From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: [PATCH v2 3/6] pinctrl: Add a possibility to configure pins from a gpiolib based drivers Date: Fri, 13 Jan 2017 16:36:42 +0100 Message-ID: References: <20170110143201.53539-1-mika.westerberg@linux.intel.com> <20170110143201.53539-4-mika.westerberg@linux.intel.com> <20170111133304.GQ2330@lahna.fi.intel.com> <20170112092255.GX2330@lahna.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <20170112092255.GX2330@lahna.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Mika Westerberg Cc: Heikki Krogerus , "David E . Box" , Andy Shevchenko , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" List-Id: linux-gpio@vger.kernel.org On Thu, Jan 12, 2017 at 10:22 AM, Mika Westerberg wrote: > Hmm, looking at users of .set_debounce() I can see that the debounce > time can be quite large. For example some signals which are connected to > physical push-buttons may need > 64ms debounce time. > > However, the current pinconfig value is defined to be unsigned long > which on 32-bit architecture is 32-bits. From that the higher 16-bits > are used as config leaving the value to be 16-bits. This gives maximum > debounce time of 65535us. I don't think it can cover all the uses of > .set_debounce(). This could also be problematic when specifying values > for pull resistors. > > One solution is to convert the packed value to be u64 instead, leaving > up to 48-bits for the value. Alternatively we could provide a scale > field with the packed format. Hm yeah as long as all in-kernel users survive I don't see why we couldn't just make it 64bit. Is it a big deal? A scale field (multiplier) can also work, I don't know which is most elegant. Yours, Linus Walleij