On Di, 2022-03-22 at 03:22 +0000, Dylan Hung wrote: > > -----Original Message----- > > From: Andrew Lunn [mailto:andrew@xxxxxxx] > > Sent: 2022年3月22日 11:01 AM > > To: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx> > > Cc: Krzysztof Kozlowski <krzk@xxxxxxxxxx>; robh+dt@xxxxxxxxxx; > > joel@xxxxxxxxx; andrew@xxxxxxxx; hkallweit1@xxxxxxxxx; > > linux@xxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx; > > pabeni@xxxxxxxxxx; p.zabel@xxxxxxxxxxxxxx; > > devicetree@xxxxxxxxxxxxxxx; > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > linux-aspeed@xxxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; BMC-SW > > <BMC-SW@xxxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset properties > > into MDIO > > nodes > > > > On Tue, Mar 22, 2022 at 02:32:13AM +0000, Dylan Hung wrote: > > > > -----Original Message----- > > > > From: Krzysztof Kozlowski [mailto:krzk@xxxxxxxxxx] > > > > Sent: 2022年3月21日 11:53 PM > > > > To: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx>; robh+dt@xxxxxxxxxx; > > > > joel@xxxxxxxxx; andrew@xxxxxxxx; andrew@xxxxxxx; > > > > hkallweit1@xxxxxxxxx; linux@xxxxxxxxxxxxxxx; > > > > davem@xxxxxxxxxxxxx; > > > > kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; p.zabel@xxxxxxxxxxxxxx; > > > > devicetree@xxxxxxxxxxxxxxx; > > > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > > > > linux-aspeed@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > > > netdev@xxxxxxxxxxxxxxx > > > > Cc: BMC-SW <BMC-SW@xxxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx > > > > Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset > > > > properties > > > > into MDIO nodes > > > > > > > > On 21/03/2022 10:56, Dylan Hung wrote: > > > > > Add reset control properties into MDIO nodes. The 4 MDIO > > > > > controllers in > > > > > AST2600 SOC share one reset control bit SCU50[3]. > > > > > > > > > > Signed-off-by: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx> > > > > > Cc: stable@xxxxxxxxxxxxxxx > > > > > > > > Please describe the bug being fixed. See stable-kernel-rules. > > > > > > Thank you for your comment. > > > The reset deassertion of the MDIO device was usually done by the > > bootloader (u-boot). > > > However, one of our clients uses proprietary bootloader and > > > doesn't > > > deassert the MDIO reset so failed to access the HW in kernel > > > driver. > > > > So are you saying mainline u-boot releases the reset? > > > Yes, if the mdio devices are used in u-boot. > > > > The reset deassertion is missing in the kernel driver since it > > > was > > > created, should I add a BugFix for the first commit of this > > > driver? > > > > Yes, that is normal. Ideally the kernel should not depend on u- > > boot, because > > often people want to use other bootloaders, e.g. barebox. You > > should also > > consider kexec, where one kernel hands over to another kernel, > > without the > > bootloader being involved. In such a situation, you ideally want to > > assert and > > deassert the reset just to clean away any state the old kernel left > > around. > > > > But please do note, that the reset is optional, since you need to > > be able to > > work with old DT blobs which don't have the reset property in them. > > > > Thank you. I will let the reset property be optional and modify the > error-checking in the driver accordingly in V3. No need to change the error checking, just use devm_reset_control_get_optional_shared(). regards Philipp
