On Wed, Jul 09, 2014 at 03:54:38PM +0800, Chen-Yu Tsai wrote: > The 8250_dw driver fails to probe if the specified clock isn't > registered at probe time. Even if a clock frequency is given, > the required clock might be gated because it wasn't properly > enabled. > > This happened to me when the device is registered through DT, > and the clock was part of an MFD, the PRCM found on A31 and A23 > SoCs. Unlike core clocks that are registered with OF_CLK_DECLARE, > which happen almost immediately after the kernel starts, the > clocks are registered as sub-devices of the PRCM MFD platform > device. Even though devices are registered in the order they are > found in the DT, the drivers are registered in a different, > arbitrary order. It is possible that the 8250_dw driver is > registered, and thus associated with the device and probed, before > the clock driver is registered and probed. > > 8250_dw then reports unable to get the clock, and fails. Without > a working console, the kernel panics. > > This patch adds support for deferred probe handling for the clock > and reset controller. > > Signed-off-by: Chen-Yu Tsai <wens@xxxxxxxx> Acked-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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