[Intel-gfx] [PATCH] drm/i915/ehl: Add support for DPLL4 (v10)

[Ville Syrjälä]

On Wed, Jul 03, 2019 at 04:03:53PM -0700, Vivek Kasireddy wrote:
> This patch adds support for DPLL4 on EHL that include the
> following restrictions:
> 
> - DPLL4 cannot be used with DDIA (combo port A internal eDP usage).
>   DPLL4 can be used with other DDIs, including DDID
>   (combo port A external usage).
> 
> - DPLL4 cannot be enabled when DC5 or DC6 are enabled.
> 
> - The DPLL4 enable, lock, power enabled, and power state are connected
>   to the MGPLL1_ENABLE register.
> 
> v2: (suggestions from Bob Paauwe)
> - Rework ehl_get_dpll() function to call intel_find_shared_dpll() and
>   iterate twice: once for Combo plls and once for MG plls.
> 
> - Use MG pll funcs for DPLL4 instead of creating new ones and modify
>   mg_pll_enable to include the restrictions for EHL.
> 
> v3: Fix compilation error
> 
> v4: (suggestions from Lucas and Ville)
> - Treat DPLL4 as a combo phy PLL and not as MG PLL
> - Disable DC states when this DPLL is being enabled
> - Reuse icl_get_dpll instead of creating a separate one for EHL
> 
> v5: (suggestion from Ville)
> - Refcount the DC OFF power domains during the enabling and disabling
>   of this DPLL.
> 
> v6: rebase
> 
> v7: (suggestion from Imre)
> - Add a new power domain instead of iterating over the domains
>   assoicated with DC OFF power well.
> 
> v8: (Ville and Imre)
> - Rename POWER_DOMAIN_DPLL4 TO POWER_DOMAIN_DPLL_DC_OFF
> - Grab a reference in intel_modeset_setup_hw_state() if this
>   DPLL was already enabled perhaps by BIOS.
> - Check for the port type instead of the encoder
> 
> v9: (Ville)
> - Move the block of code that grabs a reference to the power domain
>   POWER_DOMAIN_DPLL_DC_OFF to intel_modeset_readout_hw_state() to ensure
>   that there is a reference present before this DPLL might get disabled.
> 
> v10: rebase
> 
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Cc: Imre Deak <imre.deak at intel.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy at intel.com>

lgtm. Picked up José's r-b from an earlier posting (in the future plese
collect those yourself so they don't get lost), and pushed to dinq.
Thanks for the patch.

-- 
Ville Syrjälä
Intel