linux-kernel - Re: [PATCH v8 2/2] mfd: max597x: Add support for MAX5970 and MAX5978

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Message-ID: <Y3IGR887iuyP2SoL@google.com>
Date:   Mon, 14 Nov 2022 09:11:35 +0000
From:   Lee Jones <lee@...nel.org>
To:     Naresh Solanki <naresh.solanki@...ements.com>
Cc:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        Patrick Rudolph <patrick.rudolph@...ements.com>,
        Marcello Sylvester Bauer <sylv@...v.io>
Subject: Re: [PATCH v8 2/2] mfd: max597x: Add support for MAX5970 and MAX5978

On Fri, 11 Nov 2022, Naresh Solanki wrote:
> On 07-11-2022 03:06 pm, Lee Jones wrote:
> > On Thu, 03 Nov 2022, Naresh Solanki wrote:
> > 
> > > From: Patrick Rudolph <patrick.rudolph@...ements.com>
> > > 
> > > Implement a regulator driver with IRQ support for fault management.
> > 
> > This is not a "regulator driver".
> > 
> > > Written against documentation [1] and [2] and tested on real hardware.
> > > 
> > > Every channel has its own regulator supplies nammed 'vss1-supply' and
> > > 'vss2-supply'. The regulator supply is used to determine the output
> > > voltage, as the smart switch provides no output regulation.
> > > The driver requires the 'shunt-resistor-micro-ohms' property to be
> > > present in Device Tree to properly calculate current related
> > > values.
> > > 
> > > Datasheet links:
> > > 1: https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
> > > 2: https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
> > > 
> > > Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
> > > Signed-off-by: Marcello Sylvester Bauer <sylv@...v.io>
> > > Signed-off-by: Naresh Solanki <Naresh.Solanki@...ements.com>

[...]

> > > +static const struct of_device_id max597x_of_match[] = {
> > > +	{ .compatible = "maxim,max5970", .data = (void *)MAX597x_TYPE_MAX5970 },
> > > +	{ .compatible = "maxim,max5978", .data = (void *)MAX597x_TYPE_MAX5978 },
> > 
> > Where is .data used?
> The .data isn't used.

Then why add it?

[...]

> > > +#include <linux/device.h>
> > > +#include <linux/regmap.h>
> > > +
> > > +/* Number of switch based on chip variant */
> > 
> > This comment is superfluous.
> You mean this comment should be removed ?

I do.

> > > +#define MAX5970_NUM_SWITCHES 2
> > > +#define MAX5978_NUM_SWITCHES 1
> > > +/* Both chip variant have 4 indication LEDs used by LED cell */
> > 
> > Here too I think.
> > 
> > > +#define MAX597X_NUM_LEDS     4
> > > +
> > > +enum max597x_chip_type {
> > > +	MAX597x_TYPE_MAX5978 = 1,
> > 
> > Why 1?
> MAX5978 & single power switch wheres MAX5970 has two.

That's not what this enum means.

You are just describing the type to be matched on.

The value should be arbitrary, no?

[...]

> > > +#define  OC_STATUS_WARN(ch)				BIT(ch)
> > > +
> > > +#define MAX5970_REG_CHXEN				0x3b
> > > +#define  CHXEN(ch)						(3 << (ch * 2))
> > > +
> > > +#define MAX5970_REG_LED_FLASH			0x43
> > 
> > Do these all need to be shared?
> > 
> > Or can they be isolated into, say, the Regulator driver?
> > 
> Shared reg.

Where else are they used?

-- 
Lee Jones [李琼斯]