[PATCH v6 08/19] HID: hid-lenovo-go: Add OS Mode Toggle

["Derek J. Clark" <derekjohn.clark@gmail.com>]

Adds OS Mode toggle, who's primary function is to change the built-in
functional chords to use the right handle legion button instead of the
left handle legion button as the mode shift key.

Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com>
---
v6:
  - Use NULL instead of 0 in mcu_propery_out when there is no data.
v5:
  - Remove reset_resume as it doesn't run, the device disconnects are
    reconnects during suspend. Udev or userspace will reset os_mode
    after resume.
v3:
  - Fix collision with os_mode_index attribute and os_mode_index enum.
---
 drivers/hid/hid-lenovo-go.c | 101 ++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)

diff --git a/drivers/hid/hid-lenovo-go.c b/drivers/hid/hid-lenovo-go.c
index 082d1b85d679..54861f2e04fc 100644
--- a/drivers/hid/hid-lenovo-go.c
+++ b/drivers/hid/hid-lenovo-go.c
@@ -76,6 +76,7 @@ static struct hid_go_cfg {
 	u32 mcu_version_product;
 	u32 mcu_version_protocol;
 	u32 mouse_dpi;
+	u8 os_mode;
 	u8 rgb_effect;
 	u8 rgb_en;
 	u8 rgb_mode;
@@ -166,6 +167,8 @@ enum feature_status_index {
 	FEATURE_GAMEPAD_MODE = 0x0e,
 };
 
+#define FEATURE_OS_MODE 0x69
+
 enum fps_switch_status_index {
 	FPS_STATUS_UNKNOWN,
 	GAMEPAD,
@@ -311,6 +314,23 @@ enum device_status_index {
 	GET_HOTKEY_TRIGG_STATUS,
 };
 
+enum os_mode_cfg_index {
+	SET_OS_MODE = 0x09,
+	GET_OS_MODE,
+};
+
+enum os_mode_type_index {
+	OS_UNKNOWN,
+	WINDOWS,
+	LINUX,
+};
+
+static const char *const os_mode_text[] = {
+	[OS_UNKNOWN] = "unknown",
+	[WINDOWS] = "windows",
+	[LINUX] = "linux",
+};
+
 static int hid_go_version_event(struct command_report *cmd_rep)
 {
 	switch (cmd_rep->sub_cmd) {
@@ -593,6 +613,21 @@ static int hid_go_device_status_event(struct command_report *cmd_rep)
 	}
 }
 
+static int hid_go_os_mode_cfg_event(struct command_report *cmd_rep)
+{
+	switch (cmd_rep->sub_cmd) {
+	case SET_OS_MODE:
+		if (cmd_rep->data[0] != 1)
+			return -EIO;
+		return 0;
+	case GET_OS_MODE:
+		drvdata.os_mode = cmd_rep->data[0];
+		return 0;
+	default:
+		return -EINVAL;
+	};
+}
+
 static int hid_go_set_event_return(struct command_report *cmd_rep)
 {
 	if (cmd_rep->data[0] != 0)
@@ -666,6 +701,9 @@ static int hid_go_raw_event(struct hid_device *hdev, struct hid_report *report,
 			break;
 		};
 		break;
+	case OS_MODE_DATA:
+		ret = hid_go_os_mode_cfg_event(cmd_rep);
+		break;
 	default:
 		goto passthrough;
 	};
@@ -1343,6 +1381,64 @@ static ssize_t calibrate_config_options(struct device *dev,
 	return count;
 }
 
+static ssize_t os_mode_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	size_t size = 1;
+	int ret;
+	u8 val;
+
+	ret = sysfs_match_string(os_mode_text, buf);
+	if (ret <= 0)
+		return ret;
+
+	val = ret;
+	ret = mcu_property_out(drvdata.hdev, OS_MODE_DATA, FEATURE_OS_MODE,
+			       SET_OS_MODE, USB_MCU, &val, size);
+	if (ret < 0)
+		return ret;
+
+	drvdata.os_mode = val;
+
+	return count;
+}
+
+static ssize_t os_mode_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
+{
+	ssize_t count = 0;
+	int ret;
+	u8 i;
+
+	ret = mcu_property_out(drvdata.hdev, OS_MODE_DATA, FEATURE_OS_MODE,
+			       GET_OS_MODE, USB_MCU, NULL, 0);
+	if (ret)
+		return ret;
+
+	i = drvdata.os_mode;
+	if (i >= ARRAY_SIZE(os_mode_text))
+		return -EINVAL;
+
+	count = sysfs_emit(buf, "%s\n", os_mode_text[i]);
+
+	return count;
+}
+
+static ssize_t os_mode_index_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	ssize_t count = 0;
+	unsigned int i;
+
+	for (i = 1; i < ARRAY_SIZE(os_mode_text); i++)
+		count += sysfs_emit_at(buf, count, "%s ", os_mode_text[i]);
+
+	if (count)
+		buf[count - 1] = '\n';
+
+	return count;
+}
+
 static int rgb_cfg_call(struct hid_device *hdev, enum mcu_command_index cmd,
 			enum rgb_config_index index, u8 *val, size_t size)
 {
@@ -1712,6 +1808,9 @@ static DEVICE_ATTR_RO_NAMED(gamepad_rumble_intensity_index,
 static DEVICE_ATTR_RW(fps_mode_dpi);
 static DEVICE_ATTR_RO(fps_mode_dpi_index);
 
+static DEVICE_ATTR_RW(os_mode);
+static DEVICE_ATTR_RO(os_mode_index);
+
 static struct attribute *mcu_attrs[] = {
 	&dev_attr_fps_mode_dpi.attr,
 	&dev_attr_fps_mode_dpi_index.attr,
@@ -1720,6 +1819,8 @@ static struct attribute *mcu_attrs[] = {
 	&dev_attr_gamepad_mode_index.attr,
 	&dev_attr_gamepad_rumble_intensity.attr,
 	&dev_attr_gamepad_rumble_intensity_index.attr,
+	&dev_attr_os_mode.attr,
+	&dev_attr_os_mode_index.attr,
 	&dev_attr_reset_mcu.attr,
 	&dev_attr_version_firmware_mcu.attr,
 	&dev_attr_version_gen_mcu.attr,
-- 
2.53.0