diff mbox series

[v2,3/3] ARM: dts: aspeed: add reset properties into MDIO nodes

Message ID 20220321095648.4760-4-dylan_hung@aspeedtech.com (mailing list archive)
State New, archived
Headers show
Series Add reset deassertion for Aspeed MDIO | expand

Commit Message

Dylan Hung March 21, 2022, 9:56 a.m. UTC 
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@aspeedtech.com>
Cc: stable@vger.kernel.org
---
 arch/arm/boot/dts/aspeed-g6.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Krzysztof Kozlowski March 22, 2022, 8:40 a.m. UTC | #1 
On 22/03/2022 03:32, Dylan Hung wrote:
>> -----Original Message-----
>> From: Krzysztof Kozlowski [mailto:krzk@kernel.org]
>> Sent: 2022年3月21日 11:53 PM
>> To: Dylan Hung <dylan_hung@aspeedtech.com>; robh+dt@kernel.org;
>> joel@jms.id.au; andrew@aj.id.au; andrew@lunn.ch; hkallweit1@gmail.com;
>> linux@armlinux.org.uk; davem@davemloft.net; kuba@kernel.org;
>> pabeni@redhat.com; p.zabel@pengutronix.de; devicetree@vger.kernel.org;
>> linux-arm-kernel@lists.infradead.org; linux-aspeed@lists.ozlabs.org;
>> linux-kernel@vger.kernel.org; netdev@vger.kernel.org
>> Cc: BMC-SW <BMC-SW@aspeedtech.com>; stable@vger.kernel.org
>> 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@aspeedtech.com>
>>> Cc: stable@vger.kernel.org
>>
>> 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.  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?
> Or would it be better if I remove " Cc: stable@vger.kernel.org"?

This rather looks like a missing feature, not a bug. Anyway any
description must be in commit message.


Best regards,
Krzysztof
Dylan Hung March 22, 2022, 8:44 a.m. UTC | #2 
> -----Original Message-----
> From: Krzysztof Kozlowski [mailto:krzk@kernel.org]
> Sent: 2022年3月22日 4:40 PM
> To: Dylan Hung <dylan_hung@aspeedtech.com>; robh+dt@kernel.org;
> joel@jms.id.au; andrew@aj.id.au; andrew@lunn.ch; hkallweit1@gmail.com;
> linux@armlinux.org.uk; davem@davemloft.net; kuba@kernel.org;
> pabeni@redhat.com; p.zabel@pengutronix.de; devicetree@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-aspeed@lists.ozlabs.org;
> linux-kernel@vger.kernel.org; netdev@vger.kernel.org
> Cc: BMC-SW <BMC-SW@aspeedtech.com>; stable@vger.kernel.org
> Subject: Re: [PATCH v2 3/3] ARM: dts: aspeed: add reset properties into MDIO
> nodes
> 
> On 22/03/2022 03:32, Dylan Hung wrote:
> >> -----Original Message-----
> >> From: Krzysztof Kozlowski [mailto:krzk@kernel.org]
> >> Sent: 2022年3月21日 11:53 PM
> >> To: Dylan Hung <dylan_hung@aspeedtech.com>; robh+dt@kernel.org;
> >> joel@jms.id.au; andrew@aj.id.au; andrew@lunn.ch;
> >> hkallweit1@gmail.com; linux@armlinux.org.uk; davem@davemloft.net;
> >> kuba@kernel.org; pabeni@redhat.com; p.zabel@pengutronix.de;
> >> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> >> linux-aspeed@lists.ozlabs.org; linux-kernel@vger.kernel.org;
> >> netdev@vger.kernel.org
> >> Cc: BMC-SW <BMC-SW@aspeedtech.com>; stable@vger.kernel.org
> >> 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@aspeedtech.com>
> >>> Cc: stable@vger.kernel.org
> >>
> >> 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.
> > 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?
> > Or would it be better if I remove " Cc: stable@vger.kernel.org"?
> 
> This rather looks like a missing feature, not a bug. Anyway any description
> must be in commit message.

Thank you. I will remove " Cc: stable@vger.kernel.org" and add more description
in commit message in V3.

> 
> 
> Best regards,
> Krzysztof
Philipp Zabel March 22, 2022, 9:08 a.m. UTC | #3 
On Di, 2022-03-22 at 03:22 +0000, Dylan Hung wrote:
> > -----Original Message-----
> > From: Andrew Lunn [mailto:andrew@lunn.ch]
> > Sent: 2022年3月22日 11:01 AM
> > To: Dylan Hung <dylan_hung@aspeedtech.com>
> > Cc: Krzysztof Kozlowski <krzk@kernel.org>; robh+dt@kernel.org;
> > joel@jms.id.au; andrew@aj.id.au; hkallweit1@gmail.com;
> > linux@armlinux.org.uk; davem@davemloft.net; kuba@kernel.org;
> > pabeni@redhat.com; p.zabel@pengutronix.de; 
> > devicetree@vger.kernel.org;
> > linux-arm-kernel@lists.infradead.org;
> > linux-aspeed@lists.ozlabs.org;
> > linux-kernel@vger.kernel.org; netdev@vger.kernel.org; BMC-SW
> > <BMC-SW@aspeedtech.com>; stable@vger.kernel.org
> > 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@kernel.org]
> > > > Sent: 2022年3月21日 11:53 PM
> > > > To: Dylan Hung <dylan_hung@aspeedtech.com>; robh+dt@kernel.org;
> > > > joel@jms.id.au; andrew@aj.id.au; andrew@lunn.ch;
> > > > hkallweit1@gmail.com; linux@armlinux.org.uk; 
> > > > davem@davemloft.net;
> > > > kuba@kernel.org; pabeni@redhat.com; p.zabel@pengutronix.de;
> > > > devicetree@vger.kernel.org; 
> > > > linux-arm-kernel@lists.infradead.org;
> > > > linux-aspeed@lists.ozlabs.org; linux-kernel@vger.kernel.org;
> > > > netdev@vger.kernel.org
> > > > Cc: BMC-SW <BMC-SW@aspeedtech.com>; stable@vger.kernel.org
> > > > 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@aspeedtech.com>
> > > > > Cc: stable@vger.kernel.org
> > > > 
> > > > 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
diff mbox series

Patch

diff --git a/arch/arm/boot/dts/aspeed-g6.dtsi b/arch/arm/boot/dts/aspeed-g6.dtsi
index c32e87fad4dc..ab20ea8d829d 100644
--- a/arch/arm/boot/dts/aspeed-g6.dtsi
+++ b/arch/arm/boot/dts/aspeed-g6.dtsi
@@ -181,6 +181,7 @@  mdio0: mdio@1e650000 {
 			status = "disabled";
 			pinctrl-names = "default";
 			pinctrl-0 = <&pinctrl_mdio1_default>;
+			resets = <&syscon ASPEED_RESET_MII>;
 		};
 
 		mdio1: mdio@1e650008 {
@@ -191,6 +192,7 @@  mdio1: mdio@1e650008 {
 			status = "disabled";
 			pinctrl-names = "default";
 			pinctrl-0 = <&pinctrl_mdio2_default>;
+			resets = <&syscon ASPEED_RESET_MII>;
 		};
 
 		mdio2: mdio@1e650010 {
@@ -201,6 +203,7 @@  mdio2: mdio@1e650010 {
 			status = "disabled";
 			pinctrl-names = "default";
 			pinctrl-0 = <&pinctrl_mdio3_default>;
+			resets = <&syscon ASPEED_RESET_MII>;
 		};
 
 		mdio3: mdio@1e650018 {
@@ -211,6 +214,7 @@  mdio3: mdio@1e650018 {
 			status = "disabled";
 			pinctrl-names = "default";
 			pinctrl-0 = <&pinctrl_mdio4_default>;
+			resets = <&syscon ASPEED_RESET_MII>;
 		};
 
 		mac0: ftgmac@1e660000 {