From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f50.google.com (mail-qv1-f50.google.com [209.85.219.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6CC452BE7D2 for ; Wed, 28 Jan 2026 02:53:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769568796; cv=none; b=STBFlLmQ7UEl6kW00fiSiuaFyr1KifsPkSE65/y9gjhlZfB4eFZegQ4A9WmNMxuROQOKLeHlZ+b46k3V7FEMpIhetroyyg4gprMIi8O8x5rpVimF/KIrFtNrXFc+7lighKtvBssEpuhtlSovrST8h994BaJTYngZLdwExLHSMis= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769568796; c=relaxed/simple; bh=9KL0qFGhdBvOIIw6GVscMMDXp1h7L+qs/1b2H49sp40=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GenfbRfxD593LN7qMahgbjVyZ4dkOqgALQbipoxusyMMrP1+QIVTD+M3mitjUueK9JGB0H1DdA41lP4quy3yeH52tRv910HzsbMh1DOjH4LbBaHQEJj9k80oY5nAS2VIHMdekMwxGNDGRSCesk/iFn5zcoEZh7kgzC75JBKy4J4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=SiIQOE+W; arc=none smtp.client-ip=209.85.219.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SiIQOE+W" Received: by mail-qv1-f50.google.com with SMTP id 6a1803df08f44-88a26ce6619so81441616d6.3 for ; Tue, 27 Jan 2026 18:53:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1769568794; x=1770173594; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=yluvfUNr6pH7GOU/s+jQXcqg7WVVoVQL2cZIk1rM12A=; b=SiIQOE+WNstIDMT5YlVCQsJtZWphJZJr3NdEDMdV5NDb67FflCWbfmi3VIVT0kk6ut Eqvh/niJq2sI0m/kI7RTwI5BZC9UZIq6s50meT0FW+1yG0LTGneqVw71RkKu2BH2L4OB uAdj0yV5PMH47KKYtVJZid4JEn/6KRfjQt8tWwF/ufLdmqQqAgUXOgkzCoMEdFoEUTk8 tqlCWumtPztW5G/VJ6/2OdX/qUhpIsUFVtFjDQ+KAhc+rfUPFLpKr6IvGmxCsK8TTZbW riyZr8g0rDrhdE11+KTpoiCHOwkbxmeBXDglcBQKaGzWiTVtBM+a/TyVL0rClf2Plb27 oK9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769568794; x=1770173594; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=yluvfUNr6pH7GOU/s+jQXcqg7WVVoVQL2cZIk1rM12A=; b=uEwyHY3lwuo3r6iaOeJbUbMaHOe3jyQRbALqXHsY4RjNXTy8CUrKeFU9MbM17MqfOm iMl0kAiRy9XOcWXWuf3x+IxDgppJaQU/Zx5gohNtNJR2lGLMMJ3gjD15XtkbXX39JbKA 5+Ig59JCM3xZBUe/+ujka+q1w+oTD8nVgKBYKxMFbR6yxQKrlnU7z+zZ2P+K3kn2GidN xqN0pSqJkrABs8Ja+gKCi0CXFPa0KE3Cm4uUr/AkXw5Lqp0Jajuf3qEhB4T4fOizlAg3 oAhgvvnf0X6l6bJq6Ct3Yp89PpKs903Go2MaJIV00LfG8Xizkg2zTV7CiJX6jvrqPfSO 15jg== X-Forwarded-Encrypted: i=1; AJvYcCUWWp8otLrCbTZh3T40lJYPgJ+raPkDV8HGLasgXVJ4TiSuyas5WLZicbFIdBxbBBfUFqiDa7Ks6M49@vger.kernel.org X-Gm-Message-State: AOJu0YzS7UzaxhXOnirr5Yfg5QetaB2BU+vBG3QjauRBJjaBnROlrYmj 21g2SkfInp7AhaSsGJh8OpYUEd3UogX/lSWT14SqFl6nM3MWu3kZQKy/ X-Gm-Gg: AZuq6aIbuZz9NRIXsOweK//bYSgC7PaNUzhD7bb4RtdH5/HiWsHCdAjWhOzB/3MKULl ht8P+9DSZ+lqFrfI6KC5WQ5ctcVAkQEPlGKBqj6UI5MB/uPK4663gy5QLfEgB+BCBqGrWYs5Sgs kCpwRbZg7kJn/6gjT/OdF3yXAtLclIYdAgd5FpsYxvvBXuEskb8SCakyQ645INwPtwTwcnl4VPq /0V4Sh94uBz85KXNXnrnDW2pg0C74+U+3FEx55yUSvRMMVhIP+aiIsK13sFA3dqDS2HbtC16R0b hVSeHf/CC317Cp4DNQVxbMlXKIH6oNvFVb/wJR3GbQcUX44KhqqPIRs94SLQ201QRwsw53QDtQy TsbMzvFmyGHUN2VDFBNHsHZO/opePKVgslHkwEtnh3cICGq3TgTutdSd2QuTBSVOqXXNqD0lTy+ IE2Tj+a519DOQrLQ== X-Received: by 2002:a05:6214:da5:b0:894:6e5d:eb8d with SMTP id 6a1803df08f44-894cc8c977dmr49820206d6.34.1769568794147; Tue, 27 Jan 2026 18:53:14 -0800 (PST) Received: from localhost ([184.144.58.243]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-894d375ed92sm8696686d6.44.2026.01.27.18.53.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Jan 2026 18:53:13 -0800 (PST) Date: Tue, 27 Jan 2026 21:53:38 -0500 From: Richard Acayan To: Sakari Ailus Cc: Bryan O'Donoghue , Mauro Carvalho Chehab , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bjorn Andersson , Konrad Dybcio , Tianshu Qiu , linux-media@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, Robert Mader , Vladimir Zapolskiy , David Heidelberg , phone-devel@vger.kernel.org Subject: Re: [PATCH v7 2/5] media: i2c: imx355: Support devicetree and power management Message-ID: References: <20260117040657.27043-1-mailingradian@gmail.com> <20260117040657.27043-3-mailingradian@gmail.com> <578668b0-cba2-4550-b676-26ed0b447bf2@linaro.org> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Jan 20, 2026 at 04:49:21PM +0200, Sakari Ailus wrote: > Hi Bryan, others, > > On Tue, Jan 20, 2026 at 12:44:24PM +0000, Bryan O'Donoghue wrote: > > I think reset should be asserted before regulators and power are switched > > on. i.e. before you try to switch the chip on, you should establish that the > > reset pin is in the state that the timing diagram calls for. > > Indeed. I think the discussion is more about whether there should be an assert in the same function as the de-assert. > The xshutdown pin, as it is typically called labelled as "reset" in this > case, functions as both hardware reset and hardware standby mode control. > It should be asserted (i.e. be set to low level) whenever the sensor is > expected to be powered off. Typically deasserting it is the last step in > the sensor's power-up sequence. This applies to nearly all CSI-2 and DVP > (parallel) camera sensors. (There are some exceptions that use explicitly > two GPIOs for similar functions but there are very few of them.) This patch has the reset asserted by the time it gets to imx355_power_on(): - when coming from runtime PM, the suspend callback asserted it - when coming from probe, GPIOD_OUT_HIGH asserted it (considering that active-low also affects the initial output setting) Should it be asserted again inside the function, or should the initial `gpiod_set_value_cansleep()` be removed?