Commits
Philipp Tomsich committed 765246a18c9
rockchip: rk3399-puma: reduce sd card max-frequency to 40MHz Some SanDisk Ultra cards trigger intermittent errors on detection resulting in an -EOPNOTSUPP, when running at 50MHz. Waveform analysis suggest that the level shifters that are used on the RK3399-Q7 module (for voltage translation between the on-module voltages and the 3.3V required on the card-edge) don't handle clock rates at or above 48MHz properly. This change reduces the maximum frequency on the external SD-interface to 40MHz (for a safety margin of 20%). Reported-by: Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com> Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com> Tested-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>