[PATCH v2 4/5] thunderbolt: Clarify register definitions for `tb_cap_plug_events`

[Mario Limonciello]

The USB4 1.0 specification outlines the `cap_plug_events` structure as
`VSC_CS_1`.  This shows that 4 bits of `VSC_CS_1` are TBT3 compatible in
USB4, but TBT3 controllers also support disabling XHCI.

Update the names and comments to more closely match the specification.
This should not change anything functionally.

Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v1->v2:
 * Update commit message
 * Don't reassign plug_events to 4 bits.  It's 5 in TBT3 controllers and
   4 in USB4 controllers that are TBT3 compatible but not actually used
   anywhere.
 * Rename prefix of CS_1 bit assignments
 drivers/thunderbolt/tb_regs.h | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 70795a2aa9bb..db3005cba203 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -146,14 +146,14 @@ struct tb_eeprom_ctl {
 
 struct tb_cap_plug_events {
 	struct tb_cap_extended_short cap_header;
-	u32 __unknown1:2;
-	u32 plug_events:5;
-	u32 __unknown2:25;
-	u32 __unknown3;
-	u32 __unknown4;
+	u32 __unknown1:2; /* VSC_CS_1 */
+	u32 plug_events:5; /* VSC_CS_1 */
+	u32 __unknown2:25; /* VSC_CS_1 */
+	u32 vsc_cs_2;
+	u32 vsc_cs_3;
 	struct tb_eeprom_ctl eeprom_ctl;
-	u32 __unknown5[7];
-	u32 drom_offset; /* 32 bit register, but eeprom addresses are 16 bit */
+	u32 __unknown5[7]; /* VSC_CS_5 -> VSC_CS_11 */
+	u32 drom_offset; /* VSC_CS_12: 32 bit register, but eeprom addresses are 16 bit */
 } __packed;
 
 /* device headers */
@@ -464,6 +464,10 @@ struct tb_regs_hop {
 
 /* Plug Events registers */
 #define TB_PLUG_EVENTS_USB_DISABLE		BIT(2)
+#define TB_PLUG_EVENTS_CS_1_LANE_DISABLE	BIT(3)
+#define TB_PLUG_EVENTS_CS_1_DPOUT_DISABLE	BIT(4)
+#define TB_PLUG_EVENTS_CS_1_LOW_DPIN_DISABLE	BIT(5)
+#define TB_PLUG_EVENTS_CS_1_HIGH_DPIN_DISABLE	BIT(6)
 
 #define TB_PLUG_EVENTS_PCIE_WR_DATA		0x1b
 #define TB_PLUG_EVENTS_PCIE_CMD			0x1c
-- 
2.34.1