[v6,4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

Message ID	20240129115216.96479-5-krzysztof.kozlowski@linaro.org (mailing list archive)
State	Not Applicable
Headers	show Received: from mail-lj1-f169.google.com (mail-lj1-f169.google.com [209.85.208.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7CBE7604D3 for <linux-arm-msm@vger.kernel.org>; Mon, 29 Jan 2024 11:52:31 +0000 (UTC) From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, Banajit Goswami <bgoswami@quicinc.com>, Bjorn Andersson <andersson@kernel.org>, Konrad Dybcio <konrad.dybcio@linaro.org>, Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, Philipp Zabel <p.zabel@pengutronix.de>, "Rafael J. Wysocki" <rafael@kernel.org>, Viresh Kumar <viresh.kumar@linaro.org>, Frank Rowand <frowand.list@gmail.com>, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org, linux-arm-msm@vger.kernel.org, linux-sound@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>, Bartosz Golaszewski <brgl@bgdev.pl>, Chris Packham <chris.packham@alliedtelesis.co.nz>, Sean Anderson <sean.anderson@seco.com> Subject: [PATCH v6 4/6] reset: Instantiate reset GPIO controller for shared reset-gpios Date: Mon, 29 Jan 2024 12:52:14 +0100 Message-Id: <20240129115216.96479-5-krzysztof.kozlowski@linaro.org> In-Reply-To: <20240129115216.96479-1-krzysztof.kozlowski@linaro.org> References: <20240129115216.96479-1-krzysztof.kozlowski@linaro.org> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	reset: gpio: ASoC: shared GPIO resets \| expand [v6,0/6] reset: gpio: ASoC: shared GPIO resets [v6,1/6] of: Add of_phandle_args_equal() helper [v6,2/6] cpufreq: do not open-code of_phandle_args_equal() [v6,3/6] reset: gpio: Add GPIO-based reset controller [v6,4/6] reset: Instantiate reset GPIO controller for shared reset-gpios [v6,5/6] ASoC: dt-bindings: qcom,wsa8840: Add reset-gpios for shared line [v6,6/6] ASoC: codecs: wsa884x: Allow sharing reset GPIO

diff --git a/drivers/reset/core.c b/drivers/reset/core.c index 4d5a78d3c085..dba74e857be6 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -5,14 +5,19 @@ * Copyright 2013 Philipp Zabel, Pengutronix */ #include <linux/atomic.h> +#include <linux/cleanup.h> #include <linux/device.h> #include <linux/err.h> #include <linux/export.h> #include <linux/kernel.h> #include <linux/kref.h> +#include <linux/gpio/driver.h> +#include <linux/gpio/machine.h> +#include <linux/idr.h> #include <linux/module.h> #include <linux/of.h> #include <linux/acpi.h> +#include <linux/platform_device.h> #include <linux/reset.h> #include <linux/reset-controller.h> #include <linux/slab.h> @@ -23,6 +28,11 @@ static LIST_HEAD(reset_controller_list); static DEFINE_MUTEX(reset_lookup_mutex); static LIST_HEAD(reset_lookup_list); +/* Protects reset_gpio_lookup_list */ +static DEFINE_MUTEX(reset_gpio_lookup_mutex); +static LIST_HEAD(reset_gpio_lookup_list); +static DEFINE_IDA(reset_gpio_ida); + /** * struct reset_control - a reset control * @rcdev: a pointer to the reset controller device @@ -63,6 +73,16 @@ struct reset_control_array { struct reset_control *rstc[] __counted_by(num_rstcs); }; +/** + * struct reset_gpio_lookup - lookup key for ad-hoc created reset-gpio devices + * @of_args: phandle to the reset controller with all the args like GPIO number + * @list: list entry for the reset_gpio_lookup_list + */ +struct reset_gpio_lookup { + struct of_phandle_args of_args; + struct list_head list; +}; + static const char *rcdev_name(struct reset_controller_dev *rcdev) { if (rcdev->dev) @@ -71,6 +91,9 @@ static const char *rcdev_name(struct reset_controller_dev *rcdev) if (rcdev->of_node) return rcdev->of_node->full_name; + if (rcdev->of_args) + return rcdev->of_args->np->full_name; + return NULL; } @@ -99,6 +122,9 @@ static int of_reset_simple_xlate(struct reset_controller_dev *rcdev, */ int reset_controller_register(struct reset_controller_dev *rcdev) { + if (rcdev->of_node && rcdev->of_args) + return -EINVAL; + if (!rcdev->of_xlate) { rcdev->of_reset_n_cells = 1; rcdev->of_xlate = of_reset_simple_xlate; @@ -813,12 +839,171 @@ static void __reset_control_put_internal(struct reset_control *rstc) kref_put(&rstc->refcnt, __reset_control_release); } +static int __reset_add_reset_gpio_lookup(int id, struct device_node *np, + unsigned int gpio, + unsigned int of_flags) +{ + const struct fwnode_handle *fwnode = of_fwnode_handle(np); + unsigned int lookup_flags; + const char *label_tmp; + + /* + * Later we map GPIO flags between OF and Linux, however not all + * constants from include/dt-bindings/gpio/gpio.h and + * include/linux/gpio/machine.h match each other. + */ + if (of_flags > GPIO_ACTIVE_LOW) { + pr_err("reset-gpio code does not support GPIO flags %u for GPIO %u\n", + of_flags, gpio); + return -EINVAL; + } + + struct gpio_device *gdev __free(gpio_device_put) = gpio_device_find_by_fwnode(fwnode); + if (!gdev) + return -EPROBE_DEFER; + + label_tmp = gpio_device_get_label(gdev); + if (!label_tmp) + return -EINVAL; + + char *label __free(kfree) = kstrdup(label_tmp, GFP_KERNEL); + if (!label) + return -ENOMEM; + + /* Size: one lookup entry plus sentinel */ + struct gpiod_lookup_table *lookup __free(kfree) = kzalloc(struct_size(lookup, table, 2), + GFP_KERNEL); + if (!lookup) + return -ENOMEM; + + lookup->dev_id = kasprintf(GFP_KERNEL, "reset-gpio.%d", id); + if (!lookup->dev_id) + return -ENOMEM; + + lookup_flags = GPIO_PERSISTENT; + lookup_flags |= of_flags & GPIO_ACTIVE_LOW; + lookup->table[0] = GPIO_LOOKUP(no_free_ptr(label), gpio, "reset", + lookup_flags); + + /* Not freed on success, because it is persisent subsystem data. */ + gpiod_add_lookup_table(no_free_ptr(lookup)); + + return 0; +} + +/* + * @args: phandle to the GPIO provider with all the args like GPIO number + */ +static int __reset_add_reset_gpio_device(const struct of_phandle_args *args) +{ + struct reset_gpio_lookup *rgpio_dev; + struct platform_device *pdev; + int id, ret; + + /* + * Currently only #gpio-cells=2 is supported with the meaning of: + * args[0]: GPIO number + * args[1]: GPIO flags + * TODO: Handle other cases. + */ + if (args->args_count != 2) + return -ENOENT; + + /* + * Registering reset-gpio device might cause immediate + * bind, resulting in its probe() registering new reset controller thus + * taking reset_list_mutex lock via reset_controller_register(). + */ + lockdep_assert_not_held(&reset_list_mutex); + + mutex_lock(&reset_gpio_lookup_mutex); + + list_for_each_entry(rgpio_dev, &reset_gpio_lookup_list, list) { + if (args->np == rgpio_dev->of_args.np) { + if (of_phandle_args_equal(args, &rgpio_dev->of_args)) + goto out; /* Already on the list, done */ + } + } + + id = ida_alloc(&reset_gpio_ida, GFP_KERNEL); + if (id < 0) { + ret = id; + goto err_unlock; + } + + /* Not freed on success, because it is persisent subsystem data. */ + rgpio_dev = kzalloc(sizeof(*rgpio_dev), GFP_KERNEL); + if (!rgpio_dev) { + ret = -ENOMEM; + goto err_ida_free; + } + + ret = __reset_add_reset_gpio_lookup(id, args->np, args->args[0], + args->args[1]); + if (ret < 0) + goto err_kfree; + + rgpio_dev->of_args = *args; + /* + * We keep the device_node reference, but of_args.np is put at the end + * of __of_reset_control_get(), so get it one more time. + * Hold reference as long as rgpio_dev memory is valid. + */ + of_node_get(rgpio_dev->of_args.np); + pdev = platform_device_register_data(NULL, "reset-gpio", id, + &rgpio_dev->of_args, + sizeof(rgpio_dev->of_args)); + ret = PTR_ERR_OR_ZERO(pdev); + if (ret) + goto err_put; + + list_add(&rgpio_dev->list, &reset_gpio_lookup_list); + +out: + mutex_unlock(&reset_gpio_lookup_mutex); + + return 0; + +err_put: + of_node_put(rgpio_dev->of_args.np); +err_kfree: + kfree(rgpio_dev); +err_ida_free: + ida_free(&reset_gpio_ida, id); +err_unlock: + mutex_unlock(&reset_gpio_lookup_mutex); + + return ret; +} + +static struct reset_controller_dev *__reset_find_rcdev(const struct of_phandle_args *args, + bool gpio_fallback) +{ + struct reset_controller_dev *rcdev; + + lockdep_assert_held(&reset_list_mutex); + + list_for_each_entry(rcdev, &reset_controller_list, list) { + if (gpio_fallback) { + if (rcdev->of_args && of_phandle_args_equal(args, + rcdev->of_args)) + return rcdev; + } else { + if (args->np == rcdev->of_node) + return rcdev; + } + } + + return NULL; +} + struct reset_control * __of_reset_control_get(struct device_node *node, const char *id, int index, bool shared, bool optional, bool acquired) { + bool gpio_fallback = false; struct reset_control *rstc; - struct reset_controller_dev *r, *rcdev; + struct reset_controller_dev *rcdev; struct of_phandle_args args; int rstc_id; int ret; @@ -839,39 +1024,52 @@ __of_reset_control_get(struct device_node *node, const char *id, int index, index, &args); if (ret == -EINVAL) return ERR_PTR(ret); - if (ret) - return optional ? NULL : ERR_PTR(ret); + if (ret) { + if (!IS_ENABLED(CONFIG_RESET_GPIO)) + return optional ? NULL : ERR_PTR(ret); - mutex_lock(&reset_list_mutex); - rcdev = NULL; - list_for_each_entry(r, &reset_controller_list, list) { - if (args.np == r->of_node) { - rcdev = r; - break; + /* + * There can be only one reset-gpio for regular devices, so + * don't bother with the "reset-gpios" phandle index. + */ + ret = of_parse_phandle_with_args(node, "reset-gpios", "#gpio-cells", + 0, &args); + if (ret) + return optional ? NULL : ERR_PTR(ret); + + gpio_fallback = true; + + ret = __reset_add_reset_gpio_device(&args); + if (ret) { + rstc = ERR_PTR(ret); + goto out_put; } } + mutex_lock(&reset_list_mutex); + rcdev = __reset_find_rcdev(&args, gpio_fallback); if (!rcdev) { rstc = ERR_PTR(-EPROBE_DEFER); - goto out; + goto out_unlock; } if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) { rstc = ERR_PTR(-EINVAL); - goto out; + goto out_unlock; } rstc_id = rcdev->of_xlate(rcdev, &args); if (rstc_id < 0) { rstc = ERR_PTR(rstc_id); - goto out; + goto out_unlock; } /* reset_list_mutex also protects the rcdev's reset_control list */ rstc = __reset_control_get_internal(rcdev, rstc_id, shared, acquired); -out: +out_unlock: mutex_unlock(&reset_list_mutex); +out_put: of_node_put(args.np); return rstc; diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h index 0fa4f60e1186..357df16ede32 100644 --- a/include/linux/reset-controller.h +++ b/include/linux/reset-controller.h @@ -60,6 +60,9 @@ struct reset_control_lookup { * @reset_control_head: head of internal list of requested reset controls * @dev: corresponding driver model device struct * @of_node: corresponding device tree node as phandle target + * @of_args: for reset-gpios controllers: corresponding phandle args with + * of_node and GPIO number complementing of_node; either this or + * of_node should be present * @of_reset_n_cells: number of cells in reset line specifiers * @of_xlate: translation function to translate from specifier as found in the * device tree to id as given to the reset control ops, defaults @@ -73,6 +76,7 @@ struct reset_controller_dev { struct list_head reset_control_head; struct device *dev; struct device_node *of_node; + const struct of_phandle_args *of_args; int of_reset_n_cells; int (*of_xlate)(struct reset_controller_dev *rcdev, const struct of_phandle_args *reset_spec);

[v6,4/6] reset: Instantiate reset GPIO controller for shared reset-gpios

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