From patchwork Thu Jul 11 10:20:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bryan O'Donoghue X-Patchwork-Id: 812402 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (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 F31A115887C for ; Thu, 11 Jul 2024 10:20:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720693207; cv=none; b=RE+kvVLasN5FAmbu6ilvz0fJXdjKP8qmglhamSjWmZPoUKbgFWdNVuVUtVi0GF+1Gs1Hx2WD8aaE5EhFTJwfYj6GKyF79rJmgdxr2r9+4LjuWnqcfaApqcLgyvJPG6xHMmizl/13xZ5UBrmgH9+nX3hsXl1HIjJub89E3LXPhzI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720693207; c=relaxed/simple; bh=bKIdUuVmWv5FJkFDtu2H6clQsAHCUTFbn8+qyaw6hHg=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=N6NU3XawD3fLsPPC+BiZGsqklsXtYYSyYgTlh/EQA0nWERhK/8i/cIGTwx6D1rVRfkcNNbeR4ITp+KvdnwbV8Mgf6KBKEmaJPB0hSjBHsFftIo17DTX1dM8AKiu0qG1DhcIzwb+/Zb5QdW8UR3JQv217jU9n1SZ01WeHsX+nXe0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=AeDeOfgq; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="AeDeOfgq" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-4279c924ca7so35395e9.2 for ; Thu, 11 Jul 2024 03:20:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1720693203; x=1721298003; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:from:to:cc:subject:date:message-id :reply-to; bh=Jw6bLyA4dVnYszcIqA96Q05ikE6tm67ysRPS44gZ2Bo=; b=AeDeOfgqmtP6YqYtgTpYNinb9oqMQl3i7j38vK4+io3o2BdQ00xqcjagYE4jzCULnB E4zK8QAZ7vgI18tg4Wl9bxBcVnzYW/fUdzoUskWQc+r5st4WQBPQ18QdyrnbNCK/CkK9 9by3L7M9izvLBeYybfLp7EGrHzIkly9reeppj256TLUcJTas4KaaYGDeL6blF2Xj67po 7JmFAm3A3hjbGCAd7Q45WmwhiU9R7cNAbVHuzPXOMnlorAPMeRcyY1KCUJmq8r2iA7vm Jmdj+/wNpcM5s0aaCWbWTgk2OVrKksnQfoAsrNXjLVa1Ng0pN2u+TS64yQ0ie+9HuytJ lUbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720693203; x=1721298003; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :mime-version:subject:date:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Jw6bLyA4dVnYszcIqA96Q05ikE6tm67ysRPS44gZ2Bo=; b=Jw6ev/WrFlZjf73GPlzCavoVlW8KlbV3iEvAZVXT3RT7hO1Fp1LtfRjRT/jdGC+ia9 gS/STO3VMq0Et2caiGpB9QiTij7zaVI7QZaL7ozO2A57ldqnYfiIEHPO1d02RGnOBT/H eqXe6Zlg/tF4+1A8WWkzqA+BFmR2gu0FrK/sR1cmXDiZZV9/uDNZvNrl4fzwZsEqBR8j kGzj+du3tIVbMv4oOY4pSCpSml1WSqKYWOa8CczvhLYsg2sVysfst/Fe9hwRK8xi5dnV StBsLNES2stGdfJv3XjsS9ytzNuRZ4jjaDkM62eGlVgGoV1P6YhCC4CRd8TtSS7tEhT2 orwQ== X-Forwarded-Encrypted: i=1; AJvYcCUF2z9XLRwSMXYyurjvy9j/pAoBX/nm0JF/0A/IHg8etp8i4+kG3q7jzfr+Gy/KEqLlq68b081WEkBQ9x1CcVBtR0w3kDQm+vepoS4= X-Gm-Message-State: AOJu0YxRI0mcQc0G4WsOOj3gBcWG6qN73rwt+vDGgBx1URePWSrzEqKH GzgUltx4uGkabjd5Z4wLHT3b0nYRibSbjY6DCsrUDF9GguI/c3Jj2NT5GBOxAj4= X-Google-Smtp-Source: AGHT+IEPG6ALVrKC0vxITNNnj0AxUU2b5IhohOK+zwxcy7Y2DoKsbVYQ4rwu1v3iMbA9+oXaQb0Gcw== X-Received: by 2002:a05:600c:228f:b0:426:668f:5eca with SMTP id 5b1f17b1804b1-426706c6878mr52146665e9.7.1720693203327; Thu, 11 Jul 2024 03:20:03 -0700 (PDT) Received: from [127.0.1.1] ([176.61.106.227]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4266e861339sm125270025e9.12.2024.07.11.03.20.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Jul 2024 03:20:02 -0700 (PDT) From: Bryan O'Donoghue Date: Thu, 11 Jul 2024 11:20:02 +0100 Subject: [PATCH 2/2] media: ov5675: Elongate reset to first transaction minimum gap Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240711-linux-next-ov5675-v1-2-69e9b6c62c16@linaro.org> References: <20240711-linux-next-ov5675-v1-0-69e9b6c62c16@linaro.org> In-Reply-To: <20240711-linux-next-ov5675-v1-0-69e9b6c62c16@linaro.org> To: Sakari Ailus , Mauro Carvalho Chehab , Quentin Schulz , Jacopo Mondi Cc: Johan Hovold , Kieran Bingham , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Bryan O'Donoghue , stable@vger.kernel.org X-Mailer: b4 0.15-dev-13183 The ov5675 specification says that the gap between XSHUTDN deassert and the first I2C transaction should be a minimum of 8192 XVCLK cycles. Right now we use a usleep_rage() that gives a sleep time of between about 430 and 860 microseconds. On the Lenovo X13s we have observed that in about 1/20 cases the current timing is too tight and we start transacting before the ov5675's reset cycle completes, leading to I2C bus transaction failures. The reset racing is sometimes triggered at initial chip probe but, more usually on a subsequent power-off/power-on cycle e.g. [ 71.451662] ov5675 24-0010: failed to write reg 0x0103. error = -5 [ 71.451686] ov5675 24-0010: failed to set plls The current quiescence period we have is too tight, doubling the minimum appears to fix the issue observed on X13s. Fixes: 49d9ad719e89 ("media: ov5675: add device-tree support and support runtime PM") Cc: stable@vger.kernel.org Signed-off-by: Bryan O'Donoghue --- drivers/media/i2c/ov5675.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/media/i2c/ov5675.c b/drivers/media/i2c/ov5675.c index 92bd35133a5d..0498f8f3064d 100644 --- a/drivers/media/i2c/ov5675.c +++ b/drivers/media/i2c/ov5675.c @@ -1018,8 +1018,13 @@ static int ov5675_power_on(struct device *dev) gpiod_set_value_cansleep(ov5675->reset_gpio, 0); - /* 8192 xvclk cycles prior to the first SCCB transation */ - usleep_range(delay_us, delay_us * 2); + /* The spec calls for a minimum delay of 8192 XVCLK cycles prior to + * transacting on the I2C bus, which translates to about 430 + * microseconds at 19.2 MHz. + * Testing shows the range 8192 - 16384 cycles to be unreliable. + * Grant a more liberal 2x -3x clock cycle grace time. + */ + usleep_range(delay_us * 2, delay_us * 3); return 0; }