linux-kernel - Re: [RESEND PATCH v1 05/13] mfd: tps6594-spi: Add TI TPS65224 PMIC SPI

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Message-ID: <20240416122504.GV2399047@google.com>
Date: Tue, 16 Apr 2024 13:25:04 +0100
From: Lee Jones <lee@...nel.org>
To: Bhargav Raviprakash <bhargav.r@...s.com>
Cc: arnd@...db.de, broonie@...nel.org, conor+dt@...nel.org,
	devicetree@...r.kernel.org, eblanc@...libre.com,
	gregkh@...uxfoundation.org, jpanis@...libre.com, kristo@...nel.org,
	krzysztof.kozlowski+dt@...aro.org, lgirdwood@...il.com,
	linus.walleij@...aro.org, linux-arm-kernel@...ts.infradead.org,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	m.nirmaladevi@...s.com, nm@...com, robh+dt@...nel.org,
	vigneshr@...com, khilman@...nel.org
Subject: Re: [RESEND PATCH v1 05/13] mfd: tps6594-spi: Add TI TPS65224 PMIC
 SPI

On Mon, 15 Apr 2024, Bhargav Raviprakash wrote:

> Hello,
> 
> On Wed, 14 Feb 2024 10:10:17 -0800, Lee Jones wrote:
> > On Mon, 08 Apr 2024, Bhargav Raviprakash wrote:
> > 
> > > Introduces a new struct tps6594_match_data. This struct holds fields for
> > > chip id and regmap config. Using this struct in of_device_id data field.
> > > This helps in adding support for TPS65224 PMIC.
> > > 
> > > Signed-off-by: Bhargav Raviprakash <bhargav.r@...s.com>
> > > Acked-by: Julien Panis <jpanis@...libre.com>
> > > ---
> > >  drivers/mfd/tps6594-i2c.c   | 24 ++++++++++++++++--------
> > >  drivers/mfd/tps6594-spi.c   | 24 ++++++++++++++++--------
> > >  include/linux/mfd/tps6594.h | 11 +++++++++++
> > >  3 files changed, 43 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/drivers/mfd/tps6594-i2c.c b/drivers/mfd/tps6594-i2c.c
> > > index c125b474b..9e2ed48b7 100644
> > > --- a/drivers/mfd/tps6594-i2c.c
> > > +++ b/drivers/mfd/tps6594-i2c.c
> > > @@ -192,10 +192,16 @@ static const struct regmap_config tps6594_i2c_regmap_config = {
> > >  	.write = tps6594_i2c_write,
> > >  };
> > >  
> > > +static const struct tps6594_match_data match_data[] = {
> > > +	[TPS6594] = {TPS6594, &tps6594_i2c_regmap_config},
> > > +	[TPS6593] = {TPS6593, &tps6594_i2c_regmap_config},
> > > +	[LP8764] = {LP8764, &tps6594_i2c_regmap_config},
> > 
> > Nit: There should be spaces after the '{' and before the '}'.
> > 
> 
> Sure! will fix it in the next version.
> 
> > > +};
> > > +
> > >  static const struct of_device_id tps6594_i2c_of_match_table[] = {
> > > -	{ .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
> > > -	{ .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
> > > -	{ .compatible = "ti,lp8764-q1",  .data = (void *)LP8764,  },
> > > +	{ .compatible = "ti,tps6594-q1", .data = &match_data[TPS6594], },
> > > +	{ .compatible = "ti,tps6593-q1", .data = &match_data[TPS6593], },
> > > +	{ .compatible = "ti,lp8764-q1",  .data = &match_data[LP8764], },
> > 
> > Not keen on this.  Why do you pass the regmap data through here and
> > leave everything else to be matched on device ID?  It would be better to
> > keep passing the device ID through and match everything off of that.
> > 
> > 
> > -- 
> > Lee Jones [李琼斯]
> 
> Thanks for the feedback!
> 
> These changes were made because of the following message:
> https://lore.kernel.org/all/7hcysy6ho6.fsf@baylibre.com/
> 
> Please let us know which one to follow.

Right, except this doesn't eliminate "any \"if (chip_id)\" checking".
Instead you have a hodge-podge of passing a little bit of (Regmap) data
via match and the rest via "if (chip_id)".  So either pass all platform
type data via .data or just the chip ID.  My suggestion 99% of the time
is the latter.

-- 
Lee Jones [李琼斯]