypad columns as open-drain (KPCR[15:8])
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*/
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reg_val = readw(keypad->mmio_base + KPCR);
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reg_val |= keypad->rows_en_mask & 0xff; /* rows */
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reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */
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writew(reg_val, keypad->mmio_base + KPCR);
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/* Write 0's to KPDR[15:8] (Colums) */
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reg_val = readw(keypad->mmio_base + KPDR);
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reg_val &= 0x00ff;
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writew(reg_val, keypad->mmio_base + KPDR);
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/* Configure columns as output, rows as input (KDDR[15:0]) */
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writew(0xff00, keypad->mmio_base + KDDR);
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/*
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* Clear Key Depress and Key Release status bit.
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* Clear both synchronizer chain.
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*/
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD |
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KBD_STAT_KDSC | KBD_STAT_KRSS;
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writew(reg_val, keypad->mmio_base + KPSR);
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/* Enable KDI and disable KRI (avoid false release events). */
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reg_val |= KBD_STAT_KDIE;
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reg_val &= ~KBD_STAT_KRIE;
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writew(reg_val, keypad->mmio_base + KPSR);
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}
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static void imx_keypad_inhibit(struct imx_keypad *keypad)
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{
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unsigned short reg_val;
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/* Inhibit KDI and KRI interrupts. */
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reg_val = readw(keypad->mmio_base + KPSR);
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reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
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writew(reg_val, keypad->mmio_base + KPSR);
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/* Colums as open drain and disable all rows */
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writew(0xff00, keypad->mmio_base + KPCR);
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}
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static int __init imx_keypad_probe(struct device_d *dev)
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{
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struct imx_keypad *keypad;
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const struct matrix_keymap_data *keymap_data = dev->platform_data;
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struct console_device *cdev;
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int i;
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if (!keymap_data) {
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pr_err("no keymap defined\n");
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return -ENODEV;
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}
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keypad = xzalloc(sizeof(struct imx_keypad));
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keypad->dev = dev;
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keypad->mmio_base = dev_request_mem_region(dev, 0);
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if (IS_ERR(keypad->mmio_base))
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return PTR_ERR(keypad->mmio_base);
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if(!keypad->fifo_size)
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keypad->fifo_size = 50;
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keypad->recv_fifo = kfifo_alloc(keypad->fifo_size);
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/* Search for rows and cols enabled */
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for (i = 0; i < keymap_data->keymap_size; i++) {
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keypad->rows_en_mask |= 1 << KEY_ROW(keymap_data->keymap[i]);
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keypad->cols_en_mask |= 1 << KEY_COL(keymap_data->keymap[i]);
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}
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if (keypad->rows_en_mask > ((1 << MAX_MATRIX_KEY_ROWS) - 1) ||
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keypad->cols_en_mask > ((1 << MAX_MATRIX_KEY_COLS) - 1)) {
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pr_err("invalid key data (too many rows or colums)\n");
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free(keypad);
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return -EINVAL;
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}
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pr_debug("enabled rows mask: %x\n", keypad->rows_en_mask);
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pr_debug("enabled cols mask: %x\n", keypad->cols_en_mask);
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matrix_keypad_build_keymap(keymap_data, MATRIX_ROW_SHIFT,
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keypad->keycodes);
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imx_keypad_config(keypad);
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/* Ensure that the keypad will stay dormant until opened */
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imx_keypad_inhibit(keypad);
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keypad->poller.func = imx_keypad_check_for_events;
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cdev = &keypad->cdev;
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dev->type_data = cdev;
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cdev->dev = dev;
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cdev->tstc = imx_keypad_tstc;
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cdev->getc = imx_keypad_getc;
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cdev->f_active = CONSOLE_STDIN;
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console_register(&keypad->cdev);
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return poller_register(&keypad->poller);
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}
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static struct driver_d imx_keypad_driver = {
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.name = "imx-kpp",
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.probe = imx_keypad_probe,
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};
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device_platform_driver(imx_keypad_driver);
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