Re: [PATCH v4 14/16] drm: bridge: analogix/dp: try force hpd after plug in lookup failed

[Rob Herring <robherring2@gmail.com>]

On Tue, Sep 1, 2015 at 1:14 AM, Yakir Yang <ykk@rock-chips.com> wrote:
> Some edp screen do not have hpd signal, so we can't just return
> failed when hpd plug in detect failed.

This is a property of the panel (or connector perhaps), so this
property should be located there. At least, it is a common issue and
not specific to this chip. We could have an HDMI connector and failed
to hook up HPD for example. A connector node is also where hpd-gpios
should be located instead (and are already defined by
../bindings/video/hdmi-connector.txt). Perhaps we need a eDP connector
binding, too.

Are there any eDP panels which don't have EDID and need panel details in DT?

Rob

> This is an hardware property, so we need add a devicetree property
> "analogix,need-force-hpd" to indicate this sutiation.
>
> Signed-off-by: Yakir Yang <ykk@rock-chips.com>
> ---
> Changes in v4: None
> Changes in v3:
> - Add "analogix,need-force-hpd" to indicate whether driver need foce
>   hpd when hpd detect failed.
>
> Changes in v2: None
>
>  .../devicetree/bindings/drm/bridge/analogix_dp.txt |  4 ++-
>  .../bindings/video/analogix_dp-rockchip.txt        |  1 +
>  .../devicetree/bindings/video/exynos_dp.txt        |  1 +
>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 36 +++++++++++++++++++---
>  drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  2 ++
>  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  |  9 ++++++
>  6 files changed, 47 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/drm/bridge/analogix_dp.txt b/Documentation/devicetree/bindings/drm/bridge/analogix_dp.txt
> index f54dc3e..c310367 100644
> --- a/Documentation/devicetree/bindings/drm/bridge/analogix_dp.txt
> +++ b/Documentation/devicetree/bindings/drm/bridge/analogix_dp.txt
> @@ -22,6 +22,9 @@ Required properties for dp-controller:
>                 from general PHY binding: Should be "dp".
>
>  Optional properties for dp-controller:
> +       -analogix,need-force-hpd:
> +               Indicate driver need force hpd when hpd detect failed, this
> +               is used for some eDP screen which don't have hpd signal.
>         -hpd-gpios:
>                 Hotplug detect GPIO.
>                 Indicates which GPIO should be used for hotplug detection
> @@ -31,7 +34,6 @@ Optional properties for dp-controller:
>                 * Documentation/devicetree/bindings/video/exynos_dp.txt
>                 * Documentation/devicetree/bindings/video/analogix_dp-rockchip.txt
>
> -
>  [1]: Documentation/devicetree/bindings/media/video-interfaces.txt
>  -------------------------------------------------------------------------------
>
> diff --git a/Documentation/devicetree/bindings/video/analogix_dp-rockchip.txt b/Documentation/devicetree/bindings/video/analogix_dp-rockchip.txt
> index 502483e..8b9ed7d 100644
> --- a/Documentation/devicetree/bindings/video/analogix_dp-rockchip.txt
> +++ b/Documentation/devicetree/bindings/video/analogix_dp-rockchip.txt
> @@ -28,6 +28,7 @@ For the below properties, please refer to Analogix DP binding document:
>  - phys (required)
>  - phy-names (required)
>  - hpd-gpios (optional)
> +- analogix,need-force-hpd (optional)
>  -------------------------------------------------------------------------------
>
>  Example:
> diff --git a/Documentation/devicetree/bindings/video/exynos_dp.txt b/Documentation/devicetree/bindings/video/exynos_dp.txt
> index ea03b3a..4f06e80 100644
> --- a/Documentation/devicetree/bindings/video/exynos_dp.txt
> +++ b/Documentation/devicetree/bindings/video/exynos_dp.txt
> @@ -41,6 +41,7 @@ For the below properties, please refer to Analogix DP binding document:
>         -phys (required)
>         -phy-names (required)
>         -hpd-gpios (optional)
> +       -analogix,need-force-hpd (optional)
>         -video interfaces (optional)
>
>  Deprecated properties for DisplayPort:
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index f7227ec..e6b328a 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -63,15 +63,38 @@ static int analogix_dp_detect_hpd(struct analogix_dp_device *dp)
>  {
>         int timeout_loop = 0;
>
> -       while (analogix_dp_get_plug_in_status(dp) != 0) {
> +       while (timeout_loop < DP_TIMEOUT_LOOP_COUNT) {
> +               if (analogix_dp_get_plug_in_status(dp) == 0)
> +                       return 0;
> +
>                 timeout_loop++;
> -               if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
> -                       dev_err(dp->dev, "failed to get hpd plug status\n");
> -                       return -ETIMEDOUT;
> -               }
>                 usleep_range(10, 11);
>         }
>
> +       /*
> +        * Some edp screen do not have hpd signal, so we can't just
> +        * return failed when hpd plug in detect failed, DT property
> +        * "need-force-hpd" would indicate whether driver need this.
> +        */
> +       if (!dp->need_force_hpd)
> +               return -ETIMEDOUT;
> +
> +       /*
> +        * The eDP TRM indicate that if HPD_STATUS(RO) is 0, AUX CH
> +        * will not work, so we need to give a force hpd action to
> +        * set HPD_STATUS manually.
> +        */
> +       dev_dbg(dp->dev, "failed to get hpd plug status, try to force hpd\n");
> +
> +       analogix_dp_force_hpd(dp);
> +
> +       if (analogix_dp_get_plug_in_status(dp) != 0) {
> +               dev_err(dp->dev, "failed to get hpd plug in status\n");
> +               return -EINVAL;
> +       }
> +
> +       dev_dbg(dp->dev, "success to get plug in status after force hpd\n");
> +
>         return 0;
>  }
>
> @@ -1287,6 +1310,9 @@ int analogix_dp_bind(struct device *dev, struct drm_device *drm_dev,
>         if (IS_ERR(dp->reg_base))
>                 return PTR_ERR(dp->reg_base);
>
> +       dp->need_force_hpd =
> +               of_property_read_bool(dev->of_node, "analogix,need-force-hpd");
> +
>         dp->hpd_gpio = of_get_named_gpio(dev->of_node, "hpd-gpios", 0);
>         if (gpio_is_valid(dp->hpd_gpio))
>                 dp->hpd_gpio = of_get_named_gpio(dev->of_node,
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index d8945e2..6960ab3 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -160,6 +160,7 @@ struct analogix_dp_device {
>         struct phy              *phy;
>         int                     dpms_mode;
>         int                     hpd_gpio;
> +       bool                    need_force_hpd;
>
>         struct analogix_dp_plat_data *plat_data;
>  };
> @@ -180,6 +181,7 @@ void analogix_dp_set_analog_power_down(struct analogix_dp_device *dp,
>                                        bool enable);
>  void analogix_dp_init_analog_func(struct analogix_dp_device *dp);
>  void analogix_dp_init_hpd(struct analogix_dp_device *dp);
> +void analogix_dp_force_hpd(struct analogix_dp_device *dp);
>  enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp);
>  void analogix_dp_clear_hotplug_interrupts(struct analogix_dp_device *dp);
>  void analogix_dp_reset_aux(struct analogix_dp_device *dp);
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> index 15346fe..3086afc 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> @@ -365,6 +365,15 @@ void analogix_dp_init_hpd(struct analogix_dp_device *dp)
>         writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
>  }
>
> +void analogix_dp_force_hpd(struct analogix_dp_device *dp)
> +{
> +       u32 reg;
> +
> +       reg = readl(dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
> +       reg = (F_HPD | HPD_CTRL);
> +       writel(reg, dp->reg_base + ANALOGIX_DP_SYS_CTL_3);
> +}
> +
>  enum dp_irq_type analogix_dp_get_irq_type(struct analogix_dp_device *dp)
>  {
>         u32 reg;
> --
> 2.1.2
>
>