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Thu, 30 Apr 2026 08:40:13 -0700 (PDT) Message-ID: Subject: Re: [PATCH v4] i2c: Add FTDI FT4222H USB I2C adapter From: Francesco Lavra To: Andi Shyti , linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org Date: Thu, 30 Apr 2026 17:40:12 +0200 In-Reply-To: <20260225112046.2394231-1-flavra@baylibre.com> References: <20260225112046.2394231-1-flavra@baylibre.com> Organization: BayLibre Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.4-2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Friendly ping On Wed, 2026-02-25 at 12:20 +0100, Francesco Lavra wrote: > FT4222H exports a USB interface to operate as I2C bus master when set up > (via the DCNF pins) in configuration mode 0 or 3. > The USB communication protocol implemented by the FT4222 chip is not > publicly documented, therefore the name assigned to the various defines > used in the USB communication code is a semi-educated guess after > sniffing > USB traffic generated with the FTDI FT4222 userspace library. >=20 > Signed-off-by: Francesco Lavra