--- /dev/null
+/*
+ * Driver for the IMX keypad port.
+ * Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * <<Power management needs to be implemented>>.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.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(unsigned long data)
+{
+ struct imx_keypad *keypad = (struct imx_keypad *) data;
+ 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;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id imx_keypad_of_match[] = {
+ { .compatible = "fsl,imx21-kpp", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, imx_keypad_of_match);
+#endif
+
+static int imx_keypad_probe(struct platform_device *pdev)
+{
+ const struct matrix_keymap_data *keymap_data =
+ dev_get_platdata(&pdev->dev);
+ struct imx_keypad *keypad;
+ struct input_dev *input_dev;
+ struct resource *res;
+ int irq, error, i, row, col;
+
+ if (!keymap_data && !pdev->dev.of_node) {
+ dev_err(&pdev->dev, "no keymap defined\n");
+ return -EINVAL;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "no irq defined in platform data\n");
+ 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;
+
+ setup_timer(&keypad->check_matrix_timer,
+ imx_keypad_check_for_events, (unsigned long) keypad);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ keypad->mmio_base = devm_ioremap_resource(&pdev->dev, res);
+ 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(keymap_data, 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 */
+ clk_prepare_enable(keypad->clk);
+ 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_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;
+
+ /* imx kbd can wake up system even clock is disabled */
+ mutex_lock(&input_dev->mutex);
+
+ if (input_dev->users)
+ clk_disable_unprepare(kbd->clk);
+
+ mutex_unlock(&input_dev->mutex);
+
+ if (device_may_wakeup(&pdev->dev))
+ enable_irq_wake(kbd->irq);
+
+ return 0;
+}
+
+static int __maybe_unused imx_kbd_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_dev->users) {
+ ret = clk_prepare_enable(kbd->clk);
+ if (ret)
+ goto err_clk;
+ }
+
+err_clk:
+ mutex_unlock(&input_dev->mutex);
+
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume);
+
+static struct platform_driver imx_keypad_driver = {
+ .driver = {
+ .name = "imx-keypad",
+ .pm = &imx_kbd_pm_ops,
+ .of_match_table = of_match_ptr(imx_keypad_of_match),
+ },
+ .probe = imx_keypad_probe,
+};
+module_platform_driver(imx_keypad_driver);
+
+MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
+MODULE_DESCRIPTION("IMX Keypad Port Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:imx-keypad");
Code Review / kvmfornfv.git / blobdiff