[PATCH v4 2/4] Input: pinephone-keyboard - Add PinePhone keyboard driver

From: Samuel Holland
Date: Sat Jun 18 2022 - 13:06:06 EST

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@xxxxxxxxxxxx>
---

Changes in v4:
- Rebase to resolve MAINTAINERS merge conflict
- Add missing newlines in error messages

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 f52543aedd61..c40d236ba0be 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15820,6 +15820,12 @@ F: Documentation/devicetree/bindings/pinctrl/sunplus,*
F: drivers/pinctrl/sunplus/
F: include/dt-bindings/pinctrl/sppctl*.h

+PINE64 PINEPHONE KEYBOARD DRIVER
+M: Samuel Holland <samuel@xxxxxxxxxxxx>
+S: Supported
+F: Documentation/devicetree/bindings/input/pine64,pinephone-keyboard.yaml
+F: drivers/input/keyboard/pinephone-keyboard.c
+
PKTCDVD DRIVER
M: linux-block@xxxxxxxxxxxxxxx
S: Orphan
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..a021c9deee19
--- /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@xxxxxxxxxxxx>
+
+#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\n");
+
+ ret = regulator_enable(vbat_supply);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to enable VBAT\n");
+
+ 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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Pine64 PinePhone keyboard driver");
+MODULE_LICENSE("GPL");
--
2.35.1