[Intel-gfx] [BXT MIPI PATCH v3 12/14] drm/i915/bxt: Program Backlight PWM frequency

[Jani Nikula]

On Tue, 01 Sep 2015, Uma Shankar <uma.shankar at intel.com> wrote:
> In some cases, BIOS doesn't initializes DSI panel.DSI and
> backlight registers are thereby not initialized. Programming
> the same in driver backlight setup.
>
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>

This is probably obsolete now. See current bxt_setup_backlight.

BR,
Jani.


> ---
>  drivers/gpu/drm/i915/i915_reg.h    |    3 +++
>  drivers/gpu/drm/i915/intel_panel.c |   11 +++++++++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 8407b5c..10f73b1 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7166,6 +7166,9 @@ enum skl_disp_power_wells {
>  #define  TRANS_MSA_12_BPC		(3<<5)
>  #define  TRANS_MSA_16_BPC		(4<<5)
>  
> +/* Max CDCLK freq for BXT in HZ */
> +#define BXT_CDCLK_MAX                   624000000
> +
>  /* LCPLL Control */
>  #define LCPLL_CTL			0x130040
>  #define  LCPLL_PLL_DISABLE		(1<<31)
> diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
> index 9fcf86c..8225cea 100644
> --- a/drivers/gpu/drm/i915/intel_panel.c
> +++ b/drivers/gpu/drm/i915/intel_panel.c
> @@ -1427,6 +1427,17 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
>  	panel->backlight.max = I915_READ(
>  			BXT_BLC_PWM_FREQ(panel->backlight.controller));
>  
> +	if (!panel->backlight.max) {
> +		DRM_DEBUG_KMS("PWM freq not programmed by BIOS\n");
> +		DRM_DEBUG_KMS("Programming PWM freq\n");
> +
> +		/* Max Backlight = Max CD Clock / pwm freq) */
> +		panel->backlight.max = (BXT_CDCLK_MAX /
> +				dev_priv->vbt.backlight.pwm_freq_hz);
> +		I915_WRITE(BXT_BLC_PWM_FREQ(panel->backlight.controller),
> +				panel->backlight.max);
> +	}
> +
>  	val = bxt_get_backlight(connector);
>  	panel->backlight.level = intel_panel_compute_brightness(connector, val);
>  
> -- 
> 1.7.9.5
>

-- 
Jani Nikula, Intel Open Source Technology Center