[linux-sunxi] Re: [PATCH v5 02/16] phy: Distinguish between Rx and Tx for MIPI D-PHY with submodes
Hi everyone,
On Fri 15 Jan 21, 21:01, Paul Kocialkowski wrote:
> As some D-PHY controllers support both Rx and Tx mode, we need a way for
> users to explicitly request one or the other. For instance, Rx mode can
> be used along with MIPI CSI-2 while Tx mode can be used with MIPI DSI.
>
> Introduce new MIPI D-PHY PHY submodes to use with PHY_MODE_MIPI_DPHY.
> The default (zero value) is kept to Tx so only the rkisp1 driver, which
> uses D-PHY in Rx mode, needs to be adapted.
I think it was Laurent who brought up on IRC that using a submode is probably
not a correct way to distinguish between Rx and Tx modes.
Thinking about it again, it feels like selecting the direction at run-time
would only be relevant if there's D-PHY hardware than can do both Tx and Rx
*and* that can be muxed to either a MIPI DSI and a CSI-2 controller at
run-time.
For the Allwinner case, the D-PHY is the same hardware for both but there will
be one instance attached to each controller, not a single shared instance.
It feels rather unlikely that a device with both MIPI DSI and CSI-2 would only
have one PHY for the two as this wouldn't allow concurrent use of the two
controllers. Even in a case where there'd be n controllers and m < n
bi-directional PHYs, it feels safe to assume that a static attribution would
be sufficient.
As a result it feels more relevant to have this distinction in device-tree
rather than via the PHY API.
What do you think?
Any suggestion on how this should be represented in device-tree?
Cheers,
Paul
> Signed-off-by: Paul Kocialkowski
> Acked-by: Helen Koike
> ---
> drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c | 3 ++-
> include/linux/phy/phy-mipi-dphy.h | 13 +
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> index 2e5b57e3aedc..cab261644102 100644
> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> @@ -948,7 +948,8 @@ static int rkisp1_mipi_csi2_start(struct rkisp1_isp *isp,
>
> phy_mipi_dphy_get_default_config(pixel_clock, isp->sink_fmt->bus_width,
>sensor->lanes, cfg);
> - phy_set_mode(sensor->dphy, PHY_MODE_MIPI_DPHY);
> + phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
> + PHY_MIPI_DPHY_SUBMODE_RX);
> phy_configure(sensor->dphy, );
> phy_power_on(sensor->dphy);
>
> diff --git a/include/linux/phy/phy-mipi-dphy.h
> b/include/linux/phy/phy-mipi-dphy.h
> index a877ffee845d..0f57ef46a8b5 100644
> --- a/include/linux/phy/phy-mipi-dphy.h
> +++ b/include/linux/phy/phy-mipi-dphy.h
> @@ -6,6 +6,19 @@
> #ifndef __PHY_MIPI_DPHY_H_
> #define __PHY_MIPI_DPHY_H_
>
> +/**
> + * enum phy_mipi_dphy_submode - MIPI D-PHY sub-mode
> + *
> + * A MIPI D-PHY can be used to transmit or receive data.
> + * Since some controllers can support both, the direction to enable is
> specified
> + * with the PHY sub-mode. Transmit is assumed by default with phy_set_mode.
> + */
> +
> +enum phy_mipi_dphy_submode {
> + PHY_MIPI_DPHY_SUBMODE_TX = 0,
> + PHY_MIPI_DPHY_SUBMODE_RX,
> +};
> +
> /**
> * struct phy_configure_opts_mipi_dphy - MIPI D-PHY configuration set
> *
> --
> 2.30.0
>
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
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[linux-sunxi] Re: [PATCH v5 02/16] phy: Distinguish between Rx and Tx for MIPI D-PHY with submodes
Hi,
On Wed 26 May 21, 13:50, Hans Verkuil wrote:
> On 15/01/2021 21:01, Paul Kocialkowski wrote:
> > As some D-PHY controllers support both Rx and Tx mode, we need a way for
> > users to explicitly request one or the other. For instance, Rx mode can
> > be used along with MIPI CSI-2 while Tx mode can be used with MIPI DSI.
> >
> > Introduce new MIPI D-PHY PHY submodes to use with PHY_MODE_MIPI_DPHY.
> > The default (zero value) is kept to Tx so only the rkisp1 driver, which
> > uses D-PHY in Rx mode, needs to be adapted.
> >
> > Signed-off-by: Paul Kocialkowski
> > Acked-by: Helen Koike
> > ---
> > drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c | 3 ++-
> > include/linux/phy/phy-mipi-dphy.h | 13 +
> > 2 files changed, 15 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > index 2e5b57e3aedc..cab261644102 100644
> > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> > @@ -948,7 +948,8 @@ static int rkisp1_mipi_csi2_start(struct rkisp1_isp
> > *isp,
> >
> > phy_mipi_dphy_get_default_config(pixel_clock, isp->sink_fmt->bus_width,
> > sensor->lanes, cfg);
> > - phy_set_mode(sensor->dphy, PHY_MODE_MIPI_DPHY);
> > + phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
> > +PHY_MIPI_DPHY_SUBMODE_RX);
>
> drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c: In function
> ‘rkisp1_mipi_csi2_start’:
> drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c:951:19: error: ‘cdev’
> undeclared (first use in this function)
> 951 | phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
> | ^~~~
>
> Huh?
Oh wow that's quite shameful. Apologies here.
Note that I'll rebase/respin this series. I also remember that it wasn't very
consensual (on IRC) to use a submode to indicate rx vs tx mode and that
specifying that in the deivce-tree would be a better fit.
Cheers,
Paul
> Regards,
>
> Hans
>
> > phy_configure(sensor->dphy, );
> > phy_power_on(sensor->dphy);
> >
> > diff --git a/include/linux/phy/phy-mipi-dphy.h
> > b/include/linux/phy/phy-mipi-dphy.h
> > index a877ffee845d..0f57ef46a8b5 100644
> > --- a/include/linux/phy/phy-mipi-dphy.h
> > +++ b/include/linux/phy/phy-mipi-dphy.h
> > @@ -6,6 +6,19 @@
> > #ifndef __PHY_MIPI_DPHY_H_
> > #define __PHY_MIPI_DPHY_H_
> >
> > +/**
> > + * enum phy_mipi_dphy_submode - MIPI D-PHY sub-mode
> > + *
> > + * A MIPI D-PHY can be used to transmit or receive data.
> > + * Since some controllers can support both, the direction to enable is
> > specified
> > + * with the PHY sub-mode. Transmit is assumed by default with phy_set_mode.
> > + */
> > +
> > +enum phy_mipi_dphy_submode {
> > + PHY_MIPI_DPHY_SUBMODE_TX = 0,
> > + PHY_MIPI_DPHY_SUBMODE_RX,
> > +};
> > +
> > /**
> > * struct phy_configure_opts_mipi_dphy - MIPI D-PHY configuration set
> > *
> >
>
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
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[linux-sunxi] Re: [PATCH v5 02/16] phy: Distinguish between Rx and Tx for MIPI D-PHY with submodes
On 15/01/2021 21:01, Paul Kocialkowski wrote:
> As some D-PHY controllers support both Rx and Tx mode, we need a way for
> users to explicitly request one or the other. For instance, Rx mode can
> be used along with MIPI CSI-2 while Tx mode can be used with MIPI DSI.
>
> Introduce new MIPI D-PHY PHY submodes to use with PHY_MODE_MIPI_DPHY.
> The default (zero value) is kept to Tx so only the rkisp1 driver, which
> uses D-PHY in Rx mode, needs to be adapted.
>
> Signed-off-by: Paul Kocialkowski
> Acked-by: Helen Koike
> ---
> drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c | 3 ++-
> include/linux/phy/phy-mipi-dphy.h | 13 +
> 2 files changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> index 2e5b57e3aedc..cab261644102 100644
> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> @@ -948,7 +948,8 @@ static int rkisp1_mipi_csi2_start(struct rkisp1_isp *isp,
>
> phy_mipi_dphy_get_default_config(pixel_clock, isp->sink_fmt->bus_width,
>sensor->lanes, cfg);
> - phy_set_mode(sensor->dphy, PHY_MODE_MIPI_DPHY);
> + phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
> + PHY_MIPI_DPHY_SUBMODE_RX);
drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c: In function
‘rkisp1_mipi_csi2_start’:
drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c:951:19: error: ‘cdev’
undeclared (first use in this function)
951 | phy_set_mode_ext(cdev->dphy, PHY_MODE_MIPI_DPHY,
| ^~~~
Huh?
Regards,
Hans
> phy_configure(sensor->dphy, );
> phy_power_on(sensor->dphy);
>
> diff --git a/include/linux/phy/phy-mipi-dphy.h
> b/include/linux/phy/phy-mipi-dphy.h
> index a877ffee845d..0f57ef46a8b5 100644
> --- a/include/linux/phy/phy-mipi-dphy.h
> +++ b/include/linux/phy/phy-mipi-dphy.h
> @@ -6,6 +6,19 @@
> #ifndef __PHY_MIPI_DPHY_H_
> #define __PHY_MIPI_DPHY_H_
>
> +/**
> + * enum phy_mipi_dphy_submode - MIPI D-PHY sub-mode
> + *
> + * A MIPI D-PHY can be used to transmit or receive data.
> + * Since some controllers can support both, the direction to enable is
> specified
> + * with the PHY sub-mode. Transmit is assumed by default with phy_set_mode.
> + */
> +
> +enum phy_mipi_dphy_submode {
> + PHY_MIPI_DPHY_SUBMODE_TX = 0,
> + PHY_MIPI_DPHY_SUBMODE_RX,
> +};
> +
> /**
> * struct phy_configure_opts_mipi_dphy - MIPI D-PHY configuration set
> *
>
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