From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 13075577E5C; Tue, 22 Sep 2026 17:24:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790097898; cv=none; b=JZEc+FpbSeA1/AIwUl8qCGg7wKvy3g7dsuQUyNLoIH3H5qdl5N2Eetq5ErFtmLWuXuNKEUvrvWYGEYFQQfWnlKOnHGn/jNmykkEqaBorsslfQ+r4S3goWrHQceCihjQvuum1Z7LEXS+Ps8GQpdQ4ISOwoyINR+Tt82R+KcwMNSs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790097898; c=relaxed/simple; bh=QRiEBIreO4v6EWgEvqWAHlOBMpxbQOzEEApQipVV4gk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Pvp+vXkIZ+3LKvKVLZC5Ghc6vwomwBCn1XWj3lP6SN6kYGJLN6jRVkKHsFS8dw7M1RDuToGshXCVHPeb3d51jo6OcfhGv5fiaj2sRK0lyCd88xSbGMsBbIS1/rpkZ54qEbdWVyh4IUhIq+1x1u7LvFgQc4pLCQX6Kus11oT02Hg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R3WYGHec; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R3WYGHec" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56AF31F000FF; Tue, 22 Sep 2026 17:24:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790097896; bh=kqcg//RK9J1hGxjYO0Ag5gWb1sgH7VyD5IOAC8lCeKw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=R3WYGHecbU9+Ibf9zY5MdkQmKuOsrjPQEL/MCiUNpcs6zoyvpKLQUVNSlFXs8erwM lR7hqJ12pGhbTlt3Jy6n+zDaa1W4Rwvpii7GJPeXvtRJXMzh0p3XVvmD0j2Lc7Yg0u wSPYWlUROPSQfHpEkBmmC8TLOfKqDQ0U9x7U3x22AMmlq0cLfywH0FZZaW0KX6QAkq UaUcSjDvi9of3xUBNl5L6DG0KZGva6brgyH4f7T8AYzzDOyeUtYeaeyZgPxu+nim8o kt23VAOdMNR3qzZ6in65nspPX3kqzNsYYdRkxbIWstCYQhGEzLv8F2zkR3GG8ZOuHE kEqnImGgcUEnA== Date: Tue, 22 Sep 2026 18:24:52 +0100 From: Conor Dooley To: Frank Li Cc: Michal Simek , Shubham Patil , alexandre.belloni@bootlin.com, Frank.Li@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linux-i3c@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, git@amd.com Subject: Re: [PATCH v3 1/3] dt-bindings: i3c: xlnx: Add IBI and hot-join capability properties Message-ID: <20260922-purple-overnight-2cdd2ddd5270@spud> References: <20260908094257.3196120-2-shubhamsanjay.patil@amd.com> <20260908-groin-undivided-0af701135404@spud> <778da629-2f23-412b-885f-e87827ce2b5c@amd.com> <20260922-ethics-flap-9760347e869d@spud> <20260922-bullpen-reprise-f62e01922d88@spud> <20260922-immersion-salvage-00450539f1ce@spud> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="J3nqrcEMORpacz8T" Content-Disposition: inline In-Reply-To: --J3nqrcEMORpacz8T Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 22, 2026 at 11:25:30AM -0500, Frank Li wrote: > On Tue, Sep 22, 2026 at 10:39:23AM +0100, Conor Dooley wrote: > > On Tue, Sep 22, 2026 at 10:38:17AM +0100, Conor Dooley wrote: > > > On Tue, Sep 22, 2026 at 10:33:44AM +0100, Conor Dooley wrote: > > > > On Thu, Sep 17, 2026 at 01:23:19PM +0200, Michal Simek wrote: > > > > > > > > > > > > > > > On 9/10/26 17:44, Frank Li wrote: > > > > > > On Thu, Sep 10, 2026 at 12:36:45PM +0100, Conor Dooley wrote: > > > > > > > On Wed, Sep 09, 2026 at 11:21:41AM -0500, Frank Li wrote: > > > > > > > > On Tue, Sep 08, 2026 at 06:54:31PM +0100, Conor Dooley wrot= e: > > > > > > > > > On Tue, Sep 08, 2026 at 03:12:55PM +0530, Shubham Patil w= rote: > > > > > > > > > > In-Band Interrupt and Hot-Join are synthesis-time optio= ns of the AXI I3C > > > > > > > > > > IP. Describe them with two boolean properties. > > > > > > > > > > > > > > > > > > > > A Hot-Join request is acknowledged by the IBI machinery= , so a hot-join > > > > > > > > > > capable design is always IBI capable as well. Both even= ts are reported > > > > > > > > > > through the controller interrupt, which is therefore re= quired whenever > > > > > > > > > > the capability is present. > > > > > > > > > > > > > > > > > > > > Signed-off-by: Shubham Patil > > > > > > > > > > --- > > > > > > > > > > Changes in V3: > > > > > > > > > > - Move in-band-interrupt-capable and hot-join-capable i= nto the common > > > > > > > > > > i3c.yaml schema and drop the xlnx, prefix. > > > > > > > > > > - Keep dependencies in the AMD binding. > > > > > > > > > > - Update the commit description accordingly. > > > > > > > > > > - Conor Dooley acked v2 with the xlnx,-prefixed propert= ies in the AMD > > > > > > > > > > binding [1]. > > > > > > > > > > That Acked-by is not carried here: the names lost th= e vendor prefix > > > > > > > > > > and the definitions moved to i3c.yaml after Frank Li= 's comment. > > > > > > > > > > [1]:https://lore.kernel.org/all/20260824-tightwad-im= pose-495476599087@spud/ > > > > > > > > > > > > > > > > > > I disagree with Frank. These properties make sense for Xi= linx because it > > > > > > > > > is an FPGA IP and synthesis options impact this. For othe= r devices, this > > > > > > > > > should be determined from the compatible. > > > > > > > > > Please revert to how things were done in v2, especially a= s no rationale > > > > > > > > > was provided for why these should be common. > > > > > > > > > > > > > > > > It is common problems, when IP intergrate by SOC, which may= defeature some > > > > > > > > part, It is not appeared now just because IBI and HJ have n= ot enabled > > > > > > > > widely. > > > > > > > > > > > > > > > > IBI and HJ is optional features of I3C. Ideally it should b= e indicated by > > > > > > > > some registers. But not all vendor implement provide this C= AP registers. > > > > > > > > > > > > > > > > IBI and HJ depend on some slow clocks, which monitor SDA li= ne change. > > > > > > > > Some instances of IP may not have such slow clocks. Some IP= 's IBI and HJ > > > > > > > > use seperate IRQ line, but these irq line may not connect o= f difference > > > > > > > > instances. > > > > > > > > > > > > > > All of this should be able to be dealt with by appropriate us= e of > > > > > > > specific compatibles. > > > > > > > > > > > > I understand compatible can cover most cases. Need variance for= property. > > > > > > > > > > > > > > > > > > > > > like previous SPI vendor customized property, we takes effo= rts to convert > > > > > > > > to common one and also meet back compatiblity problem at co= nvert. I don't > > > > > > > > want to do it again. This kind property is most likely as b= elow. > > > > > > > > > > > > > > What SPI controller specific properties are you talking about= here? > > > > > > > There are relatively few properties in spi-controller.yaml, a= nd none of > > > > > > > them deal with these kinds of capabilities. > > > > > > > > > > > > num-cs vs fsl,espi-num-chipselects. Total number CS of IP is fi= xed, but > > > > > > some instances have not route all CS to pad. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > default: decide by comaptible string or hardware cap > > > > > > > > force-disabled: force disable for some reason, like, miss c= onnect irq line > > > > > > > > or missed some clock, or IP bugs, or board desgin's some le= vel shift chip > > > > > > > > broken IBI/HJ timing requirements. > > > > > > > > > > > > > > Of these, only the last would be a valid reason for having a = property > > > > > > > for it. Missing interrupts, clocks or IP bugs should all be d= ealt with > > > > > > > using device specific compatibles. > > > > > > > If board wiring causes the breakage, the property may be more > > > > > > > appropriate at the i3c device level rather than the controlle= r given > > > > > > > that wiring to some devices on the bus may not have the probl= ems? > > > > > > > > > > > > I3C.yaml is for both master controller and devices now. I3C is = bus, which > > > > > > connect many devices, if wiring issue, whole bus can't support = IBI. And > > > > > > if any broken devices happen at address arbitation, whole bus c= an't support > > > > > > IBI. > > > > > > > > > > > > at beging, I suggest 3 state, > > > > > > > > > > > > [default, enable, disable], but now I think IBI_broken, HJ_brok= en is more > > > > > > reasonable to disable it, default value should be set by compat= ible > > > > > > string or DCR of I3C regiser. > > > > > > > > > > > > And some I3C device may be failure to work with IBI even DCR of= I3C register > > > > > > show it support IBI. > > > > > > > > > > > > I don't want to appear two similar property between vendor and = common, like > > > > > > num-cs vs fsl,espi-num-chipselects. > > > > > > > > > > > > such as IBI-broken can be used for controller and devices case. > > > > > > > > > > > > > That said, I think that problem should be dealt with when it = arises, > > > > > > > rather than starting a trend of adding capabilities propertie= s at the > > > > > > > controller level when I am not convinced that there's going t= o be other > > > > > > > users in the same vein. > > > > > > > > > > > > > > > > Understand, I3C is realtive new protocal. 'IBI-broken' is more = easy > > > > > > understand, logically equial to in-band-interrupt-capable. > > > > > Conor: Any update on this one? I think this thread is stuck at th= is stage. > > > > > > > > I didn't think there was any need to reply. I took the first senten= ce of > > > > this snippet to be acceptance of what I was saying. > > > > > > > > If yous desperately want to have a generic property, the negative > > > > connotation of the "-broken" is probably better in that it'd be more > > > > likely to make people set stuff by compatible rather than have to u= se a > > > > property with that word in it. > > > > > > That said, technically this platform could be both > > > "amd,in-band-interrupt-capable" and "ibi-broken" at the same time, si= nce > > > one describes the way the IP has been compiled and the other wiring. = I'm > > > not entirely sure whether conflating the two is possible? Depends on = if > > > your IP's programming model changes if the option is enabled even if = it > > > cannot be used. Not beyond the realms of possibility. > > > > > > Also, ibi-broken doesn't work for your platform, since the default > > > before this patch is no ibi and requiring a property for no ibi would= be > > > an ABI break. > > > > The perils of FPGA IP I suppose, and not being quite careful enough to > > document all of the relevant options from the start. Been guilty of that > > myself. > > >=20 > Check impliment code >=20 > + /* > + * The interrupt only carries IBI events, so it is only described= for > + * designs synthesized with that feature. > + */ > + if (master->ibi_capable) { > + xi3c_master_init_ibi_ops(master); > + > + master->irq =3D platform_get_irq(pdev, 0); > + if (master->irq < 0) > + return master->irq; > + > + ret =3D devm_request_irq(master->dev, master->irq, > + xi3c_master_irq_handler, IRQF_NO_A= UTOEN, > + dev_name(master->dev), master); > + if (ret) > + return dev_err_probe(master->dev, ret, > + "Failed to request IRQ\n"); > + } >=20 > They can use master->irq is determinate if support IBI. That seems viable. Where does that leave them for hot join though? --J3nqrcEMORpacz8T Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCarK55AAKCRB4tDGHoIJi 0pgrAQCZOUKpGZ97g8Pqr2PmEJ8iGu2CWN3e1h6AAb6t6XhAgwEAu45jKDI+1aBv fLMBFK82hDYeI+nh/MY6f6CJRebxVAE= =Dihe -----END PGP SIGNATURE----- --J3nqrcEMORpacz8T--