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([2a00:1fa0:2d5:373e:50fc:221d:1226:f18a]) by smtp.gmail.com with ESMTPSA id l16sm2119454lfg.2.2020.05.29.01.49.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 29 May 2020 01:49:27 -0700 (PDT) Subject: Re: [PATCH v5 01/16] spi: dw: Set xfer effective_speed_hz To: Serge Semin , Mark Brown Cc: Serge Semin , Georgy Vlasov , Ramil Zaripov , Alexey Malahov , Thomas Bogendoerfer , Arnd Bergmann , Feng Tang , Andy Shevchenko , Rob Herring , linux-mips@vger.kernel.org, devicetree@vger.kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200529035915.20790-1-Sergey.Semin@baikalelectronics.ru> <20200529035915.20790-2-Sergey.Semin@baikalelectronics.ru> From: Sergei Shtylyov Message-ID: Date: Fri, 29 May 2020 11:49:12 +0300 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <20200529035915.20790-2-Sergey.Semin@baikalelectronics.ru> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org Hello! On 29.05.2020 6:58, Serge Semin wrote: > Seeing DW APB SSI controller doesn't support setting the exactly > requested SPI bus frequency, but only a rounded frequency determined > by means of the odd-numbered half-worded reference clock divider, > it would be good tune the SPI core up and initialize the current ^ to? > transfer effective_speed_hz. By doing so the core will be able to > execute the xfer-related delays with better accuracy. > > Signed-off-by: Serge Semin > Cc: Georgy Vlasov > Cc: Ramil Zaripov > Cc: Alexey Malahov > Cc: Thomas Bogendoerfer > Cc: Arnd Bergmann > Cc: Feng Tang > Cc: Andy Shevchenko > Cc: Rob Herring > Cc: linux-mips@vger.kernel.org > Cc: devicetree@vger.kernel.org [...] MBR, Sergei