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 A0AD625B0B2; Thu, 25 Jun 2026 13:51:08 +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=1782395469; cv=none; b=QSHAj/5nxFIypqKcDdzLXDLOMw5M6KHYEGREka+W9xRBs/MT2CUEC4IrvxulSQQCCVe4VMRgKAvOYHzhFoCLEW51+XPu0JfuDQRsJ26uSqJ2IwGcMAz0iB+2ZLBOvpeVEUtltYQuPDBEExyasr/iBbT1WEoX/ze9M23Wr/02SbM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782395469; c=relaxed/simple; bh=njBTN4Cztk6q/NHx4oY93q8YuA081cP2rs6ToF7LFnI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=KGd92DfLk46H5BzAggNzWfkOCnFSKdFcD5BchF/VJ+Xj8u8nscLL42yjdy5wbE+NpGbbBMkd3i+TTT3Sx/XlzHzvfhICz11zUUpMXrGUtN6H83b/dQ4egzVVxo1K3+LgAfPEG4gaEObNAq3/vnPuYHi/Gb1bbwN3BqlcV95gliI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cz2Gtm/7; 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="cz2Gtm/7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27C611F000E9; Thu, 25 Jun 2026 13:51:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782395468; bh=jWToBIL5m9uigLFzc/+YrKGhjYbdNomJ4Aeysudoj8w=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=cz2Gtm/7Gtfa3gQQG5eAs7V0aCLDlfTgiizaeiV6lc7SNfU1paxAHWsvo0f64KGjB a+18yaTOHhe+NWi+dlWVhWM4Zzszu7buMlxKQm13zndbPyr5Td9lSkt6sPTAEDFRHr h/fEgFEz4v9bddePfQX6gwcl7HMhgb6GBimITlABB4DtSse9JqmevXDGqijGBG1s4A vPb92krGwLzWd7YRIobFHlcPtdY1xLTFp6kJ2tRs4MteKIcAWEVT35YguHafWx8Mxj +QcXx6QpyAKPL0S3nJ9gLW0UXnJP07pq6cbu+eCF7zrUzGOnlNFxOjfOEeKkVp+nxD mDQt77h4yz+gg== Message-ID: <8a14ed89-fe48-4d57-8f46-800d228eb9ed@kernel.org> Date: Thu, 25 Jun 2026 15:50:58 +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 15:26, Sunyun Yang wrote: > Krzysztof Kozlowski 于2026年6月25日周四 21:17写道： >> >> 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? >> > > devicetree: reset-gpios = <&tlmm 128 GPIO_ACTIVE_HIGH>; That's irrelevant. I do not talk about DT. Review is happening in specific place - here I question driver code. If you do not have actual arguments why device is left in reset stage, then please fix it. Best regards, Krzysztof