Re: [PATCH v2] dt-bindings: phy: ti,tcan104x-can: Document TI TCAN1046

[Conor Dooley <conor@kernel.org>]

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On Fri, Dec 12, 2025 at 12:21:03PM +0100, Marc Kleine-Budde wrote:
> On 10.12.2025 18:21:34, Conor Dooley wrote:
> > On Wed, Dec 10, 2025 at 08:52:58AM +0100, Marc Kleine-Budde wrote:
> > > On 09.12.2025 16:21:19, Prabhakar wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > >
> > > > Document the TI TCAN1046 automotive CAN transceiver. The TCAN1046 is a
> > > > dual high-speed CAN transceiver with sleep-mode support and no EN pin,
> > > > mirroring the behaviour of the NXP TJA1048, which also provides dual
> > > > channels and STB1/2 sleep-control lines.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > > > ---
> > > > TCAN 1046, https://www.ti.com/lit/ds/symlink/tcan1046v-q1.pdf?ts=1765297159307&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTCAN1046V-Q1
> > > > NXP TJA1048, https://www.nxp.com/docs/en/data-sheet/TJA1048.pdf
> > >
> > > The polarity of the standby line of the chips is different.
> > >
> > > You must set the correct active high/low property for the GPIO, as the
> > > driver uses logical levels.
> > >
> > > Reviewed-by: Marc Kleine-Budde <mkl@pengutronix.de>
> >
> > What you're saying seems to contradict the tag you've given, is a
> > fallback really suitable if the standby polarity is not the same?
> 
> The driver uses _logical_ levels to switch the GPIOs. For example to
> power on the PHY, it disables the standby GPIO by setting the value to
> "0".
> 
> | static int can_transceiver_phy_power_on(struct phy *phy)
> | {
> [...]
> |         gpiod_set_value_cansleep(can_transceiver_phy->standby_gpio, 0);
> [...]
> | }
> 
> You have to use GPIO_ACTIVE_HIGH/GPIO_ACTIVE_LOW in the DT to configure
> the actual level of the GPIO.

Ah okay, I prob should have looked a bit further into the binding.
Acked-by: Conor Dooley <conor.dooley@microchip.com>


> 
> If you connect the PHY's standby input directly to the SoC's GPIO....
> 
> | TJA1048: HIGH = Normal mode, LOW = Standby mode
> | TCAN1046: High = Standby mode, Low = Normal Mode
> 
> ...for the TJA1048 you would use GPIO_ACTIVE_LOW, while for the
> TCAN1046 you would use GPIO_ACTIVE_HIGH.
> 
> regards,
> Marc
> 
> -- 
> Pengutronix e.K.                 | Marc Kleine-Budde          |
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