From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20D6EBD; Thu, 14 Dec 2023 06:49:45 -0800 (PST) X-IronPort-AV: E=McAfee;i="6600,9927,10924"; a="2213382" X-IronPort-AV: E=Sophos;i="6.04,275,1695711600"; d="scan'208";a="2213382" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2023 06:49:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10924"; a="767629176" X-IronPort-AV: E=Sophos;i="6.04,275,1695711600"; d="scan'208";a="767629176" Received: from smile.fi.intel.com ([10.237.72.54]) by orsmga007.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Dec 2023 06:49:31 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.97) (envelope-from ) id 1rDn1j-00000005s2k-2Jqg; Thu, 14 Dec 2023 16:49:27 +0200 Date: Thu, 14 Dec 2023 16:49:27 +0200 From: Andy Shevchenko To: Michael Walle Cc: =?utf-8?B?VFlfQ2hhbmdb5by15a2Q6YC4XQ==?= , Linus Walleij , Bartosz Golaszewski , Rob Herring , Krzysztof Kozlowski , Conor Dooley , linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/2] Add GPIO support for Realtek DHC(Digital Home Center) RTD SoCs. Message-ID: References: <20231207100723.15015-1-tychang@realtek.com> <20231207100723.15015-3-tychang@realtek.com> <989146448858478b975c66899b8f3fed@realtek.com> <23574204547646779d02f0109c20b3ff@realtek.com> <0f0b3b65a838aea6797ae78c47d6af49@walle.cc> Precedence: bulk X-Mailing-List: devicetree@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: <0f0b3b65a838aea6797ae78c47d6af49@walle.cc> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Thu, Dec 14, 2023 at 03:35:18PM +0100, Michael Walle wrote: > > > >> >> This driver enables configuration of GPIO direction, GPIO values, > > > >> >> GPIO debounce settings and handles GPIO interrupts. > > > >> > > > > >> >Why gpio-regmap can't be used? > > > >> > > > >> I will try to use gpio-remap in the next version. > > > > > > > >If it appears that it makes code uglier / complicated, please add the note > > > >somewhere to answer the above question. > > > > > > I've traced the gpio-regmap.c file. It appears that for the driver > > > to register > > > gpio_irq_chip, it must create the irq_domain and add it into > > > gpio_regmap_config. > > > Additionally, the driver needs to register the irq handler by itself. > > > However, this process can be managed by the gpiolib if the driver > > > fills in the struct > > > gpio_irq_chip inside struct gpio_chip before invoking > > > gpiochip_add_data. > > > > Hmm... I thought this is solvable issue. > > Michael, is there a limitation in GPIO regmap that this driver can't be > > converted? > > gpio-regmap is designed that regmap-irq (drivers/base/regmap/irq.c) can be > used. So, if regmap-irq fit this driver, then it can be used together with > gpio-regmap. > > From a quick glance at the patch, it looks like the gpio portion might fit > gpio-regmap. > > > > Moreover, apart from managing the registers for gpio direction and > > > value, there > > > are several other registers that require access(interrupt enable, > > > debounce...). > > > The GPIO IRQ status registers are located at different base > > > addresses and are > > > not contiguous. It may need to create an additional regmap and > > > assign the access > > > table to this regmap. > > > > AFAIK this is not a problem as you can provide your own xlate function > > that > > will take care about register mapping. > > Just for the gpio part. IIRC regmap has it own translation (regmap fields). > > > > With the above consideration, I tend to keep using the existing > > > method. > > > > I would like to hear from Michael if it's indeed a big obstacle. > > So, regarding the irq portion, again, it must fit the regmap-irq. For the > additional requirement to set the debounce, you can add a .set_config to > gpio_regmap_config and supply your own set_config callback. See also [1]. Thank you, Michael, for the prompt answer. It's insightful to me, I will try to remember these aspects for the future reviews. > [1] > https://lore.kernel.org/linux-gpio/d4a6a640c373b6d939e147691efa596c@walle.cc/ -- With Best Regards, Andy Shevchenko