[PATCH v2 0/6] Fixes to Tegra USB role switching and phy handling

[PATCH v2 0/6] Fixes to Tegra USB role switching and phy handling

[Diogo Ivo]

Hello,

This patch series contains fixes/improvements for USB role switching on the
Tegra210 and Tegra186 SoCs.

The first patch addresses a wrong check on the logic that disables the
VBUS regulator.

The second patch removes a redundant mutex lock when setting the PHY
mode.

The third patch guarantees proper ordering of events when switching PHY
roles.

The remaining patches are included to standardize the PHY .set_mode()
callback between Tegra186 and Tegra210.

With this patch series this feature can only be controlled from userspace,
by writing the desired role to sysfs as

echo "role" > /sys/class/usb_role/usb2-0-role-switch/role

with role being one of {device, host, none}.

Further patches will enable automatic role switching via the 'cros_ec_typec'
driver which is currently broken on Smaug.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Changes in v2:
- Remove DT patches already taken to be upstreamed
- Add standardization between Tegra210 and Tegra186
- Address review comments from v1, detailed descriptions in each patch
- Link to v1: https://lore.kernel.org/r/20251204-diogo-tegra_phy-v1-0-51a2016d0be8@tecnico.ulisboa.pt

---
Diogo Ivo (6):
      phy: tegra: xusb: Fix USB2 port regulator disable logic
      usb: xhci: tegra: Remove redundant mutex when setting phy mode
      phy: tegra: xusb: Fix ordering issue when switching roles on USB2 ports
      phy: tegra: xusb: Add ID override support to padctl
      phy: tegra: xusb: Move .set_mode() to a shared location
      phy: tegra: xusb: Move T186 .set_mode() to common implementation

 drivers/phy/tegra/xusb-tegra186.c   | 73 +++++----------------------------
 drivers/phy/tegra/xusb-tegra210.c   | 42 +------------------
 drivers/phy/tegra/xusb.c            | 80 +++++++++++++++++++++++++++++++++++++
 drivers/phy/tegra/xusb.h            |  4 ++
 drivers/usb/gadget/udc/tegra-xudc.c |  4 ++
 drivers/usb/host/xhci-tegra.c       | 14 ++++---
 include/linux/phy/tegra/xusb.h      |  3 ++
 7 files changed, 111 insertions(+), 109 deletions(-)
---
base-commit: b02a5530af8abe0d3cd4852ba48990716e962934
change-id: 20251201-diogo-tegra_phy-86c89cab7377

Best regards,
-- 
Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>

[PATCH v2 1/6] phy: tegra: xusb: Fix USB2 port regulator disable logic

[Diogo Ivo]

The USB2 PHY mode handling on Tegra210 incorrectly relied on
regulator_is_enabled() when determining whether the VBUS supply should
be disabled during role changes. This is because regulator_is_enabled()
reports exactly what is states and not if there is an unbalanced number
of calls between regulator_enable() and regulator_disable(). For
example, regulator_is_enabled() always reports true on a fixed-regulator
with no enable gpio, which is the case on the Pixel C.

This then leads to the PHY driver wrongfully calling regulator_disable()
when transitioning from USB_ROLE_DEVICE to USB_ROLE_NONE since the driver
did not previously call the corresponding regulator_enable().

Fix this by keeping track of the current role and updating the logic to
disable the regulator only when the previous role was USB_ROLE_HOST.

Cc: stable@vger.kernel.org
Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
v1->v2:
- Do not fix typo in comment
---
 drivers/phy/tegra/xusb-tegra210.c | 4 +++-
 drivers/phy/tegra/xusb.h          | 1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/tegra/xusb-tegra210.c b/drivers/phy/tegra/xusb-tegra210.c
index 3409924498e9..3abdf0182d67 100644
--- a/drivers/phy/tegra/xusb-tegra210.c
+++ b/drivers/phy/tegra/xusb-tegra210.c
@@ -1936,12 +1936,14 @@ static int tegra210_usb2_phy_set_mode(struct phy *phy, enum phy_mode mode,
 			 * USB_ROLE_NONE from USB_ROLE_DEVICE, regulator is not
 			 * be enabled.
 			 */
-			if (regulator_is_enabled(port->supply))
+			if (port->role == USB_ROLE_HOST)
 				regulator_disable(port->supply);
 
 			tegra210_xusb_padctl_id_override(padctl, false);
 			tegra210_xusb_padctl_vbus_override(padctl, false);
 		}
+
+		port->role = submode;
 	}
 
 	mutex_unlock(&padctl->lock);
diff --git a/drivers/phy/tegra/xusb.h b/drivers/phy/tegra/xusb.h
index d2b5f9565132..273af147dfd3 100644
--- a/drivers/phy/tegra/xusb.h
+++ b/drivers/phy/tegra/xusb.h
@@ -317,6 +317,7 @@ struct tegra_xusb_usb2_port {
 	enum usb_dr_mode mode;
 	bool internal;
 	int usb3_port_fake;
+	enum usb_role role;
 };
 
 static inline struct tegra_xusb_usb2_port *

-- 
2.52.0

Re: [PATCH v2 0/6] Fixes to Tegra USB role switching and phy handling

[Diogo Ivo]

Hello,

Gentle ping on this series.

Best regards,
Diogo

On 1/27/26 15:11, Diogo Ivo wrote:
> Hello,
> 
> This patch series contains fixes/improvements for USB role switching on the
> Tegra210 and Tegra186 SoCs.
> 
> The first patch addresses a wrong check on the logic that disables the
> VBUS regulator.
> 
> The second patch removes a redundant mutex lock when setting the PHY
> mode.
> 
> The third patch guarantees proper ordering of events when switching PHY
> roles.
> 
> The remaining patches are included to standardize the PHY .set_mode()
> callback between Tegra186 and Tegra210.
> 
> With this patch series this feature can only be controlled from userspace,
> by writing the desired role to sysfs as
> 
> echo "role" > /sys/class/usb_role/usb2-0-role-switch/role
> 
> with role being one of {device, host, none}.
> 
> Further patches will enable automatic role switching via the 'cros_ec_typec'
> driver which is currently broken on Smaug.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---
> Changes in v2:
> - Remove DT patches already taken to be upstreamed
> - Add standardization between Tegra210 and Tegra186
> - Address review comments from v1, detailed descriptions in each patch
> - Link to v1: https://lore.kernel.org/r/20251204-diogo-tegra_phy-v1-0-51a2016d0be8@tecnico.ulisboa.pt
> 
> ---
> Diogo Ivo (6):
>        phy: tegra: xusb: Fix USB2 port regulator disable logic
>        usb: xhci: tegra: Remove redundant mutex when setting phy mode
>        phy: tegra: xusb: Fix ordering issue when switching roles on USB2 ports
>        phy: tegra: xusb: Add ID override support to padctl
>        phy: tegra: xusb: Move .set_mode() to a shared location
>        phy: tegra: xusb: Move T186 .set_mode() to common implementation
> 
>   drivers/phy/tegra/xusb-tegra186.c   | 73 +++++----------------------------
>   drivers/phy/tegra/xusb-tegra210.c   | 42 +------------------
>   drivers/phy/tegra/xusb.c            | 80 +++++++++++++++++++++++++++++++++++++
>   drivers/phy/tegra/xusb.h            |  4 ++
>   drivers/usb/gadget/udc/tegra-xudc.c |  4 ++
>   drivers/usb/host/xhci-tegra.c       | 14 ++++---
>   include/linux/phy/tegra/xusb.h      |  3 ++
>   7 files changed, 111 insertions(+), 109 deletions(-)
> ---
> base-commit: b02a5530af8abe0d3cd4852ba48990716e962934
> change-id: 20251201-diogo-tegra_phy-86c89cab7377
> 
> Best regards,

Re: [PATCH v2 0/6] Fixes to Tegra USB role switching and phy handling

[Vinod Koul]

On 27-01-26, 15:11, Diogo Ivo wrote:
> Hello,
> 
> This patch series contains fixes/improvements for USB role switching on the
> Tegra210 and Tegra186 SoCs.

Thierry, Jonathan

can you folks check this and r-b/t-b please

-- 
~Vinod

Re: [PATCH v2 0/6] Fixes to Tegra USB role switching and phy handling

[Diogo Ivo]

Hello,

Ping on this series as it has been quite a while since this was sent out
originally.

Best regards,

Diogo

On 1/27/26 15:11, Diogo Ivo wrote:
> Hello,
> 
> This patch series contains fixes/improvements for USB role switching on the
> Tegra210 and Tegra186 SoCs.
> 
> The first patch addresses a wrong check on the logic that disables the
> VBUS regulator.
> 
> The second patch removes a redundant mutex lock when setting the PHY
> mode.
> 
> The third patch guarantees proper ordering of events when switching PHY
> roles.
> 
> The remaining patches are included to standardize the PHY .set_mode()
> callback between Tegra186 and Tegra210.
> 
> With this patch series this feature can only be controlled from userspace,
> by writing the desired role to sysfs as
> 
> echo "role" > /sys/class/usb_role/usb2-0-role-switch/role
> 
> with role being one of {device, host, none}.
> 
> Further patches will enable automatic role switching via the 'cros_ec_typec'
> driver which is currently broken on Smaug.
> 
> Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
> ---
> Changes in v2:
> - Remove DT patches already taken to be upstreamed
> - Add standardization between Tegra210 and Tegra186
> - Address review comments from v1, detailed descriptions in each patch
> - Link to v1: https://lore.kernel.org/r/20251204-diogo-tegra_phy-v1-0-51a2016d0be8@tecnico.ulisboa.pt
> 
> ---
> Diogo Ivo (6):
>        phy: tegra: xusb: Fix USB2 port regulator disable logic
>        usb: xhci: tegra: Remove redundant mutex when setting phy mode
>        phy: tegra: xusb: Fix ordering issue when switching roles on USB2 ports
>        phy: tegra: xusb: Add ID override support to padctl
>        phy: tegra: xusb: Move .set_mode() to a shared location
>        phy: tegra: xusb: Move T186 .set_mode() to common implementation
> 
>   drivers/phy/tegra/xusb-tegra186.c   | 73 +++++----------------------------
>   drivers/phy/tegra/xusb-tegra210.c   | 42 +------------------
>   drivers/phy/tegra/xusb.c            | 80 +++++++++++++++++++++++++++++++++++++
>   drivers/phy/tegra/xusb.h            |  4 ++
>   drivers/usb/gadget/udc/tegra-xudc.c |  4 ++
>   drivers/usb/host/xhci-tegra.c       | 14 ++++---
>   include/linux/phy/tegra/xusb.h      |  3 ++
>   7 files changed, 111 insertions(+), 109 deletions(-)
> ---
> base-commit: b02a5530af8abe0d3cd4852ba48990716e962934
> change-id: 20251201-diogo-tegra_phy-86c89cab7377
> 
> Best regards,