From patchwork Sat May 31 16:31:42 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 893716 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8158D175D53 for ; Sat, 31 May 2025 16:32:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748709131; cv=none; b=YkvkfKSSpSk8Z4gxuhuZaKINExOliXf0pa+kSdgNniWwzAWAyg16CzllgKmCubCkVWgg57dDjDgVHzMSizKT2M2nBeXJSCVC9PKavy4qI89ECgeaIcHESK5W4L8vuHXXTiDUUZwIwgbDRJGCxHUcwuHZk+In5vcKgF7E4nMS6OA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748709131; c=relaxed/simple; bh=OEefwPIAykmQwDwijRLibsprpZb0BzXfAAn/GoAPEAc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e1HdOtG6r95fOtNsVVme2g/2WUXrvD0xl73a0NYp0qK46mWKruh9IxkalvZYOac+mzSFd6VvmNSIVtUMNR3iWSDo88iJ4Ra/k+3DivOwM/oVX5NWTT6oaMm2s7TkzMmxiOLnXT8zvYRsb2bGen9bOm0qoGsHedvyTe0odSkx7Fs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NLQoWmHF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NLQoWmHF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C4509C4CEEE; Sat, 31 May 2025 16:32:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748709131; bh=OEefwPIAykmQwDwijRLibsprpZb0BzXfAAn/GoAPEAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NLQoWmHFvzQeA4yp1IDOjRsqZ0jij8jNS4xvsgGf9b21KcfrDz7RpE+Zurh0dC6Wm usW2aWnE+aO27PQ8GR5iqlxVv7tTe1xCl75f7BZzDsY1yEyj6jh7VHfbZhabZruUVg l8HKRYYZTMgpLzOuMOmxoEStfhbCvDblQ6BfWlQJiCsr0pdJfESNQHmdY1/g5pZ79V wmf7JqG/E5Nq31ixCJihMafZt35aXQfY8CdoYtJzVVv2HQjJRvPgjDAxYqaHzlaCv9 CJ79RdsD98iqLuMACWt9CM1vced/vTMvvXWdkmfX+f31XUe9GbeNKlS6CegIZqyYP5 kWS5hZlmCTAIQ== From: Hans de Goede To: Sakari Ailus , Laurent Pinchart Cc: Hans de Goede , Mathis Foerst , Mauro Carvalho Chehab , linux-media@vger.kernel.org, Hans de Goede Subject: [PATCH v2 07/12] media: mt9m114: Avoid a reset low spike during probe() Date: Sat, 31 May 2025 18:31:42 +0200 Message-ID: <20250531163148.83497-8-hansg@kernel.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250531163148.83497-1-hansg@kernel.org> References: <20250531163148.83497-1-hansg@kernel.org> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 mt9m114_probe() requests the reset GPIO in output low state: sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); and then almost immediately afterwards calls mt9m114_power_on() which does: gpiod_set_value(sensor->reset, 1); fsleep(duration); gpiod_set_value(sensor->reset, 0); which means that if the reset pin was high before this code runs that it will very briefly be driven low because of passing GPIOD_OUT_LOW when requesting the GPIO only to be driven high again possibly directly after that. Such a very brief driving low of the reset pin may put the chip in a confused state. Request the GPIO in high (reset the chip) state instead to avoid this, turning the initial gpiod_set_value() in mt9m114_power_on() into a no-op. and the fsleep() ensures that it will stay high long enough to properly reset the chip. Reviewed-by: Laurent Pinchart Signed-off-by: Hans de Goede --- drivers/media/i2c/mt9m114.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c index 371e96d9e281..fe30b9ff84ad 100644 --- a/drivers/media/i2c/mt9m114.c +++ b/drivers/media/i2c/mt9m114.c @@ -2439,7 +2439,7 @@ static int mt9m114_probe(struct i2c_client *client) } } - sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + sensor->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(sensor->reset)) { ret = PTR_ERR(sensor->reset); dev_err_probe(dev, ret, "Failed to get reset GPIO\n");