From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (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 6E215288B1; Mon, 3 Feb 2025 09:23:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738574600; cv=none; b=sy4jLejYR1FK9dSBkytGARtj8Jkdc+l7OaOp7XmSwP3PIxFYA0cRjXssXdT9lEpN6iiOHgYI0RAzX/3rR4cUGWtQ/hy99+K9Aj56pXWJ4M50SpBNK3zCOe/KChc/DNjs+VUnChsIJi2pQ18fl7gIoJf3qPcUMNhABgKBPvCsXA0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738574600; c=relaxed/simple; bh=VbFDT5cjrVHHigACBdyZriVMCPiqVugmKlgYJpkK1oY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WN5nuo2/yU7lcEcFBWdJiAJhEwAVIIj9JlVHXLnRedLj0Cf9A/wTqfOWgRPObpVzIPO/b374qi/6gooOd3pROxl5issNctHnlAMOBAAWLEVii5YJIGwMP3aKWO9kFBS4I1LjWcZETFmGLYtXFKhvsGhkCHWEhi06LWsPTpKoz5U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=C2+ljKe0; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="C2+ljKe0" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1738574599; x=1770110599; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=VbFDT5cjrVHHigACBdyZriVMCPiqVugmKlgYJpkK1oY=; b=C2+ljKe0dwlck0yytXn8XKas3E4t8ZS5PVKukDGp2dkPUn4vhyThdIvU M8YCd61DpyAoJHQsV5AJK6P27a74R5Qv6Sbz9U16gKkodpx1HFMb48AKU 4u5Fn/gBuOIHtlT7VV+ayJrfUoZB0CcGUU0ze1MxKxGCoGeo26YQ06gQX OIToHuyCsSKrz38DFX26aFiypyPM07R9gwE6Gh79YDYR8dG7ahejlgsak xed66hzNynrAPMz07GQVDl1U7Tbt1kIn3PHn9U8dq9ZFI6eWlLpVqY/dP os+84bV7Ng20rcX2t4R84jXOLCC3N5CxdMoQ6o2urHWN7T2l8jfoz1dPg A==; X-CSE-ConnectionGUID: o44FPI0KSU68Es3tHDcOLw== X-CSE-MsgGUID: /7IfYiXoQK+qC771vjkIxQ== X-IronPort-AV: E=McAfee;i="6700,10204,11334"; a="42715525" X-IronPort-AV: E=Sophos;i="6.13,255,1732608000"; d="scan'208";a="42715525" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2025 01:23:19 -0800 X-CSE-ConnectionGUID: m0M9MAp9R8OwBWrMZDL5xQ== X-CSE-MsgGUID: OLzlCXTAQ+uSHd8kFDcFBQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,199,1725346800"; d="scan'208";a="115209673" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by ORVIESA003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Feb 2025 01:23:17 -0800 Received: from kekkonen.localdomain (localhost [127.0.0.1]) by kekkonen.fi.intel.com (Postfix) with SMTP id D417311F9C3; Mon, 3 Feb 2025 11:23:14 +0200 (EET) Date: Mon, 3 Feb 2025 09:23:14 +0000 Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo From: Sakari Ailus To: Tomi Valkeinen Cc: Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Devarsh Thakkar , Jai Luthra Subject: Re: [PATCH 07/19] media: i2c: ds90ub953: Speed-up I2C watchdog timer Message-ID: References: <20250110-ub9xx-improvements-v1-0-e0b9a1f644da@ideasonboard.com> <20250110-ub9xx-improvements-v1-7-e0b9a1f644da@ideasonboard.com> <7e034745-831a-4518-8c4e-003fa7773a57@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7e034745-831a-4518-8c4e-003fa7773a57@ideasonboard.com> Moi, On Fri, Jan 24, 2025 at 03:19:32PM +0200, Tomi Valkeinen wrote: > Hi, > > On 15/01/2025 16:17, Sakari Ailus wrote: > > Moi, > > > > On Fri, Jan 10, 2025 at 11:14:07AM +0200, Tomi Valkeinen wrote: > > > From: Jai Luthra > > > > > > On the I2C bus for remote clients (sensors), by default the watchdog > > > timer expires in 1s. To allow for a quicker system bring-up time, TI > > > recommends to speed it up to 50us [1]. > > > > > > [1]: Section 7.3.1.1 - https://www.ti.com/lit/gpn/ds90ub953-q1 > > > > > > Signed-off-by: Jai Luthra > > > Signed-off-by: Tomi Valkeinen > > > --- > > > drivers/media/i2c/ds90ub953.c | 11 +++++++++++ > > > 1 file changed, 11 insertions(+) > > > > > > diff --git a/drivers/media/i2c/ds90ub953.c b/drivers/media/i2c/ds90ub953.c > > > index 99a4852b9381..6c36980e8beb 100644 > > > --- a/drivers/media/i2c/ds90ub953.c > > > +++ b/drivers/media/i2c/ds90ub953.c > > > @@ -54,6 +54,10 @@ > > > #define UB953_REG_CLKOUT_CTRL0 0x06 > > > #define UB953_REG_CLKOUT_CTRL1 0x07 > > > +#define UB953_REG_I2C_CONTROL2 0x0a > > > +#define UB953_REG_I2C_CONTROL2_SDA_OUTPUT_SETUP_SHIFT 4 > > > +#define UB953_REG_I2C_CONTROL2_BUS_SPEEDUP BIT(1) > > > + > > > #define UB953_REG_SCL_HIGH_TIME 0x0b > > > #define UB953_REG_SCL_LOW_TIME 0x0c > > > @@ -1320,6 +1324,13 @@ static int ub953_hw_init(struct ub953_data *priv) > > > if (ret) > > > return ret; > > > + v = 0; > > > + v |= 1 << UB953_REG_I2C_CONTROL2_SDA_OUTPUT_SETUP_SHIFT; > > > > BIT()? Or at least 1U <<< ...;. > > It's a three-bit field, the value just happens to be 1. What's wrong with 1 > << SHIFT? Shifting a signed value leads to the sign bit being undefined on some architectures. > > > > > > + v |= UB953_REG_I2C_CONTROL2_BUS_SPEEDUP; > > > + ret = ub953_write(priv, UB953_REG_I2C_CONTROL2, v, NULL); > > > > I'd just do this without a temporary variable. If you prefer to keep it, do > > assign the first calculated value there first and remove the assignment to > > zero. > > I think we can do without. > > > > + if (ret) > > > + return ret; > > > > No need for this. > > No, but it keeps the code structure consistent and allows easy future/debug > modifications. Please still remove such redundancies. -- Terveisin, Sakari Ailus