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585 lines
16 KiB
585 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// |
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// Driver for the IMX keypad port. |
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// Copyright (C) 2009 Alberto Panizzo <[email protected]> |
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#include <linux/clk.h> |
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#include <linux/delay.h> |
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#include <linux/device.h> |
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#include <linux/err.h> |
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#include <linux/input/matrix_keypad.h> |
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#include <linux/interrupt.h> |
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#include <linux/io.h> |
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#include <linux/jiffies.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/timer.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 input_dev *input_dev; |
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void __iomem *mmio_base; |
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int irq; |
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struct timer_list check_matrix_timer; |
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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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bool enabled; |
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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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/* 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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struct input_dev *input_dev = keypad->input_dev; |
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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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input_event(input_dev, EV_MSC, MSC_SCAN, code); |
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input_report_key(input_dev, keypad->keycodes[code], |
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matrix_volatile_state[col] & (1 << row)); |
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dev_dbg(&input_dev->dev, "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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input_sync(input_dev); |
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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 timer_list *t) |
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{ |
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struct imx_keypad *keypad = from_timer(keypad, t, check_matrix_timer); |
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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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mod_timer(&keypad->check_matrix_timer, |
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jiffies + msecs_to_jiffies(10)); |
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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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mod_timer(&keypad->check_matrix_timer, |
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jiffies + msecs_to_jiffies(60)); |
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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 irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) |
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{ |
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struct imx_keypad *keypad = dev_id; |
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unsigned short reg_val; |
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reg_val = readw(keypad->mmio_base + KPSR); |
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/* Disable both interrupt types */ |
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reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); |
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/* Clear interrupts status bits */ |
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reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; |
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writew(reg_val, keypad->mmio_base + KPSR); |
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if (keypad->enabled) { |
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/* The matrix is supposed to be changed */ |
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keypad->stable_count = 0; |
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/* Schedule the scanning procedure near in the future */ |
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mod_timer(&keypad->check_matrix_timer, |
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jiffies + msecs_to_jiffies(2)); |
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} |
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return IRQ_HANDLED; |
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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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reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; |
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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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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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static void imx_keypad_close(struct input_dev *dev) |
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{ |
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struct imx_keypad *keypad = input_get_drvdata(dev); |
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dev_dbg(&dev->dev, ">%s\n", __func__); |
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/* Mark keypad as being inactive */ |
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keypad->enabled = false; |
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synchronize_irq(keypad->irq); |
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del_timer_sync(&keypad->check_matrix_timer); |
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imx_keypad_inhibit(keypad); |
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/* Disable clock unit */ |
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clk_disable_unprepare(keypad->clk); |
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} |
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static int imx_keypad_open(struct input_dev *dev) |
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{ |
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struct imx_keypad *keypad = input_get_drvdata(dev); |
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int error; |
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dev_dbg(&dev->dev, ">%s\n", __func__); |
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/* Enable the kpp clock */ |
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error = clk_prepare_enable(keypad->clk); |
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if (error) |
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return error; |
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/* We became active from now */ |
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keypad->enabled = true; |
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imx_keypad_config(keypad); |
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/* Sanity control, not all the rows must be actived now. */ |
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if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { |
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dev_err(&dev->dev, |
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"too many keys pressed, control pins initialisation\n"); |
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goto open_err; |
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} |
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return 0; |
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open_err: |
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imx_keypad_close(dev); |
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return -EIO; |
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} |
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static const struct of_device_id imx_keypad_of_match[] = { |
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{ .compatible = "fsl,imx21-kpp", }, |
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{ /* sentinel */ } |
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}; |
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MODULE_DEVICE_TABLE(of, imx_keypad_of_match); |
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static int imx_keypad_probe(struct platform_device *pdev) |
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{ |
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struct imx_keypad *keypad; |
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struct input_dev *input_dev; |
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int irq, error, i, row, col; |
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irq = platform_get_irq(pdev, 0); |
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if (irq < 0) |
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return irq; |
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input_dev = devm_input_allocate_device(&pdev->dev); |
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if (!input_dev) { |
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dev_err(&pdev->dev, "failed to allocate the input device\n"); |
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return -ENOMEM; |
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} |
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keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL); |
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if (!keypad) { |
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dev_err(&pdev->dev, "not enough memory for driver data\n"); |
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return -ENOMEM; |
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} |
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keypad->input_dev = input_dev; |
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keypad->irq = irq; |
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keypad->stable_count = 0; |
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timer_setup(&keypad->check_matrix_timer, |
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imx_keypad_check_for_events, 0); |
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keypad->mmio_base = devm_platform_ioremap_resource(pdev, 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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keypad->clk = devm_clk_get(&pdev->dev, NULL); |
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if (IS_ERR(keypad->clk)) { |
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dev_err(&pdev->dev, "failed to get keypad clock\n"); |
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return PTR_ERR(keypad->clk); |
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} |
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/* Init the Input device */ |
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input_dev->name = pdev->name; |
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input_dev->id.bustype = BUS_HOST; |
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input_dev->dev.parent = &pdev->dev; |
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input_dev->open = imx_keypad_open; |
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input_dev->close = imx_keypad_close; |
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error = matrix_keypad_build_keymap(NULL, NULL, |
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MAX_MATRIX_KEY_ROWS, |
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MAX_MATRIX_KEY_COLS, |
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keypad->keycodes, input_dev); |
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if (error) { |
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dev_err(&pdev->dev, "failed to build keymap\n"); |
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return error; |
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} |
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/* Search for rows and cols enabled */ |
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for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { |
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for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { |
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i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); |
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if (keypad->keycodes[i] != KEY_RESERVED) { |
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keypad->rows_en_mask |= 1 << row; |
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keypad->cols_en_mask |= 1 << col; |
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} |
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} |
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} |
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dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); |
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dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); |
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__set_bit(EV_REP, input_dev->evbit); |
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input_set_capability(input_dev, EV_MSC, MSC_SCAN); |
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input_set_drvdata(input_dev, keypad); |
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/* Ensure that the keypad will stay dormant until opened */ |
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error = clk_prepare_enable(keypad->clk); |
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if (error) |
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return error; |
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imx_keypad_inhibit(keypad); |
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clk_disable_unprepare(keypad->clk); |
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error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0, |
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pdev->name, keypad); |
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if (error) { |
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dev_err(&pdev->dev, "failed to request IRQ\n"); |
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return error; |
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} |
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/* Register the input device */ |
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error = input_register_device(input_dev); |
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if (error) { |
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dev_err(&pdev->dev, "failed to register input device\n"); |
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return error; |
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} |
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platform_set_drvdata(pdev, keypad); |
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device_init_wakeup(&pdev->dev, 1); |
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return 0; |
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} |
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static int __maybe_unused imx_kbd_noirq_suspend(struct device *dev) |
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{ |
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struct platform_device *pdev = to_platform_device(dev); |
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struct imx_keypad *kbd = platform_get_drvdata(pdev); |
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struct input_dev *input_dev = kbd->input_dev; |
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unsigned short reg_val = readw(kbd->mmio_base + KPSR); |
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/* imx kbd can wake up system even clock is disabled */ |
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mutex_lock(&input_dev->mutex); |
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if (input_device_enabled(input_dev)) |
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clk_disable_unprepare(kbd->clk); |
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mutex_unlock(&input_dev->mutex); |
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if (device_may_wakeup(&pdev->dev)) { |
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if (reg_val & KBD_STAT_KPKD) |
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reg_val |= KBD_STAT_KRIE; |
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if (reg_val & KBD_STAT_KPKR) |
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reg_val |= KBD_STAT_KDIE; |
|
writew(reg_val, kbd->mmio_base + KPSR); |
|
|
|
enable_irq_wake(kbd->irq); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int __maybe_unused imx_kbd_noirq_resume(struct device *dev) |
|
{ |
|
struct platform_device *pdev = to_platform_device(dev); |
|
struct imx_keypad *kbd = platform_get_drvdata(pdev); |
|
struct input_dev *input_dev = kbd->input_dev; |
|
int ret = 0; |
|
|
|
if (device_may_wakeup(&pdev->dev)) |
|
disable_irq_wake(kbd->irq); |
|
|
|
mutex_lock(&input_dev->mutex); |
|
|
|
if (input_device_enabled(input_dev)) { |
|
ret = clk_prepare_enable(kbd->clk); |
|
if (ret) |
|
goto err_clk; |
|
} |
|
|
|
err_clk: |
|
mutex_unlock(&input_dev->mutex); |
|
|
|
return ret; |
|
} |
|
|
|
static const struct dev_pm_ops imx_kbd_pm_ops = { |
|
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_kbd_noirq_suspend, imx_kbd_noirq_resume) |
|
}; |
|
|
|
static struct platform_driver imx_keypad_driver = { |
|
.driver = { |
|
.name = "imx-keypad", |
|
.pm = &imx_kbd_pm_ops, |
|
.of_match_table = imx_keypad_of_match, |
|
}, |
|
.probe = imx_keypad_probe, |
|
}; |
|
module_platform_driver(imx_keypad_driver); |
|
|
|
MODULE_AUTHOR("Alberto Panizzo <[email protected]>"); |
|
MODULE_DESCRIPTION("IMX Keypad Port Driver"); |
|
MODULE_LICENSE("GPL v2"); |
|
MODULE_ALIAS("platform:imx-keypad");
|
|
|