[V2,0/2] Re-initialize DLL when MCLK is gated dynamically

Message

Veerabhadrarao Badiganti Nov. 12, 2018, 6:38 a.m. UTC

On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually, result in data CRC and command CRC/timeout errors.
To fix this issue, the DLL needs to be re-initialized and restored with
its old settings once clocks are ungated. SDHC cotroller on SDM845 SOC
has this limitation.

Changes since V3:
	- Introduced SoC specific dt compatible string for sdhci-msm
	controller
	- Moved the condition which checks whether tuning is needed or
	not, to a common function.

Changes since V2:
	- Removed an unused variable.
	- Renamed the newly introduced flags to be more meaningful.
	- Added new dt compatible string for SDM845 SOC.

Changes since V1:
	- Replaced dt flag with a dt compatible string to
	indicate SHDCI-MSM controller varients which need this fix.
	- Moved the DLL settings restoration logic from request 
	context to platform driver runtime pm context.

Tested on: sdm845
Veerabhadrarao Badiganti (2):
  dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings
  mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

 .../devicetree/bindings/mmc/sdhci-msm.txt          | 21 ++++--
 drivers/mmc/host/sdhci-msm.c                       | 78 +++++++++++++++++++---
 2 files changed, 84 insertions(+), 15 deletions(-)