[alsa-devel] [PATCH v3 1/2] drm/i915: provide interface for audio driver to query cdclk

[Takashi Iwai]

At Fri,  4 Jul 2014 10:00:37 +0800,
mengdong.lin at intel.com wrote:
> 
> From: Jani Nikula <jani.nikula at intel.com>
> 
> For Haswell and Broadwell, if the display power well has been disabled,
> the display audio controller divider values EM4 M VALUE and EM5 N VALUE
> will have been lost. The CDCLK frequency is required for reprogramming them
> to generate 24MHz HD-A link BCLK. So provide a private interface for the
> audio driver to query CDCLK.
> 
> This is a stopgap solution until a more generic interface between audio
> and display drivers has been implemented.
> 
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> Reviewed-by: Damien Lespiau <damien.lespiau at intel.com>
> Signed-off-by: Mengdong Lin <mengdong.lin at intel.com>

Thanks, applied (with Cc to stable).


Takashi

> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index a90fdbd..21170e5 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -6256,6 +6256,27 @@ int i915_release_power_well(void)
>  }
>  EXPORT_SYMBOL_GPL(i915_release_power_well);
>  
> +/*
> + * Private interface for the audio driver to get CDCLK in kHz.
> + *
> + * Caller must request power well using i915_request_power_well() prior to
> + * making the call.
> + */
> +int i915_get_cdclk_freq(void)
> +{
> +	struct drm_i915_private *dev_priv;
> +
> +	if (!hsw_pwr)
> +		return -ENODEV;
> +
> +	dev_priv = container_of(hsw_pwr, struct drm_i915_private,
> +				power_domains);
> +
> +	return intel_ddi_get_cdclk_freq(dev_priv);
> +}
> +EXPORT_SYMBOL_GPL(i915_get_cdclk_freq);
> +
> +
>  #define POWER_DOMAIN_MASK (BIT(POWER_DOMAIN_NUM) - 1)
>  
>  #define HSW_ALWAYS_ON_POWER_DOMAINS (			\
> diff --git a/include/drm/i915_powerwell.h b/include/drm/i915_powerwell.h
> index 2baba99..baa6f11 100644
> --- a/include/drm/i915_powerwell.h
> +++ b/include/drm/i915_powerwell.h
> @@ -32,5 +32,6 @@
>  /* For use by hda_i915 driver */
>  extern int i915_request_power_well(void);
>  extern int i915_release_power_well(void);
> +extern int i915_get_cdclk_freq(void);
>  
>  #endif				/* _I915_POWERWELL_H_ */
> -- 
> 1.8.1.2
>