On Tue, Jan 27, 2026 at 09:53:38PM -0500, Richard Acayan wrote: > On Tue, Jan 20, 2026 at 04:49:21PM +0200, Sakari Ailus wrote: > > Hi Bryan, others, > > > > On Tue, Jan 20, 2026 at 12:44:24PM +0000, Bryan O'Donoghue wrote: > > > I think reset should be asserted before regulators and power are switched > > > on. i.e. before you try to switch the chip on, you should establish that > > > the > > > reset pin is in the state that the timing diagram calls for. > > > > Indeed. > > I think the discussion is more about whether there should be an assert > in the same function as the de-assert. > > > The xshutdown pin, as it is typically called labelled as "reset" in this > > case, functions as both hardware reset and hardware standby mode control. > > It should be asserted (i.e. be set to low level) whenever the sensor is > > expected to be powered off. Typically deasserting it is the last step in > > the sensor's power-up sequence. This applies to nearly all CSI-2 and DVP > > (parallel) camera sensors. (There are some exceptions that use explicitly > > two GPIOs for similar functions but there are very few of them.) > > This patch has the reset asserted by the time it gets to > imx355_power_on(): > > - when coming from runtime PM, the suspend callback asserted it > - when coming from probe, GPIOD_OUT_HIGH asserted it (considering that > active-low also affects the initial output setting) > > Should it be asserted again inside the function, or > should the initial `gpiod_set_value_cansleep()` be removed?
Please remove it as requested. -- Sakari Ailus
