On 01/22/2013 11:29 AM, Mike Turquette wrote: > Quoting Stephen Warren (2013-01-14 10:16:40) >> From: Stephen Warren <swarren@xxxxxxxxxx> >> >> Tegra's clock implementation uses pointers as the clock cookies, and >> hence chooses to make NULL an invalid clock cookie. However, there are >> gaps in the assigned device tree clock IDs, and hence the array mapping >> DT clock ID contains entries with NULL values (uninitialized BSS) unless >> explicit action is taken. This patch enhances the Tegra clock code to >> detect this case and explicitly initialize those lookup table entries to >> an error value. This prevents clk_get() from ever returning NULL. Hence, >> Tegra's clock APIs don't have to check the clock cookie they're passed >> for NULL. >> >> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> >> --- >> Mike, this also will need to go through the Tegra tree; just looking for >> any review/ack from you. Thanks. > > Stephen, > > I think this is a bit strange. Will you have gaps in the DT clock id's > forever or is this a temporary issue? Forever as far as I know. Since the clock IDs are just arbitrary tokens, I don't see any particular need for them to be strictly packed. > Also it is important than any driver using the clock api does not > dereference the struct clk pointer and assume that a NULL clk is > invalid. I know that this series doesn't imply any such thing but I > wanted to state that anyways. Right. This ensures that clk_get() returns an IS_ERR() pointer, or a valid cookie that the clock driver is prepared to handle (which doesn't include NULL). > Also are you planning to roll this into the existing tegra ccf series? It's already rolled into the latest version of the series which I posted. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
