[PATCH] usb: typec: tcpm: Fix altmode re-registration causes sysfs create fail

[cy_huang <u0084500@gmail.com>]

From: ChiYuan Huang <cy_huang@richtek.com>

There's the altmode re-registeration issue after data role
swap (DR_SWAP).

Comparing to USBPD 2.0, in USBPD 3.0, it loose the limit that only DFP
can initiate the VDM command to get partner identity information.

For a USBPD 3.0 UFP device, it may already get the identity information
from its port partner before DR_SWAP. If DR_SWAP send or receive at the
mean time, 'send_discover' flag will be raised again. It causes discover
identify action restart while entering ready state. And after all
discover actions are done, the 'tcpm_register_altmodes' will be called.
If old altmode is not unregistered, this sysfs create fail can be found.

In 'DR_SWAP_CHANGE_DR' state case, only DFP will unregister altmodes.
For UFP, the original altmodes keep registered.

This patch fix the logic that after DR_SWAP, 'tcpm_unregister_altmodes'
must be called whatever the current data role is.

Fixes: ae8a2ca8a221 ("usb: typec: Group all TCPCI/TCPM code together)
Reported-by: TommyYl Chen <tommyyl.chen@mediatek.com>
Cc: stable@vger.kernel.org
Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
---
Hi,

Below's the issue log for the reference.

*TCPM
[    3.856679] AMS DISCOVER_MODES start
[    3.856687] PD TX, header: 0x188f
[    3.858827] PD TX complete, status: 0
[    3.865330] PD RX, header: 0x2daf [1]
[    3.865340] Rx VDM cmd 0xff01a043 type 1 cmd 3 len 2
[    3.865348] AMS DISCOVER_MODES finished
[    3.865352]  Alternate mode 0: SVID 0xff01, VDO 1: 0x001c0045
[    3.865362] AMS DISCOVER_MODES start
[    3.865367] PD TX, header: 0x1a8f
[    3.867802] PD TX complete, status: 0
[    3.875208] PD RX, header: 0x2faf [1]
[    3.875216] Rx VDM cmd 0x413ca043 type 1 cmd 3 len 2
[    3.875222] AMS DISCOVER_MODES finished
[    3.875225]  Alternate mode 1: SVID 0x413c, VDO 1: 0x00000001
[    3.938243] AMS GET_SINK_CAPABILITIES start
[    3.938255] state change SNK_READY -> AMS_START [rev3 GET_SINK_CAPABILITIES]
[    3.938266] state change AMS_START -> GET_SINK_CAP [rev3 GET_SINK_CAPABILITIES]
[    3.938274] PD TX, header: 0xe88
[    3.940268] PD TX complete, status: 0
[    3.940310] pending state change GET_SINK_CAP -> GET_SINK_CAP_TIMEOUT @ 60 ms
[rev3 GET_SINK_CAPABILITIES]
[    3.946291] PD RX, header: 0x13a4 [1]
[    3.946295] Port partner FRS capable partner_frs_current:0 port_frs_current:0 enable:n
[    3.946298] state change GET_SINK_CAP -> SNK_READY [rev3 GET_SINK_CAPABILITIES]
[    3.946304] AMS GET_SINK_CAPABILITIES finished
[    4.239342] CC1: 5 -> 4, CC2: 0 -> 0 [state SNK_READY, polarity 0, connected]
[    4.256594] PD RX, header: 0x5a9 [1]
[    4.256603] state change SNK_READY -> DR_SWAP_ACCEPT [rev3 DATA_ROLE_SWAP]
[    4.256609] PD TX, header: 0x83
[    4.258528] PD TX complete, status: 0
[    4.258584] state change DR_SWAP_ACCEPT -> DR_SWAP_CHANGE_DR [rev3 DATA_ROLE_SWAP]
[    4.258591] Requesting mux state 1, usb-role 1, orientation 1
[    4.259588] AMS DATA_ROLE_SWAP finished
[    4.259592] state change DR_SWAP_CHANGE_DR -> SNK_READY [rev3 NONE_AMS]
[    4.259605] AMS DISCOVER_IDENTITY start
[    4.259609] Sink TX No Go
[    4.260874] CC1: 4 -> 5, CC2: 0 -> 0 [state SNK_READY, polarity 0, connected]
[    4.359636] AMS DISCOVER_IDENTITY start
[    4.359642] PD TX, header: 0x12af
[    4.361884] PD TX complete, status: 0
[    4.369433] PD RX, header: 0x578f [1]
[    4.369439] Rx VDM cmd 0xff00a041 type 1 cmd 1 len 5
[    4.369448] AMS DISCOVER_IDENTITY finished
[    4.369515] Identity: 413c:c013.0712
[    4.369521] AMS DISCOVER_SVIDS start
[    4.369524] PD TX, header: 0x14af
[    4.371696] PD TX complete, status: 0
[    4.378564] PD RX, header: 0x398f [1]
[    4.378573] Rx VDM cmd 0xff00a042 type 1 cmd 2 len 3
[    4.378579] AMS DISCOVER_SVIDS finished
[    4.378582] SVID 1: 0xff01
[    4.378584] SVID 2: 0x413c
[    4.378594] AMS DISCOVER_MODES start
[    4.378597] PD TX, header: 0x16af
[    4.380696] PD TX complete, status: 0
[    4.387008] PD RX, header: 0x2b8f [1]
[    4.387014] Rx VDM cmd 0xff01a043 type 1 cmd 3 len 2
[    4.387021] AMS DISCOVER_MODES finished
[    4.387023]  Alternate mode 0: SVID 0xff01, VDO 1: 0x001c0045
[    4.387029] AMS DISCOVER_MODES start
[    4.387031] PD TX, header: 0x18af
[    4.389134] PD TX complete, status: 0
[    4.395528] PD RX, header: 0x2d8f [1]
[    4.395538] Rx VDM cmd 0x413ca043 type 1 cmd 3 len 2
[    4.395546] AMS DISCOVER_MODES finished
[    4.395548]  Alternate mode 1: SVID 0x413c, VDO 1: 0x00000001

*Kernel TRACE
sysfs: cannot create duplicate filename
'/devices/platform/soc/11d01000.i2c/i2c-0/0-0034/mt6360-tcpc.6.auto/typec/port0/port0.0/partner'
CPU: 2 PID: 299 Comm: mt6360-tcpc.6.a Tainted: GO      5.15.37-mtk+g880abc5122e7 #1
Hardware name: MediaTek MT8195 demo board (DT)
Call trace:
 dump_backtrace+0x0/0x1ac
 show_stack+0x24/0x30
 dump_stack_lvl+0x68/0x84
 dump_stack+0x1c/0x38
 sysfs_warn_dup+0x70/0x90
 typec_probe+0xa4/0x134 [typec]
 really_probe.part.0+0xa4/0x310
 __device_attach_driver+0x100/0x16c
 bus_for_each_drv+0x84/0xe0
 __device_attach+0xe0/0x1ac
 device_add+0x39c/0x8b0
 device_register+0x2c/0x40
 typec_register_altmode+0x1f4/0x360 [typec]
 typec_partner_register_altmode+0x1c/0x30 [typec]
 tcpm_pd_rx_handler+0x19d4/0x1c0c [tcpm]
 kthread_worker_fn+0xb8/0x290
 kthread+0x15c/0x170
 ret_from_fork+0x10/0x20
[    4.395962] typec_displayport port0-partner.2: failed to create symlinks
[    4.395967] typec_displayport: probe of port0-partner.2 failed with error -17

It seems it's a common issue if typec port supports the modal operation.

---
 drivers/usb/typec/tcpm/tcpm.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 904c7b4..59b366b 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4594,14 +4594,13 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, ready_state(port), 0);
 		break;
 	case DR_SWAP_CHANGE_DR:
-		if (port->data_role == TYPEC_HOST) {
-			tcpm_unregister_altmodes(port);
+		tcpm_unregister_altmodes(port);
+		if (port->data_role == TYPEC_HOST)
 			tcpm_set_roles(port, true, port->pwr_role,
 				       TYPEC_DEVICE);
-		} else {
+		else
 			tcpm_set_roles(port, true, port->pwr_role,
 				       TYPEC_HOST);
-		}
 		tcpm_ams_finish(port);
 		tcpm_set_state(port, ready_state(port), 0);
 		break;
-- 
2.7.4