[PATCH v3 0/4] Pine64 PinePhone keyboard support

[PATCH v3 0/4] Pine64 PinePhone keyboard support

[Samuel Holland]

This series adds support for the official keyboard case for the Pine64
PinePhone and PinePhone Pro. This accessory contains a keyboard MCU and
an IP5209 power bank IC. The keyboard MCU firmware[0] is free software.
It exposes the keyboard scan matrix over I2C, and also provides commands
for SMBus access to the IP5209. In order to keep the IP5209 driver
(CONFIG_IP5XXX_POWER) generic, this is modeled as a child I2C bus.

[0]: https://megous.com/git/pinephone-keyboard/about/

Changes in v3:
 - Replace unevaluatedProperties with additionalProperties
 - Rename i2c-bus to i2c

Changes in v2:
 - Drop keymap DT properties
 - Add vbat-supply property
 - Fix missing key release events when FN state changes
 - Add VBAT consumer to ensure enough power is available for the MCU
 - Use a single fixed-size, fixed-contents keymap for both layers

Samuel Holland (4):
  dt-bindings: input: Add the PinePhone keyboard binding
  Input: pinephone-keyboard - Add PinePhone keyboard driver
  Input: pinephone-keyboard - Support the proxied I2C bus
  [DO NOT MERGE] arm64: dts: allwinner: pinephone: Add keyboard

 .../input/pine64,pinephone-keyboard.yaml      |  66 +++
 MAINTAINERS                                   |   6 +
 .../dts/allwinner/sun50i-a64-pinephone.dtsi   |  18 +
 drivers/input/keyboard/Kconfig                |  10 +
 drivers/input/keyboard/Makefile               |   1 +
 drivers/input/keyboard/pinephone-keyboard.c   | 438 ++++++++++++++++++
 6 files changed, 539 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
 create mode 100644 drivers/input/keyboard/pinephone-keyboard.c

-- 
2.35.1

[PATCH v3 1/4] dt-bindings: input: Add the PinePhone keyboard binding

[Samuel Holland]

Add devicetree support for the PinePhone keyboard case, which provides a
matrix keyboard interface and a proxied I2C bus.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v3:
 - Replace unevaluatedProperties with additionalProperties
 - Rename i2c-bus to i2c

Changes in v2:
 - Drop keymap DT properties
 - Add vbat-supply property

 .../input/pine64,pinephone-keyboard.yaml      | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml

diff --git a/Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml b/Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
new file mode 100644
index 000000000000..e4a0ac0fff9a
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
@@ -0,0 +1,66 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/pine64,pinephone-keyboard.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Pine64 PinePhone keyboard device tree bindings
+
+maintainers:
+  - Samuel Holland <samuel@sholland.org>
+
+description:
+  A keyboard accessory is available for the Pine64 PinePhone and PinePhone Pro.
+  It connects via I2C, providing a raw scan matrix, a flashing interface, and a
+  subordinate I2C bus for communication with a battery charger IC.
+
+properties:
+  compatible:
+    const: pine64,pinephone-keyboard
+
+  reg:
+    const: 0x15
+
+  interrupts:
+    maxItems: 1
+
+  vbat-supply:
+    description: Supply for the keyboard MCU
+
+  wakeup-source: true
+
+  i2c:
+    $ref: /schemas/i2c/i2c-controller.yaml#
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/input/input.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      keyboard@15 {
+        compatible = "pine64,pinephone-keyboard";
+        reg = <0x15>;
+        interrupt-parent = <&r_pio>;
+        interrupts = <0 12 IRQ_TYPE_EDGE_FALLING>; /* PL12 */
+
+        i2c {
+          #address-cells = <1>;
+          #size-cells = <0>;
+
+          charger@75 {
+            reg = <0x75>;
+          };
+        };
+      };
+    };
-- 
2.35.1

[PATCH v3 2/4] Input: pinephone-keyboard - Add PinePhone keyboard driver

[Samuel Holland]

The official Pine64 PinePhone keyboard case contains a matrix keypad and
a MCU which runs a libre firmware. Add support for its I2C interface.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

(no changes since v2)

Changes in v2:
 - Fix missing key release events when FN state changes
 - Add VBAT consumer to ensure enough power is available for the MCU
 - Use a single fixed-size, fixed-contents keymap for both layers

 MAINTAINERS                                 |   6 +
 drivers/input/keyboard/Kconfig              |  10 +
 drivers/input/keyboard/Makefile             |   1 +
 drivers/input/keyboard/pinephone-keyboard.c | 365 ++++++++++++++++++++
 4 files changed, 382 insertions(+)
 create mode 100644 drivers/input/keyboard/pinephone-keyboard.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fd768d43e048..2f77efd8362e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15648,6 +15648,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.yaml
 F:	drivers/iio/chemical/pms7003.c
 
+PINE64 PINEPHONE KEYBOARD DRIVER
+M:	Samuel Holland <samuel@sholland.org>
+S:	Supported
+F:	Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
+F:	drivers/input/keyboard/pinephone-keyboard.c
+
 PLDMFW LIBRARY
 M:	Jacob Keller <jacob.e.keller@intel.com>
 S:	Maintained
diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index 4ea79db8f134..0a84aa4b6209 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -524,6 +524,16 @@ config KEYBOARD_OPENCORES
 	  To compile this driver as a module, choose M here; the
 	  module will be called opencores-kbd.
 
+config KEYBOARD_PINEPHONE
+	tristate "Pine64 PinePhone Keyboard"
+	depends on I2C && REGULATOR
+	select CRC8
+	select INPUT_MATRIXKMAP
+	help
+	  Say Y here to enable support for the keyboard in the Pine64 PinePhone
+	  keyboard case. This driver supports the FLOSS firmware available at
+	  https://megous.com/git/pinephone-keyboard/
+
 config KEYBOARD_PXA27x
 	tristate "PXA27x/PXA3xx keypad support"
 	depends on PXA27x || PXA3xx || ARCH_MMP
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index 721936e90290..5f67196bb2c1 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_KEYBOARD_NSPIRE)		+= nspire-keypad.o
 obj-$(CONFIG_KEYBOARD_OMAP)		+= omap-keypad.o
 obj-$(CONFIG_KEYBOARD_OMAP4)		+= omap4-keypad.o
 obj-$(CONFIG_KEYBOARD_OPENCORES)	+= opencores-kbd.o
+obj-$(CONFIG_KEYBOARD_PINEPHONE)	+= pinephone-keyboard.o
 obj-$(CONFIG_KEYBOARD_PMIC8XXX)		+= pmic8xxx-keypad.o
 obj-$(CONFIG_KEYBOARD_PXA27x)		+= pxa27x_keypad.o
 obj-$(CONFIG_KEYBOARD_PXA930_ROTARY)	+= pxa930_rotary.o
diff --git a/drivers/input/keyboard/pinephone-keyboard.c b/drivers/input/keyboard/pinephone-keyboard.c
new file mode 100644
index 000000000000..2ee74cbe68dd
--- /dev/null
+++ b/drivers/input/keyboard/pinephone-keyboard.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright (C) 2021-2022 Samuel Holland <samuel@sholland.org>
+
+#include <linux/crc8.h>
+#include <linux/i2c.h>
+#include <linux/input/matrix_keypad.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+
+#define DRV_NAME			"pinephone-keyboard"
+
+#define PPKB_CRC8_POLYNOMIAL		0x07
+
+#define PPKB_DEVICE_ID_HI		0x00
+#define PPKB_DEVICE_ID_HI_VALUE			'K'
+#define PPKB_DEVICE_ID_LO		0x01
+#define PPKB_DEVICE_ID_LO_VALUE			'B'
+#define PPKB_FW_REVISION		0x02
+#define PPKB_FW_FEATURES		0x03
+#define PPKB_MATRIX_SIZE		0x06
+#define PPKB_SCAN_CRC			0x07
+#define PPKB_SCAN_DATA			0x08
+#define PPKB_SYS_CONFIG			0x20
+#define PPKB_SYS_CONFIG_DISABLE_SCAN		BIT(0)
+
+#define PPKB_ROWS			6
+#define PPKB_COLS			12
+
+/* Size of the scan buffer, including the CRC byte at the beginning. */
+#define PPKB_BUF_LEN			(1 + PPKB_COLS)
+
+static const uint32_t ppkb_keymap[] = {
+	KEY(0,  0, KEY_ESC),
+	KEY(0,  1, KEY_1),
+	KEY(0,  2, KEY_2),
+	KEY(0,  3, KEY_3),
+	KEY(0,  4, KEY_4),
+	KEY(0,  5, KEY_5),
+	KEY(0,  6, KEY_6),
+	KEY(0,  7, KEY_7),
+	KEY(0,  8, KEY_8),
+	KEY(0,  9, KEY_9),
+	KEY(0, 10, KEY_0),
+	KEY(0, 11, KEY_BACKSPACE),
+
+	KEY(1,  0, KEY_TAB),
+	KEY(1,  1, KEY_Q),
+	KEY(1,  2, KEY_W),
+	KEY(1,  3, KEY_E),
+	KEY(1,  4, KEY_R),
+	KEY(1,  5, KEY_T),
+	KEY(1,  6, KEY_Y),
+	KEY(1,  7, KEY_U),
+	KEY(1,  8, KEY_I),
+	KEY(1,  9, KEY_O),
+	KEY(1, 10, KEY_P),
+	KEY(1, 11, KEY_ENTER),
+
+	KEY(2,  0, KEY_LEFTMETA),
+	KEY(2,  1, KEY_A),
+	KEY(2,  2, KEY_S),
+	KEY(2,  3, KEY_D),
+	KEY(2,  4, KEY_F),
+	KEY(2,  5, KEY_G),
+	KEY(2,  6, KEY_H),
+	KEY(2,  7, KEY_J),
+	KEY(2,  8, KEY_K),
+	KEY(2,  9, KEY_L),
+	KEY(2, 10, KEY_SEMICOLON),
+
+	KEY(3,  0, KEY_LEFTSHIFT),
+	KEY(3,  1, KEY_Z),
+	KEY(3,  2, KEY_X),
+	KEY(3,  3, KEY_C),
+	KEY(3,  4, KEY_V),
+	KEY(3,  5, KEY_B),
+	KEY(3,  6, KEY_N),
+	KEY(3,  7, KEY_M),
+	KEY(3,  8, KEY_COMMA),
+	KEY(3,  9, KEY_DOT),
+	KEY(3, 10, KEY_SLASH),
+
+	KEY(4,  1, KEY_LEFTCTRL),
+	KEY(4,  4, KEY_SPACE),
+	KEY(4,  6, KEY_APOSTROPHE),
+	KEY(4,  8, KEY_RIGHTBRACE),
+	KEY(4,  9, KEY_LEFTBRACE),
+
+	KEY(5,  2, KEY_FN),
+	KEY(5,  3, KEY_LEFTALT),
+	KEY(5,  5, KEY_RIGHTALT),
+
+	/* FN layer */
+	KEY(PPKB_ROWS + 0,  0, KEY_FN_ESC),
+	KEY(PPKB_ROWS + 0,  1, KEY_F1),
+	KEY(PPKB_ROWS + 0,  2, KEY_F2),
+	KEY(PPKB_ROWS + 0,  3, KEY_F3),
+	KEY(PPKB_ROWS + 0,  4, KEY_F4),
+	KEY(PPKB_ROWS + 0,  5, KEY_F5),
+	KEY(PPKB_ROWS + 0,  6, KEY_F6),
+	KEY(PPKB_ROWS + 0,  7, KEY_F7),
+	KEY(PPKB_ROWS + 0,  8, KEY_F8),
+	KEY(PPKB_ROWS + 0,  9, KEY_F9),
+	KEY(PPKB_ROWS + 0, 10, KEY_F10),
+	KEY(PPKB_ROWS + 0, 11, KEY_DELETE),
+
+	KEY(PPKB_ROWS + 1, 10, KEY_PAGEUP),
+
+	KEY(PPKB_ROWS + 2,  0, KEY_SYSRQ),
+	KEY(PPKB_ROWS + 2,  9, KEY_PAGEDOWN),
+	KEY(PPKB_ROWS + 2, 10, KEY_INSERT),
+
+	KEY(PPKB_ROWS + 3,  0, KEY_LEFTSHIFT),
+	KEY(PPKB_ROWS + 3,  8, KEY_HOME),
+	KEY(PPKB_ROWS + 3,  9, KEY_UP),
+	KEY(PPKB_ROWS + 3, 10, KEY_END),
+
+	KEY(PPKB_ROWS + 4, 1, KEY_LEFTCTRL),
+	KEY(PPKB_ROWS + 4, 6, KEY_LEFT),
+	KEY(PPKB_ROWS + 4, 8, KEY_RIGHT),
+	KEY(PPKB_ROWS + 4, 9, KEY_DOWN),
+
+	KEY(PPKB_ROWS + 5, 3, KEY_LEFTALT),
+	KEY(PPKB_ROWS + 5, 5, KEY_RIGHTALT),
+};
+
+static const struct matrix_keymap_data ppkb_keymap_data = {
+	.keymap		= ppkb_keymap,
+	.keymap_size	= ARRAY_SIZE(ppkb_keymap),
+};
+
+struct pinephone_keyboard {
+	struct input_dev *input;
+	u8 buf[2][PPKB_BUF_LEN];
+	u8 crc_table[CRC8_TABLE_SIZE];
+	u8 fn_state[PPKB_COLS];
+	bool buf_swap;
+	bool fn_pressed;
+};
+
+static void ppkb_update(struct i2c_client *client)
+{
+	struct pinephone_keyboard *ppkb = i2c_get_clientdata(client);
+	unsigned short *keymap = ppkb->input->keycode;
+	int row_shift = get_count_order(PPKB_COLS);
+	u8 *old_buf = ppkb->buf[!ppkb->buf_swap];
+	u8 *new_buf = ppkb->buf[ppkb->buf_swap];
+	int col, crc, ret, row;
+	struct device *dev = &client->dev;
+
+	ret = i2c_smbus_read_i2c_block_data(client, PPKB_SCAN_CRC,
+					    PPKB_BUF_LEN, new_buf);
+	if (ret != PPKB_BUF_LEN) {
+		dev_err(dev, "Failed to read scan data: %d\n", ret);
+		return;
+	}
+
+	crc = crc8(ppkb->crc_table, &new_buf[1], PPKB_COLS, CRC8_INIT_VALUE);
+	if (crc != new_buf[0]) {
+		dev_err(dev, "Bad scan data (%02x != %02x)\n", crc, new_buf[0]);
+		return;
+	}
+
+	ppkb->buf_swap = !ppkb->buf_swap;
+
+	for (col = 0; col < PPKB_COLS; ++col) {
+		u8 old = old_buf[1 + col];
+		u8 new = new_buf[1 + col];
+		u8 changed = old ^ new;
+
+		if (!changed)
+			continue;
+
+		for (row = 0; row < PPKB_ROWS; ++row) {
+			u8 mask = BIT(row);
+			u8 value = new & mask;
+			unsigned short code;
+			bool fn_state;
+
+			if (!(changed & mask))
+				continue;
+
+			/*
+			 * Save off the FN key state when the key was pressed,
+			 * and use that to determine the code during a release.
+			 */
+			fn_state = value ? ppkb->fn_pressed : ppkb->fn_state[col] & mask;
+			if (fn_state)
+				ppkb->fn_state[col] ^= mask;
+
+			/* The FN layer is a second set of rows. */
+			code = MATRIX_SCAN_CODE(fn_state ? PPKB_ROWS + row : row,
+						col, row_shift);
+			input_event(ppkb->input, EV_MSC, MSC_SCAN, code);
+			input_report_key(ppkb->input, keymap[code], value);
+			if (keymap[code] == KEY_FN)
+				ppkb->fn_pressed = value;
+		}
+	}
+	input_sync(ppkb->input);
+}
+
+static irqreturn_t ppkb_irq_thread(int irq, void *data)
+{
+	struct i2c_client *client = data;
+
+	ppkb_update(client);
+
+	return IRQ_HANDLED;
+}
+
+static int ppkb_set_scan(struct i2c_client *client, bool enable)
+{
+	struct device *dev = &client->dev;
+	int ret, val;
+
+	ret = i2c_smbus_read_byte_data(client, PPKB_SYS_CONFIG);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read config: %d\n", ret);
+		return ret;
+	}
+
+	if (enable)
+		val = ret & ~PPKB_SYS_CONFIG_DISABLE_SCAN;
+	else
+		val = ret | PPKB_SYS_CONFIG_DISABLE_SCAN;
+	ret = i2c_smbus_write_byte_data(client, PPKB_SYS_CONFIG, val);
+	if (ret) {
+		dev_err(dev, "Failed to write config: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ppkb_open(struct input_dev *input)
+{
+	struct i2c_client *client = input_get_drvdata(input);
+	int ret;
+
+	ret = ppkb_set_scan(client, true);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void ppkb_close(struct input_dev *input)
+{
+	struct i2c_client *client = input_get_drvdata(input);
+
+	ppkb_set_scan(client, false);
+}
+
+static void ppkb_regulator_disable(void *regulator)
+{
+	regulator_disable(regulator);
+}
+
+static int ppkb_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	unsigned int phys_rows, phys_cols;
+	struct pinephone_keyboard *ppkb;
+	struct regulator *vbat_supply;
+	u8 info[PPKB_MATRIX_SIZE + 1];
+	int ret;
+
+	vbat_supply = devm_regulator_get(dev, "vbat");
+	if (IS_ERR(vbat_supply))
+		return dev_err_probe(dev, PTR_ERR(vbat_supply),
+				     "Failed to get VBAT supply");
+
+	ret = regulator_enable(vbat_supply);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable VBAT");
+
+	ret = devm_add_action_or_reset(dev, ppkb_regulator_disable, vbat_supply);
+	if (ret)
+		return ret;
+
+	ret = i2c_smbus_read_i2c_block_data(client, 0, sizeof(info), info);
+	if (ret != sizeof(info))
+		return dev_err_probe(dev, -ENODEV, "Failed to read device ID\n");
+
+	if (info[PPKB_DEVICE_ID_HI] != PPKB_DEVICE_ID_HI_VALUE ||
+	    info[PPKB_DEVICE_ID_LO] != PPKB_DEVICE_ID_LO_VALUE)
+		return dev_err_probe(dev, -ENODEV, "Unexpected device ID\n");
+
+	dev_info(dev, "Found firmware version %d.%d features %#x\n",
+		 info[PPKB_FW_REVISION] >> 4,
+		 info[PPKB_FW_REVISION] & 0xf,
+		 info[PPKB_FW_FEATURES]);
+
+	phys_rows = info[PPKB_MATRIX_SIZE] & 0xf;
+	phys_cols = info[PPKB_MATRIX_SIZE] >> 4;
+	if (phys_rows != PPKB_ROWS || phys_cols != PPKB_COLS)
+		return dev_err_probe(dev, -EINVAL, "Unexpected keyboard size %ux%u\n",
+				     phys_rows, phys_cols);
+
+	/* Disable scan by default to save power. */
+	ret = ppkb_set_scan(client, false);
+	if (ret)
+		return ret;
+
+	ppkb = devm_kzalloc(dev, sizeof(*ppkb), GFP_KERNEL);
+	if (!ppkb)
+		return -ENOMEM;
+
+	i2c_set_clientdata(client, ppkb);
+
+	crc8_populate_msb(ppkb->crc_table, PPKB_CRC8_POLYNOMIAL);
+
+	ppkb->input = devm_input_allocate_device(dev);
+	if (!ppkb->input)
+		return -ENOMEM;
+
+	input_set_drvdata(ppkb->input, client);
+
+	ppkb->input->name = "PinePhone Keyboard";
+	ppkb->input->phys = DRV_NAME "/input0";
+	ppkb->input->id.bustype = BUS_I2C;
+	ppkb->input->open = ppkb_open;
+	ppkb->input->close = ppkb_close;
+
+	input_set_capability(ppkb->input, EV_MSC, MSC_SCAN);
+	__set_bit(EV_REP, ppkb->input->evbit);
+
+	ret = matrix_keypad_build_keymap(&ppkb_keymap_data, NULL, 2 * PPKB_ROWS,
+					 PPKB_COLS, NULL, ppkb->input);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to build keymap\n");
+
+	ret = input_register_device(ppkb->input);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register input\n");
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL, ppkb_irq_thread,
+					IRQF_ONESHOT, client->name, client);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
+
+	return 0;
+}
+
+static const struct of_device_id ppkb_of_match[] = {
+	{ .compatible = "pine64,pinephone-keyboard" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ppkb_of_match);
+
+static struct i2c_driver ppkb_driver = {
+	.probe_new	= ppkb_probe,
+	.driver		= {
+		.name		= DRV_NAME,
+		.of_match_table = ppkb_of_match,
+	},
+};
+module_i2c_driver(ppkb_driver);
+
+MODULE_AUTHOR("Samuel Holland <samuel@sholland.org>");
+MODULE_DESCRIPTION("Pine64 PinePhone keyboard driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1

[PATCH v3 3/4] Input: pinephone-keyboard - Support the proxied I2C bus

[Samuel Holland]

The PinePhone keyboard case contains a battery managed by an integrated
power bank IC. The power bank IC communicates over I2C, and the keyboard
MCU firmware provides an interface to read and write its registers.
Let's use this interface to implement a SMBus adapter, so we can reuse
the driver for the power bank IC.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v3:
 - Rename i2c-bus to i2c

 drivers/input/keyboard/pinephone-keyboard.c | 73 +++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/drivers/input/keyboard/pinephone-keyboard.c b/drivers/input/keyboard/pinephone-keyboard.c
index 2ee74cbe68dd..008e1322bd2d 100644
--- a/drivers/input/keyboard/pinephone-keyboard.c
+++ b/drivers/input/keyboard/pinephone-keyboard.c
@@ -3,6 +3,7 @@
 // Copyright (C) 2021-2022 Samuel Holland <samuel@sholland.org>
 
 #include <linux/crc8.h>
+#include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/input/matrix_keypad.h>
 #include <linux/interrupt.h>
@@ -24,6 +25,11 @@
 #define PPKB_SCAN_DATA			0x08
 #define PPKB_SYS_CONFIG			0x20
 #define PPKB_SYS_CONFIG_DISABLE_SCAN		BIT(0)
+#define PPKB_SYS_SMBUS_COMMAND		0x21
+#define PPKB_SYS_SMBUS_DATA		0x22
+#define PPKB_SYS_COMMAND		0x23
+#define PPKB_SYS_COMMAND_SMBUS_READ		0x91
+#define PPKB_SYS_COMMAND_SMBUS_WRITE		0xa1
 
 #define PPKB_ROWS			6
 #define PPKB_COLS			12
@@ -132,6 +138,7 @@ static const struct matrix_keymap_data ppkb_keymap_data = {
 };
 
 struct pinephone_keyboard {
+	struct i2c_adapter adapter;
 	struct input_dev *input;
 	u8 buf[2][PPKB_BUF_LEN];
 	u8 crc_table[CRC8_TABLE_SIZE];
@@ -140,6 +147,57 @@ struct pinephone_keyboard {
 	bool fn_pressed;
 };
 
+static int ppkb_adap_smbus_xfer(struct i2c_adapter *adap, u16 addr,
+				unsigned short flags, char read_write,
+				u8 command, int size,
+				union i2c_smbus_data *data)
+{
+	struct i2c_client *client = adap->algo_data;
+	u8 buf[3];
+	int ret;
+
+	buf[0] = command;
+	buf[1] = data->byte;
+	buf[2] = read_write == I2C_SMBUS_READ ? PPKB_SYS_COMMAND_SMBUS_READ
+					      : PPKB_SYS_COMMAND_SMBUS_WRITE;
+
+	ret = i2c_smbus_write_i2c_block_data(client, PPKB_SYS_SMBUS_COMMAND,
+					     sizeof(buf), buf);
+	if (ret)
+		return ret;
+
+	/* Read back the command status until it passes or fails. */
+	do {
+		usleep_range(300, 500);
+		ret = i2c_smbus_read_byte_data(client, PPKB_SYS_COMMAND);
+	} while (ret == buf[2]);
+	if (ret < 0)
+		return ret;
+	/* Commands return 0x00 on success and 0xff on failure. */
+	if (ret)
+		return -EIO;
+
+	if (read_write == I2C_SMBUS_READ) {
+		ret = i2c_smbus_read_byte_data(client, PPKB_SYS_SMBUS_DATA);
+		if (ret < 0)
+			return ret;
+
+		data->byte = ret;
+	}
+
+	return 0;
+}
+
+static u32 ppkg_adap_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_SMBUS_BYTE_DATA;
+}
+
+static const struct i2c_algorithm ppkb_adap_algo = {
+	.smbus_xfer		= ppkb_adap_smbus_xfer,
+	.functionality		= ppkg_adap_functionality,
+};
+
 static void ppkb_update(struct i2c_client *client)
 {
 	struct pinephone_keyboard *ppkb = i2c_get_clientdata(client);
@@ -266,6 +324,7 @@ static int ppkb_probe(struct i2c_client *client)
 	struct pinephone_keyboard *ppkb;
 	struct regulator *vbat_supply;
 	u8 info[PPKB_MATRIX_SIZE + 1];
+	struct device_node *i2c_bus;
 	int ret;
 
 	vbat_supply = devm_regulator_get(dev, "vbat");
@@ -311,6 +370,20 @@ static int ppkb_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, ppkb);
 
+	i2c_bus = of_get_child_by_name(dev->of_node, "i2c");
+	if (i2c_bus) {
+		ppkb->adapter.owner = THIS_MODULE;
+		ppkb->adapter.algo = &ppkb_adap_algo;
+		ppkb->adapter.algo_data = client;
+		ppkb->adapter.dev.parent = dev;
+		ppkb->adapter.dev.of_node = i2c_bus;
+		strscpy(ppkb->adapter.name, DRV_NAME, sizeof(ppkb->adapter.name));
+
+		ret = devm_i2c_add_adapter(dev, &ppkb->adapter);
+		if (ret)
+			return dev_err_probe(dev, ret, "Failed to add I2C adapter\n");
+	}
+
 	crc8_populate_msb(ppkb->crc_table, PPKB_CRC8_POLYNOMIAL);
 
 	ppkb->input = devm_input_allocate_device(dev);
-- 
2.35.1

[PATCH v3 4/4] [DO NOT MERGE] arm64: dts: allwinner: pinephone: Add keyboard

[Samuel Holland]

The official PinePhone keyboard accessory connects to the phone's POGO
pins for I2C and interrupts. It has an Injoinic IP5209 power bank IC
connected to the keyboard's internal I2C bus.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v3:
 - Rename i2c-bus to i2c

 .../dts/allwinner/sun50i-a64-pinephone.dtsi    | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
index 87847116ab6d..1d757cce246a 100644
--- a/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
+++ b/arch/arm64/boot/dts/allwinner/sun50i-a64-pinephone.dtsi
@@ -208,6 +208,24 @@ accelerometer@68 {
 /* Connected to pogo pins (external spring based pinheader for user addons) */
 &i2c2 {
 	status = "okay";
+
+	keyboard@15 {
+		compatible = "pine64,pinephone-keyboard";
+		reg = <0x15>;
+		interrupt-parent = <&r_pio>;
+		interrupts = <0 12 IRQ_TYPE_EDGE_FALLING>; /* PL12 */
+		wakeup-source;
+
+		i2c {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			charger@75 {
+				compatible = "injoinic,ip5209";
+				reg = <0x75>;
+			};
+		};
+	};
 };
 
 &lradc {
-- 
2.35.1

Re: [PATCH v3 1/4] dt-bindings: input: Add the PinePhone keyboard binding

[Krzysztof Kozlowski]

On 24/04/2022 18:04, Samuel Holland wrote:
> Add devicetree support for the PinePhone keyboard case, which provides a
> matrix keyboard interface and a proxied I2C bus.
> 
> Signed-off-by: Samuel Holland <samuel@sholland.org>


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof