On 4/30/24 10:54, André Draszik wrote: > The system hangs when any of these clocks are turned off. > > With the introduction of pinctrl clock support [1], the approach taken > in this clock driver for the APM clocks to rely solely on the > clk_ignore_unused kernel command line option does not work anymore and > the system hangs during boot. > > gout_apm_func is a parent clock to the clocks that are going to be > handled by the pinctrl driver [2], namely > gout_apm_apbif_gpio_alive_pclk and gout_apm_apbif_gpio_far_alive_pclk. > It also is the parent to the clocks marked as critical in this commit > here (and some others that aren't relevant for this commit)). This > means that once the pinctrl driver decides to turn off clocks, the > clock framework will subsequently turn off parent clocks of those > pinctrl clocks if they have no (apparent) user. Since gout_apm_func is > the parent, and since no drivers are hooked up to it or any of its > other children, gout_apm_func will be turned off. This will cause the > system to hang, as the clocks marked as critical in this commit stop > having an input. > > We might have to add a driver for these clocks, but in the meantime > let's just ensure they stay on even if siblings are turned off. It's sane, yes. > > For the avoidance of doubt: This commit doesn't mean that we can boot > with clk_ignore_unused. > s/with/without. Because there are still other clocks that are not yet handled/marked as critical where needed. There's still work to do. With the typo addressed: Reviewed-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxx>
