于 2021年8月6日 GMT+08:00 下午8:05:56, Chen-Yu Tsai <wens@xxxxxxxx> 写到: >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. Well we must agree that we have some more suitable property that delays for a constant span, see lines below in the function I mentioned. > > >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. >
