Hi Chris, > Subject: RE: Regarding SDHI clocks on RZ/G2L > > Hi Biju, > > > -----Original Message----- > > From: Biju Das > > Sent: Tuesday, July 20, 2021 11:55 AM > > > RZ/G2L document says we should not turn off cd clock during suspend. > > Otherwise card detection > > From a hardware standpoint....yes. > > > Won't work. So whether SDHI can reliably work in this case? Basically > > if there is no activity, this module can go into suspend state. If the > > cd clock turned off and card detection fails during resume, how the > > SDHI functionality going to work? > > What I am saying is that from a system design standpoint, you need to wake > up the system first before you can use the SD card (even detecting a card > insert/remove). Agreed. That is the usual flow. > > > > Note:- > > Currently I am configuring CD pin as gpio rather than function due to > > some reset issue[1]. After reset cd detection fails. But it works ok, > > if it configured as GPIO. > > > 1) Handle it in SDHI driver? ie, enable it during probe only once and > > > avoid turning it off > > > > > > or > > > > > > 2) Add this clock as critical clock, so it will be turned on > > > permanently and don't handle it in SDHI driver? > > So does that mean your #1 and #2 both do not work unless the pin is > configured as GPIO? With upstream kernel it doesn't work, because of the reset handling patch[1] 4.19 it works, where it doesn't have this patch. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/mmc/host/renesas_sdhi_core.c?h=v5.14-rc2&id=b4d86f37eacb724690d0d300576b82806bc743d5 Regards, Biju
