linux-kernel - Re: [PATCH v2] mux: mmio: use reg property when parent device is not a syscon

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Message-ID: <20230807182645.ct2uvkb3s2tuplon@improve>
Date:   Mon, 7 Aug 2023 13:26:45 -0500
From:   Nishanth Menon <nm@...com>
To:     Andrew Davis <afd@...com>, Peter Rosin <peda@...ntia.se>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     Peter Rosin <peda@...ntia.se>, Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] mux: mmio: use reg property when parent device is not
 a syscon

On 15:12-20230713, Andrew Davis wrote:
> On 6/5/23 10:41 AM, Andrew Davis wrote:
> > The DT binding for the reg-mux compatible states it can be used when the
> > "parent device of mux controller is not syscon device". It also allows
> > for a reg property. When the reg property is provided, use that to
> > identify the address space for this mux. If not provided fallback to
> > using the parent device as a regmap provider.
> > 
> > Signed-off-by: Andrew Davis <afd@...com>
> > ---
> 
> Ping, still needed and applies cleanly on v6.5-rc1.
> 
> Andrew
> 
> > 
> > Changes from v1:
> >   - Flip logic as suggested in v1[0]
> > 
> > [0] https://lore.kernel.org/lkml/1c27d9d4-b1cc-c158-90f7-f7e47e02c424@ti.com/T/
> > 
> >   drivers/mux/mmio.c | 9 ++++++---
> >   1 file changed, 6 insertions(+), 3 deletions(-)


Reviewed-by: Nishanth Menon <nm@...com>

Greg: looks like you were missed in CC

Peter/Greg: Any chance of Looking at this? This is a basic corner stone
for us to clean up much of the mess we have created up in the device
tree syscon nodes and trying to transition those into simple-bus.

> > 
> > diff --git a/drivers/mux/mmio.c b/drivers/mux/mmio.c
> > index 44a7a0e885b8d..2c9e4df9d6f2c 100644
> > --- a/drivers/mux/mmio.c
> > +++ b/drivers/mux/mmio.c
> > @@ -44,10 +44,13 @@ static int mux_mmio_probe(struct platform_device *pdev)
> >   	int ret;
> >   	int i;
> > -	if (of_device_is_compatible(np, "mmio-mux"))
> > +	if (of_device_is_compatible(np, "mmio-mux")) {
> >   		regmap = syscon_node_to_regmap(np->parent);
> > -	else
> > -		regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
> > +	} else {
> > +		regmap = device_node_to_regmap(np);
> > +		if (IS_ERR(regmap))
> > +			regmap = dev_get_regmap(dev->parent, NULL) ?: ERR_PTR(-ENODEV);
> > +	}
> >   	if (IS_ERR(regmap)) {
> >   		ret = PTR_ERR(regmap);
> >   		dev_err(dev, "failed to get regmap: %d\n", ret);

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D