On Mon, Sep 22, 2014 at 12:11:54PM +0200, Thierry Reding wrote:
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On Mon, Sep 22, 2014 at 11:00:56AM +0200, Lucas Stach wrote:
Am Freitag, den 19.09.2014, 15:53 -0400 schrieb Sean Paul:
Per NVidia, this clock rate should be around 70MHz in order to properly sample reads on data lane 0. In order to achieve this rate, we need to reparent the clock from clk_m which can only achieve 12MHz. Add parent_lp to the dts bindings and set the parent & rate on init.
Signed-off-by: Sean Paul seanpaul@chromium.org
NACK
You are pushing SoC integration details into the binding of the device.
You have two reasonable routes to go here: either the clock driver needs to be made smarter to reparent the clock in case the required clock rate could not be achieved with the current parent or you go the easy route and reparent the clock as part of the initial configuration.
Agreed. There doesn't seem to be a case where it would make sense to have this configurable per-board. Can you achieve the same effect by adding this to the clock initialization table?
Oh, I just see that we have this in the Tegra124 clock initialization table:
{TEGRA114_CLK_DSIALP, TEGRA114_CLK_PLL_P, 68000000, 0}, {TEGRA114_CLK_DSIBLP, TEGRA114_CLK_PLL_P, 68000000, 0},
Doesn't that work for you already? If not that'd be a bug that should be fixed in the clock driver.
This seems the better approach indeed. Unless the rate would differ based on board or other external factors.
Cheers,
Peter.