linux-kernel - Re: [PATCH v16 2/3] i2c: aspeed: support AST2600 i2c new register mode driver

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Message-ID: <db8dad75c03d747d16cdc67ebbedd5c2f8c27a6d.camel@pengutronix.de>
Date: Mon, 24 Feb 2025 10:32:27 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Ryan Chen <ryan_chen@...eedtech.com>, "benh@...nel.crashing.org"
	 <benh@...nel.crashing.org>, "joel@....id.au" <joel@....id.au>, 
	"andi.shyti@...nel.org"
	 <andi.shyti@...nel.org>, "robh@...nel.org" <robh@...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>, "andriy.shevchenko@...ux.intel.com"
	 <andriy.shevchenko@...ux.intel.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 v16 2/3] i2c: aspeed: support AST2600 i2c new register
 mode driver

On Mo, 2025-02-24 at 09:04 +0000, Ryan Chen wrote:
> > Subject: Re: [PATCH v16 2/3] i2c: aspeed: support AST2600 i2c new
> > register
> > mode driver
> > 
> > On Mo, 2025-02-24 at 13:59 +0800, Ryan Chen wrote:
> > > Add i2c new register mode driver to support AST2600 i2c new
> > > register
> > > mode. AST2600 i2c controller have legacy and new register mode.
> > > The
> > > new register mode have global register support 4 base clock for
> > > scl
> > > clock selection, and new clock divider mode. The new register
> > > mode
> > > have separate register set to control i2c controller and target.
> > > This
> > > patch is for i2c controller mode driver.
> > > 
> > > Signed-off-by: Ryan Chen <ryan_chen@...eedtech.com>
> > > ---
> > >  drivers/i2c/busses/Kconfig       |   11 +
> > >  drivers/i2c/busses/Makefile      |    1 +
> > >  drivers/i2c/busses/i2c-ast2600.c | 1036
> > > ++++++++++++++++++++++++++++++
> > >  3 files changed, 1048 insertions(+)
> > >  create mode 100644 drivers/i2c/busses/i2c-ast2600.c
> > > 
> > [...]
> > > diff --git a/drivers/i2c/busses/i2c-ast2600.c
> > > b/drivers/i2c/busses/i2c-ast2600.c
> > > new file mode 100644
> > > index 000000000000..bfac507693dd
> > > --- /dev/null
> > > +++ b/drivers/i2c/busses/i2c-ast2600.c
> > > @@ -0,0 +1,1036 @@
> > [...]
> > > +static int ast2600_i2c_probe(struct platform_device *pdev) {
> > > +	struct device *dev = &pdev->dev;
> > > +	struct ast2600_i2c_bus *i2c_bus;
> > > +	struct resource *res;
> > > +	u32 global_ctrl;
> > > +	int ret;
> > > +
> > > +	i2c_bus = devm_kzalloc(dev, sizeof(*i2c_bus),
> > > GFP_KERNEL);
> > > +	if (!i2c_bus)
> > > +		return -ENOMEM;
> > > +
> > > +	i2c_bus->reg_base = devm_platform_ioremap_resource(pdev,
> > > 0);
> > > +	if (IS_ERR(i2c_bus->reg_base))
> > > +		return PTR_ERR(i2c_bus->reg_base);
> > > +
> > > +	i2c_bus->rst = devm_reset_control_get_shared(dev, NULL);
> > > +	if (IS_ERR(i2c_bus->rst))
> > > +		return dev_err_probe(dev, PTR_ERR(i2c_bus->rst),
> > > "Missing reset
> > > +ctrl\n");
> > > +
> > > +	reset_control_deassert(i2c_bus->rst);
> > 
> > No reset_control_assert() in the error paths below? You could get
> > that and
> > simplify this by using devm_reset_control_get_shared_deasserted().
> > 
> Sorry, devm_reset_control_get_shared_deasserted is new for me.
> Do you mean modify by following 
> 
> i2c_bus->rst = devm_reset_control_get_shared_deasserted(dev, NULL);
> if (IS_ERR(i2c_bus->rst))
>     return dev_err_probe(dev, PTR_ERR(i2c_bus->rst), "Missing reset
> ctrl\n");
> 
> - reset_control_deassert(i2c_bus->rst);

Yes see [1]. Remove the reset_control_assert() in ast2600_i2c_remove()
as well.

[1] https://docs.kernel.org/driver-api/reset.html#c.devm_reset_control_get_shared_deasserted

regards
Philipp