From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 433812ECE91; Thu, 25 Jun 2026 13:17:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782393446; cv=none; b=YgXCWGW/lCCfAlH3nDRVANtHwnjXlZP7kru9e63FnDcU9gNgGdtGSIxZCPMb9QOSSPpA5loHd7myP5m8AxF6CcfnMH20hzcvVWChTiu9QdB66/sevRbjuhq8jfC7d95j+25TFuQh48oh6y5hQN66VwBdUeQ0e/Ggu1v1OWXAaaU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782393446; c=relaxed/simple; bh=6IbPOgmZcSBeju3AwDGP+i6TxpBta5JSXveLLDf7fbU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Ih/XdzAln9Wb1n5+vSn/wfQk46fCQ/lCmX0NLUQWvhKUZv8wmh6LiGAepeKAWSgrIpK9j7V9sWZRxNTOVkV8Q831gI+AiZLcmkFCWJuevWG9AxG8F31Ih2URH4NwcIqtxvLTwCXPu8QEhO6IZ8kGm8H7S4lu/ZLGeM1fCMQjTSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bSZphNHu; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bSZphNHu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE0E21F000E9; Thu, 25 Jun 2026 13:17:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782393445; bh=tLDWZHBxAvhJmAdKRVfoGt+VPmVdp958Xi2NsJAjS08=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=bSZphNHuhd8Q2O13lRLvPwzZhliGnMH3ZZimPP8Jl8gy+SF9+IlrUySwnYBy55ZAE 5TcZQj1g5vKIefcbodbl0zCUhfI0VKOCW83qu3tc/fa/Qz3aM5XbjqAIaVBju2WSRr C7FLetrbUqGiZ1jFZr5CD9+eBGuiHNoR/TjTKK3GzvHBt6JSMAIaEEoAFUC/QK+WXW +jEfV6X/py980J1HIHoRwhTccXfPuJXk4cE0hbutG7Z3pJvml9ThiOzHsNxCeScOnW Ta3pd2ob2F9GmUgfaSYHMuc1zDvMoqb8Sa9AlU/6matrtjg+L5wRdX+HhAx9O8YAhe eUM33uILwCwNA== Message-ID: Date: Thu, 25 Jun 2026 15:17:13 +0200 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 v6 2/2] drm/bridge: Add Lontium LT9611C(EX/UXD) MIPI DSI to HDMI driver To: Sunyun Yang Cc: robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, andrzej.hajda@intel.com, neil.armstrong@linaro.org, dmitry.baryshkov@oss.qualcomm.com, maarten.lankhorst@linux.intel.com, rfoss@kernel.org, mripard@kernel.org, Laurent.pinchart@ideasonboard.com, tzimmermann@suse.de, jonas@kwiboo.se, jernej.skrabec@gmail.com, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, xmzhu@lontium.corp-partner.google.com, xmzhu@lontium.com, rlyu@lontium.com, xbpeng@lontium.com References: <20260508134009.4582-1-syyang@lontium.com> <20260508134009.4582-3-syyang@lontium.com> <3188f63f-5358-48d7-b934-af20a8f95c6f@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 25/06/2026 15:14, Sunyun Yang wrote: > Krzysztof Kozlowski 于2026年6月25日周四 20:54写道： >> >> On 08/05/2026 15:40, syyang@lontium.com wrote: >>> + >>> +static void lt9611c_reset(struct lt9611c *lt9611c) >>> +{ >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); >>> + msleep(20); >>> + >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 0); >>> + msleep(20); >>> + >>> + gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); >> >> This is just plain wrong. Why do you assert, then de-assert and then >> finally assert AGAIN the reset leaving the device in powerdown stage? >> > I am using software to emulate the hardware RESET button on our EVB. > When the hardware RESET button is pressed while our chip is running, > the signal level changes from HIGH to LOW and then back to HIGH. > > Of course, we can also use the following: > static void lt9611c_reset(struct lt9611c *lt9611c) > { > gpiod_set_value_cansleep(lt9611c->reset_gpio, 0); > msleep(50); > gpiod_set_value_cansleep(lt9611c->reset_gpio, 1); > msleep(20); > } Makes no sense either and you just did not get the point and did not answer my question. I asked WHY you leave asserted. Answer "we emulate" is just plain wrong. So again please answer: Why do you leave device with reset asserted? Best regards, Krzysztof