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[75.72.117.212]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8fc2c9229c8sm680230385a.36.2026.05.02.18.45.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 02 May 2026 18:45:52 -0700 (PDT) Message-ID: <30cec7dd-ac3c-47ab-896a-c29992bd5ba5@riscstar.com> Date: Sat, 2 May 2026 20:45:48 -0500 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next 09/12] gpio: tc956x: add TC956x/QPS615 support To: Andrew Lunn Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, maxime.chevallier@bootlin.com, rmk+kernel@armlinux.org.uk, andersson@kernel.org, konradybcio@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linusw@kernel.org, brgl@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, daniel@riscstar.com, mohd.anwar@oss.qualcomm.com, a0987203069@gmail.com, alexandre.torgue@foss.st.com, ast@kernel.org, boon.khai.ng@altera.com, chenchuangyu@xiaomi.com, chenhuacai@kernel.org, daniel@iogearbox.net, hawk@kernel.org, hkallweit1@gmail.com, inochiama@gmail.com, john.fastabend@gmail.com, julianbraha@gmail.com, livelycarpet87@gmail.com, matthew.gerlach@altera.com, mcoquelin.stm32@gmail.com, me@ziyao.cc, prabhakar.mahadev-lad.rj@bp.renesas.com, richardcochran@gmail.com, rohan.g.thomas@altera.com, sdf@fomichev.me, siyanteng@cqsoftware.com.cn, weishangjuan@eswincomputing.com, wens@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-gpio@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20260501155421.3329862-1-elder@riscstar.com> <20260501155421.3329862-10-elder@riscstar.com> <736fb3b7-c88a-4ec4-96ad-d1b79cc48d30@lunn.ch> Content-Language: en-US From: Alex Elder In-Reply-To: <736fb3b7-c88a-4ec4-96ad-d1b79cc48d30@lunn.ch> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/1/26 1:36 PM, Andrew Lunn wrote: >> + * There is a TC956X PCI power controller driver that accesses the >> + * direction and output value registers for GPIOs 2 and 3. These >> + * GPIOs control the reset signal for the two downstream PCIe ports. >> + * Their values will never change during operation of this driver, and >> + * this driver reserves these two GPIOS. > > Why doesn't this power controller driver actually use this driver to > control the GPIOs? Chicken/egg? I am not the one with authority on this, but yes, that's my understanding. *Something* about this chip requires that the PCIe ports need to have some configuration done on them *before* PCIe is powered up. So that driver uses the I2C interface to apply these settings. Meanwhile this driver uses the PCIe-mapped memory to manage the GPIO registers. > Maybe add a comment why gpio-regmap.c cannot be used. You probably > need to instantiate it twice, but i still think you will end up with > less code. It's possible gpio-regmap.c *could* be used. We started with vendor code and this code got separated at some point along the way. It was working, and I don't think I pursued other options at that point. I'll look at this possibility before we send out the next version. What do you mean instantiate it twice? -Alex > > Andrew