From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9AE8521FF26; Thu, 19 Jun 2025 11:53:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750334032; cv=none; b=s+P+uH55Ibacxvjb7GtNO5Iew/h5QcYDdyKt6OOWhBYj3ZkKaieilmOUhE7g2my+wLc3K1o10pwJ5D/B8C768tfMZY34/jamT8ZJcNW/pf2hPfwf5/d+wwdUH2bQbAII7uz49lIWpo3Qj5e9Gg90uUpR3r+XCqZNMmNydoid5F4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750334032; c=relaxed/simple; bh=Tfq8NMCtMxIzB90AN2oTeQY3u4pSOFzZv4JlxXKP5Dw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NSf9Nhytq9rykCyvfgCBC5HfpXUckT+wNhN1p6gWDaG/xN43ROh+VKDxa3pRNlIe5R1PZXNKFd1Tr9r9MIYbqVMw10EbcrxCAM2jGxRuCm28JO3EPvJxuItvKknaiX86m6zvCbeuhx1YFtUTRnBhGewiPDXIwvOV4fR3zdmG5XA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TLK1SjZk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TLK1SjZk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D61C3C4CEEA; Thu, 19 Jun 2025 11:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750334032; bh=Tfq8NMCtMxIzB90AN2oTeQY3u4pSOFzZv4JlxXKP5Dw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TLK1SjZkJKtOa2GDJx0KT8zWbLM0Onmv52DVFQ4AgL5lHXTrikKxzDBx0mCXJu0EN Kikw4V92eV1H6BgfWAD0506FOAnY8rnH1rNzo65+cKAO7IxMzGgfpByWyUWKoN/oQZ a/375VH0yWoRtXkMpmxMPNo+RdAMgQClaCjI+Lt8kFC68jMuzWKaiaPhAm3LPn25eI 5Vy86Tzf6tejlWflhZQN+1rjxhvEe5apntIF1YAuOrVyqUvW7YVikRy+Q996WPIZP4 kAlTbt4BkJHrwYniPmoJu47rcDrOBqbU6tXRNpgMfWqdRT9Ggd1nwTem3wpNIbwqLL kNsKtxHhfGesA== Date: Thu, 19 Jun 2025 12:53:45 +0100 From: Lee Jones To: Ming Yu Cc: linus.walleij@linaro.org, brgl@bgdev.pl, andi.shyti@kernel.org, mkl@pengutronix.de, mailhol.vincent@wanadoo.fr, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, wim@linux-watchdog.org, linux@roeck-us.net, jdelvare@suse.com, alexandre.belloni@bootlin.com, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-watchdog@vger.kernel.org, linux-hwmon@vger.kernel.org, linux-rtc@vger.kernel.org, linux-usb@vger.kernel.org, Ming Yu Subject: Re: [PATCH v12 1/7] mfd: Add core driver for Nuvoton NCT6694 Message-ID: <20250619115345.GL587864@google.com> References: <20250604041418.1188792-1-tmyu0@nuvoton.com> <20250604041418.1188792-2-tmyu0@nuvoton.com> <20250612140041.GF381401@google.com> <20250612152313.GP381401@google.com> <20250613131133.GR381401@google.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, 13 Jun 2025, Ming Yu wrote: > Lee Jones 於 2025年6月13日 週五 下午9:11寫道： > > > > On Fri, 13 Jun 2025, Ming Yu wrote: > > > > > Lee Jones 於 2025年6月12日 週四 下午11:23寫道： > > > > > > > > On Thu, 12 Jun 2025, Ming Yu wrote: > > > > > > > > > Dear Lee, > > > > > > > > > > Thank you for reviewing, > > > > > > > > > > Lee Jones 於 2025年6月12日 週四 下午10:00寫道： > > > > > > > > > > > ... > > > > > > > +static const struct mfd_cell nct6694_devs[] = { > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 0), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 1), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 2), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 3), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 4), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 5), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 6), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 7), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 8), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 9), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 10), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 11), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 12), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 13), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 14), > > > > > > > + MFD_CELL_BASIC("nct6694-gpio", NULL, NULL, 0, 15), > > > > > > > + > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 0), > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 1), > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 2), > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 3), > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 4), > > > > > > > + MFD_CELL_BASIC("nct6694-i2c", NULL, NULL, 0, 5), > > > > > > > > > > > > Why have we gone back to this silly numbering scheme? > > > > > > > > > > > > What happened to using IDA in the child driver? > > > > > > > > > > > > > > > > In a previous version, I tried to maintain a static IDA in each > > > > > sub-driver. However, I didn’t consider the case where multiple NCT6694 > > > > > devices are bound to the same driver — in that case, the IDs are not > > > > > fixed and become unusable for my purpose. > > > > > > > > Not sure I understand. > > > > > > > > > > As far as I know, if I maintain the IDA in the sub-drivers and use > > > multiple MFD_CELL_NAME("nct6694-gpio") entries in the MFD, the first > > > NCT6694 device bound to the GPIO driver will receive IDs 0~15. > > > However, when a second NCT6694 device is connected to the system, it > > > will receive IDs 16~31. > > > Because of this behavior, I switched back to using platform_device->id. > > > > Each of the devices will probe once. > > > > The first one will be given 0, the second will be given 1, etc. > > > > Why would you give multiple IDs to a single device bound to a driver? > > > > The device exposes multiple peripherals — 16 GPIO controllers, 6 I2C > adapters, 2 CAN FD controllers, and 2 watchdog timers. Each peripheral > is independently addressable, has its own register region, and can > operate in isolation. The IDs are used to distinguish between these > instances. > For example, the GPIO driver will be probed 16 times, allocating 16 > separate gpio_chip instances to control 8 GPIO lines each. > > If another device binds to this driver, it is expected to expose > peripherals with the same structure and behavior. I still don't see why having a per-device IDA wouldn't render each probed device with its own ID. Just as you have above. -- Lee Jones [李琼斯]