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

[Shankar, Uma]

>-----Original Message-----
>From: Nikula, Jani
>Sent: Friday, September 18, 2015 7:03 PM
>To: Shankar, Uma; intel-gfx at lists.freedesktop.org
>Cc: Kumar, Shobhit; Deak, Imre; Shankar, Uma
>Subject: Re: [BXT MIPI PATCH v3 12/14] drm/i915/bxt: Program Backlight PWM
>frequency
>
>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.
>

Yeah, we can drop this patch since the values will be updated in VBT. Thanks Jani for notifying.

>> ---
>>  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);
>>