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([179.179.238.247]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5eae97f0a94sm3505688e0c.11.2026.10.21.08.37.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Oct 2026 08:37:49 -0700 (PDT) From: Vinicius Pedrosa To: Andy Shevchenko Cc: linux-serial@vger.kernel.org, gregkh@linuxfoundation.org, jirislaby@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, ilpo.jarvinen@linux.intel.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev, Andre Przywara , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Enzo Adriano , stable@vger.kernel.org Subject: Re: [PATCH v2 1/4] serial: 8250_dw: Keep the BUSY-safe divisor hook when DLF is present Date: Wed, 21 Oct 2026 12:37:32 -0300 Message-ID: <20261021153732.1978410-1-vinicius.eduardo.pedrosa@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: <20261020104753.28703-1-vinicius.eduardo.pedrosa@gmail.com> <20261021100049.16504-1-vinicius.eduardo.pedrosa@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Andy, On Wed, 21 Oct 2026, Andy Shevchenko wrote: > Ah, dw8250_idle_*() are already BUSY-functionality aware. So, what we need > is to provide dw8250_idlej_*() callbacks via struct dw8250_port_data and > make current 8250_dw::dw8250_set_divisor() to be part of dwlib. > > Patch 1 (dwlib): Add callback definitions for dw8250_idle_*() to struct dw8250_port_data > Patch 2 (dw): Assign new callbacks and use them in dw8250_set_divisor() > Patch 3 (lpss): Introduce stubs and assign new callbacks to them > Patch 4 (dwlib): Use dw8250_idle_*() in dw8250_set_divisor() > Patch 5 (dw): Kill now duplicate code pieces > > Would it work? Yes, I think the approach works. Two details from checking the call paths. dw8250_setup_port() is skipped for Octeon (skip_autocfg), so 8250_dw would still have to install the setter from probe. For LPSS, I wonder if the idle callbacks could simply be optional. 8250_dw would provide them and LPSS could leave them NULL, avoiding stubs and a separate LPSS patch. The common setter in dwlib would use them when present. I'd still prefer to keep patch 1 as the small fix with the stable tag and do the refactoring as a separate follow-up series. Would that work for you? I don't have LPSS hardware, but I can build-test the LPSS side. Thanks, Vinicius