On Wed, Jan 30, 2019 at 06:08:42PM +0530, Faiz Abbas wrote:
Errata i929 in certain OMAP5/DRA7XX/AM57XX silicon revisions (SPRZ426D - November 2014 - Revised February 2018 [1]) mentions unexpected tuning pattern errors. A small failure band may be present in the tuning range which may be missed by the current algorithm. Furthermore, the failure bands vary with temperature leading to different optimum tuning values for different temperatures.
As suggested in the related Application Report (SPRACA9B - October 2017
- Revised July 2018 [2]), tuning should be done in two stages.
In stage 1, assign the optimum ratio in the maximum pass window for the current temperature. In stage 2, if the chosen value is close to the small failure band, move away from it in the appropriate direction.
References: [1] http://www.ti.com/lit/pdf/sprz426 [2] http://www.ti.com/lit/pdf/SPRACA9
Signed-off-by: Faiz Abbas faiz_abbas@ti.com
Applied to u-boot/master, thanks!