From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=walle.cc header.i=@walle.cc header.b="g3Lza4ep" Received: from mail.3ffe.de (0001.3ffe.de [IPv6:2a01:4f8:c0c:9d57::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78675115; Thu, 14 Dec 2023 06:35:20 -0800 (PST) Received: from 3ffe.de (0001.3ffe.de [IPv6:2a01:4f8:c0c:9d57::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.3ffe.de (Postfix) with ESMTPSA id 711003AF; Thu, 14 Dec 2023 15:35:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2022082101; t=1702564518; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4+Xi2xa3RNrJtFpkg486v39REZonzsV1FXE9gDFjBxY=; b=g3Lza4epRiuQ2jTvpphPjZoq8XhgvlU0duoNfiNvaz+QSZo3DEjdaCOuI9dEzVsXPYvCmO Is77hlxOSz0X/ogZkX7fV3Wku80MP2Fb9ENujYzgDB/aFLmdYkpZ7AOvV7OrQvaQfinrCJ rxQK8Obe/A+poz8FWsFDpuJpOv1cqbsMZ0k9E1RN4OugyWI9az82iOxayHG/qw1P5nyIAf XEePHJTE+ZVA87rPf7iyA14xWrhdv+3WPv99sdwgwHTQZUM1Qjbgr9jMD6SfETRlhpeD/0 d6UEVSDNVHGshTwP3ayoSFWk5ehad4szdiCePvyHwldcxWYxfOyC9fJzhRTUHA== Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Thu, 14 Dec 2023 15:35:18 +0100 From: Michael Walle To: Andy Shevchenko , =?UTF-8?Q?TY=5FChang=5B=E5=BC=B5?= =?UTF-8?Q?=E5=AD=90=E9=80=B8=5D?= Cc: 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. In-Reply-To: References: <20231207100723.15015-1-tychang@realtek.com> <20231207100723.15015-3-tychang@realtek.com> <989146448858478b975c66899b8f3fed@realtek.com> <23574204547646779d02f0109c20b3ff@realtek.com> Message-ID: <0f0b3b65a838aea6797ae78c47d6af49@walle.cc> X-Sender: michael@walle.cc Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Hi, >> >> >> 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]. -michael [1] https://lore.kernel.org/linux-gpio/d4a6a640c373b6d939e147691efa596c@walle.cc/