[PATCH 2/8] drm/i915/ddi: use intel_de_wait_custom() instead of wait_for_us()

[Jani Nikula]

On Thu, 26 Jun 2025, Jani Nikula <jani.nikula at intel.com> wrote:
> Prefer the register read specific wait function over i915 wait_for_us().
>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 0405396c7750..39613f86f1ce 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -2561,6 +2561,7 @@ mtl_ddi_enable_d2d(struct intel_encoder *encoder)
>  	enum port port = encoder->port;
>  	i915_reg_t reg;
>  	u32 set_bits, wait_bits;
> +	int ret;
>  
>  	if (DISPLAY_VER(display) < 14)
>  		return;
> @@ -2576,7 +2577,11 @@ mtl_ddi_enable_d2d(struct intel_encoder *encoder)
>  	}
>  
>  	intel_de_rmw(display, reg, 0, set_bits);
> -	if (wait_for_us(intel_de_read(display, reg) & wait_bits, 100)) {
> +
> +	ret = intel_de_wait_custom(display, reg,
> +				   wait_bits, wait_bits,
> +				   100, 0, NULL);
> +	if (ret) {
>  		drm_err(display->drm, "Timeout waiting for D2D Link enable for DDI/PORT_BUF_CTL %c\n",
>  			port_name(port));
>  	}
> @@ -3058,6 +3063,7 @@ mtl_ddi_disable_d2d(struct intel_encoder *encoder)
>  	enum port port = encoder->port;
>  	i915_reg_t reg;
>  	u32 clr_bits, wait_bits;
> +	int ret;
>  
>  	if (DISPLAY_VER(display) < 14)
>  		return;
> @@ -3073,7 +3079,11 @@ mtl_ddi_disable_d2d(struct intel_encoder *encoder)
>  	}
>  
>  	intel_de_rmw(display, reg, clr_bits, 0);
> -	if (wait_for_us(!(intel_de_read(display, reg) & wait_bits), 100))
> +
> +	ret = intel_de_wait_custom(display, reg,
> +				   wait_bits, wait_bits,

As reported by Xe BAT, this should be "wait_bits, 0,". Missed the ! in
the original.

> +				   100, 0, NULL);
> +	if (ret)
>  		drm_err(display->drm, "Timeout waiting for D2D Link disable for DDI/PORT_BUF_CTL %c\n",
>  			port_name(port));
>  }

-- 
Jani Nikula, Intel