Re: [PATCH v10 14/17] drm: bridge: analogix/dp: try force hpd after plug in lookup failed

[Rob Herring <robh@kernel.org>]

On Mon, Dec 07, 2015 at 02:40:42PM +0800, Yakir Yang wrote:
> Some edp screen do not have hpd signal, so we can't just return
> failed when hpd plug in detect failed.
> 
> This is an hardware property, so we need add a devicetree property
> "analogix,need-force-hpd" to indicate this sutiation.

I can see this being common. Just make it "force-hpd".

Rob

> 
> Signed-off-by: Yakir Yang <ykk@rock-chips.com>
> Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
> ---
> Changes in v10: None
> Changes in v9: None
> Changes in v8: None
> Changes in v7: None
> Changes in v6: None
> Changes in v5: None
> 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
> 
>  .../bindings/display/bridge/analogix_dp.txt        |  4 ++-
>  .../bindings/display/exynos/exynos_dp.txt          |  1 +
>  .../display/rockchip/analogix_dp-rockchip.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/display/bridge/analogix_dp.txt b/Documentation/devicetree/bindings/display/bridge/analogix_dp.txt
> index 7659a7a..74f0e80 100644
> --- a/Documentation/devicetree/bindings/display/bridge/analogix_dp.txt
> +++ b/Documentation/devicetree/bindings/display/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/display/exynos/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/display/exynos/exynos_dp.txt b/Documentation/devicetree/bindings/display/exynos/exynos_dp.txt
> index 9905081..8800164 100644
> --- a/Documentation/devicetree/bindings/display/exynos/exynos_dp.txt
> +++ b/Documentation/devicetree/bindings/display/exynos/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/Documentation/devicetree/bindings/display/rockchip/analogix_dp-rockchip.txt b/Documentation/devicetree/bindings/display/rockchip/analogix_dp-rockchip.txt
> index dae86c4..1f1e594 100644
> --- a/Documentation/devicetree/bindings/display/rockchip/analogix_dp-rockchip.txt
> +++ b/Documentation/devicetree/bindings/display/rockchip/analogix_dp-rockchip.txt
> @@ -32,6 +32,7 @@ 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/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index a11504b..94968e4 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -59,15 +59,38 @@ 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 (timeout_loop > DP_TIMEOUT_LOOP_COUNT) {
> -			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;
>  }
>  
> @@ -1246,6 +1269,9 @@ 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 e6f8243..d3c7e0a 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 21a3287..c7e2959 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;
> -- 
> 1.9.1
> 
>