| // 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; |
| 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) |
| 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(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_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 = 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"); |