diff mbox series

[v5,02/16] phy: Distinguish between Rx and Tx for MIPI D-PHY with submodes

Message ID 20210115200141.1397785-3-paul.kocialkowski@bootlin.com (mailing list archive)
State New, archived
Headers show
Series Allwinner MIPI CSI-2 support for A31/V3s/A83T | expand

Commit Message

Paul Kocialkowski Jan. 15, 2021, 8:01 p.m. UTC
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 <paul.kocialkowski@bootlin.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
---
 drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c |  3 ++-
 include/linux/phy/phy-mipi-dphy.h                   | 13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

Comments

Hans Verkuil May 26, 2021, 11:50 a.m. UTC | #1
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 <paul.kocialkowski@bootlin.com>
> Acked-by: Helen Koike <helen.koike@collabora.com>
> ---
>  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, &opts);
>  	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 May 26, 2021, 11:56 a.m. UTC | #2
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 <paul.kocialkowski@bootlin.com>
> > Acked-by: Helen Koike <helen.koike@collabora.com>
> > ---
> >  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, &opts);
> >  	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 May 26, 2021, 2:24 p.m. UTC | #3
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 <paul.kocialkowski@bootlin.com>
> Acked-by: Helen Koike <helen.koike@collabora.com>
> ---
>  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, &opts);
>  	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
>
diff mbox series

Patch

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, &opts);
 	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
  *