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AJvYcCVyJnxxuMVpWkiEwJNdtuOXjiS9R7eUkKy7k2EbQxnjfz09mHMlKXNIieb6fFdaIA5EK00PDdx3Ln/OjursRapJykfwdbcljecFyw== X-Gm-Message-State: AOJu0YzghaOujTW5UsJDusbBHrCjKgAvRkkCnnqKGsOZjcICf/9ATvfu 1EH9TsnWBMDHp3Q5iFCJ4iM2Y38h0KTdGDXtscdk6I+j9WYKlq1jvMoh6j3EMwc= X-Google-Smtp-Source: AGHT+IGHj2HvbZP4hc88ihdmh15kc6PiOMtrsrZeH+p1UwP0kL1uZIIQk4Qau93XYXPUg/qe5DNZZw== X-Received: by 2002:a5d:654d:0:b0:367:8f98:c503 with SMTP id ffacd0b85a97d-367cea45cffmr6602885f8f.1.1720770550532; Fri, 12 Jul 2024 00:49:10 -0700 (PDT) Received: from [192.168.50.4] ([82.78.167.171]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-367cdfa0613sm9565691f8f.88.2024.07.12.00.49.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 12 Jul 2024 00:49:10 -0700 (PDT) Message-ID: Date: Fri, 12 Jul 2024 10:49:07 +0300 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 v3 04/11] i2c: riic: Enable runtime PM autosuspend support Content-Language: en-US To: Biju Das , Chris Brandt , "andi.shyti@kernel.org" , "robh@kernel.org" , "krzk+dt@kernel.org" , "conor+dt@kernel.org" , "geert+renesas@glider.be" , "magnus.damm@gmail.com" , "p.zabel@pengutronix.de" , "wsa+renesas@sang-engineering.com" Cc: "linux-renesas-soc@vger.kernel.org" , "linux-i2c@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Claudiu Beznea References: <20240711115207.2843133-1-claudiu.beznea.uj@bp.renesas.com> <20240711115207.2843133-5-claudiu.beznea.uj@bp.renesas.com> From: claudiu beznea In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12.07.2024 10:45, Biju Das wrote: > Hi Claudiu, > >> -----Original Message----- >> From: claudiu beznea >> Sent: Friday, July 12, 2024 8:41 AM >> Subject: Re: [PATCH v3 04/11] i2c: riic: Enable runtime PM autosuspend support >> >> Hi, Biju, >> >> On 12.07.2024 10:15, Biju Das wrote: >>> Hi Claudiu, >>> >>>> -----Original Message----- >>>> From: Claudiu >>>> Sent: Thursday, July 11, 2024 12:52 PM >>>> Subject: [PATCH v3 04/11] i2c: riic: Enable runtime PM autosuspend >>>> support >>>> >>>> From: Claudiu Beznea >>>> >>>> Enable runtime PM autosuspend support for the RIIC driver. With this, >>>> in case there are consecutive xfer requests the device wouldn't be >>>> runtime enabled/disabled after each consecutive xfer but after the >>>> the delay configured by user. With this, we can avoid touching >>>> hardware registers involved in runtime PM suspend/resume saving in this way some cycles. The >> default chosen autosuspend delay is zero to keep the previous driver behavior. >>> >>> On the other hand, you are saving power. Currently the driver is >>> highly optimized for Power usage. >>> >>> Before transfer turn on the clock >>> After transfer turn off the clock, this is the optimal power usage correspond to suspend delay. >>> >>> By adding suspend delay, you are consuming power corresponding to that >>> delay. >> >> The default delay is zero, see the following diff in this patch: >> >> @@ -479,6 +481,8 @@ static int riic_i2c_probe(struct platform_device *pdev) >> >> i2c_parse_fw_timings(dev, &i2c_t, true); >> >> + pm_runtime_set_autosuspend_delay(dev, 0); > > I just provided justification, why you addes 0 msec here, compared to xx msec > in the original internal version. Isn't it in the commit description already? "The default chosen autosuspend delay is zero to keep the previous driver behavior." > > Cheers, > Biju