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[75.72.117.212]) by smtp.gmail.com with ESMTPSA id 8926c6da1cb9f-53d3a591637sm1058871173.15.2025.09.18.08.58.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Sep 2025 08:58:32 -0700 (PDT) Message-ID: <000a41ee-a099-4944-8ef5-eed768f905cb@riscstar.com> Date: Thu, 18 Sep 2025 10:58:30 -0500 Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] spi: spacemit: introduce SpacemiT K1 SPI controller driver To: Yixun Lan Cc: broonie@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, p.zabel@pengutronix.de, spacemit@lists.linux.dev, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org References: <20250917220724.288127-1-elder@riscstar.com> <20250917220724.288127-3-elder@riscstar.com> <20250918124120-GYA1273705@gentoo.org> <034cecd3-c168-4c8d-9ad5-10cc1853894b@riscstar.com> <20250918143928-GYB1274501@gentoo.org> Content-Language: en-US From: Alex Elder In-Reply-To: <20250918143928-GYB1274501@gentoo.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/18/25 9:39 AM, Yixun Lan wrote: >>>> + virt = drv_data->ioaddr + SSP_TOP_CTRL; >>>> + val = readl(virt); >>>> + val |= TOP_TRAIL; /* Trailing bytes handled by DMA */ >>>> + writel(val, virt); >>> I'd prefer to do like this, it's more easy for people to grep.. >>> val = readl(drv_data->ioaddr + SSP_TOP_CTRL) | TOP_TRAIL; >>> writel(val, drv_data->ioaddr + SSP_TOP_CTRL); >> This is an idiom I use to make it very clear that: >> - The address being read is exactly the same as what's being >> written >> - The value read is being updated with bits/values >> >> I find that putting the "| TOP_TRAIL" on the same line as the >> readl() call obscures things a bit. Like my eye doesn't notice >> it as readiliy somehow... > fair, let's put it into another line > >> Yours is a pure coding style comment. There are two pieces, and >> I'd like you to tell me how strongly you feel about them: >> - Using virt to grab the address being written and read (versus >> just using drv_data->ioaddr + SSP_TOP_CTRL twice) >> - Put the "| TOP_TRAIL" on the same line as the readl() (versus >> having that be assigned on a separate line). >> To me, the second one is more important than the first. >> >> Let me know how strongly you feel about these and I'll update >> my convention througout. >> > I'd strongly prefer not to introduce 'virt', so be something like this: > val = readl(drv_data->ioaddr + SSP_TOP_CTRL); > val |= TOP_TRAIL; > writel(val, drv_data->ioaddr + SSP_TOP_CTRL); > OK. I'll do it this way throughout the driver in the next version. -Alex