// SPDX-License-Identifier: GPL-2.0
//
// Driver for the IMX keypad port.
// Copyright (C) 2009 Alberto Panizzo <[email protected]>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/input.h>
#include <linux/input/matrix_keypad.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/timer.h>
/*
* Keypad Controller registers (halfword)
*/
#define KPCR 0x00 /* Keypad Control Register */
#define KPSR 0x02 /* Keypad Status Register */
#define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */
#define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */
#define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/
#define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/
#define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */
#define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */
#define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */
#define KDDR 0x04 /* Keypad Data Direction Register */
#define KPDR 0x06 /* Keypad Data Register */
#define MAX_MATRIX_KEY_ROWS 8
#define MAX_MATRIX_KEY_COLS 8
#define MATRIX_ROW_SHIFT 3
#define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)
struct imx_keypad {
struct clk *clk;
struct input_dev *input_dev;
void __iomem *mmio_base;
int irq;
struct timer_list check_matrix_timer;
/*
* The matrix is stable only if no changes are detected after
* IMX_KEYPAD_SCANS_FOR_STABILITY scans
*/
#define IMX_KEYPAD_SCANS_FOR_STABILITY 3
int stable_count;
bool enabled;
/* Masks for enabled rows/cols */
unsigned short rows_en_mask;
unsigned short cols_en_mask;
unsigned short keycodes[MAX_MATRIX_KEY_NUM];
/*
* Matrix states:
* -stable: achieved after a complete debounce process.
* -unstable: used in the debouncing process.
*/
unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS];
unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS];
};
/* Scan the matrix and return the new state in *matrix_volatile_state. */
static void imx_keypad_scan_matrix(struct imx_keypad *keypad,
unsigned short *matrix_volatile_state)
{
int col;
unsigned short reg_val;
for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
if ((keypad->cols_en_mask & (1 << col)) == 0)
continue;
/*
* Discharge keypad capacitance:
* 2. write 1s on column data.
* 3. configure columns as totem-pole to discharge capacitance.
* 4. configure columns as open-drain.
*/
reg_val = readw(keypad->mmio_base + KPDR);
reg_val |= 0xff00;
writew(reg_val, keypad->mmio_base + KPDR);
reg_val = readw(keypad->mmio_base + KPCR);
reg_val &= ~((keypad->cols_en_mask & 0xff) << 8);
writew(reg_val, keypad->mmio_base + KPCR);
udelay(2);
reg_val = readw(keypad->mmio_base + KPCR);
reg_val |= (keypad->cols_en_mask & 0xff) << 8;
writew(reg_val, keypad->mmio_base + KPCR);
/*
* 5. Write a single column to 0, others to 1.
* 6. Sample row inputs and save data.
* 7. Repeat steps 2 - 6 for remaining columns.
*/
reg_val = readw(keypad->mmio_base + KPDR);
reg_val &= ~(1 << (8 + col));
writew(reg_val, keypad->mmio_base + KPDR);
/*
* Delay added to avoid propagating the 0 from column to row
* when scanning.
*/
udelay(5);
/*
* 1s in matrix_volatile_state[col] means key pressures
* throw data from non enabled rows.
*/
reg_val = readw(keypad->mmio_base + KPDR);
matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
}
/*
* Return in standby mode:
* 9. write 0s to columns
*/
reg_val = readw(keypad->mmio_base + KPDR);
reg_val &= 0x00ff;
writew(reg_val, keypad->mmio_base + KPDR);
}
/*
* Compare the new matrix state (volatile) with the stable one stored in
* keypad->matrix_stable_state and fire events if changes are detected.
*/
static void imx_keypad_fire_events(struct imx_keypad *keypad,
unsigned short *matrix_volatile_state)
{
struct input_dev *input_dev = keypad->input_dev;
int row, col;
for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
unsigned short bits_changed;
int code;
if ((keypad->cols_en_mask & (1 << col)) == 0)
continue; /* Column is not enabled */
bits_changed = keypad->matrix_stable_state[col] ^
matrix_volatile_state[col];
if (bits_changed == 0)
continue; /* Column does not contain changes */
for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
if ((keypad->rows_en_mask & (1 << row)) == 0)
continue; /* Row is not enabled */
if ((bits_changed & (1 << row)) == 0)
continue; /* Row does not contain changes */
code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
input_event(input_dev, EV_MSC, MSC_SCAN, code);
input_report_key(input_dev, keypad->keycodes[code],
matrix_volatile_state[col] & (1 << row));
dev_dbg(&input_dev->dev, "Event code: %d, val: %d",
keypad->keycodes[code],
matrix_volatile_state[col] & (1 << row));
}
}
input_sync(input_dev);
}
/*
* imx_keypad_check_for_events is the timer handler.
*/
static void imx_keypad_check_for_events(struct timer_list *t)
{
struct imx_keypad *keypad = from_timer(keypad, t, check_matrix_timer);
unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS];
unsigned short reg_val;
bool state_changed, is_zero_matrix;
int i;
memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));
imx_keypad_scan_matrix(keypad, matrix_volatile_state);
state_changed = false;
for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
if ((keypad->cols_en_mask & (1 << i)) == 0)
continue;
if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
state_changed = true;
break;
}
}
/*
* If the matrix state is changed from the previous scan
* (Re)Begin the debouncing process, saving the new state in
* keypad->matrix_unstable_state.
* else
* Increase the count of number of scans with a stable state.
*/
if (state_changed) {
memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
sizeof(matrix_volatile_state));
keypad->stable_count = 0;
} else
keypad->stable_count++;
/*
* If the matrix is not as stable as we want reschedule scan
* in the near future.
*/
if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
mod_timer(&keypad->check_matrix_timer,
jiffies + msecs_to_jiffies(10));
return;
}
/*
* If the matrix state is stable, fire the events and save the new
* stable state. Note, if the matrix is kept stable for longer
* (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all
* events have already been generated.
*/
if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
imx_keypad_fire_events(keypad, matrix_volatile_state);
memcpy(keypad->matrix_stable_state, matrix_volatile_state,
sizeof(matrix_volatile_state));
}
is_zero_matrix = true;
for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
if (matrix_volatile_state[i] != 0) {
is_zero_matrix = false;
break;
}
}
if (is_zero_matrix) {
/*
* All keys have been released. Enable only the KDI
* interrupt for future key presses (clear the KDI
* status bit and its sync chain before that).
*/
reg_val = readw(keypad->mmio_base + KPSR);
reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC;
writew(reg_val, keypad->mmio_base + KPSR);
reg_val = readw(keypad->mmio_base + KPSR);
reg_val |= KBD_STAT_KDIE;
reg_val &= ~KBD_STAT_KRIE;
writew(reg_val, keypad->mmio_base + KPSR);
} else {
/*
* Some keys are still pressed. Schedule a rescan in
* attempt to detect multiple key presses and enable
* the KRI interrupt to react quickly to key release
* event.
*/
mod_timer(&keypad->check_matrix_timer,
jiffies + msecs_to_jiffies(60));
reg_val = readw(keypad->mmio_base + KPSR);
reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS;
writew(reg_val, keypad->mmio_base + KPSR);
reg_val = readw(keypad->mmio_base + KPSR);
reg_val |= KBD_STAT_KRIE;
reg_val &= ~KBD_STAT_KDIE;
writew(reg_val, keypad->mmio_base + KPSR);
}
}
static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id)
{
struct imx_keypad *keypad = dev_id;
unsigned short reg_val;
reg_val = readw(keypad->mmio_base + KPSR);
/* Disable both interrupt types */
reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
/* Clear interrupts status bits */
reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
writew(reg_val, keypad->mmio_base + KPSR);
if (keypad->enabled) {
/* The matrix is supposed to be changed */
keypad->stable_count = 0;
/* Schedule the scanning procedure near in the future */
mod_timer(&keypad->check_matrix_timer,
jiffies + msecs_to_jiffies(2));
}
return IRQ_HANDLED;
}
static void imx_keypad_config(struct imx_keypad *keypad)
{
unsigned short reg_val;
/*
* Include enabled rows in interrupt generation (KPCR[7:0])
* Configure keypad columns as open-drain (KPCR[15:8])
*/
reg_val = readw(keypad->mmio_base + KPCR);
reg_val |= keypad->rows_en_mask & 0xff; /* rows */
reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */
writew(reg_val, keypad->mmio_base + KPCR);
/* Write 0's to KPDR[15:8] (Colums) */
reg_val = readw(keypad->mmio_base + KPDR);
reg_val &= 0x00ff;
writew(reg_val, keypad->mmio_base + KPDR);
/* Configure columns as output, rows as input (KDDR[15:0]) */
writew(0xff00, keypad->mmio_base + KDDR);
/*
* Clear Key Depress and Key Release status bit.
* Clear both synchronizer chain.
*/
reg_val = readw(keypad->mmio_base + KPSR);
reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD |
KBD_STAT_KDSC | KBD_STAT_KRSS;
writew(reg_val, keypad->mmio_base + KPSR);
/* Enable KDI and disable KRI (avoid false release events). */
reg_val |= KBD_STAT_KDIE;
reg_val &= ~KBD_STAT_KRIE;
writew(reg_val, keypad->mmio_base + KPSR);
}
static void imx_keypad_inhibit(struct imx_keypad *keypad)
{
unsigned short reg_val;
/* Inhibit KDI and KRI interrupts. */
reg_val = readw(keypad->mmio_base + KPSR);
reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
writew(reg_val, keypad->mmio_base + KPSR);
/* Colums as open drain and disable all rows */
reg_val = (keypad->cols_en_mask & 0xff) << 8;
writew(reg_val, keypad->mmio_base + KPCR);
}
static void imx_keypad_close(struct input_dev *dev)
{
struct imx_keypad *keypad = input_get_drvdata(dev);
dev_dbg(&dev->dev, ">%s\n", __func__);
/* Mark keypad as being inactive */
keypad->enabled = false;
synchronize_irq(keypad->irq);
del_timer_sync(&keypad->check_matrix_timer);
imx_keypad_inhibit(keypad);
/* Disable clock unit */
clk_disable_unprepare(keypad->clk);
}
static int imx_keypad_open(struct input_dev *dev)
{
struct imx_keypad *keypad = input_get_drvdata(dev);
int error;
dev_dbg(&dev->dev, ">%s\n", __func__);
/* Enable the kpp clock */
error = clk_prepare_enable(keypad->clk);
if (error)
return error;
/* We became active from now */
keypad->enabled = true;
imx_keypad_config(keypad);
/* Sanity control, not all the rows must be actived now. */
if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) {
dev_err(&dev->dev,
"too many keys pressed, control pins initialisation\n");
goto open_err;
}
return 0;
open_err:
imx_keypad_close(dev);
return -EIO;
}
static const struct of_device_id imx_keypad_of_match[] = {
{ .compatible = "fsl,imx21-kpp", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_keypad_of_match);
static int imx_keypad_probe(struct platform_device *pdev)
{
struct imx_keypad *keypad;
struct input_dev *input_dev;
int irq, error, i, row, col;
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
input_dev = devm_input_allocate_device(&pdev->dev);
if (!input_dev) {
dev_err(&pdev->dev, "failed to allocate the input device\n");
return -ENOMEM;
}
keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
if (!keypad) {
dev_err(&pdev->dev, "not enough memory for driver data\n");
return -ENOMEM;
}
keypad->input_dev = input_dev;
keypad->irq = irq;
keypad->stable_count = 0;
timer_setup(&keypad->check_matrix_timer,
imx_keypad_check_for_events, 0);
keypad->mmio_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(keypad->mmio_base))
return PTR_ERR(keypad->mmio_base);
keypad->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(keypad->clk)) {
dev_err(&pdev->dev, "failed to get keypad clock\n");
return PTR_ERR(keypad->clk);
}
/* Init the Input device */
input_dev->name = pdev->name;
input_dev->id.bustype = BUS_HOST;
input_dev->dev.parent = &pdev->dev;
input_dev->open = imx_keypad_open;
input_dev->close = imx_keypad_close;
error = matrix_keypad_build_keymap(NULL, NULL,
MAX_MATRIX_KEY_ROWS,
MAX_MATRIX_KEY_COLS,
keypad->keycodes, input_dev);
if (error) {
dev_err(&pdev->dev, "failed to build keymap\n");
return error;
}
/* Search for rows and cols enabled */
for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
if (keypad->keycodes[i] != KEY_RESERVED) {
keypad->rows_en_mask |= 1 << row;
keypad->cols_en_mask |= 1 << col;
}
}
}
dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask);
dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask);
__set_bit(EV_REP, input_dev->evbit);
input_set_capability(input_dev, EV_MSC, MSC_SCAN);
input_set_drvdata(input_dev, keypad);
/* Ensure that the keypad will stay dormant until opened */
error = clk_prepare_enable(keypad->clk);
if (error)
return error;
imx_keypad_inhibit(keypad);
clk_disable_unprepare(keypad->clk);
error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0,
pdev->name, keypad);
if (error) {
dev_err(&pdev->dev, "failed to request IRQ\n");
return error;
}
/* Register the input device */
error = input_register_device(input_dev);
if (error) {
dev_err(&pdev->dev, "failed to register input device\n");
return error;
}
platform_set_drvdata(pdev, keypad);
device_init_wakeup(&pdev->dev, 1);
return 0;
}
static int __maybe_unused imx_kbd_noirq_suspend(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;
unsigned short reg_val = readw(kbd->mmio_base + KPSR);
/* imx kbd can wake up system even clock is disabled */
mutex_lock(&input_dev->mutex);
if (input_device_enabled(input_dev))
clk_disable_unprepare(kbd->clk);
mutex_unlock(&input_dev->mutex);
if (device_may_wakeup(&pdev->dev)) {
if (reg_val & KBD_STAT_KPKD)
reg_val |= KBD_STAT_KRIE;
if (reg_val & KBD_STAT_KPKR)
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");
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