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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZlYzf6mW8RF9w_R7@surfacebook.localdomain>
Date: Tue, 28 May 2024 22:41:51 +0300
From: Andy Shevchenko <andy.shevchenko@...il.com>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-gpio@...r.kernel.org, linux-pwm@...r.kernel.org,
	Alexandru Ardelean <alexandru.ardelean@...log.com>,
	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>,
	Clark Wang <xiaoning.wang@....com>
Subject: Re: [PATCH v2 4/4] pwm: adp5585: Add Analog Devices ADP5585 support

Tue, May 28, 2024 at 10:03:14PM +0300, Laurent Pinchart kirjoitti:
> From: Clark Wang <xiaoning.wang@....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 PWM function using the platform device
> registered by the core MFD driver.
> 
> The driver is derived from an initial implementation from NXP, available
> in commit 113113742208 ("MLK-25922-1 pwm: adp5585: add adp5585 PWM
> support") in their BSP kernel tree. It has been extensively rewritten.

..

> +#include <linux/device.h>

+ err.h

> +#include <linux/math64.h>
> +#include <linux/minmax.h>
> +#include <linux/mfd/adp5585.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +#include <linux/time.h>

..

> +#define ADP5585_PWM_OSC_FREQ_HZ		1000000U

(1 * HZ_PER_MHZ) ?

> +#define ADP5585_PWM_MIN_PERIOD_NS	(2ULL * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ)
> +#define ADP5585_PWM_MAX_PERIOD_NS	(2ULL * 0xffff * NSEC_PER_SEC / ADP5585_PWM_OSC_FREQ_HZ)

Wouldn't be better to use GENMASK() or (BIT(x) - 1) notation to show that
the limit is due to HW register bits in use?

..

> +	ret = regmap_write(regmap, ADP5585_PWM_OFFT_LOW,
> +			   off & 0xff);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(regmap, ADP5585_PWM_OFFT_HIGH,
> +			   (off >> 8) & 0xff);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(regmap, ADP5585_PWM_ONT_LOW,
> +			   on & 0xff);
> +	if (ret)
> +		return ret;
> +	ret = regmap_write(regmap, ADP5585_PWM_ONT_HIGH,
> +			   (on >> 8) & 0xff);
> +	if (ret)
> +		return ret;

Can be proper __le16/__be16 be used in conjunction with regmap bulk API?

..

> +	/* Enable PWM in continuous mode and no external AND'ing. */
> +	ret = regmap_update_bits(regmap, ADP5585_PWM_CFG,
> +				 ADP5585_PWM_IN_AND | ADP5585_PWM_MODE |
> +				 ADP5585_PWM_EN, ADP5585_PWM_EN);
> +	if (ret)
> +		return ret;
> +
> +	return 0;

	return regmap_update_bits(...);

..

> +	regmap_read(regmap, ADP5585_PWM_OFFT_LOW, &off);
> +	regmap_read(regmap, ADP5585_PWM_OFFT_HIGH, &val);
> +	off |= val << 8;
> +
> +	regmap_read(regmap, ADP5585_PWM_ONT_LOW, &on);
> +	regmap_read(regmap, ADP5585_PWM_ONT_HIGH, &val);
> +	on |= val << 8;

As per above, can it be converted to use proper __le16/__be16 type and
regmap bulk API?

..

> +	device_set_of_node_from_dev(dev, dev->parent);

Why this one? What's wrong with device_set_node()?

-- 
With Best Regards,
Andy Shevchenko