Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid

Pull HID updates from Jiri Kosina:

 - quite a few firmware fixes for RMI driver by Andrew Duggan

 - huion and uclogic drivers have been substantially overlaping in
   functionality laterly.  This redundancy is fixed by hid-huion driver
   being merged into hid-uclogic; work done by Benjamin Tissoires and
   Nikolai Kondrashov

 - i2c-hid now supports ACPI GPIO interrupts; patch from Mika Westerberg

 - Some of the quirks, that got separated into individual drivers, have
   historically had EXPERT dependency.  As HID subsystem matured (as
   well as the individual drivers), this made less and less sense.  This
   dependency is now being removed by patch from Jean Delvare

 - Logitech lg4ff driver received a couple of improvements for mode
   switching, by Michal Malý

 - multitouch driver now supports clickpads, patches by Benjamin
   Tissoires and Seth Forshee

 - hid-sensor framework received a substantial update; namely support
   for Custom and Generic pages is being added; work done by Srinivas
   Pandruvada

 - wacom driver received substantial update; it now supports
   i2c-conntected devices (Mika Westerberg), Bamboo PADs are now
   properly supported (Benjamin Tissoires), much improved battery
   reporting (Jason Gerecke) and pen proximity cleanups (Ping Cheng)

 - small assorted fixes and device ID additions

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid: (68 commits)
  HID: sensor: Update document for custom sensor
  HID: sensor: Custom and Generic sensor support
  HID: debug: fix error handling in hid_debug_events_read()
  Input - mt: Fix input_mt_get_slot_by_key
  HID: logitech-hidpp: fix error return code
  HID: wacom: Add support for Cintiq 13HD Touch
  HID: logitech-hidpp: add a module parameter to keep firmware gestures
  HID: usbhid: yet another mouse with ALWAYS_POLL
  HID: usbhid: more mice with ALWAYS_POLL
  HID: wacom: set stylus_in_proximity before checking touch_down
  HID: wacom: use wacom_wac_finger_count_touches to set touch_down
  HID: wacom: remove hardcoded WACOM_QUIRK_MULTI_INPUT
  HID: pidff: effect can't be NULL
  HID: add quirk for PIXART OEM mouse used by HP
  HID: add HP OEM mouse to quirk ALWAYS_POLL
  HID: wacom: ask for a in-prox report when it was missed
  HID: hid-sensor-hub: Fix sparse warning
  HID: hid-sensor-hub: fix attribute read for logical usage id
  HID: plantronics: fix Kconfig default
  HID: pidff: support more than one concurrent effect
  ...

1 files changed, 527 insertions, 73 deletions

diff --git a/drivers/hid/hid-lg4ff.c b/drivers/hid/hid-lg4ff.c
index db0dd9b17e53..1232210b1cc5 100644
--- a/drivers/hid/hid-lg4ff.c
+++ b/drivers/hid/hid-lg4ff.c
@@ -30,23 +30,44 @@
 
 #include "usbhid/usbhid.h"
 #include "hid-lg.h"
+#include "hid-lg4ff.h"
 #include "hid-ids.h"
 
-#define DFGT_REV_MAJ 0x13
-#define DFGT_REV_MIN 0x22
-#define DFGT2_REV_MIN 0x26
-#define DFP_REV_MAJ 0x11
-#define DFP_REV_MIN 0x06
-#define FFEX_REV_MAJ 0x21
-#define FFEX_REV_MIN 0x00
-#define G25_REV_MAJ 0x12
-#define G25_REV_MIN 0x22
-#define G27_REV_MAJ 0x12
-#define G27_REV_MIN 0x38
-#define G27_2_REV_MIN 0x39
-
 #define to_hid_device(pdev) container_of(pdev, struct hid_device, dev)
 
+#define LG4FF_MMODE_IS_MULTIMODE 0
+#define LG4FF_MMODE_SWITCHED 1
+#define LG4FF_MMODE_NOT_MULTIMODE 2
+
+#define LG4FF_MODE_NATIVE_IDX 0
+#define LG4FF_MODE_DFEX_IDX 1
+#define LG4FF_MODE_DFP_IDX 2
+#define LG4FF_MODE_G25_IDX 3
+#define LG4FF_MODE_DFGT_IDX 4
+#define LG4FF_MODE_G27_IDX 5
+#define LG4FF_MODE_MAX_IDX 6
+
+#define LG4FF_MODE_NATIVE BIT(LG4FF_MODE_NATIVE_IDX)
+#define LG4FF_MODE_DFEX BIT(LG4FF_MODE_DFEX_IDX)
+#define LG4FF_MODE_DFP BIT(LG4FF_MODE_DFP_IDX)
+#define LG4FF_MODE_G25 BIT(LG4FF_MODE_G25_IDX)
+#define LG4FF_MODE_DFGT BIT(LG4FF_MODE_DFGT_IDX)
+#define LG4FF_MODE_G27 BIT(LG4FF_MODE_G27_IDX)
+
+#define LG4FF_DFEX_TAG "DF-EX"
+#define LG4FF_DFEX_NAME "Driving Force / Formula EX"
+#define LG4FF_DFP_TAG "DFP"
+#define LG4FF_DFP_NAME "Driving Force Pro"
+#define LG4FF_G25_TAG "G25"
+#define LG4FF_G25_NAME "G25 Racing Wheel"
+#define LG4FF_G27_TAG "G27"
+#define LG4FF_G27_NAME "G27 Racing Wheel"
+#define LG4FF_DFGT_TAG "DFGT"
+#define LG4FF_DFGT_NAME "Driving Force GT"
+
+#define LG4FF_FFEX_REV_MAJ 0x21
+#define LG4FF_FFEX_REV_MIN 0x00
+
 static void hid_lg4ff_set_range_dfp(struct hid_device *hid, u16 range);
 static void hid_lg4ff_set_range_g25(struct hid_device *hid, u16 range);
 
@@ -59,6 +80,10 @@ struct lg4ff_device_entry {
 	__u8  led_state;
 	struct led_classdev *led[5];
 #endif
+	u32 alternate_modes;
+	const char *real_tag;
+	const char *real_name;
+	u16 real_product_id;
 	struct list_head list;
 	void (*set_range)(struct hid_device *hid, u16 range);
 };
@@ -77,6 +102,35 @@ struct lg4ff_wheel {
 	void (*set_range)(struct hid_device *hid, u16 range);
 };
 
+struct lg4ff_compat_mode_switch {
+	const __u8 cmd_count;	/* Number of commands to send */
+	const __u8 cmd[];
+};
+
+struct lg4ff_wheel_ident_info {
+	const u16 mask;
+	const u16 result;
+	const u16 real_product_id;
+};
+
+struct lg4ff_wheel_ident_checklist {
+	const u32 count;
+	const struct lg4ff_wheel_ident_info *models[];
+};
+
+struct lg4ff_multimode_wheel {
+	const u16 product_id;
+	const u32 alternate_modes;
+	const char *real_tag;
+	const char *real_name;
+};
+
+struct lg4ff_alternate_mode {
+	const u16 product_id;
+	const char *tag;
+	const char *name;
+};
+
 static const struct lg4ff_wheel lg4ff_devices[] = {
 	{USB_DEVICE_ID_LOGITECH_WHEEL,       lg4ff_wheel_effects, 40, 270, NULL},
 	{USB_DEVICE_ID_LOGITECH_MOMO_WHEEL,  lg4ff_wheel_effects, 40, 270, NULL},
@@ -88,46 +142,106 @@ static const struct lg4ff_wheel lg4ff_devices[] = {
 	{USB_DEVICE_ID_LOGITECH_WII_WHEEL,   lg4ff_wheel_effects, 40, 270, NULL}
 };
 
-struct lg4ff_native_cmd {
-	const __u8 cmd_num;	/* Number of commands to send */
-	const __u8 cmd[];
+static const struct lg4ff_multimode_wheel lg4ff_multimode_wheels[] = {
+	{USB_DEVICE_ID_LOGITECH_DFP_WHEEL,
+	 LG4FF_MODE_NATIVE | LG4FF_MODE_DFP | LG4FF_MODE_DFEX,
+	 LG4FF_DFP_TAG, LG4FF_DFP_NAME},
+	{USB_DEVICE_ID_LOGITECH_G25_WHEEL,
+	 LG4FF_MODE_NATIVE | LG4FF_MODE_G25 | LG4FF_MODE_DFP | LG4FF_MODE_DFEX,
+	 LG4FF_G25_TAG, LG4FF_G25_NAME},
+	{USB_DEVICE_ID_LOGITECH_DFGT_WHEEL,
+	 LG4FF_MODE_NATIVE | LG4FF_MODE_DFGT | LG4FF_MODE_DFP | LG4FF_MODE_DFEX,
+	 LG4FF_DFGT_TAG, LG4FF_DFGT_NAME},
+	{USB_DEVICE_ID_LOGITECH_G27_WHEEL,
+	 LG4FF_MODE_NATIVE | LG4FF_MODE_G27 | LG4FF_MODE_G25 | LG4FF_MODE_DFP | LG4FF_MODE_DFEX,
+	 LG4FF_G27_TAG, LG4FF_G27_NAME},
 };
 
-struct lg4ff_usb_revision {
-	const __u16 rev_maj;
-	const __u16 rev_min;
-	const struct lg4ff_native_cmd *command;
+static const struct lg4ff_alternate_mode lg4ff_alternate_modes[] = {
+	[LG4FF_MODE_NATIVE_IDX] = {0, "native", ""},
+	[LG4FF_MODE_DFEX_IDX] = {USB_DEVICE_ID_LOGITECH_WHEEL, LG4FF_DFEX_TAG, LG4FF_DFEX_NAME},
+	[LG4FF_MODE_DFP_IDX] = {USB_DEVICE_ID_LOGITECH_DFP_WHEEL, LG4FF_DFP_TAG, LG4FF_DFP_NAME},
+	[LG4FF_MODE_G25_IDX] = {USB_DEVICE_ID_LOGITECH_G25_WHEEL, LG4FF_G25_TAG, LG4FF_G25_NAME},
+	[LG4FF_MODE_DFGT_IDX] = {USB_DEVICE_ID_LOGITECH_DFGT_WHEEL, LG4FF_DFGT_TAG, LG4FF_DFGT_NAME},
+	[LG4FF_MODE_G27_IDX] = {USB_DEVICE_ID_LOGITECH_G27_WHEEL, LG4FF_G27_TAG, LG4FF_G27_NAME}
 };
 
-static const struct lg4ff_native_cmd native_dfp = {
-	1,
-	{0xf8, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00}
+/* Multimode wheel identificators */
+static const struct lg4ff_wheel_ident_info lg4ff_dfp_ident_info = {
+	0xf000,
+	0x1000,
+	USB_DEVICE_ID_LOGITECH_DFP_WHEEL
+};
+
+static const struct lg4ff_wheel_ident_info lg4ff_g25_ident_info = {
+	0xff00,
+	0x1200,
+	USB_DEVICE_ID_LOGITECH_G25_WHEEL
+};
+
+static const struct lg4ff_wheel_ident_info lg4ff_g27_ident_info = {
+	0xfff0,
+	0x1230,
+	USB_DEVICE_ID_LOGITECH_G27_WHEEL
 };
 
-static const struct lg4ff_native_cmd native_dfgt = {
+static const struct lg4ff_wheel_ident_info lg4ff_dfgt_ident_info = {
+	0xff00,
+	0x1300,
+	USB_DEVICE_ID_LOGITECH_DFGT_WHEEL
+};
+
+/* Multimode wheel identification checklists */
+static const struct lg4ff_wheel_ident_checklist lg4ff_main_checklist = {
+	4,
+	{&lg4ff_dfgt_ident_info,
+	 &lg4ff_g27_ident_info,
+	 &lg4ff_g25_ident_info,
+	 &lg4ff_dfp_ident_info}
+};
+
+/* Compatibility mode switching commands */
+/* EXT_CMD9 - Understood by G27 and DFGT */
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext09_dfex = {
 	2,
-	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 1st command */
-	 0xf8, 0x09, 0x03, 0x01, 0x00, 0x00, 0x00}	/* 2nd command */
+	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* Revert mode upon USB reset */
+	 0xf8, 0x09, 0x00, 0x01, 0x00, 0x00, 0x00}	/* Switch mode to DF-EX with detach */
 };
 
-static const struct lg4ff_native_cmd native_g25 = {
-	1,
-	{0xf8, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00}
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext09_dfp = {
+	2,
+	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* Revert mode upon USB reset */
+	 0xf8, 0x09, 0x01, 0x01, 0x00, 0x00, 0x00}	/* Switch mode to DFP with detach */
+};
+
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext09_g25 = {
+	2,
+	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* Revert mode upon USB reset */
+	 0xf8, 0x09, 0x02, 0x01, 0x00, 0x00, 0x00}	/* Switch mode to G25 with detach */
+};
+
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext09_dfgt = {
+	2,
+	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* Revert mode upon USB reset */
+	 0xf8, 0x09, 0x03, 0x01, 0x00, 0x00, 0x00}	/* Switch mode to DFGT with detach */
 };
 
-static const struct lg4ff_native_cmd native_g27 = {
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext09_g27 = {
 	2,
-	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* 1st command */
-	 0xf8, 0x09, 0x04, 0x01, 0x00, 0x00, 0x00}	/* 2nd command */
+	{0xf8, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00,	/* Revert mode upon USB reset */
+	 0xf8, 0x09, 0x04, 0x01, 0x00, 0x00, 0x00}	/* Switch mode to G27 with detach */
 };
 
-static const struct lg4ff_usb_revision lg4ff_revs[] = {
-	{DFGT_REV_MAJ, DFGT_REV_MIN, &native_dfgt},	/* Driving Force GT */
-	{DFGT_REV_MAJ, DFGT2_REV_MIN, &native_dfgt},	/* Driving Force GT v2 */
-	{DFP_REV_MAJ,  DFP_REV_MIN,  &native_dfp},	/* Driving Force Pro */
-	{G25_REV_MAJ,  G25_REV_MIN,  &native_g25},	/* G25 */
-	{G27_REV_MAJ,  G27_REV_MIN,  &native_g27},	/* G27 */
-	{G27_REV_MAJ,  G27_2_REV_MIN,  &native_g27},	/* G27 v2 */
+/* EXT_CMD1 - Understood by DFP, G25, G27 and DFGT */
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext01_dfp = {
+	1,
+	{0xf8, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00}
+};
+
+/* EXT_CMD16 - Understood by G25 and G27 */
+static const struct lg4ff_compat_mode_switch lg4ff_mode_switch_ext16_g25 = {
+	1,
+	{0xf8, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00}
 };
 
 /* Recalculates X axis value accordingly to currently selected range */
@@ -396,20 +510,216 @@ static void hid_lg4ff_set_range_dfp(struct hid_device *hid, __u16 range)
 	hid_hw_request(hid, report, HID_REQ_SET_REPORT);
 }
 
-static void hid_lg4ff_switch_native(struct hid_device *hid, const struct lg4ff_native_cmd *cmd)
+static const struct lg4ff_compat_mode_switch *lg4ff_get_mode_switch_command(const u16 real_product_id, const u16 target_product_id)
+{
+	switch (real_product_id) {
+	case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+		switch (target_product_id) {
+		case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+			return &lg4ff_mode_switch_ext01_dfp;
+		/* DFP can only be switched to its native mode */
+		default:
+			return NULL;
+		}
+		break;
+	case USB_DEVICE_ID_LOGITECH_G25_WHEEL:
+		switch (target_product_id) {
+		case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+			return &lg4ff_mode_switch_ext01_dfp;
+		case USB_DEVICE_ID_LOGITECH_G25_WHEEL:
+			return &lg4ff_mode_switch_ext16_g25;
+		/* G25 can only be switched to DFP mode or its native mode */
+		default:
+			return NULL;
+		}
+		break;
+	case USB_DEVICE_ID_LOGITECH_G27_WHEEL:
+		switch (target_product_id) {
+		case USB_DEVICE_ID_LOGITECH_WHEEL:
+			return &lg4ff_mode_switch_ext09_dfex;
+		case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+			return &lg4ff_mode_switch_ext09_dfp;
+		case USB_DEVICE_ID_LOGITECH_G25_WHEEL:
+			return &lg4ff_mode_switch_ext09_g25;
+		case USB_DEVICE_ID_LOGITECH_G27_WHEEL:
+			return &lg4ff_mode_switch_ext09_g27;
+		/* G27 can only be switched to DF-EX, DFP, G25 or its native mode */
+		default:
+			return NULL;
+		}
+		break;
+	case USB_DEVICE_ID_LOGITECH_DFGT_WHEEL:
+		switch (target_product_id) {
+		case USB_DEVICE_ID_LOGITECH_WHEEL:
+			return &lg4ff_mode_switch_ext09_dfex;
+		case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+			return &lg4ff_mode_switch_ext09_dfp;
+		case USB_DEVICE_ID_LOGITECH_DFGT_WHEEL:
+			return &lg4ff_mode_switch_ext09_dfgt;
+		/* DFGT can only be switched to DF-EX, DFP or its native mode */
+		default:
+			return NULL;
+		}
+		break;
+	/* No other wheels have multiple modes */
+	default:
+		return NULL;
+	}
+}
+
+static int lg4ff_switch_compatibility_mode(struct hid_device *hid, const struct lg4ff_compat_mode_switch *s)
 {
 	struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
 	struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
-	__u8 i, j;
+	__s32 *value = report->field[0]->value;
+	u8 i;
 
-	j = 0;
-	while (j < 7*cmd->cmd_num) {
-		for (i = 0; i < 7; i++)
-			report->field[0]->value[i] = cmd->cmd[j++];
+	for (i = 0; i < s->cmd_count; i++) {
+		u8 j;
+
+		for (j = 0; j < 7; j++)
+			value[j] = s->cmd[j + (7*i)];
 
 		hid_hw_request(hid, report, HID_REQ_SET_REPORT);
 	}
+	hid_hw_wait(hid);
+	return 0;
+}
+
+static ssize_t lg4ff_alternate_modes_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
+	ssize_t count = 0;
+	int i;
+
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
+	}
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
+		return 0;
+	}
+
+	if (!entry->real_name) {
+		hid_err(hid, "NULL pointer to string\n");
+		return 0;
+	}
+
+	for (i = 0; i < LG4FF_MODE_MAX_IDX; i++) {
+		if (entry->alternate_modes & BIT(i)) {
+			/* Print tag and full name */
+			count += scnprintf(buf + count, PAGE_SIZE - count, "%s: %s",
+					   lg4ff_alternate_modes[i].tag,
+					   !lg4ff_alternate_modes[i].product_id ? entry->real_name : lg4ff_alternate_modes[i].name);
+			if (count >= PAGE_SIZE - 1)
+				return count;
+
+			/* Mark the currently active mode with an asterisk */
+			if (lg4ff_alternate_modes[i].product_id == entry->product_id ||
+			    (lg4ff_alternate_modes[i].product_id == 0 && entry->product_id == entry->real_product_id))
+				count += scnprintf(buf + count, PAGE_SIZE - count, " *\n");
+			else
+				count += scnprintf(buf + count, PAGE_SIZE - count, "\n");
+
+			if (count >= PAGE_SIZE - 1)
+				return count;
+		}
+	}
+
+	return count;
+}
+
+static ssize_t lg4ff_alternate_modes_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
+	const struct lg4ff_compat_mode_switch *s;
+	u16 target_product_id = 0;
+	int i, ret;
+	char *lbuf;
+
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return -EINVAL;
+	}
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
+		return -EINVAL;
+	}
+
+	/* Allow \n at the end of the input parameter */
+	lbuf = kasprintf(GFP_KERNEL, "%s", buf);
+	if (!lbuf)
+		return -ENOMEM;
+
+	i = strlen(lbuf);
+	if (lbuf[i-1] == '\n') {
+		if (i == 1) {
+			kfree(lbuf);
+			return -EINVAL;
+		}
+		lbuf[i-1] = '\0';
+	}
+
+	for (i = 0; i < LG4FF_MODE_MAX_IDX; i++) {
+		const u16 mode_product_id = lg4ff_alternate_modes[i].product_id;
+		const char *tag = lg4ff_alternate_modes[i].tag;
+
+		if (entry->alternate_modes & BIT(i)) {
+			if (!strcmp(tag, lbuf)) {
+				if (!mode_product_id)
+					target_product_id = entry->real_product_id;
+				else
+					target_product_id = mode_product_id;
+				break;
+			}
+		}
+	}
+
+	if (i == LG4FF_MODE_MAX_IDX) {
+		hid_info(hid, "Requested mode \"%s\" is not supported by the device\n", lbuf);
+		kfree(lbuf);
+		return -EINVAL;
+	}
+	kfree(lbuf); /* Not needed anymore */
+
+	if (target_product_id == entry->product_id) /* Nothing to do */
+		return count;
+
+	/* Automatic switching has to be disabled for the switch to DF-EX mode to work correctly */
+	if (target_product_id == USB_DEVICE_ID_LOGITECH_WHEEL && !lg4ff_no_autoswitch) {
+		hid_info(hid, "\"%s\" cannot be switched to \"DF-EX\" mode. Load the \"hid_logitech\" module with \"lg4ff_no_autoswitch=1\" parameter set and try again\n",
+			 entry->real_name);
+		return -EINVAL;
+	}
+
+	/* Take care of hardware limitations */
+	if ((entry->real_product_id == USB_DEVICE_ID_LOGITECH_DFP_WHEEL || entry->real_product_id == USB_DEVICE_ID_LOGITECH_G25_WHEEL) &&
+	    entry->product_id > target_product_id) {
+		hid_info(hid, "\"%s\" cannot be switched back into \"%s\" mode\n", entry->real_name, lg4ff_alternate_modes[i].name);
+		return -EINVAL;
+	}
+
+	s = lg4ff_get_mode_switch_command(entry->real_product_id, target_product_id);
+	if (!s) {
+		hid_err(hid, "Invalid target product ID %X\n", target_product_id);
+		return -EINVAL;
+	}
+
+	ret = lg4ff_switch_compatibility_mode(hid, s);
+	return (ret == 0 ? count : ret);
 }
+static DEVICE_ATTR(alternate_modes, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH, lg4ff_alternate_modes_show, lg4ff_alternate_modes_store);
 
 /* Read current range and display it in terminal */
 static ssize_t range_show(struct device *dev, struct device_attribute *attr,
@@ -472,6 +782,41 @@ static ssize_t range_store(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RW(range);
 
+static ssize_t lg4ff_real_id_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct hid_device *hid = to_hid_device(dev);
+	struct lg4ff_device_entry *entry;
+	struct lg_drv_data *drv_data;
+	size_t count;
+
+	drv_data = hid_get_drvdata(hid);
+	if (!drv_data) {
+		hid_err(hid, "Private driver data not found!\n");
+		return 0;
+	}
+
+	entry = drv_data->device_props;
+	if (!entry) {
+		hid_err(hid, "Device properties not found!\n");
+		return 0;
+	}
+
+	if (!entry->real_tag || !entry->real_name) {
+		hid_err(hid, "NULL pointer to string\n");
+		return 0;
+	}
+
+	count = scnprintf(buf, PAGE_SIZE, "%s: %s\n", entry->real_tag, entry->real_name);
+	return count;
+}
+
+static ssize_t lg4ff_real_id_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
+{
+	/* Real ID is a read-only value */
+	return -EPERM;
+}
+static DEVICE_ATTR(real_id, S_IRUGO, lg4ff_real_id_show, lg4ff_real_id_store);
+
 #ifdef CONFIG_LEDS_CLASS
 static void lg4ff_set_leds(struct hid_device *hid, __u8 leds)
 {
@@ -555,20 +900,119 @@ static enum led_brightness lg4ff_led_get_brightness(struct led_classdev *led_cde
 }
 #endif
 
+static u16 lg4ff_identify_multimode_wheel(struct hid_device *hid, const u16 reported_product_id, const u16 bcdDevice)
+{
+	const struct lg4ff_wheel_ident_checklist *checklist;
+	int i, from_idx, to_idx;
+
+	switch (reported_product_id) {
+	case USB_DEVICE_ID_LOGITECH_WHEEL:
+	case USB_DEVICE_ID_LOGITECH_DFP_WHEEL:
+		checklist = &lg4ff_main_checklist;
+		from_idx = 0;
+		to_idx = checklist->count - 1;
+		break;
+	case USB_DEVICE_ID_LOGITECH_G25_WHEEL:
+		checklist = &lg4ff_main_checklist;
+		from_idx = 0;
+		to_idx = checklist->count - 2; /* End identity check at G25 */
+		break;
+	case USB_DEVICE_ID_LOGITECH_G27_WHEEL:
+		checklist = &lg4ff_main_checklist;
+		from_idx = 1; /* Start identity check at G27 */
+		to_idx = checklist->count - 3; /* End identity check at G27 */
+		break;
+	case USB_DEVICE_ID_LOGITECH_DFGT_WHEEL:
+		checklist = &lg4ff_main_checklist;
+		from_idx = 0;
+		to_idx = checklist->count - 4; /* End identity check at DFGT */
+		break;
+	default:
+		return 0;
+	}
+
+	for (i = from_idx; i <= to_idx; i++) {
+		const u16 mask = checklist->models[i]->mask;
+		const u16 result = checklist->models[i]->result;
+		const u16 real_product_id = checklist->models[i]->real_product_id;
+
+		if ((bcdDevice & mask) == result) {
+			dbg_hid("Found wheel with real PID %X whose reported PID is %X\n", real_product_id, reported_product_id);
+			return real_product_id;
+		}
+	}
+
+	/* No match found. This is either Driving Force or an unknown
+	 * wheel model, do not touch it */
+	dbg_hid("Wheel with bcdDevice %X was not recognized as multimode wheel, leaving in its current mode\n", bcdDevice);
+	return 0;
+}
+
+static int lg4ff_handle_multimode_wheel(struct hid_device *hid, u16 *real_product_id, const u16 bcdDevice)
+{
+	const u16 reported_product_id = hid->product;
+	int ret;
+
+	*real_product_id = lg4ff_identify_multimode_wheel(hid, reported_product_id, bcdDevice);
+	/* Probed wheel is not a multimode wheel */
+	if (!*real_product_id) {
+		*real_product_id = reported_product_id;
+		dbg_hid("Wheel is not a multimode wheel\n");
+		return LG4FF_MMODE_NOT_MULTIMODE;
+	}
+
+	/* Switch from "Driving Force" mode to native mode automatically.
+	 * Otherwise keep the wheel in its current mode */
+	if (reported_product_id == USB_DEVICE_ID_LOGITECH_WHEEL &&
+	    reported_product_id != *real_product_id &&
+	    !lg4ff_no_autoswitch) {
+		const struct lg4ff_compat_mode_switch *s = lg4ff_get_mode_switch_command(*real_product_id, *real_product_id);
+
+		if (!s) {
+			hid_err(hid, "Invalid product id %X\n", *real_product_id);
+			return LG4FF_MMODE_NOT_MULTIMODE;
+		}
+
+		ret = lg4ff_switch_compatibility_mode(hid, s);
+		if (ret) {
+			/* Wheel could not have been switched to native mode,
+			 * leave it in "Driving Force" mode and continue */
+			hid_err(hid, "Unable to switch wheel mode, errno %d\n", ret);
+			return LG4FF_MMODE_IS_MULTIMODE;
+		}
+		return LG4FF_MMODE_SWITCHED;
+	}
+
+	return LG4FF_MMODE_IS_MULTIMODE;
+}
+
+
 int lg4ff_init(struct hid_device *hid)
 {
 	struct hid_input *hidinput = list_entry(hid->inputs.next, struct hid_input, list);
 	struct input_dev *dev = hidinput->input;
+	const struct usb_device_descriptor *udesc = &(hid_to_usb_dev(hid)->descriptor);
+	const u16 bcdDevice = le16_to_cpu(udesc->bcdDevice);
 	struct lg4ff_device_entry *entry;
 	struct lg_drv_data *drv_data;
-	struct usb_device_descriptor *udesc;
 	int error, i, j;
-	__u16 bcdDevice, rev_maj, rev_min;
+	int mmode_ret, mmode_idx = -1;
+	u16 real_product_id;
 
 	/* Check that the report looks ok */
 	if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 7))
 		return -1;
 
+	/* Check if a multimode wheel has been connected and
+	 * handle it appropriately */
+	mmode_ret = lg4ff_handle_multimode_wheel(hid, &real_product_id, bcdDevice);
+
+	/* Wheel has been told to switch to native mode. There is no point in going on
+	 * with the initialization as the wheel will do a USB reset when it switches mode
+	 */
+	if (mmode_ret == LG4FF_MMODE_SWITCHED)
+		return 0;
+
 	/* Check what wheel has been connected */
 	for (i = 0; i < ARRAY_SIZE(lg4ff_devices); i++) {
 		if (hid->product == lg4ff_devices[i].product_id) {
@@ -583,25 +1027,15 @@ int lg4ff_init(struct hid_device *hid)
 		return -1;
 	}
 
-	/* Attempt to switch wheel to native mode when applicable */
-	udesc = &(hid_to_usb_dev(hid)->descriptor);
-	if (!udesc) {
-		hid_err(hid, "NULL USB device descriptor\n");
-		return -1;
-	}
-	bcdDevice = le16_to_cpu(udesc->bcdDevice);
-	rev_maj = bcdDevice >> 8;
-	rev_min = bcdDevice & 0xff;
-
-	if (lg4ff_devices[i].product_id == USB_DEVICE_ID_LOGITECH_WHEEL) {
-		dbg_hid("Generic wheel detected, can it do native?\n");
-		dbg_hid("USB revision: %2x.%02x\n", rev_maj, rev_min);
+	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
+		for (mmode_idx = 0; mmode_idx < ARRAY_SIZE(lg4ff_multimode_wheels); mmode_idx++) {
+			if (real_product_id == lg4ff_multimode_wheels[mmode_idx].product_id)
+				break;
+		}
 
-		for (j = 0; j < ARRAY_SIZE(lg4ff_revs); j++) {
-			if (lg4ff_revs[j].rev_maj == rev_maj && lg4ff_revs[j].rev_min == rev_min) {
-				hid_lg4ff_switch_native(hid, lg4ff_revs[j].command);
-				hid_info(hid, "Switched to native mode\n");
-			}
+		if (mmode_idx == ARRAY_SIZE(lg4ff_multimode_wheels)) {
+			hid_err(hid, "Device product ID %X is not listed as a multimode wheel", real_product_id);
+			return -1;
 		}
 	}
 
@@ -630,14 +1064,23 @@ int lg4ff_init(struct hid_device *hid)
 	drv_data->device_props = entry;
 
 	entry->product_id = lg4ff_devices[i].product_id;
+	entry->real_product_id = real_product_id;
 	entry->min_range = lg4ff_devices[i].min_range;
 	entry->max_range = lg4ff_devices[i].max_range;
 	entry->set_range = lg4ff_devices[i].set_range;
+	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
+		BUG_ON(mmode_idx == -1);
+		entry->alternate_modes = lg4ff_multimode_wheels[mmode_idx].alternate_modes;
+		entry->real_tag = lg4ff_multimode_wheels[mmode_idx].real_tag;
+		entry->real_name = lg4ff_multimode_wheels[mmode_idx].real_name;
+	}
 
 	/* Check if autocentering is available and
 	 * set the centering force to zero by default */
 	if (test_bit(FF_AUTOCENTER, dev->ffbit)) {
-		if (rev_maj == FFEX_REV_MAJ && rev_min == FFEX_REV_MIN)	/* Formula Force EX expects different autocentering command */
+		/* Formula Force EX expects different autocentering command */
+		if ((bcdDevice >> 8) == LG4FF_FFEX_REV_MAJ &&
+		    (bcdDevice & 0xff) == LG4FF_FFEX_REV_MIN)
 			dev->ff->set_autocenter = hid_lg4ff_set_autocenter_ffex;
 		else
 			dev->ff->set_autocenter = hid_lg4ff_set_autocenter_default;
@@ -649,6 +1092,14 @@ int lg4ff_init(struct hid_device *hid)
 	error = device_create_file(&hid->dev, &dev_attr_range);
 	if (error)
 		return error;
+	if (mmode_ret == LG4FF_MMODE_IS_MULTIMODE) {
+		error = device_create_file(&hid->dev, &dev_attr_real_id);
+		if (error)
+			return error;
+		error = device_create_file(&hid->dev, &dev_attr_alternate_modes);
+		if (error)
+			return error;
+	}
 	dbg_hid("sysfs interface created\n");
 
 	/* Set the maximum range to start with */
@@ -711,24 +1162,26 @@ out:
 	return 0;
 }
 
-
-
 int lg4ff_deinit(struct hid_device *hid)
 {
 	struct lg4ff_device_entry *entry;
 	struct lg_drv_data *drv_data;
 
-	device_remove_file(&hid->dev, &dev_attr_range);
-
 	drv_data = hid_get_drvdata(hid);
 	if (!drv_data) {
 		hid_err(hid, "Error while deinitializing device, no private driver data.\n");
 		return -1;
 	}
 	entry = drv_data->device_props;
-	if (!entry) {
-		hid_err(hid, "Error while deinitializing device, no device properties data.\n");
-		return -1;
+	if (!entry)
+		goto out; /* Nothing more to do */
+
+	device_remove_file(&hid->dev, &dev_attr_range);
+
+	/* Multimode devices will have at least the "MODE_NATIVE" bit set */
+	if (entry->alternate_modes) {
+		device_remove_file(&hid->dev, &dev_attr_real_id);
+		device_remove_file(&hid->dev, &dev_attr_alternate_modes);
 	}
 
 #ifdef CONFIG_LEDS_CLASS
@@ -752,6 +1205,7 @@ int lg4ff_deinit(struct hid_device *hid)
 	/* Deallocate memory */
 	kfree(entry);
 
+out:
 	dbg_hid("Device successfully unregistered\n");
 	return 0;
 }