From patchwork Thu Feb 20 13:01:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 207263 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FD75C11D04 for ; Thu, 20 Feb 2020 13:02:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2DD7B24670 for ; Thu, 20 Feb 2020 13:02:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727943AbgBTNCF (ORCPT ); Thu, 20 Feb 2020 08:02:05 -0500 Received: from michel.telenet-ops.be ([195.130.137.88]:34982 "EHLO michel.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726959AbgBTNCA (ORCPT ); Thu, 20 Feb 2020 08:02:00 -0500 Received: from ramsan ([84.195.182.253]) by michel.telenet-ops.be with bizsmtp id 511u220025USYZQ0611udK; Thu, 20 Feb 2020 14:01:58 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1j4lSj-000567-W6; Thu, 20 Feb 2020 14:01:53 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1j4lSj-0007Lt-Ug; Thu, 20 Feb 2020 14:01:53 +0100 From: Geert Uytterhoeven To: Linus Walleij , Bartosz Golaszewski , Pantelis Antoniou , Frank Rowand , Rob Herring , Mark Rutland Cc: Peter Ujfalusi , Chris Brandt , linux-gpio@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 2/2] gpio: of: Add DT overlay support for GPIO hogs Date: Thu, 20 Feb 2020 14:01:49 +0100 Message-Id: <20200220130149.26283-3-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200220130149.26283-1-geert+renesas@glider.be> References: <20200220130149.26283-1-geert+renesas@glider.be> Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org As GPIO hogs are configured at GPIO controller initialization time, adding/removing GPIO hogs in DT overlays does not work. Add support for GPIO hogs described in DT overlays by registering an OF reconfiguration notifier, to handle the addition and removal of GPIO hog subnodes to/from a GPIO controller device node. Note that when a GPIO hog device node is being removed, its "gpios" properties is no longer available, so we have to keep track of which node a hog belongs to, which is done by adding a pointer to the hog's device node to struct gpio_desc. Signed-off-by: Geert Uytterhoeven --- v2: - Drop RFC state, - Document that modifying existing gpio-hog nodes is not supported. --- drivers/gpio/gpiolib-of.c | 90 +++++++++++++++++++++++++++++++++++++++ drivers/gpio/gpiolib-of.h | 2 + drivers/gpio/gpiolib.c | 14 ++++-- drivers/gpio/gpiolib.h | 3 ++ 4 files changed, 106 insertions(+), 3 deletions(-) diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index 2b47f93886075294..ccc449df3792ae97 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -628,6 +628,10 @@ static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog) ret = gpiod_hog(desc, name, lflags, dflags); if (ret < 0) return ret; + +#ifdef CONFIG_OF_DYNAMIC + desc->hog = hog; +#endif } return 0; @@ -655,11 +659,97 @@ static int of_gpiochip_scan_gpios(struct gpio_chip *chip) of_node_put(np); return ret; } + + of_node_set_flag(np, OF_POPULATED); } return 0; } +#ifdef CONFIG_OF_DYNAMIC +/** + * of_gpiochip_remove_hog - Remove all hogs in a hog device node + * @chip: gpio chip to act on + * @hog: device node describing the hogs + */ +static void of_gpiochip_remove_hog(struct gpio_chip *chip, + struct device_node *hog) +{ + struct gpio_desc *descs = chip->gpiodev->descs; + unsigned int i; + + for (i = 0; i < chip->ngpio; i++) { + if (test_bit(FLAG_IS_HOGGED, &descs[i].flags) && + descs[i].hog == hog) + gpiochip_free_own_desc(&descs[i]); + } +} + +static int of_gpiochip_match_node(struct gpio_chip *chip, void *data) +{ + return chip->gpiodev->dev.of_node == data; +} + +static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np) +{ + return gpiochip_find(np, of_gpiochip_match_node); +} + +static int of_gpio_notify(struct notifier_block *nb, unsigned long action, + void *arg) +{ + struct of_reconfig_data *rd = arg; + struct gpio_chip *chip; + int ret; + + /* + * This only supports adding and removing complete gpio-hog nodes. + * Modifying an existing gpio-hog node is not supported (except for + * changing its "status" property, which is treated the same as + * addition/removal). + */ + switch (of_reconfig_get_state_change(action, arg)) { + case OF_RECONFIG_CHANGE_ADD: + if (!of_property_read_bool(rd->dn, "gpio-hog")) + return NOTIFY_OK; /* not for us */ + + if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) + return NOTIFY_OK; + + chip = of_find_gpiochip_by_node(rd->dn->parent); + if (chip == NULL) + return NOTIFY_OK; /* not for us */ + + ret = of_gpiochip_add_hog(chip, rd->dn); + if (ret < 0) { + pr_err("%s: failed to add hogs for %pOF\n", __func__, + rd->dn); + of_node_clear_flag(rd->dn, OF_POPULATED); + return notifier_from_errno(ret); + } + break; + + case OF_RECONFIG_CHANGE_REMOVE: + if (!of_node_check_flag(rd->dn, OF_POPULATED)) + return NOTIFY_OK; /* already depopulated */ + + chip = of_find_gpiochip_by_node(rd->dn->parent); + if (chip == NULL) + return NOTIFY_OK; /* not for us */ + + of_gpiochip_remove_hog(chip, rd->dn); + of_node_clear_flag(rd->dn, OF_POPULATED); + break; + } + + return NOTIFY_OK; +} + +struct notifier_block gpio_of_notifier = { + .notifier_call = of_gpio_notify, +}; +#endif /* CONFIG_OF_DYNAMIC */ + /** * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags * @gc: pointer to the gpio_chip structure diff --git a/drivers/gpio/gpiolib-of.h b/drivers/gpio/gpiolib-of.h index 9768831b1fe2f25b..ed26664f153782fc 100644 --- a/drivers/gpio/gpiolib-of.h +++ b/drivers/gpio/gpiolib-of.h @@ -35,4 +35,6 @@ static inline bool of_gpio_need_valid_mask(const struct gpio_chip *gc) } #endif /* CONFIG_OF_GPIO */ +extern struct notifier_block gpio_of_notifier; + #endif /* GPIOLIB_OF_H */ diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 56de871060ea211e..6f312220fe80acaf 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2925,6 +2925,9 @@ static bool gpiod_free_commit(struct gpio_desc *desc) clear_bit(FLAG_PULL_DOWN, &desc->flags); clear_bit(FLAG_BIAS_DISABLE, &desc->flags); clear_bit(FLAG_IS_HOGGED, &desc->flags); +#ifdef CONFIG_OF_DYNAMIC + desc->hog = NULL; +#endif ret = true; } @@ -5126,10 +5129,15 @@ static int __init gpiolib_dev_init(void) if (ret < 0) { pr_err("gpiolib: failed to allocate char dev region\n"); bus_unregister(&gpio_bus_type); - } else { - gpiolib_initialized = true; - gpiochip_setup_devs(); + return ret; } + + gpiolib_initialized = true; + gpiochip_setup_devs(); + + if (IS_ENABLED(CONFIG_OF_DYNAMIC)) + WARN_ON(of_reconfig_notifier_register(&gpio_of_notifier)); + return ret; } core_initcall(gpiolib_dev_init); diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index 3e0aab2945d82974..18c75e83fd7679ec 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -119,6 +119,9 @@ struct gpio_desc { const char *label; /* Name of the GPIO */ const char *name; +#ifdef CONFIG_OF_DYNAMIC + struct device_node *hog; +#endif }; int gpiod_request(struct gpio_desc *desc, const char *label);