linux-kernel - Re: [PATCH v2 2/4] mfd: adp5585: Add Analog Devices ADP5585 core support

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Date: Tue, 28 May 2024 23:13:26 +0300
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-gpio@...r.kernel.org, linux-pwm@...r.kernel.org,
	Bartosz Golaszewski <brgl@...ev.pl>,
	Conor Dooley <conor+dt@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Lee Jones <lee@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Rob Herring <robh@...nel.org>,
	Uwe Kleine-König <ukleinek@...nel.org>,
	Haibo Chen <haibo.chen@....com>
Subject: Re: [PATCH v2 2/4] mfd: adp5585: Add Analog Devices ADP5585 core
 support

On Tue, May 28, 2024 at 10:27:34PM +0300, Andy Shevchenko wrote:
> Tue, May 28, 2024 at 10:03:12PM +0300, Laurent Pinchart kirjoitti:
> > From: Haibo Chen <haibo.chen@....com>
> > 
> > The ADP5585 is a 10/11 input/output port expander with a built in keypad
> > matrix decoder, programmable logic, reset generator, and PWM generator.
> > This driver supports the chip by modelling it as an MFD device, with two
> > child devices for the GPIO and PWM functions.
> > 
> > The driver is derived from an initial implementation from NXP, available
> > in commit 8059835bee19 ("MLK-25917-1 mfd: adp5585: add ADI adp5585 core
> > support") in their BSP kernel tree. It has been extensively rewritten.
> 
> ...
> 
> > +	tristate "Analog Devices ADP5585 MFD driver"
> > +	select MFD_CORE
> > +	select REGMAP_I2C
> > +	depends on I2C && OF
> 
> Why OF?

Because the driver works on OF systems only.

> No COMPILE_TEST?

The driver won't compile without CONFIG_I2C, so I can use

	depends on I2C
	depends on OF || COMPILE_TEST

Do you think that's better ?

> 
> ...
> 
> + array_size.h
> + device.h // e.g., devm_kzalloc()
> 
> > +#include <linux/module.h>
> > +#include <linux/moduleparam.h>
> > +#include <linux/init.h>
> > +#include <linux/slab.h>

I'll drop those 3 headers, there's not needed anymore.

> > +#include <linux/i2c.h>
> 
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> 
> You don't need them, instead of proxying...

of.h for of_device_get_match_data() and of_match_ptr(). I'll drop the
former, but I need the latter, so I'll keep of.h

of_device.h for historical reasons probably, I'll drop it.

> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/adp5585.h>
> 
> m is earlier than 'o', but with above drop no more issue :-)
> 
> ...just include mod_devicetable.h.
> 
> > +#include <linux/regmap.h>
> 
> + types.h // e.g., u8
> 
> ...
> 
> > +	regmap_config = of_device_get_match_data(&i2c->dev);
> 
> We have i2c_get_match_data().

Sounds good.

> ...
> 
> > +#ifndef __LINUX_MFD_ADP5585_H_
> > +#define __LINUX_MFD_ADP5585_H_
> > +
> > +#include <linux/bits.h>
> 
> ...
> 
> > +#define		ADP5585_MAN_ID(v)		(((v) & 0xf0) >> 4)
> 
> GENMASK()

This is not a mask. Or do you mean

	(((v) & GENMASK(7, 4)) >> 4)

? I think that's overkill.

> ...
> 
> > +#define		ADP5585_Rx_PULL_CFG_MASK	(3)
> 
> GENMASK()

Not here, as this value is meant to be passed to ADP5585_Rx_PULL_CFG().

> Why parentheses in all of them, btw?

Probably for consistency, but I don't mind dropping them.

> ...
> 
> > +#define		ADP5585_C4_EXTEND_CFG_MASK	(1U << 6)
> 
> > +#define		ADP5585_R4_EXTEND_CFG_MASK	(1U << 5)
> 
> > +#define		ADP5585_R3_EXTEND_CFG_MASK	(3U << 2)
> 
> > +#define		ADP5585_R0_EXTEND_CFG_MASK	(1U << 0)
> 
> > +#define		ADP5585_OSC_FREQ_MASK		(3U << 5)
> 
> BIT() / GENMASK()

I'll use GENMASK for the masks.

> > +#endif

-- 
Regards,

Laurent Pinchart