Re: [PATCH RFC 1/4] phy: Add MIPI C-PHY mode and configuration options

[Loic Poulain]

On Fri, Oct 16, 2026 at 12:20 AM George Neacsu via B4 Relay
<devnull+geocausa.gmail.com@xxxxxxxxxx> wrote:
>
> From: George Neacsu <geocausa@xxxxxxxxx>
>
> The generic PHY framework has a mode and configuration options for MIPI
> D-PHY but none for C-PHY, so a CSI-2 receiver has no way to ask a PHY
> that does both for C-PHY. Add PHY_MODE_MIPI_CPHY and struct
> phy_configure_opts_mipi_cphy. The options are the two values a receiver
> knows: the symbol rate on each trio and the number of trios.
>
> The first user is the Qualcomm CSI2 PHY, whose X1E80100 instances carry
> the C-PHY front camera of the Surface Pro 11.
>
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: George Neacsu <geocausa@xxxxxxxxx>
> ---
>  include/linux/phy/phy-mipi-cphy.h | 27 +++++++++++++++++++++++++++
>  include/linux/phy/phy.h           |  5 +++++
>  2 files changed, 32 insertions(+)
>
> diff --git a/include/linux/phy/phy-mipi-cphy.h b/include/linux/phy/phy-mipi-cphy.h
> new file mode 100644
> index 000000000..e3f0a8257
> --- /dev/null
> +++ b/include/linux/phy/phy-mipi-cphy.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __PHY_MIPI_CPHY_H_
> +#define __PHY_MIPI_CPHY_H_
> +
> +/**
> + * struct phy_configure_opts_mipi_cphy - MIPI C-PHY configuration set
> + *
> + * This structure is used to represent the configuration state of a
> + * MIPI C-PHY phy.
> + */
> +struct phy_configure_opts_mipi_cphy {
> +       /**
> +        * @symbol_rate:
> +        *
> +        * Symbol rate on each trio, in symbols per second.
> +        */
> +       unsigned long           symbol_rate;
> +
> +       /**
> +        * @lanes:
> +        *
> +        * Number of active trios.
> +        */
> +       unsigned char           lanes;

So, wouldn't 'trios' be a more accurate and specific name for this variable?

> +
> +#endif /* __PHY_MIPI_CPHY_H_ */
> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> index c480d6cb4..f12337834 100644
> --- a/include/linux/phy/phy.h
> +++ b/include/linux/phy/phy.h
> @@ -19,6 +19,7 @@
>  #include <linux/phy/phy-dp.h>
>  #include <linux/phy/phy-hdmi.h>
>  #include <linux/phy/phy-lvds.h>
> +#include <linux/phy/phy-mipi-cphy.h>
>  #include <linux/phy/phy-mipi-dphy.h>
>  #include <linux/phy/phy-thunderbolt.h>
>
> @@ -42,6 +43,7 @@ enum phy_mode {
>         PHY_MODE_PCIE,
>         PHY_MODE_ETHERNET,
>         PHY_MODE_MIPI_DPHY,
> +       PHY_MODE_MIPI_CPHY,
>         PHY_MODE_SATA,
>         PHY_MODE_LVDS,
>         PHY_MODE_DP,
> @@ -69,6 +71,8 @@ union phy_notify {
>   *
>   * @mipi_dphy: Configuration set applicable for phys supporting
>   *             the MIPI_DPHY phy mode.
> + * @mipi_cphy: Configuration set applicable for phys supporting
> + *             the MIPI_CPHY phy mode.
>   * @dp:                Configuration set applicable for phys supporting
>   *             the DisplayPort protocol.
>   * @lvds:      Configuration set applicable for phys supporting
> @@ -78,6 +82,7 @@ union phy_notify {
>   */
>  union phy_configure_opts {
>         struct phy_configure_opts_mipi_dphy     mipi_dphy;
> +       struct phy_configure_opts_mipi_cphy     mipi_cphy;
>         struct phy_configure_opts_dp            dp;
>         struct phy_configure_opts_lvds          lvds;
>         struct phy_configure_opts_hdmi          hdmi;
>
> --
> 2.53.0
>
>