On Fri, Aug 6, 2021 at 7:49 PM Icenowy Zheng <icenowy@xxxxxxx> wrote: > > 在 2021-07-22星期四的 10:16 +0200，Maxime Ripard写道： > > On Thu, Jul 22, 2021 at 12:55:53AM -0500, Samuel Holland wrote: > > > On 7/21/21 9:04 AM, Maxime Ripard wrote: > > > > The regulator-ramp-delay property isn't documented in the binding > > > > for > > > > the AXP806, and it's ignored by the driver. Remove those > > > > properties. > > > > > > This is a generic regulator property, parsed by > > > of_get_regulation_constraints, which is called by > > > regulator_of_get_init_data in the regulator core. And it appears in > > > bindings/regulator/regulator.yaml. I believe the binding needs to be > > > fixed, not the device trees. > > > > It's indeed parsed by the regulator framework, but then it calls into > > the driver if that property is set using set_ramp_delay if it's set. > > Not only is it used for set_ramp_delay, but it's also used to calculate > a post-change delay, see the following position (it can be overrided by > a custom set_voltage_time in the driver): > > https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L3339 Having just dug through the regulator core code at work, I agree. Furthermore, the commit log for this addition specifically mentions the reason for adding this property is to provide a (guessed) ramp rate for the core to do a proper delay for the regulator to ramp up, not to set the actual ramp rate in hardware. ChenYu [1] https://git.kernel.org/torvalds/c/fe79ea577be81e1e71642826ab00e676dc59c194 > > > > https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L1378 > > > > We don't set that hook for the AXP806 DCDC-A and DCDC-E regulators > > (that > > use AXP_DESC_RANGES) at all: > > > > https://elixir.bootlin.com/linux/latest/source/drivers/regulator/axp20x-regulator.c#L343 > > > > And the only implementation we have (set for AXP_DESC and AXP_DESC_IO) > > works only for the AXP209: > > > > https://elixir.bootlin.com/linux/latest/source/drivers/regulator/axp20x-regulator.c#L368 > > > > So, it just looks like those properties have never been tested since > > they were just ignored. > > > > Maxime > > > > -- > You received this message because you are subscribed to the Google Groups "linux-sunxi" group. > To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web, visit https://groups.google.com/d/msgid/linux-sunxi/68e4820ead3107aa4e80dcaf9243bd11de5fce98.camel%40aosc.io.
