Re: [BXT MIPI PATCH v3 10/14] drm/i915/bxt: get DSI pixelclock

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

On Tue, 01 Sep 2015, Uma Shankar <uma.shankar@intel.com> wrote:
> From: Shashank Sharma <shashank.sharma@intel.com>
>
> BXT's DSI PLL is different from that of VLV. So this patch
> adds a new function to get the current DSI pixel clock based
> on the PLL divider ratio and lane count.
>
> This function is required for intel_dsi_get_config() function.
>
> v2: Fixed Jani's review comments.
>
> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
> Signed-off-by: Uma Shankar <uma.shankar@intel.com>

Reviewed-by: Jani Nikula <jani.nikula@intel.com>


> ---
>  drivers/gpu/drm/i915/intel_dsi.c     |    8 ++++++--
>  drivers/gpu/drm/i915/intel_dsi.h     |    1 +
>  drivers/gpu/drm/i915/intel_dsi_pll.c |   35 ++++++++++++++++++++++++++++++++++
>  3 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dsi.c b/drivers/gpu/drm/i915/intel_dsi.c
> index 001569b..6a0071f 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.c
> +++ b/drivers/gpu/drm/i915/intel_dsi.c
> @@ -687,7 +687,7 @@ static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
>  static void intel_dsi_get_config(struct intel_encoder *encoder,
>  				 struct intel_crtc_state *pipe_config)
>  {
> -	u32 pclk;
> +	u32 pclk = 0;
>  	DRM_DEBUG_KMS("\n");
>  
>  	/*
> @@ -696,7 +696,11 @@ static void intel_dsi_get_config(struct intel_encoder *encoder,
>  	 */
>  	pipe_config->dpll_hw_state.dpll_md = 0;
>  
> -	pclk = vlv_get_dsi_pclk(encoder, pipe_config->pipe_bpp);
> +	if (IS_BROXTON(encoder->base.dev))
> +		pclk = bxt_get_dsi_pclk(encoder, pipe_config->pipe_bpp);
> +	else if (IS_VALLEYVIEW(encoder->base.dev))
> +		pclk = vlv_get_dsi_pclk(encoder, pipe_config->pipe_bpp);
> +
>  	if (!pclk)
>  		return;
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
> index 078ea1b..24fc550 100644
> --- a/drivers/gpu/drm/i915/intel_dsi.h
> +++ b/drivers/gpu/drm/i915/intel_dsi.h
> @@ -124,6 +124,7 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
>  extern void intel_enable_dsi_pll(struct intel_encoder *encoder);
>  extern void intel_disable_dsi_pll(struct intel_encoder *encoder);
>  extern u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp);
> +extern u32 bxt_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp);
>  extern void intel_dsi_reset_clocks(struct intel_encoder *encoder,
>  							enum port port);
>  
> diff --git a/drivers/gpu/drm/i915/intel_dsi_pll.c b/drivers/gpu/drm/i915/intel_dsi_pll.c
> index 918bc5f..9860bb5 100644
> --- a/drivers/gpu/drm/i915/intel_dsi_pll.c
> +++ b/drivers/gpu/drm/i915/intel_dsi_pll.c
> @@ -389,6 +389,41 @@ u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp)
>  	return pclk;
>  }
>  
> +u32 bxt_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp)
> +{
> +	u32 pclk;
> +	u32 dsi_clk;
> +	u32 dsi_ratio;
> +	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
> +	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
> +
> +	/* Divide by zero */
> +	if (!pipe_bpp) {
> +		DRM_ERROR("Invalid BPP(0)\n");
> +		return 0;
> +	}
> +
> +	dsi_ratio = I915_READ(BXT_DSI_PLL_CTL) &
> +				BXT_DSI_PLL_RATIO_MASK;
> +
> +	/* Invalid DSI ratio ? */
> +	if (dsi_ratio < BXT_DSI_PLL_RATIO_MIN ||
> +			dsi_ratio > BXT_DSI_PLL_RATIO_MAX) {
> +		DRM_ERROR("Invalid DSI pll ratio(%u) programmed\n", dsi_ratio);
> +		return 0;
> +	}
> +
> +	dsi_clk = (dsi_ratio * BXT_REF_CLOCK_KHZ) / 2;
> +
> +	/* pixel_format and pipe_bpp should agree */
> +	assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);
> +
> +	pclk = DIV_ROUND_CLOSEST(dsi_clk * intel_dsi->lane_count, pipe_bpp);
> +
> +	DRM_DEBUG_DRIVER("Calculated pclk=%u\n", pclk);
> +	return pclk;
> +}
> +
>  void vlv_dsi_reset_clocks(struct intel_encoder *encoder, enum port port)
>  {
>  	u32 temp;
> -- 
> 1.7.9.5
>

-- 
Jani Nikula, Intel Open Source Technology Center
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