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Date: Thu, 24 Apr 2025 18:34:29 +0200
From: Andrew Lunn <andrew@lunn.ch>
To: Ivan Vecera <ivecera@redhat.com>
Cc: netdev@vger.kernel.org, Vadim Fedorenko <vadim.fedorenko@linux.dev>,
	Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>,
	Jiri Pirko <jiri@resnulli.us>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Prathosh Satish <Prathosh.Satish@microchip.com>,
	Lee Jones <lee@kernel.org>, Kees Cook <kees@kernel.org>,
	Andy Shevchenko <andy@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Schmidt <mschmidt@redhat.com>, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH net-next v4 3/8] mfd: Add Microchip ZL3073x support
Message-ID: <4fae1a96-ac19-46b8-8eff-2a38d28414fc@lunn.ch>
References: <20250424154722.534284-1-ivecera@redhat.com>
 <20250424154722.534284-4-ivecera@redhat.com>
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In-Reply-To: <20250424154722.534284-4-ivecera@redhat.com>

> +++ b/drivers/mfd/zl3073x-regs.h
> @@ -0,0 +1,74 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef __ZL3073X_REGS_H
> +#define __ZL3073X_REGS_H
> +
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +
> +/*
> + * Register address structure:
> + * ===========================
> + *  25        19 18   16 15     7 6           0
> + * +-------------------------------------------+
> + * | max_offset | width |  page  | page_offset |
> + * +-------------------------------------------+
> + *
> + * page_offset ... <0x00..0x7F>
> + * page .......... HW page number
> + * size .......... register byte size (1, 2, 4 or 6)
> + * max_offset .... maximal offset for indexed registers
> + *                 (for non-indexed regs max_offset == page_offset)
> + */

Something i missed earlier. This does not really describe
hardware. The upper half is meta data about the register, which you
encode into the register number.

How many other Linux drivers do you know about which does this?

Also width vs size.

	Andrew