diff options
Diffstat (limited to 'drivers/input/keyboard/imx_keypad.c')
| -rw-r--r-- | drivers/input/keyboard/imx_keypad.c | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/drivers/input/keyboard/imx_keypad.c b/drivers/input/keyboard/imx_keypad.c new file mode 100644 index 000000000..ae9c51cc8 --- /dev/null +++ b/drivers/input/keyboard/imx_keypad.c @@ -0,0 +1,598 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Driver for the IMX keypad port. +// Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com> + +#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(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; +} + +#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; + + timer_setup(&keypad->check_matrix_timer, + imx_keypad_check_for_events, 0); + + 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 */ + 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_dev->users) + 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_dev->users) { + 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 = 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"); |