diff options
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-ac100.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c index 080e3c04be43..3fe576fdd45e 100644 --- a/drivers/rtc/rtc-ac100.c +++ b/drivers/rtc/rtc-ac100.c @@ -183,7 +183,29 @@ static int ac100_clkout_determine_rate(struct clk_hw *hw, for (i = 0; i < num_parents; i++) { struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i); - unsigned long tmp, prate = clk_hw_get_rate(parent); + unsigned long tmp, prate; + + /* + * The clock has two parents, one is a fixed clock which is + * internally registered by the ac100 driver. The other parent + * is a clock from the codec side of the chip, which we + * properly declare and reference in the devicetree and is + * not implemented in any driver right now. + * If the clock core looks for the parent of that second + * missing clock, it can't find one that is registered and + * returns NULL. + * So we end up in a situation where clk_hw_get_num_parents + * returns the amount of clocks we can be parented to, but + * clk_hw_get_parent_by_index will not return the orphan + * clocks. + * Thus we need to check if the parent exists before + * we get the parent rate, so we could use the RTC + * without waiting for the codec to be supported. + */ + if (!parent) + continue; + + prate = clk_hw_get_rate(parent); tmp = ac100_clkout_round_rate(hw, req->rate, prate); |