On Tue, 10 Jul 2018, Madhav Chauhan <madhav.chauhan@xxxxxxxxx> wrote:
> This patch enables DDI buffer by writing to DDI_BUF_CTL
> register and wait for DDI status to be *not idle* for a
> port.
>
> v2: Rebase
>
> Signed-off-by: Madhav Chauhan <madhav.chauhan@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/icl_dsi.c | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/icl_dsi.c b/drivers/gpu/drm/i915/icl_dsi.c
> index dc16c1f..41faa19 100644
> --- a/drivers/gpu/drm/i915/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/icl_dsi.c
> @@ -251,6 +251,25 @@ static void gen11_dsi_voltage_swing_program_seq(struct intel_encoder *encoder)
> }
> }
>
> +static void gen11_dsi_enable_ddi_buffer(struct intel_encoder *encoder)
> +{
> + struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> + struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> + u32 tmp;
> + enum port port;
> +
> + for_each_dsi_port(port, intel_dsi->ports) {
> + tmp = I915_READ(DDI_BUF_CTL(port));
> + tmp |= DDI_BUF_CTL_ENABLE;
> + I915_WRITE(DDI_BUF_CTL(port), tmp);
> +
> + if (wait_for_us(!(I915_READ(DDI_BUF_CTL(port)) &
> + DDI_BUF_IS_IDLE),
> + 500))
IMO a "== 0" check reads better in wait_for_us.
> + DRM_ERROR("DDI port:%c buffer idle\n", port_name(port));
> + }
> +}
> +
> static void gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder)
> {
> /* step 4a: power up all lanes of the DDI used by DSI */
> @@ -261,6 +280,9 @@ static void gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder)
>
> /* step 4c: configure voltage swing and skew */
> gen11_dsi_voltage_swing_program_seq(encoder);
> +
> + /* step 4d: enable DDI buffer */
Alas, this is step 4e now, and you have a new 4d to take care of for
B0+.
Regardless,
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> + gen11_dsi_enable_ddi_buffer(encoder);
> }
>
> static void __attribute__((unused))
--
Jani Nikula, Intel Open Source Graphics Center
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