From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from fgw21-7.mail.saunalahti.fi (fgw21-7.mail.saunalahti.fi [62.142.5.82]) (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 C8190155A25 for ; Wed, 3 Apr 2024 20:21:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.142.5.82 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712175699; cv=none; b=HaQXhJJX3IyrD2USomm0bkmo5XuwWNGVCgyjOArFfVhr6og0DkTyyvZmHMQU6AaSOFq1snoc/OPFgVdTwpWz6o+JtHWanH+0/eJi8UZthpCPZQRs2n67lsS/HxGhCj4hjNux8leSSREtmNeP0O0NvDKnrGk0ZGAwoZAGBzrN38Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712175699; c=relaxed/simple; bh=6ik5zYeoSy13e/6i/ggDabkweeldqQoJRkzAijEiRh8=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KpkCMV7bUqxwByZC0dY/WzsIW4PubwnrW3zujiW3LsQrKSPvsdtkcThlm1hZlZ/35dtZgikZ6gW/kTXNqvCnWSHsTvICjKXJvZ+AsN2EkVoU7rCgg/OV8HHQQf+///ZmBfJlfDD85maraF6js/jAIjFJMZya1iQP7D2clgjJPos= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com; spf=fail smtp.mailfrom=gmail.com; arc=none smtp.client-ip=62.142.5.82 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=gmail.com Received: from localhost (88-113-26-217.elisa-laajakaista.fi [88.113.26.217]) by fgw21.mail.saunalahti.fi (Halon) with ESMTP id c0efb0c7-f1f7-11ee-abf4-005056bdd08f; Wed, 03 Apr 2024 23:21:29 +0300 (EEST) From: Andy Shevchenko Date: Wed, 3 Apr 2024 23:21:28 +0300 To: Charles Keepax Cc: broonie@kernel.org, linus.walleij@linaro.org, brgl@bgdev.pl, linux-gpio@vger.kernel.org, linux-spi@vger.kernel.org, patches@opensource.cirrus.com Subject: Re: [PATCH v3 1/3] gpio: swnode: Add ability to specify native chip selects for SPI Message-ID: References: <20240329114730.360313-1-ckeepax@opensource.cirrus.com> <20240329114730.360313-2-ckeepax@opensource.cirrus.com> Precedence: bulk X-Mailing-List: linux-gpio@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: <20240329114730.360313-2-ckeepax@opensource.cirrus.com> Fri, Mar 29, 2024 at 11:47:28AM +0000, Charles Keepax kirjoitti: > SPI devices can specify a cs-gpios property to enumerate their > chip selects. Under device tree, a zero entry in this property can > be used to specify that a particular chip select is using the SPI > controllers native chip select, for example: > > cs-gpios = <&gpio1 0 0>, <0>; > > Here the second chip select is native. However, when using swnodes > there is currently no way to specify a native chip select. The > proposal here is to register a swnode_gpio_undefined software node, > that can be specified to allow the indication of a native chip > select. For example: > > static const struct software_node_ref_args device_cs_refs[] = { > { > .node = &device_gpiochip_swnode, > .nargs = 2, > .args = { 0, GPIO_ACTIVE_LOW }, > }, > { > .node = &swnode_gpio_undefined, > .nargs = 0, > }, > }; > > Register the swnode as the gpiolib is initialised and > check in swnode_get_gpio_device if the returned node matches > swnode_gpio_undefined and return -ENOENT, which matches the behaviour > of the device tree system when it encounters a 0 phandle. ... > +const struct software_node swnode_gpio_undefined = { > + .name = "gpio-internal-undefined", This name is still too generic, perhaps "software-node-undefined-gpio"? > +}; > +EXPORT_SYMBOL_GPL(swnode_gpio_undefined); Maybe we can start using namespaces? ... > + if (!strcmp(gdev_node->name, "gpio-internal-undefined")) Probably it needs a definition to avoid typos in case somebody wants to change the name. #define GPIOLIB_SWNODE_UNDEFINED "..." ? > + return ERR_PTR(-ENOENT); ... > static int __init gpiolib_debugfs_init(void) > { > + int ret; > + > + ret = software_node_register(&swnode_gpio_undefined); > + if (ret < 0) { > + pr_err("gpiolib: failed to register swnode: %d\n", ret); > + return ret; > + } > + > /* /sys/kernel/debug/gpio */ > debugfs_create_file("gpio", 0444, NULL, NULL, &gpiolib_fops); > + > return 0; > } > subsys_initcall(gpiolib_debugfs_init); I believe now it's time to get __exitcall to be implemented. Actually the above already needs that. Besides that, what you are adding doesn't belong to debugfs AFAICS. And why it can't be done in gpiolib-swnode.c? -- With Best Regards, Andy Shevchenko