From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) (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 810BB3655F1 for ; Mon, 29 Jun 2026 06:19:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.13 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782713996; cv=none; b=m66nt0yNDJqaEnac94v6ef/UtK5Rm5godqpaYjUtv5nUAKcFoAe2+XBu/L6EHt0Mfwy5Ux5jP0sTe4nAUwN9/Z3kdzRxiuAyebrmIGIJCHgHBn8hHiF2OFRVldhwOuW1ypR6ANl7m6AdhecMCTDEirxUU88nXh4HKh8aMGWlUuM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782713996; c=relaxed/simple; bh=M+CVXNbFxnYVUHiLO8p1f8U/Oa8yWKHeFEwwNFbVCw8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YvXQsxmwCfOMkAx6U5Z9ibc7BlnQrLlFSHfQoVzjnqgn/268AgdDsTMRMKs76VxGkIus98PwhwJYrIArIlFvyhaDwHH6BcWLotK6xn5deT3BjpIKGISlsV4aANeznMGg44Itdfm1QQj4veCUBAXWhiKrjQT2VyDzcvoayZHmNwE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=WoKj80MP; arc=none smtp.client-ip=198.175.65.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="WoKj80MP" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1782713995; x=1814249995; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=M+CVXNbFxnYVUHiLO8p1f8U/Oa8yWKHeFEwwNFbVCw8=; b=WoKj80MPsCjuynuPYxwQfWg1HcpFMk+/4dryM/rOBrxPr3jNsIRzoLav JCxR/ZTc1PnX4R3nEBLH72Y+nH8i/ZxT0hsYTMGxzxUbml0nhD56T5ILf V1TYp8/uQW9x7IV+Bdd+m1+EzvCgGOxvvAl0R1GQE58W0Bl7H7Yv1Ot7J oOJeZe5lAQcBzEBObcvY4DFHwWQDPiVJSmhZVRK7BbRIFniHEDqHjlDtV P7ewzLVr2KwddTX7Q27yzOxgDV5a16IpmptJBFQVxTr7D0WIBXpkfKlBO /JVIQC+aqTVyTDE/gJArkYOAjj02SJR/FTfAIjyn/jUDDl/YCHGUzCuV6 A==; X-CSE-ConnectionGUID: LiI8idgnQ/OQyWwkQdb44Q== X-CSE-MsgGUID: uy+u7rWNS2O7EUebPKs5hg== X-IronPort-AV: E=McAfee;i="6800,10657,11831"; a="94544383" X-IronPort-AV: E=Sophos;i="6.24,231,1774335600"; d="scan'208";a="94544383" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2026 23:19:55 -0700 X-CSE-ConnectionGUID: WCXRpK0OR/W1yR4qCMVJog== X-CSE-MsgGUID: JolV0ZvlTbKLpzL6HNcWGg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.24,231,1774335600"; d="scan'208";a="256271508" Received: from kniemiec-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.244.207]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jun 2026 23:19:50 -0700 Date: Mon, 29 Jun 2026 09:19:48 +0300 From: Andy Shevchenko To: Amit Barzilai Cc: airlied@gmail.com, andy@kernel.org, azuddinadam@gmail.com, chintanlike@gmail.com, conor+dt@kernel.org, deller@gmx.de, devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, gregkh@linuxfoundation.org, javierm@redhat.com, krzk+dt@kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-staging@lists.linux.dev, maarten.lankhorst@linux.intel.com, mripard@kernel.org, robh@kernel.org, simona@ffwll.ch, tzimmermann@suse.de Subject: Re: [PATCH v2 3/4] drm/ssd130x: Add SSD135X_FAMILY and SSD1351 support Message-ID: References: <20260628154312.46185-1-amit.barzilai22@gmail.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260628154312.46185-1-amit.barzilai22@gmail.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo On Sun, Jun 28, 2026 at 06:43:12PM +0300, Amit Barzilai wrote: > On Tue, 23 Jun 2026 12:37:31 +0300, Andy Shevchenko wrote: ... > >> + const u8 cmds[] = { > > > > Why not static? > > This array can't be made static. It is initialised with runtime values > (ssd130x->width - 1 and ssd130x->height - 1), so it is not a compile-time > constant and a static/file-scope definition wouldn't compile. > The other ssd13xx_init() functions are non-static for exactly the same > reason. Ah, I see. Thanks for pointing out. > >> + 4, SSD135X_SET_CONTRAST, 0xc8, 0x80, 0xc8, > >> + 2, SSD135X_SET_CONTRAST_MASTER, 0x0f, > >> + 2, SSD135X_SET_PRECHARGE2, 0x01, > >> + 1, SSD135X_SET_DISPLAY_NORMAL, > >> + 2, SSD13XX_SET_SEG_REMAP, remap, > > > >> + 0, > > > > No trailing comma for the terminator entry. > > Removing it in v3. The other init arrays in drm-misc-next still carry the > terminator comma, but that's pre-existing code outside this series -- I've left > it alone to avoid unrelated churn. Happy to send a separate cleanup if you'd > prefer. You can issue a separate cleanup patch for those. > >> + }; ... > >> + /* > >> + * ssd130x_power_on() issues a short reset pulse, but the SSD1351 is not > >> + * ready to accept commands immediately afterwards. Give the controller > >> + * time to settle before sending the init sequence. > >> + */ > > > > Any reference to the datasheet? > > It's not a datasheet figure. fb_ssd1351 doesn't do it in init_display() either; > it inherits it from the shared fbtft_reset() helper, which deasserts reset and > then does msleep(120) before any command is sent. The 120 ms is a generic fbtft > blanket value, not an SSD1351 number -- the SSD1351 datasheet's reset timing is > microsecond-scale. > > I removed the msleep() and retested this on the hardware. The panel still > initialises reliably. > I'll drop the msleep() in v3. Yeah, I truly believe that this long delay is for the parallel type of IO, where data and control signals are usually connected to a quite low speed GPIOs. But I suggest to leave some comment in the code. -- With Best Regards, Andy Shevchenko