[PATCH v14 08/10] input: keyboard: Add support for MAX7360 keypad

Mathieu Dubois-Briand
2025-08-24T11:58:25Z

Add driver for Maxim Integrated MAX7360 keypad controller, providing
support for up to 64 keys, with a matrix of 8 columns and 8 rows.

Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
drivers/input/keyboard/Kconfig | 12 ++
drivers/input/keyboard/Makefile | 1 +
drivers/input/keyboard/max7360-keypad.c | 308 ++++++++++++++++++++++++++++++++
3 files changed, 321 insertions(+)

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 7c4f309a4cb6..1b10528b7ca3 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -422,6 +422,18 @@ config KEYBOARD_MAX7359
To compile this driver as a module, choose M here: the
module will be called max7359_keypad.

+config KEYBOARD_MAX7360
+ tristate "Maxim MAX7360 Key Switch Controller"
+ select INPUT_MATRIXKMAP
+ depends on I2C
+ depends on MFD_MAX7360
+ help
+ If you say yes here you get support for the keypad controller on the
+ Maxim MAX7360 I/O Expander.
+
+ To compile this driver as a module, choose M here: the module will be
+ called max7360_keypad.
+
config KEYBOARD_MPR121
tristate "Freescale MPR121 Touchkey"
depends on I2C
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 8bc20ab2b103..636367cd1042 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -42,6 +42,7 @@ obj-$(CONFIG_KEYBOARD_LPC32XX) += lpc32xx-keys.o
obj-$(CONFIG_KEYBOARD_MAPLE) += maple_keyb.o
obj-$(CONFIG_KEYBOARD_MATRIX) += matrix_keypad.o
obj-$(CONFIG_KEYBOARD_MAX7359) += max7359_keypad.o
+obj-$(CONFIG_KEYBOARD_MAX7360) += max7360-keypad.o
obj-$(CONFIG_KEYBOARD_MPR121) += mpr121_touchkey.o
obj-$(CONFIG_KEYBOARD_MT6779) += mt6779-keypad.o
obj-$(CONFIG_KEYBOARD_MTK_PMIC) += mtk-pmic-keys.o
diff --git a/drivers/input/keyboard/max7360-keypad.c b/drivers/input/keyboard/max7360-keypad.c
new file mode 100644
index 000000000000..503be952b0a6
--- /dev/null
+++ b/drivers/input/keyboard/max7360-keypad.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2025 Bootlin
+ *
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/dev_printk.h>
+#include <linux/device/devres.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/max7360.h>
+#include <linux/mod_devicetable.h>
+#include <linux/minmax.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/pm_wakeirq.h>
+#include <linux/regmap.h>
+
+struct max7360_keypad {
+ struct input_dev *input;
+ unsigned int rows;
+ unsigned int cols;
+ unsigned int debounce_ms;
+ int irq;
+ struct regmap *regmap;
+ unsigned short keycodes[MAX7360_MAX_KEY_ROWS * MAX7360_MAX_KEY_COLS];
+};
+
+static irqreturn_t max7360_keypad_irq(int irq, void *data)
+{
+ struct max7360_keypad *max7360_keypad = data;
+ struct device *dev = max7360_keypad->input->dev.parent;
+ unsigned int val;
+ unsigned int row, col;
+ unsigned int release;
+ unsigned int code;
+ int error;
+
+ error = regmap_read(max7360_keypad->regmap, MAX7360_REG_KEYFIFO, &val);
+ if (error) {
+ dev_err(dev, "Failed to read MAX7360 FIFO");
+ return IRQ_NONE;
+ }
+
+ /* FIFO overflow: ignore it and get next event. */
+ if (val == MAX7360_FIFO_OVERFLOW) {
+ dev_warn(dev, "max7360 FIFO overflow");
+ error = regmap_read_poll_timeout(max7360_keypad->regmap, MAX7360_REG_KEYFIFO,
+ val, val != MAX7360_FIFO_OVERFLOW, 0, 1000);
+ if (error) {
+ dev_err(dev, "Failed to empty MAX7360 FIFO");
+ return IRQ_NONE;
+ }
+ }
+
+ if (val == MAX7360_FIFO_EMPTY) {
+ dev_dbg(dev, "Got a spurious interrupt");
+
+ return IRQ_NONE;
+ }
+
+ row = FIELD_GET(MAX7360_FIFO_ROW, val);
+ col = FIELD_GET(MAX7360_FIFO_COL, val);
+ release = val & MAX7360_FIFO_RELEASE;
+
+ code = MATRIX_SCAN_CODE(row, col, get_count_order(max7360_keypad->cols));
+
+ dev_dbg(dev, "key[%d:%d] %s\n", row, col, release ? "release" : "press");
+
+ input_event(max7360_keypad->input, EV_MSC, MSC_SCAN, code);
+ input_report_key(max7360_keypad->input, max7360_keypad->keycodes[code], !release);
+ input_sync(max7360_keypad->input);
+
+ return IRQ_HANDLED;
+}
+
+static int max7360_keypad_open(struct input_dev *pdev)
+{
+ struct max7360_keypad *max7360_keypad = input_get_drvdata(pdev);
+ struct device *dev = max7360_keypad->input->dev.parent;
+ int error;
+
+ /* Somebody is using the device: get out of sleep. */
+ error = regmap_write_bits(max7360_keypad->regmap, MAX7360_REG_CONFIG,
+ MAX7360_CFG_SLEEP, MAX7360_CFG_SLEEP);
+ if (error)
+ dev_err(dev, "Failed to write max7360 configuration: %d\n", error);
+
+ return error;
+}
+
+static void max7360_keypad_close(struct input_dev *pdev)
+{
+ struct max7360_keypad *max7360_keypad = input_get_drvdata(pdev);
+ struct device *dev = max7360_keypad->input->dev.parent;
+ int error;
+
+ /* Nobody is using the device anymore: go to sleep. */
+ error = regmap_write_bits(max7360_keypad->regmap, MAX7360_REG_CONFIG, MAX7360_CFG_SLEEP, 0);
+ if (error)
+ dev_err(dev, "Failed to write max7360 configuration: %d\n", error);
+}
+
+static int max7360_keypad_hw_init(struct max7360_keypad *max7360_keypad)
+{
+ struct device *dev = max7360_keypad->input->dev.parent;
+ unsigned int val;
+ int error;
+
+ val = max7360_keypad->debounce_ms - MAX7360_DEBOUNCE_MIN;
+ error = regmap_write_bits(max7360_keypad->regmap, MAX7360_REG_DEBOUNCE,
+ MAX7360_DEBOUNCE,
+ FIELD_PREP(MAX7360_DEBOUNCE, val));
+ if (error)
+ return dev_err_probe(dev, error,
+ "Failed to write max7360 debounce configuration\n");
+
+ error = regmap_write_bits(max7360_keypad->regmap, MAX7360_REG_INTERRUPT,
+ MAX7360_INTERRUPT_TIME_MASK,
+ FIELD_PREP(MAX7360_INTERRUPT_TIME_MASK, 1));
+ if (error)
+ return dev_err_probe(dev, error,
+ "Failed to write max7360 keypad interrupt configuration\n");
+
+ return 0;
+}
+
+static int max7360_keypad_build_keymap(struct max7360_keypad *max7360_keypad)
+{
+ struct input_dev *input_dev = max7360_keypad->input;
+ struct device *dev = input_dev->dev.parent->parent;
+ struct matrix_keymap_data keymap_data;
+ const char *propname = "linux,keymap";
+ unsigned int max_keys;
+ int error;
+ int size;
+
+ size = device_property_count_u32(dev, propname);
+ if (size <= 0) {
+ dev_err(dev, "missing or malformed property %s: %d\n", propname, size);
+ return size < 0 ? size : -EINVAL;
+ }
+
+ max_keys = max7360_keypad->cols * max7360_keypad->rows;
+ if (size > max_keys) {
+ dev_err(dev, "%s size overflow (%d vs max %u)\n", propname, size, max_keys);
+ return -EINVAL;
+ }
+
+ u32 *keys __free(kfree) = kmalloc_array(size, sizeof(*keys), GFP_KERNEL);
+ if (!keys)
+ return -ENOMEM;
+
+ error = device_property_read_u32_array(dev, propname, keys, size);
+ if (error) {
+ dev_err(dev, "failed to read %s property: %d\n", propname, error);
+ return error;
+ }
+
+ keymap_data.keymap = keys;
+ keymap_data.keymap_size = size;
+ error = matrix_keypad_build_keymap(&keymap_data, NULL,
+ max7360_keypad->rows, max7360_keypad->cols,
+ max7360_keypad->keycodes, max7360_keypad->input);
+ if (error)
+ return error;
+
+ return 0;
+}
+
+static int max7360_keypad_parse_fw(struct device *dev,
+ struct max7360_keypad *max7360_keypad,
+ bool *autorepeat)
+{
+ int error;
+
+ error = matrix_keypad_parse_properties(dev->parent, &max7360_keypad->rows,
+ &max7360_keypad->cols);
+ if (error)
+ return error;
+
+ if (!max7360_keypad->rows || !max7360_keypad->cols ||
+ max7360_keypad->rows > MAX7360_MAX_KEY_ROWS ||
+ max7360_keypad->cols > MAX7360_MAX_KEY_COLS) {
+ dev_err(dev, "Invalid number of columns or rows (%ux%u)\n",
+ max7360_keypad->cols, max7360_keypad->rows);
+ return -EINVAL;
+ }
+
+ *autorepeat = device_property_read_bool(dev->parent, "autorepeat");
+
+ max7360_keypad->debounce_ms = MAX7360_DEBOUNCE_MIN;
+ error = device_property_read_u32(dev->parent, "keypad-debounce-delay-ms",
+ &max7360_keypad->debounce_ms);
+ if (error == -EINVAL) {
+ dev_info(dev, "Using default keypad-debounce-delay-ms: %u\n",
+ max7360_keypad->debounce_ms);
+ } else if (error < 0) {
+ dev_err(dev, "Failed to read keypad-debounce-delay-ms property\n");
+ return error;
+ }
+
+ if (!in_range(max7360_keypad->debounce_ms, MAX7360_DEBOUNCE_MIN,
+ MAX7360_DEBOUNCE_MAX - MAX7360_DEBOUNCE_MIN + 1)) {
+ dev_err(dev, "Invalid keypad-debounce-delay-ms: %u, should be between %u and %u.\n",
+ max7360_keypad->debounce_ms, MAX7360_DEBOUNCE_MIN, MAX7360_DEBOUNCE_MAX);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int max7360_keypad_probe(struct platform_device *pdev)
+{
+ struct max7360_keypad *max7360_keypad;
+ struct device *dev = &pdev->dev;
+ struct input_dev *input;
+ struct regmap *regmap;
+ bool autorepeat;
+ int error;
+ int irq;
+
+ regmap = dev_get_regmap(dev->parent, NULL);
+ if (!regmap)
+ return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
+
+ irq = fwnode_irq_get_byname(dev_fwnode(dev->parent), "intk");
+ if (irq < 0)
+ return dev_err_probe(dev, irq, "Failed to get IRQ\n");
+
+ max7360_keypad = devm_kzalloc(dev, sizeof(*max7360_keypad), GFP_KERNEL);
+ if (!max7360_keypad)
+ return -ENOMEM;
+
+ max7360_keypad->regmap = regmap;
+
+ error = max7360_keypad_parse_fw(dev, max7360_keypad, &autorepeat);
+ if (error)
+ return error;
+
+ input = devm_input_allocate_device(dev);
+ if (!input)
+ return -ENOMEM;
+
+ max7360_keypad->input = input;
+
+ input->id.bustype = BUS_I2C;
+ input->name = pdev->name;
+ input->open = max7360_keypad_open;
+ input->close = max7360_keypad_close;
+
+ error = max7360_keypad_build_keymap(max7360_keypad);
+ if (error)
+ return dev_err_probe(dev, error, "Failed to build keymap\n");
+
+ input_set_capability(input, EV_MSC, MSC_SCAN);
+ if (autorepeat)
+ __set_bit(EV_REP, input->evbit);
+
+ input_set_drvdata(input, max7360_keypad);
+
+ error = devm_request_threaded_irq(dev, irq, NULL, max7360_keypad_irq,
+ IRQF_ONESHOT,
+ "max7360-keypad", max7360_keypad);
+ if (error)
+ return dev_err_probe(dev, error, "Failed to register interrupt\n");
+
+ error = input_register_device(input);
+ if (error)
+ return dev_err_probe(dev, error, "Could not register input device\n");
+
+ error = max7360_keypad_hw_init(max7360_keypad);
+ if (error)
+ return dev_err_probe(dev, error, "Failed to initialize max7360 keypad\n");
+
+ device_init_wakeup(dev, true);
+ error = dev_pm_set_wake_irq(dev, irq);
+ if (error)
+ dev_warn(dev, "Failed to set up wakeup irq: %d\n", error);
+
+ return 0;
+}
+
+static void max7360_keypad_remove(struct platform_device *pdev)
+{
+ dev_pm_clear_wake_irq(&pdev->dev);
+ device_init_wakeup(&pdev->dev, false);
+}
+
+static struct platform_driver max7360_keypad_driver = {
+ .driver = {
+ .name = "max7360-keypad",
+ },
+ .probe = max7360_keypad_probe,
+ .remove = max7360_keypad_remove,
+};
+module_platform_driver(max7360_keypad_driver);
+
+MODULE_DESCRIPTION("MAX7360 Keypad driver");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");

--
2.39.5