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([37.142.156.156]) by smtp.googlemail.com with ESMTPSA id 5b1f17b1804b1-49b494228bfsm79722395e9.2.2026.08.27.15.25.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Aug 2026 15:25:58 -0700 (PDT) From: Michael Zaidman To: lee@kernel.org Cc: linusw@kernel.org, jikos@kernel.org, bentiss@kernel.org, brgl@kernel.org, linux-input@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/13] HID: ft260: add UART and GPIO support, plus I2C fixes Date: Fri, 28 Aug 2026 01:25:50 +0300 Message-ID: <20260827222550.24634-1-michael.zaidman@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260827205116.GJ2943942@google.com> References: <20260827205116.GJ2943942@google.com> Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, 27 Aug 2026 at 21:51 +0100, Lee Jones wrote: > That's precisely what MFD is. It's one chip, usually with a shared and > overlapping register spaces, that conducts multiple functions. This is > no different to any other single-chip device or SoC. > > Shoving everything into a single driver isn't how things are done in > Linux. This should be divided up into the associated sub-systems where > each part can be reviewed and looked after by the appropriate SMEs. Understood, and I am not going to argue MFD scope with you. But this is not specific to my series, so I would rather not decide it here on my own. drivers/hid already registers other subsystems' devices from a hid_driver: hid-cp2112 adds an i2c_adapter and a gpiochip, hid-mcp2221 adds an i2c_adapter, a gpiochip and an IIO device, and hid-ft260 has hosted the I2C adapter since v5.13, commit 6a82582d9fa4 ("HID: ft260: add usb hid to i2c host bridge driver"). So the split you are asking for is not a change to this series. It means moving code that has been in drivers/hid since v5.13 into an MFD parent with cells, and the same reasoning would apply to cp2112 and mcp2221. I am willing to discuss that as its own conversion, but it needs the HID maintainers to agree on the direction first, and I do not think the UART and GPIO support should wait behind it. It would also spread the driver over four trees, so a fix touching the shared chip state becomes a cross-tree series with coordinated merges between four maintainers - a cost the single driver does not have. Jiri, Benjamin - this is your call. Do you want FT260 functionality to keep growing inside hid-ft260, as cp2112 and mcp2221 do today, or do you want a drivers/hid to MFD conversion for this class of USB HID bridge chips? Thanks, Michael