Re: [RFC-v2 2/9] drm/i915/dsi: Configure transcoder operation for command mode.

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 11 Nov 2019, Vandita Kulkarni <vandita.kulkarni@intel.com> wrote:
> Configure the transcoder to operate in TE GATE command mode
> and  take TE events from GPIO.
> Also disable the periodic command mode, that GOP would have
> programmed.
>
> Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
> ---
>  drivers/gpu/drm/i915/display/icl_dsi.c | 36 ++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c b/drivers/gpu/drm/i915/display/icl_dsi.c
> index 8eb2d7f29c82..5ff2a1ffd3ea 100644
> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
> @@ -704,6 +704,10 @@ gen11_dsi_configure_transcoder(struct intel_encoder *encoder,
>  				tmp |= VIDEO_MODE_SYNC_PULSE;
>  				break;
>  			}
> +		} else {
> +			tmp &= ~OP_MODE_MASK;
> +			tmp |= CMD_MODE_TE_GATE;
> +			tmp |= TE_SOURCE_GPIO;

Do we have TE source specified in VBT or somewhere? I can live with this
*for now* but it does freak me out a bit that we might also be using the
utility pin for backlight PWM output. That would conflict magnificently.

Maybe at least add a FIXME comment about that?

>  		}
>  
>  		I915_WRITE(DSI_TRANS_FUNC_CONF(dsi_trans), tmp);
> @@ -953,6 +957,26 @@ static void gen11_dsi_setup_timeouts(struct intel_encoder *encoder)
>  	}
>  }
>  
> +static void gen11_dsi_config_util_pin(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;
> +
> +	/*
> +	 * used as TE i/p for DSI0,
> +	 * for dual link/DSI1 TE is from slave DSI1
> +	 * through GPIO.
> +	 */
> +	if (is_vid_mode(intel_dsi) || (intel_dsi->ports & BIT(PORT_B)))
> +		return;
> +
> +	tmp = I915_READ(UTIL_PIN_CTL);
> +	tmp |= UTIL_PIN_DIRECTION_INPUT;
> +	tmp |= UTIL_PIN_ENABLE;
> +	I915_WRITE(UTIL_PIN_CTL, tmp);

You'll also need to disable the utility pin somewhere, else you'll get
warnings from assert_can_enable_dc6().

> +}
> +
>  static void
>  gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder,
>  			      const struct intel_crtc_state *pipe_config)
> @@ -974,6 +998,9 @@ gen11_dsi_enable_port_and_phy(struct intel_encoder *encoder,
>  	/* setup D-PHY timings */
>  	gen11_dsi_setup_dphy_timings(encoder);
>  
> +	/* Since transcoder is configured to take events from GPIO */
> +	gen11_dsi_config_util_pin(encoder);
> +
>  	/* step 4h: setup DSI protocol timeouts */
>  	gen11_dsi_setup_timeouts(encoder);
>  
> @@ -1104,6 +1131,15 @@ static void gen11_dsi_deconfigure_trancoder(struct intel_encoder *encoder)
>  	enum transcoder dsi_trans;
>  	u32 tmp;
>  
> +	/* disable periodic update mode */
> +	if (is_cmd_mode(intel_dsi)) {
> +		for_each_dsi_port(port, intel_dsi->ports) {
> +			tmp = I915_READ(DSI_CMD_FRMCTL(port));
> +			tmp &= ~DSI_PERIODIC_FRAME_UPDATE_ENABLE;
> +			I915_WRITE(DSI_CMD_FRMCTL(port), tmp);
> +		}
> +	}
> +
>  	/* put dsi link in ULPS */
>  	for_each_dsi_port(port, intel_dsi->ports) {
>  		dsi_trans = dsi_port_to_transcoder(port);

-- 
Jani Nikula, Intel Open Source Graphics Center
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