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([2001:9e8:f10d:9d01:f9bb:2216:3277:25a0]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b879513e9f3sm782515066b.10.2026.01.18.01.43.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 18 Jan 2026 01:43:13 -0800 (PST) Message-ID: <91442f3f-0da9-4c52-89ce-2ca0a3188836@gmail.com> Date: Sun, 18 Jan 2026 10:43:12 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v5] net: sfp: extend SMBus support Content-Language: en-US To: Andrew Lunn , Maxime Chevallier Cc: Russell King , Heiner Kallweit , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?Q?Bj=C3=B8rn_Mork?= References: <20260116113105.244592-1-jelonek.jonas@gmail.com> <6a87648c-a1e8-49a2-a201-91108669ab44@bootlin.com> <6987689b-35ac-4c15-addb-1c8e54144fa7@gmail.com> <5e7c71f6-80dd-408b-a346-888e6febf07a@lunn.ch> From: Jonas Jelonek In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi, On 16.01.26 15:25, Andrew Lunn wrote: >> But let's first figure-out if word-only smbus are really a thing > Some grep foo on /drivers/i2c/busses might answer that. Did that and haven't found any driver in mainline which is word-only. All drivers with word access capability have byte access too. FWIW, I briefly looked at some specifications. SMBus doesn't seem to require any hierarchy or bare minimum operations, so it's up to the vendor which operations are implemented. Though one could argue, byte access is probably simpler to implement and if a vendor implements word access, byte access is usually implemented too. Looking at the SFP MSA [1], some sentences sound like one could assume byte access is needed at least for SFP. In Section B4, there are statements like: - "The memories are organized as a series of 8-bit data words that can be     addressed individually..." - "...provides sequential or random access to 8 bit parameters..." - "The protocol ... sequentially transmits one or more 8-bit bytes..." But that may be too vague and I can't judge if that's a valid argument to not care about word-only here. Kind regards, Jonas [1] https://members.snia.org/document/dl/26184