From: Rob Herring <robh@kernel.org> To: Chris Packham <Chris.Packham@alliedtelesis.co.nz> Cc: "wsa@kernel.org" <wsa@kernel.org>, "andriy.shevchenko@linux.intel.com" <andriy.shevchenko@linux.intel.com>, "andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>, "mpe@ellerman.id.au" <mpe@ellerman.id.au>, "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Joakim Tjernlund <Joakim.Tjernlund@infinera.com> Subject: Re: [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag Date: Tue, 11 May 2021 10:33:37 -0500 [thread overview] Message-ID: <CAL_JsqKaeubNxYwGNOJYv=VcwR_6NzwkXnQ4DjOwXDudEmZ2Rg@mail.gmail.com> (raw) In-Reply-To: <c5d6f8d0-9b8a-b3bf-b7c3-884f03f7ecee@alliedtelesis.co.nz> On Sun, May 9, 2021 at 4:08 PM Chris Packham <Chris.Packham@alliedtelesis.co.nz> wrote: > > > On 8/05/21 9:49 am, Rob Herring wrote: > > On Fri, May 07, 2021 at 12:40:45PM +1200, Chris Packham wrote: > >> Document the fsl,i2c-erratum-a004447 flag which indicates the presence > >> of an i2c erratum on some QorIQ SoCs. > >> > >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> > >> --- > >> Documentation/devicetree/bindings/i2c/i2c-mpc.yaml | 7 +++++++ > >> 1 file changed, 7 insertions(+) > >> > >> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> index 7b553d559c83..98c6fcf7bf26 100644 > >> --- a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> +++ b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> @@ -46,6 +46,13 @@ properties: > >> description: | > >> I2C bus timeout in microseconds > >> > >> + fsl,i2c-erratum-a004447: > >> + $ref: /schemas/types.yaml#/definitions/flag > >> + description: | > >> + Indicates the presence of QorIQ erratum A-004447, which > >> + says that the standard i2c recovery scheme mechanism does > >> + not work and an alternate implementation is needed. > > The problem with adding a property for an errata is you have to update > > the dtb. If you use the compatible string, then only an OS update is > > needed. That assumes you have specific enough compatible strings. > > I was following the style of the existing fsl,usb-erratum-a007792 or > fsl,erratum-a008585 properties. But that's not really a compelling reason. > > The existing compatible string is "fsl-i2c" and it's used by pretty much > every powerpc QorIQ SoC. There are some specific compatible strings in > the driver for some of the older mpc SoCs. A more specific compatible > string will work although determining which ones are affected might be a > bit troublesome. That we know of the P2041 and P1010 are affected but I > suspect there may be more. One disadvantage of using the compatible > string is that as affected SoCs are identified we'll have to update the > driver to know that SoC is affected and update the dtb to use it. With > the property we'd just have to update the dtb. If you don't have specific compatibles in the dtb already, then it's mute as the point was to avoid the dtb update. > I'm not too fussed either way so if that's a hard NACK on the property I > can send a version that uses compatible strings instead. Acked-by: Rob Herring <robh@kernel.org> You could still add compatibles for the next time...
WARNING: multiple messages have this Message-ID (diff)
From: Rob Herring <robh@kernel.org> To: Chris Packham <Chris.Packham@alliedtelesis.co.nz> Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "wsa@kernel.org" <wsa@kernel.org>, "andy.shevchenko@gmail.com" <andy.shevchenko@gmail.com>, "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>, "andriy.shevchenko@linux.intel.com" <andriy.shevchenko@linux.intel.com>, "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org> Subject: Re: [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl, i2c-erratum-a004447 flag Date: Tue, 11 May 2021 10:33:37 -0500 [thread overview] Message-ID: <CAL_JsqKaeubNxYwGNOJYv=VcwR_6NzwkXnQ4DjOwXDudEmZ2Rg@mail.gmail.com> (raw) In-Reply-To: <c5d6f8d0-9b8a-b3bf-b7c3-884f03f7ecee@alliedtelesis.co.nz> On Sun, May 9, 2021 at 4:08 PM Chris Packham <Chris.Packham@alliedtelesis.co.nz> wrote: > > > On 8/05/21 9:49 am, Rob Herring wrote: > > On Fri, May 07, 2021 at 12:40:45PM +1200, Chris Packham wrote: > >> Document the fsl,i2c-erratum-a004447 flag which indicates the presence > >> of an i2c erratum on some QorIQ SoCs. > >> > >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> > >> --- > >> Documentation/devicetree/bindings/i2c/i2c-mpc.yaml | 7 +++++++ > >> 1 file changed, 7 insertions(+) > >> > >> diff --git a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> index 7b553d559c83..98c6fcf7bf26 100644 > >> --- a/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> +++ b/Documentation/devicetree/bindings/i2c/i2c-mpc.yaml > >> @@ -46,6 +46,13 @@ properties: > >> description: | > >> I2C bus timeout in microseconds > >> > >> + fsl,i2c-erratum-a004447: > >> + $ref: /schemas/types.yaml#/definitions/flag > >> + description: | > >> + Indicates the presence of QorIQ erratum A-004447, which > >> + says that the standard i2c recovery scheme mechanism does > >> + not work and an alternate implementation is needed. > > The problem with adding a property for an errata is you have to update > > the dtb. If you use the compatible string, then only an OS update is > > needed. That assumes you have specific enough compatible strings. > > I was following the style of the existing fsl,usb-erratum-a007792 or > fsl,erratum-a008585 properties. But that's not really a compelling reason. > > The existing compatible string is "fsl-i2c" and it's used by pretty much > every powerpc QorIQ SoC. There are some specific compatible strings in > the driver for some of the older mpc SoCs. A more specific compatible > string will work although determining which ones are affected might be a > bit troublesome. That we know of the P2041 and P1010 are affected but I > suspect there may be more. One disadvantage of using the compatible > string is that as affected SoCs are identified we'll have to update the > driver to know that SoC is affected and update the dtb to use it. With > the property we'd just have to update the dtb. If you don't have specific compatibles in the dtb already, then it's mute as the point was to avoid the dtb update. > I'm not too fussed either way so if that's a hard NACK on the property I > can send a version that uses compatible strings instead. Acked-by: Rob Herring <robh@kernel.org> You could still add compatibles for the next time...
next prev parent reply other threads:[~2021-05-11 15:33 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-07 0:40 [PATCH v2 0/3] P2040/P2041 i2c recovery erratum Chris Packham 2021-05-07 0:40 ` Chris Packham 2021-05-07 0:40 ` [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag Chris Packham 2021-05-07 0:40 ` [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl, i2c-erratum-a004447 flag Chris Packham 2021-05-07 21:49 ` [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl,i2c-erratum-a004447 flag Rob Herring 2021-05-07 21:49 ` Rob Herring 2021-05-09 21:08 ` Chris Packham 2021-05-09 21:08 ` [PATCH v2 1/3] dt-bindings: i2c: mpc: Add fsl, i2c-erratum-a004447 flag Chris Packham 2021-05-11 15:33 ` Rob Herring [this message] 2021-05-11 15:33 ` Rob Herring 2021-05-07 0:40 ` [PATCH v2 2/3] powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P2041 i2c controllers Chris Packham 2021-05-07 0:40 ` [PATCH v2 2/3] powerpc/fsl: set fsl, i2c-erratum-a004447 " Chris Packham 2021-05-07 8:04 ` Joakim Tjernlund 2021-05-07 8:04 ` Joakim Tjernlund 2021-05-07 8:24 ` Joakim Tjernlund 2021-05-07 8:24 ` Joakim Tjernlund 2021-05-09 21:11 ` Chris Packham 2021-05-09 21:11 ` Chris Packham 2021-05-07 0:40 ` [PATCH v2 3/3] i2c: mpc: implement erratum A-004447 workaround Chris Packham 2021-05-07 0:40 ` Chris Packham 2021-05-07 11:46 ` Andy Shevchenko 2021-05-07 11:46 ` Andy Shevchenko 2021-05-07 14:52 ` Joakim Tjernlund 2021-05-07 14:52 ` Joakim Tjernlund 2021-05-07 15:36 ` Andy Shevchenko 2021-05-07 15:36 ` Andy Shevchenko
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to='CAL_JsqKaeubNxYwGNOJYv=VcwR_6NzwkXnQ4DjOwXDudEmZ2Rg@mail.gmail.com' \ --to=robh@kernel.org \ --cc=Chris.Packham@alliedtelesis.co.nz \ --cc=Joakim.Tjernlund@infinera.com \ --cc=andriy.shevchenko@linux.intel.com \ --cc=andy.shevchenko@gmail.com \ --cc=devicetree@vger.kernel.org \ --cc=linux-i2c@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linuxppc-dev@lists.ozlabs.org \ --cc=mpe@ellerman.id.au \ --cc=wsa@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.