linux-kernel - RE: [PATCH v18 1/3] dt-bindings: i2c: aspeed,i2c.yaml: add transfer-mode and global-regs properties and update example

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID:
 <OS8PR06MB75416F7F1B5DBC95A5E87FD1F21CA@OS8PR06MB7541.apcprd06.prod.outlook.com>
Date: Wed, 24 Sep 2025 05:31:47 +0000
From: Ryan Chen <ryan_chen@...eedtech.com>
To: Rob Herring <robh@...nel.org>, Jeremy Kerr <jk@...econstruct.com.au>
CC: "benh@...nel.crashing.org" <benh@...nel.crashing.org>, "joel@....id.au"
	<joel@....id.au>, "andi.shyti@...nel.org" <andi.shyti@...nel.org>,
	"krzk+dt@...nel.org" <krzk+dt@...nel.org>, "conor+dt@...nel.org"
	<conor+dt@...nel.org>, "andrew@...econstruct.com.au"
	<andrew@...econstruct.com.au>, "p.zabel@...gutronix.de"
	<p.zabel@...gutronix.de>, "andriy.shevchenko@...ux.intel.com"
	<andriy.shevchenko@...ux.intel.com>, "naresh.solanki@...ements.com"
	<naresh.solanki@...ements.com>, "linux-i2c@...r.kernel.org"
	<linux-i2c@...r.kernel.org>, "openbmc@...ts.ozlabs.org"
	<openbmc@...ts.ozlabs.org>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-aspeed@...ts.ozlabs.org"
	<linux-aspeed@...ts.ozlabs.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v18 1/3] dt-bindings: i2c: aspeed,i2c.yaml: add
 transfer-mode and global-regs properties and update example

> Subject: Re: [PATCH v18 1/3] dt-bindings: i2c: aspeed,i2c.yaml: add
> transfer-mode and global-regs properties and update example
> 
> On Mon, Sep 15, 2025 at 11:41:31AM +0800, Jeremy Kerr wrote:
> > Hi Ryan,
> >
> > > > OK, but the ast2400 and ast2500 I2C peripherals - which this
> > > > binding also describes - do not have that facility. Given the 2600
> > > > is a distinct peripheral (as discussed on the v16 series), this would seem
> to warrant a distinct binding.
> > > >
> > > > Should this be split out into an ast2600-specific binding, to
> > > > reflect that it is different hardware? The reference to the global
> > > > registers and transfer modes would then be added only to the
> ast2600-i2c-bus binding.
> > >
> > > I agree it would be cleaner to split out a new binding file
> > > specifically for AST2600, for example: `aspeed,ast2600-i2c.yaml` But
> > > also I think `aspeed,i2cv2.yaml` more better name, that compatible
> > > will support next generation such like AST2700 .....
> >
> > The ship may have already sailed on that one, as you already have the
> > existing compatible string describing existing hardware.
> >
> > I would assume that the compatible string should be fixed for an
> > instance of the specific hardware, but the DT maintainers may be able
> > to provide some input/precedence on changing an existing binding, if
> > necessary.
> >
> > If this does get changed, I would expect that you would need a
> > corresponding update in the old driver too.
> >
> > Or, another option may be to keep the current generation ("v2 core
> > with compat registers") as-is (ie., at ast2600-i2c-bus), and introduce
> > a new string for the next - where the primary hardware change might be
> > the removal of compat registers, but it's still new hardware
> 
> About the only place we use version numbers (without regret) is when the
> version can be traced back to the actual verilog. This is typically only IP
> targeted to FPGAs. The reality in SoCs is h/w designers can't help themselves to
> not change things. In reality, there are almost always some changes.
> 
> Rob

Thanks, I think I will work on new yaml aspeed,ast2600-i2c.yaml for ast2600 i2c driver.
That support global regs, transfer-mode properties.
Then will add ast2700-i2c.yaml for ast2700 i2c.

Ryan.