[PATCH v1 0/2] Input: Add Nuvoton MA35D1 keypad support

[PATCH v1 0/2] Input: Add Nuvoton MA35D1 keypad support

[Feng-Yi Hsueh]

This series adds support for the Nuvoton MA35D1 hardware
matrix keypad controller.

The controller supports up to eight rows and eight columns.
It provides key press and release event registers, which
the driver handles through the Linux input subsystem.

The driver uses the common clock framework and configures
the controller's scanning and debounce parameters using
fixed register settings.

The series consists of:
- A device tree binding for the MA35D1 keypad controller.
- An input driver with Kconfig and Makefile integration.

Tested on a Nuvoton MA35D1 board with a 4x1 keypad
configuration and a 1 MHz KPI clock.

Tests performed:
- Key press and release events verified using evtest.
- Input device open and close verified using evtest.

An earlier MA35D1 keypad driver was submitted by Ming-jen Chen. This series is a separate v1 submission with a revised implementation, focusing on simpler clock management and hardware event handling

Feng-Yi Hsueh (2):
  dt-bindings: input: Add Nuvoton MA35D1 keypad controller
  Input: keyboard: Add Nuvoton MA35D1 keypad driver

 .../bindings/input/nuvoton,ma35d1-keypad.yaml |  73 ++++
 drivers/input/keyboard/Kconfig                |  11 +
 drivers/input/keyboard/Makefile               |   1 +
 drivers/input/keyboard/ma35d1_keypad.c        | 405 ++++++++++++++++++
 4 files changed, 490 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/nuvoton,ma35d1-keypad.yaml
 create mode 100644 drivers/input/keyboard/ma35d1_keypad.c

-- 
2.43.0

[PATCH v1 1/2] dt-bindings: input: Add Nuvoton MA35D1 keypad controller

[Feng-Yi Hsueh]

Document the Nuvoton MA35D1 hardware matrix keypad controller.

The controller supports up to eight rows and eight columns
and generates interrupts for key press and release events.

Signed-off-by: Feng-Yi Hsueh <fyhsueh4linux@gmail.com>
---
 .../bindings/input/nuvoton,ma35d1-keypad.yaml | 73 +++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/nuvoton,ma35d1-keypad.yaml

diff --git a/Documentation/devicetree/bindings/input/nuvoton,ma35d1-keypad.yaml b/Documentation/devicetree/bindings/input/nuvoton,ma35d1-keypad.yaml
new file mode 100644
index 000000000000..be678d0b38b9
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/nuvoton,ma35d1-keypad.yaml
@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/nuvoton,ma35d1-keypad.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton MA35D1 Matrix Keypad Controller
+
+maintainers:
+  - Feng-Yi Hsueh <fyhsueh4linux@gmail.com>
+
+description: |
+  The Nuvoton MA35D1 keypad controller scans a matrix of up to eight rows
+  and eight columns and reports key press and release interrupts.
+
+allOf:
+  - $ref: /schemas/input/matrix-keymap.yaml#
+
+properties:
+  compatible:
+    const: nuvoton,ma35d1-keypad
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  keypad,num-rows:
+    minimum: 2
+    maximum: 8
+
+  keypad,num-columns:
+    minimum: 1
+    maximum: 8
+
+  autorepeat:
+    type: boolean
+    description: Enable key autorepeat events.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - keypad,num-rows
+  - keypad,num-columns
+  - linux,keymap
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/input/input.h>
+
+    keypad@404a0000 {
+        compatible = "nuvoton,ma35d1-keypad";
+        reg = <0x404a0000 0x10000>;
+        interrupts = <79>;
+        clocks = <&clk>;
+
+        keypad,num-rows = <4>;
+        keypad,num-columns = <1>;
+        linux,keymap = <
+            MATRIX_KEY(0, 0, KEY_1)
+            MATRIX_KEY(1, 0, KEY_2)
+            MATRIX_KEY(2, 0, KEY_3)
+            MATRIX_KEY(3, 0, KEY_4)
+        >;
+    };
-- 
2.43.0

[PATCH v1 2/2] Input: keyboard: Add Nuvoton MA35D1 keypad driver

[Feng-Yi Hsueh]

Add support for the Nuvoton MA35D1 hardware matrix keypad
controller.

The driver handles key press and release interrupts, reports
key events through the Linux input subsystem, and manages
the peripheral clock during device open, close, and system
suspend and resume.

Signed-off-by: Feng-Yi Hsueh <fyhsueh4linux@gmail.com>
---
 drivers/input/keyboard/Kconfig         |  11 +
 drivers/input/keyboard/Makefile        |   1 +
 drivers/input/keyboard/ma35d1_keypad.c | 405 +++++++++++++++++++++++++
 3 files changed, 417 insertions(+)
 create mode 100644 drivers/input/keyboard/ma35d1_keypad.c

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index d8c64f333462..9bbcbed3d494 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -358,6 +358,17 @@ config KEYBOARD_LPC32XX
 	  To compile this driver as a module, choose M here: the
 	  module will be called lpc32xx-keys.
 
+config KEYBOARD_MA35D1
+	tristate "Nuvoton MA35D1 keypad controller"
+	depends on ARCH_MA35 || COMPILE_TEST
+	select INPUT_MATRIXKMAP
+	help
+	  Say Y here to enable support for the Nuvoton MA35D1
+	  hardware matrix keypad controller.
+
+	  To compile this driver as a module, choose M here.
+	  The module will be called ma35d1_keypad.
+
 config KEYBOARD_MAPLE
 	tristate "Maple bus keyboard"
 	depends on SH_DREAMCAST && MAPLE
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 60bb7baf802f..fad34b7afff7 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_KEYBOARD_LM8323)		+= lm8323.o
 obj-$(CONFIG_KEYBOARD_LM8333)		+= lm8333.o
 obj-$(CONFIG_KEYBOARD_LOCOMO)		+= locomokbd.o
 obj-$(CONFIG_KEYBOARD_LPC32XX)		+= lpc32xx-keys.o
+obj-$(CONFIG_KEYBOARD_MA35D1) 		+= ma35d1_keypad.o
 obj-$(CONFIG_KEYBOARD_MAPLE)		+= maple_keyb.o
 obj-$(CONFIG_KEYBOARD_MATRIX)		+= matrix_keypad.o
 obj-$(CONFIG_KEYBOARD_MAX7359)		+= max7359_keypad.o
diff --git a/drivers/input/keyboard/ma35d1_keypad.c b/drivers/input/keyboard/ma35d1_keypad.c
new file mode 100644
index 000000000000..673ad8b9704b
--- /dev/null
+++ b/drivers/input/keyboard/ma35d1_keypad.c
@@ -0,0 +1,405 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Nuvoton MA35D1 hardware matrix keypad controller
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/input.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/property.h>
+#include <linux/types.h>
+
+#define MA35D1_KPI_CONF			0x00
+#define MA35D1_KPI_3KCONF		0x04
+#define MA35D1_KPI_STATUS		0x08
+#define MA35D1_KPI_KEST0		0x10
+#define MA35D1_KPI_KPE0			0x18
+#define MA35D1_KPI_KRE0			0x20
+#define MA35D1_KPI_PRESCALDIV		0x28
+
+#define MA35D1_KPI_KROW			GENMASK(30, 28)
+#define MA35D1_KPI_KCOL			GENMASK(26, 24)
+#define MA35D1_KPI_DBCLKSEL		GENMASK(19, 16)
+#define MA35D1_KPI_PRESCALE		GENMASK(15, 8)
+#define MA35D1_KPI_INTEN		BIT(3)
+#define MA35D1_KPI_RKINTEN		BIT(2)
+#define MA35D1_KPI_PKINTEN		BIT(1)
+#define MA35D1_KPI_ENKP			BIT(0)
+
+#define MA35D1_KPI_RST3KEY		BIT(1)
+#define MA35D1_KPI_PDWAKE		BIT(0)
+#define MA35D1_KPI_IRQ_MASK		GENMASK(4, 0)
+
+#define MA35D1_KPI_MAX_ROWS		8
+#define MA35D1_KPI_MAX_COLS		8
+#define MA35D1_KPI_BANKS		2
+#define MA35D1_KPI_ROWS_PER_BANK	(MA35D1_KPI_MAX_ROWS / MA35D1_KPI_BANKS)
+
+/*
+ * Scan timing, in KPI engine clock cycles.  PRESCALE and PRESCALDIV are
+ * encoded as the count minus one:
+ *
+ *   row scan cycles = (PRESCALE + 1) * (PRESCALDIV + 1) = 2080
+ *   debounce sample cycles = 2^DBCLKSEL = 1024
+ *
+ * With SCANROWD at its reset value (4 cycles) the TRM requires
+ * row scan time > 4 + 2 * 1024 + 3 = 2055 cycles.  These limits are expressed
+ * in cycles and therefore hold at different input rates. The actual scan
+ * and debounce intervals depend on the engine clock rate; boards should
+ * select a rate suitable for their switches (1 MHz has been validated).
+ */
+#define MA35D1_KPI_PRESCALE_VAL		0x40
+#define MA35D1_KPI_DIV_VAL		0x1f
+#define MA35D1_KPI_DEBOUNCE_SEL		10
+
+struct ma35d1_keypad {
+	void __iomem *base;
+	struct clk *clk;
+	struct input_dev *input;
+	unsigned short *keycodes;
+	unsigned int rows;
+	unsigned int cols;
+	unsigned int row_shift;
+	u32 conf;
+	int irq;
+	bool running;	/* protected by input->mutex */
+};
+
+static void ma35d1_keypad_clear_events(struct ma35d1_keypad *keypad)
+{
+	unsigned int bank;
+	u32 press, release;
+
+	for (bank = 0; bank < MA35D1_KPI_BANKS; bank++) {
+		press = readl(keypad->base + MA35D1_KPI_KPE0 + bank * 4);
+		release = readl(keypad->base + MA35D1_KPI_KRE0 + bank * 4);
+		/* The event registers are write-one-to-clear. */
+		if (press)
+			writel(press, keypad->base + MA35D1_KPI_KPE0 + bank * 4);
+		if (release)
+			writel(release, keypad->base + MA35D1_KPI_KRE0 + bank * 4);
+	}
+
+	/* Only these two KPISTATUS flags have W1C semantics. */
+	writel(MA35D1_KPI_RST3KEY | MA35D1_KPI_PDWAKE,
+	       keypad->base + MA35D1_KPI_STATUS);
+}
+
+/* Release software key states when hardware scanning is stopped. */
+static void ma35d1_keypad_release_keys(struct ma35d1_keypad *keypad)
+{
+	struct input_dev *input = keypad->input;
+	unsigned int row, col, scan, code;
+	bool reported = false;
+
+	for (row = 0; row < keypad->rows; row++) {
+		for (col = 0; col < keypad->cols; col++) {
+			scan = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
+			code = keypad->keycodes[scan];
+			if (code == KEY_RESERVED || !test_bit(code, input->key))
+				continue;
+
+			input_event(input, EV_MSC, MSC_SCAN, scan);
+			input_report_key(input, code, 0);
+			reported = true;
+		}
+	}
+
+	if (reported)
+		input_sync(input);
+}
+
+/* Called with input->mutex held (open, PM resume). */
+static int ma35d1_keypad_enable(struct ma35d1_keypad *keypad)
+{
+	int ret;
+
+	if (keypad->running)
+		return 0;
+
+	ret = clk_prepare_enable(keypad->clk);
+	if (ret)
+		return ret;
+
+	/* Keep hardware three-key reset disabled for a normal input device. */
+	writel(0, keypad->base + MA35D1_KPI_CONF);
+	writel(0, keypad->base + MA35D1_KPI_3KCONF);
+	writel(MA35D1_KPI_DIV_VAL, keypad->base + MA35D1_KPI_PRESCALDIV);
+	ma35d1_keypad_clear_events(keypad);
+	writel(keypad->conf, keypad->base + MA35D1_KPI_CONF);
+
+	keypad->running = true;
+	enable_irq(keypad->irq);
+
+	return 0;
+}
+
+/* Called with input->mutex held (close, PM suspend). */
+static void ma35d1_keypad_disable(struct ma35d1_keypad *keypad)
+{
+	if (!keypad->running)
+		return;
+
+	/* Wait for the IRQ handler while register access is still clocked. */
+	disable_irq(keypad->irq);
+	writel(0, keypad->base + MA35D1_KPI_CONF);
+	ma35d1_keypad_clear_events(keypad);
+	ma35d1_keypad_release_keys(keypad);
+	clk_disable_unprepare(keypad->clk);
+
+	keypad->running = false;
+}
+
+static int ma35d1_keypad_open(struct input_dev *input)
+{
+	struct ma35d1_keypad *keypad = input_get_drvdata(input);
+
+	return ma35d1_keypad_enable(keypad);
+}
+
+static void ma35d1_keypad_close(struct input_dev *input)
+{
+	struct ma35d1_keypad *keypad = input_get_drvdata(input);
+
+	ma35d1_keypad_disable(keypad);
+}
+
+static void ma35d1_keypad_report(struct ma35d1_keypad *keypad,
+				 unsigned int scan, unsigned short keycode,
+				 bool pressed)
+{
+	input_event(keypad->input, EV_MSC, MSC_SCAN, scan);
+	input_report_key(keypad->input, keycode, pressed);
+}
+
+static irqreturn_t ma35d1_keypad_irq(int irq, void *data)
+{
+	struct ma35d1_keypad *keypad = data;
+	struct input_dev *input = keypad->input;
+	bool reported = false;
+	u32 status, pressed, released, events, state;
+	unsigned int bank, bit, row, col, scan;
+	unsigned short keycode;
+	bool key_is_up;
+
+	status = readl(keypad->base + MA35D1_KPI_STATUS);
+	if (!(status & MA35D1_KPI_IRQ_MASK))
+		return IRQ_NONE;
+
+	for (bank = 0; bank < MA35D1_KPI_BANKS; bank++) {
+		pressed = readl(keypad->base + MA35D1_KPI_KPE0 + bank * 4);
+		released = readl(keypad->base + MA35D1_KPI_KRE0 + bank * 4);
+
+		/* Acknowledge the exact snapshots, not KPISTATUS[4:2]. */
+		if (pressed)
+			writel(pressed, keypad->base + MA35D1_KPI_KPE0 + bank * 4);
+		if (released)
+			writel(released, keypad->base + MA35D1_KPI_KRE0 + bank * 4);
+
+		events = pressed | released;
+		if (!events)
+			continue;
+
+		/* The live state is only needed to order a press/release pair. */
+		state = 0;
+		if (pressed & released)
+			state = readl(keypad->base + MA35D1_KPI_KEST0 + bank * 4);
+
+		while (events) {
+			bit = __ffs(events);
+			events &= ~BIT(bit);
+			row = bank * MA35D1_KPI_ROWS_PER_BANK +
+			      bit / MA35D1_KPI_MAX_COLS;
+			col = bit % MA35D1_KPI_MAX_COLS;
+
+			if (row >= keypad->rows || col >= keypad->cols)
+				continue;
+
+			scan = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
+			keycode = keypad->keycodes[scan];
+			if (keycode == KEY_RESERVED)
+				continue;
+
+			if ((pressed & released) & BIT(bit)) {
+				/*
+				 * Both edges were latched before this interrupt
+				 * was serviced.  KEST is active-low (1 means
+				 * released), so use the final state to order
+				 * them: up -> press then release, down ->
+				 * release then press.  Sync in between so user
+				 * space sees two separate frames.
+				 */
+				key_is_up = !!(state & BIT(bit));
+
+				ma35d1_keypad_report(keypad, scan, keycode,
+						     key_is_up);
+				input_sync(input);
+				ma35d1_keypad_report(keypad, scan, keycode,
+						     !key_is_up);
+			} else {
+				ma35d1_keypad_report(keypad, scan, keycode,
+						     !!(pressed & BIT(bit)));
+			}
+			reported = true;
+		}
+	}
+
+	if (status & (MA35D1_KPI_RST3KEY | MA35D1_KPI_PDWAKE))
+		writel(status & (MA35D1_KPI_RST3KEY | MA35D1_KPI_PDWAKE),
+		       keypad->base + MA35D1_KPI_STATUS);
+
+	if (reported)
+		input_sync(input);
+
+	return IRQ_HANDLED;
+}
+
+static int ma35d1_keypad_suspend(struct device *dev)
+{
+	struct ma35d1_keypad *keypad = dev_get_drvdata(dev);
+	struct input_dev *input = keypad->input;
+
+	mutex_lock(&input->mutex);
+	if (input_device_enabled(input))
+		ma35d1_keypad_disable(keypad);
+	mutex_unlock(&input->mutex);
+
+	return 0;
+}
+
+static int ma35d1_keypad_resume(struct device *dev)
+{
+	struct ma35d1_keypad *keypad = dev_get_drvdata(dev);
+	struct input_dev *input = keypad->input;
+	int ret = 0;
+
+	mutex_lock(&input->mutex);
+	if (input_device_enabled(input))
+		ret = ma35d1_keypad_enable(keypad);
+	mutex_unlock(&input->mutex);
+
+	return ret;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ma35d1_keypad_pm_ops,
+				ma35d1_keypad_suspend, ma35d1_keypad_resume);
+
+static int ma35d1_keypad_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ma35d1_keypad *keypad;
+	struct input_dev *input;
+	int ret;
+
+	keypad = devm_kzalloc(dev, sizeof(*keypad), GFP_KERNEL);
+	if (!keypad)
+		return -ENOMEM;
+
+	ret = matrix_keypad_parse_properties(dev, &keypad->rows, &keypad->cols);
+	if (ret)
+		return ret;
+
+	/* The controller supports 2x1 up to 8x8 keys (KROW = 0 is reserved). */
+	if (keypad->rows < 2 || keypad->rows > MA35D1_KPI_MAX_ROWS ||
+	    !keypad->cols || keypad->cols > MA35D1_KPI_MAX_COLS)
+		return dev_err_probe(dev, -EINVAL, "invalid keypad geometry\n");
+
+	keypad->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(keypad->base))
+		return PTR_ERR(keypad->base);
+
+	keypad->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(keypad->clk))
+		return dev_err_probe(dev, PTR_ERR(keypad->clk),
+				     "failed to get KPI clock\n");
+
+	keypad->irq = platform_get_irq(pdev, 0);
+	if (keypad->irq < 0)
+		return keypad->irq;
+
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	keypad->input = input;
+	keypad->row_shift = get_count_order(keypad->cols);
+	keypad->conf = FIELD_PREP(MA35D1_KPI_KROW, keypad->rows - 1) |
+		       FIELD_PREP(MA35D1_KPI_KCOL, keypad->cols - 1) |
+		       FIELD_PREP(MA35D1_KPI_DBCLKSEL, MA35D1_KPI_DEBOUNCE_SEL) |
+		       FIELD_PREP(MA35D1_KPI_PRESCALE, MA35D1_KPI_PRESCALE_VAL) |
+		       MA35D1_KPI_INTEN | MA35D1_KPI_RKINTEN |
+		       MA35D1_KPI_PKINTEN | MA35D1_KPI_ENKP;
+
+	input->name = "Nuvoton MA35D1 Keypad";
+	input->id.bustype = BUS_HOST;
+	input->open = ma35d1_keypad_open;
+	input->close = ma35d1_keypad_close;
+
+	ret = matrix_keypad_build_keymap(NULL, NULL, keypad->rows,
+					 keypad->cols, NULL, input);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to build keymap\n");
+
+	keypad->keycodes = input->keycode;
+	input_set_capability(input, EV_MSC, MSC_SCAN);
+	if (device_property_read_bool(dev, "autorepeat"))
+		__set_bit(EV_REP, input->evbit);
+
+	input_set_drvdata(input, keypad);
+	platform_set_drvdata(pdev, keypad);
+
+	/*
+	 * Clear whatever the bootloader left behind before the IRQ can be
+	 * requested.  The clock must run for the registers to be accessible.
+	 */
+	ret = clk_prepare_enable(keypad->clk);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to enable KPI clock\n");
+
+	writel(0, keypad->base + MA35D1_KPI_CONF);
+	ma35d1_keypad_clear_events(keypad);
+
+	clk_disable_unprepare(keypad->clk);
+
+	/* The IRQ stays disabled while the peripheral clock is gated. */
+	ret = devm_request_irq(dev, keypad->irq, ma35d1_keypad_irq,
+			       IRQF_NO_AUTOEN, dev_name(dev), keypad);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request IRQ\n");
+
+	ret = input_register_device(input);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register input device\n");
+
+	return 0;
+}
+
+static const struct of_device_id ma35d1_keypad_of_match[] = {
+	{ .compatible = "nuvoton,ma35d1-keypad" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ma35d1_keypad_of_match);
+
+static struct platform_driver ma35d1_keypad_driver = {
+	.probe = ma35d1_keypad_probe,
+	.driver = {
+		.name = "ma35d1-keypad",
+		.of_match_table = ma35d1_keypad_of_match,
+		.pm = pm_sleep_ptr(&ma35d1_keypad_pm_ops),
+	},
+};
+module_platform_driver(ma35d1_keypad_driver);
+
+MODULE_DESCRIPTION("Nuvoton MA35D1 hardware matrix keypad controller");
+MODULE_LICENSE("GPL");
-- 
2.43.0