[PATCH v7 3/7] input: serio: Add driver for ASUS Transformer dock keyboard and touchpad

[Svyatoslav Ryhel <clamor95@gmail.com>]

From: Michał Mirosław <mirq-linux@rere.qmqm.pl>

Add input driver for ASUS Transformer dock keyboard and touchpad.

Some keys in ASUS Dock report keycodes that don't make sense according to
their position, this patch modifies the incoming data that is sent to
serio to send proper scancodes.

Co-developed-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/input/serio/Kconfig                   |  15 ++
 drivers/input/serio/Makefile                  |   1 +
 drivers/input/serio/asus-transformer-ec-kbc.c | 157 ++++++++++++++++++
 3 files changed, 173 insertions(+)
 create mode 100644 drivers/input/serio/asus-transformer-ec-kbc.c

diff --git a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
index 5f15a6462056..fad29b950309 100644
--- a/drivers/input/serio/Kconfig
+++ b/drivers/input/serio/Kconfig
@@ -84,6 +84,21 @@ config SERIO_RPCKBD
 	  To compile this driver as a module, choose M here: the
 	  module will be called rpckbd.
 
+config SERIO_ASUS_TRANSFORMER_EC
+	tristate "Asus Transformer's Dock keyboard and touchpad controller"
+	depends on MFD_ASUS_TRANSFORMER_EC
+	help
+	  Say Y here if you want to use the keyboard and/or touchpad on
+	  Asus Transformed's Mobile Dock.
+
+	  For keyboard support you also need atkbd driver.
+
+	  For touchpad support you also need psmouse driver with Elantech
+	  touchpad option enabled.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called asus-transformer-ec-kbc.
+
 config SERIO_AMBAKMI
 	tristate "AMBA KMI keyboard controller"
 	depends on ARM_AMBA
diff --git a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
index 8ab98f4aa28d..fedc37ee102b 100644
--- a/drivers/input/serio/Makefile
+++ b/drivers/input/serio/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_SERIO_SERPORT)	+= serport.o
 obj-$(CONFIG_SERIO_RPCKBD)	+= rpckbd.o
 obj-$(CONFIG_SERIO_SA1111)	+= sa1111ps2.o
 obj-$(CONFIG_SERIO_AMBAKMI)	+= ambakmi.o
+obj-$(CONFIG_SERIO_ASUS_TRANSFORMER_EC)	+= asus-transformer-ec-kbc.o
 obj-$(CONFIG_SERIO_Q40KBD)	+= q40kbd.o
 obj-$(CONFIG_SERIO_GSCPS2)	+= gscps2.o
 obj-$(CONFIG_HP_SDC)		+= hp_sdc.o
diff --git a/drivers/input/serio/asus-transformer-ec-kbc.c b/drivers/input/serio/asus-transformer-ec-kbc.c
new file mode 100644
index 000000000000..c9707c7fbede
--- /dev/null
+++ b/drivers/input/serio/asus-transformer-ec-kbc.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/i8042.h>
+#include <linux/mfd/asus-transformer-ec.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/serio.h>
+
+struct asus_ec_kbc_data {
+	struct notifier_block nb;
+	struct asusec_core *ec;
+	struct i2c_client *parent;
+	struct serio *sdev[2];
+};
+
+static int asus_ec_kbc_notify(struct notifier_block *nb,
+			      unsigned long action, void *data_)
+{
+	struct asus_ec_kbc_data *priv = container_of(nb, struct asus_ec_kbc_data, nb);
+	unsigned int port_idx, n;
+	u8 *data = data_;
+
+	if (action & (ASUSEC_SMI_MASK | ASUSEC_SCI_MASK))
+		return NOTIFY_DONE;
+	else if (action & ASUSEC_AUX_MASK)
+		port_idx = 1;
+	else if (action & (ASUSEC_KBC_MASK | ASUSEC_KEY_MASK))
+		port_idx = 0;
+	else
+		return NOTIFY_DONE;
+
+	/*
+	 * The data[0] is the length of the packet including itself. It has to
+	 * be at least 2 bytes (length + 1 data byte) and must not exceed
+	 * the EC buffer size.
+	 */
+	if (data[0] < 2 || data[0] > DOCKRAM_ENTRY_BUFSIZE)
+		return NOTIFY_BAD;
+
+	n = data[0] - 1;
+	data += 2;
+
+	if (port_idx == 0) {
+		/*
+		 * Remap keyboard key codes to match AT layout:
+		 * SEARCH: RIGHT-META [E0 27] -> LEFT-ALT   [11]
+		 * MENU:   COMPOSE    [E0 2F] -> RIGHT-META [E0 27]
+		 */
+		if ((n == 2 || (n == 3 && data[1] == 0xF0)) && data[0] == 0xE0) {
+			u8 *keycode = &data[n - 1];
+
+			switch (*keycode) {
+			case 0x27:
+				*keycode = 0x11;
+				++data;
+				--n;
+				break;
+			case 0x2F:
+				*keycode = 0x27;
+				break;
+			}
+		}
+	}
+
+	while (n--)
+		serio_interrupt(priv->sdev[port_idx], *data++, 0);
+
+	return NOTIFY_OK;
+}
+
+static int asus_ec_serio_write(struct serio *port, unsigned char data)
+{
+	struct asus_ec_kbc_data *priv = port->port_data;
+
+	return i2c_smbus_write_word_data(priv->parent, ASUSEC_WRITE_BUF,
+					 (data << 8) | port->id.extra);
+}
+
+static void asus_ec_serio_remove(void *data)
+{
+	serio_unregister_port(data);
+}
+
+static int asus_ec_register_serio(struct platform_device *pdev, int idx,
+				  const char *name, int cmd)
+{
+	struct asus_ec_kbc_data *priv = platform_get_drvdata(pdev);
+	struct i2c_client *parent = priv->parent;
+	struct serio *port = kzalloc_obj(*port);
+
+	if (!port)
+		return -ENOMEM;
+
+	priv->sdev[idx] = port;
+	port->dev.parent = &pdev->dev;
+	port->id.type = SERIO_8042;
+	port->id.extra = cmd & 0xFF;
+	port->write = asus_ec_serio_write;
+	port->port_data = (void *)priv;
+	snprintf(port->name, sizeof(port->name), "%s %s",
+		 priv->ec->model, name);
+	snprintf(port->phys, sizeof(port->phys), "i2c-%u-%04x/serio%d",
+		 i2c_adapter_id(parent->adapter), parent->addr, idx);
+
+	serio_register_port(port);
+
+	return devm_add_action_or_reset(&pdev->dev, asus_ec_serio_remove, port);
+}
+
+static int asus_ec_kbc_probe(struct platform_device *pdev)
+{
+	struct asusec_core *ec = dev_get_drvdata(pdev->dev.parent);
+	struct asus_ec_kbc_data *priv;
+	int error;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	priv->ec = ec;
+	priv->parent = to_i2c_client(pdev->dev.parent);
+
+	error = asus_ec_register_serio(pdev, 0, "Keyboard", 0);
+	if (error)
+		return error;
+
+	error = asus_ec_register_serio(pdev, 1, "Touchpad", I8042_CMD_AUX_SEND);
+	if (error)
+		return error;
+
+	priv->nb.notifier_call = asus_ec_kbc_notify;
+
+	return blocking_notifier_chain_register(&ec->notify_list, &priv->nb);
+}
+
+static void asus_ec_kbc_remove(struct platform_device *pdev)
+{
+	struct asus_ec_kbc_data *priv = platform_get_drvdata(pdev);
+	struct asusec_core *ec = priv->ec;
+
+	blocking_notifier_chain_unregister(&ec->notify_list, &priv->nb);
+}
+
+static struct platform_driver asus_ec_kbc_driver = {
+	.driver.name = "asus-transformer-ec-kbc",
+	.probe = asus_ec_kbc_probe,
+	.remove = asus_ec_kbc_remove,
+};
+module_platform_driver(asus_ec_kbc_driver);
+
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_DESCRIPTION("ASUS Transformer's Dock keyboard and touchpad controller driver");
+MODULE_LICENSE("GPL");
-- 
2.51.0