input: keyboard: Add support for MAX7360 keypad

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>
Link: https://lore.kernel.org/r/20250824-mdb-max7360-support-v14-8-435cfda2b1ea@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: mbriand

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

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

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");