[PATCH 1/1] HID: evision: Add preliminary support for EVision keyboards

[Philippe Valembois <lephilousophe@gmail.com>]

From: Philippe Valembois <lephilousophe@users.noreply.github.com>

For now only supports one model and only filters out bogus reports sent
when the keyboard has been configured through hidraw.
Without this, as events are not released, soft repeat floods userspace
with unknown key events.

Signed-off-by: Philippe Valembois <lephilousophe@users.noreply.github.com>
---
 drivers/hid/Kconfig       |  7 ++++
 drivers/hid/Makefile      |  1 +
 drivers/hid/hid-evision.c | 79 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+)
 create mode 100644 drivers/hid/hid-evision.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index e2a5d30c8..1320ea75c 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -329,6 +329,13 @@ config HID_ELO
 	Support for the ELO USB 4000/4500 touchscreens. Note that this is for
 	different devices than those handled by CONFIG_TOUCHSCREEN_USB_ELO.
 
+config HID_EVISION
+	tristate "EVision Keyboards Support"
+	depends on USB_HID
+	help
+	Support for some EVision keyboards. Note that this is needed only when
+	applying customization using userspace programs.
+
 config HID_EZKEY
 	tristate "Ezkey BTC 8193 keyboard"
 	default !EXPERT
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index e8014c1a2..bd01571dd 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_HID_EMS_FF)	+= hid-emsff.o
 obj-$(CONFIG_HID_ELAN)		+= hid-elan.o
 obj-$(CONFIG_HID_ELECOM)	+= hid-elecom.o
 obj-$(CONFIG_HID_ELO)		+= hid-elo.o
+obj-$(CONFIG_HID_EVISION)	+= hid-evision.o
 obj-$(CONFIG_HID_EZKEY)		+= hid-ezkey.o
 obj-$(CONFIG_HID_FT260)		+= hid-ft260.o
 obj-$(CONFIG_HID_GEMBIRD)	+= hid-gembird.o
diff --git a/drivers/hid/hid-evision.c b/drivers/hid/hid-evision.c
new file mode 100644
index 000000000..6ea331575
--- /dev/null
+++ b/drivers/hid/hid-evision.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for EVision devices
+ *  For now, only ignore bogus consumer reports
+ *  sent after the keyboard has been configured
+ *
+ *  Copyright (c) 2022 Philippe Valembois
+ */
+
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+
+#define USB_VENDOR_ID_EVISION       0x320f
+#define USB_DEVICE_ID_EVISION_ICL01 0x5041
+
+static int evision_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if ((usage->hid & HID_USAGE_PAGE) != HID_UP_CONSUMER)
+		return 0;
+
+	// Ignore key down event
+	if ((usage->hid & HID_USAGE) >> 8 == 0x05)
+		return -1;
+	// Ignore key up event
+	if ((usage->hid & HID_USAGE) >> 8 == 0x06)
+		return -1;
+
+	switch (usage->hid & HID_USAGE) {
+	// Ignore configuration saved event
+	case 0x0401: return -1;
+	// Ignore reset event
+	case 0x0402: return -1;
+	}
+	return 0;
+}
+
+static int evision_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+
+	if (!hid_is_usb(hdev))
+		return -EINVAL;
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "EVision hid parse failed: %d\n", ret);
+		return ret;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "EVision hw start failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct hid_device_id evision_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_EVISION, USB_DEVICE_ID_EVISION_ICL01) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, evision_devices);
+
+static struct hid_driver evision_driver = {
+	.name = "evision",
+	.id_table = evision_devices,
+	.input_mapping = evision_input_mapping,
+	.probe = evision_probe,
+};
+module_hid_driver(evision_driver);
+
+MODULE_LICENSE("GPL");
-- 
2.38.2