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[209.132.180.67]) by mx.google.com with ESMTP id op11si8609325ejb.107.2019.11.27.00.44.47; Wed, 27 Nov 2019 00:45:11 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727080AbfK0InR (ORCPT + 99 others); Wed, 27 Nov 2019 03:43:17 -0500 Received: from andre.telenet-ops.be ([195.130.132.53]:43682 "EHLO andre.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726673AbfK0InN (ORCPT ); Wed, 27 Nov 2019 03:43:13 -0500 Received: from ramsan ([84.195.182.253]) by andre.telenet-ops.be with bizsmtp id Wwiu2100c5USYZQ01wiuXT; Wed, 27 Nov 2019 09:43:07 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1iZsuU-0000xr-Pe; Wed, 27 Nov 2019 09:42:54 +0100 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1iZsuU-0004Ox-Ms; Wed, 27 Nov 2019 09:42:54 +0100 From: Geert Uytterhoeven To: Linus Walleij , Bartosz Golaszewski , Jonathan Corbet , Rob Herring , Mark Rutland , Harish Jenny K N , Eugeniu Rosca Cc: Alexander Graf , Peter Maydell , Paolo Bonzini , Phil Reid , Marc Zyngier , Christoffer Dall , Magnus Damm , linux-gpio@vger.kernel.org, linux-doc@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, Geert Uytterhoeven Subject: [PATCH v3 5/7] gpio: Add GPIO Aggregator/Repeater driver Date: Wed, 27 Nov 2019 09:42:51 +0100 Message-Id: <20191127084253.16356-6-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191127084253.16356-1-geert+renesas@glider.be> References: <20191127084253.16356-1-geert+renesas@glider.be> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org GPIO controllers are exported to userspace using /dev/gpiochip* character devices. Access control to these devices is provided by standard UNIX file system permissions, on an all-or-nothing basis: either a GPIO controller is accessible for a user, or it is not. Currently no mechanism exists to control access to individual GPIOs. Hence add a GPIO driver to aggregate existing GPIOs, and expose them as a new gpiochip. This supports the following use cases: 1. Aggregating GPIOs using Sysfs This is useful for implementing access control, and assigning a set of GPIOs to a specific user or virtual machine. 2. GPIO Repeater in Device Tree This supports modelling e.g. GPIO inverters in DT. 3. Generic GPIO Driver This provides userspace access to a simple GPIO-operated device described in DT, cfr. e.g. spidev for SPI-operated devices. Signed-off-by: Geert Uytterhoeven --- v3: - Absorb GPIO forwarder, - Integrate GPIO Repeater and Generic GPIO driver functionality, - Use the aggregator parameters to create a GPIO lookup table instead of an array of GPIO descriptors, which allows to simplify the code: 1. This removes the need for calling gpio_name_to_desc(), gpiochip_find(), gpiochip_get_desc(), and gpiod_request(), 2. This allows the platform device to always use devm_gpiod_get_index(), regardless of the origin of the GPIOs, - Move parameter parsing from platform device probe to sysfs attribute store, removing the need for platform data passing, - Use more devm_*() functions to simplify cleanup, - Add pr_fmt(), - General refactoring. v2: - Add missing initialization of i in gpio_virt_agg_probe(), - Update for removed .need_valid_mask field and changed .init_valid_mask() signature, - Drop "virtual", rename to gpio-aggregator, - Drop bogus FIXME related to gpiod_set_transitory() expectations, - Use new GPIO Forwarder Helper, - Lift limit on the maximum number of GPIOs, - Improve parsing: - add support for specifying GPIOs by line name, - add support for specifying GPIO chips by ID, - add support for GPIO offset ranges, - names and offset specifiers must be separated by whitespace, - GPIO offsets must separated by spaces, - Use str_has_prefix() and kstrtouint(). --- drivers/gpio/Kconfig | 13 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-aggregator.c | 587 +++++++++++++++++++++++++++++++++ 3 files changed, 601 insertions(+) create mode 100644 drivers/gpio/gpio-aggregator.c diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 8adffd42f8cb0559..36b6b57a6b05e906 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1507,6 +1507,19 @@ config GPIO_VIPERBOARD endmenu +config GPIO_AGGREGATOR + tristate "GPIO Aggregator/Repeater" + help + Say yes here to enable the GPIO Aggregator and repeater, which + provides a way to aggregate and/or repeat existing GPIOs into a new + GPIO device. + This can serve the following purposes: + 1. Assign a collection of GPIOs to a user, or export them to a + virtual machine, + 2. Support GPIOs that are connected to a physical inverter, + 3. Provide a generic driver for a GPIO-operated device, to be + controlled from userspace using the GPIO chardev interface. + config GPIO_MOCKUP tristate "GPIO Testing Driver" select IRQ_SIM diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 34eb8b2b12dd656c..f9971eeb1f32335f 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -25,6 +25,7 @@ obj-$(CONFIG_GPIO_74XX_MMIO) += gpio-74xx-mmio.o obj-$(CONFIG_GPIO_ADNP) += gpio-adnp.o obj-$(CONFIG_GPIO_ADP5520) += gpio-adp5520.o obj-$(CONFIG_GPIO_ADP5588) += gpio-adp5588.o +obj-$(CONFIG_GPIO_AGGREGATOR) += gpio-aggregator.o obj-$(CONFIG_GPIO_ALTERA_A10SR) += gpio-altera-a10sr.o obj-$(CONFIG_GPIO_ALTERA) += gpio-altera.o obj-$(CONFIG_GPIO_AMD8111) += gpio-amd8111.o diff --git a/drivers/gpio/gpio-aggregator.c b/drivers/gpio/gpio-aggregator.c new file mode 100644 index 0000000000000000..873578c6f9683db8 --- /dev/null +++ b/drivers/gpio/gpio-aggregator.c @@ -0,0 +1,587 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// GPIO Aggregator and Repeater +// +// Copyright (C) 2019 Glider bvba + +#define DRV_NAME "gpio-aggregator" +#define pr_fmt(fmt) DRV_NAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "gpiolib.h" + + + /* + * GPIO Aggregator sysfs interface + */ + +struct gpio_aggregator { + struct gpiod_lookup_table *lookups; + struct platform_device *pdev; + char args[]; +}; + +static DEFINE_MUTEX(gpio_aggregator_lock); /* protects idr */ +static DEFINE_IDR(gpio_aggregator_idr); + +static char *get_arg(char **args) +{ + char *start = *args, *end; + + while (isspace(*start)) + start++; + + if (!*start) + return NULL; + + if (*start == '"') { + /* Quoted arg */ + end = strchr(++start, '"'); + if (!end) + return ERR_PTR(-EINVAL); + } else { + /* Unquoted arg */ + for (end = start; *end && !isspace(*end); end++) ; + } + + if (*end) + *end++ = '\0'; + + *args = end; + return start; +} + +static bool isrange(const char *s) +{ + size_t n = strlen(s); + + if (IS_ERR_OR_NULL(s)) + return false; + + while (1) { + n = strspn(s, "0123456789"); + if (!n) + return false; + + s += n; + + switch (*s++) { + case '\0': + return true; + + case '-': + case ',': + break; + + default: + return false; + } + } +} + +static int aggr_add_gpio(struct gpio_aggregator *aggr, const char *label, + int hwnum, unsigned int *n) +{ + struct gpiod_lookup_table *lookups; + + lookups = krealloc(aggr->lookups, struct_size(lookups, table, *n + 2), + GFP_KERNEL); + if (!lookups) + return -ENOMEM; + + lookups->table[*n].chip_label = label; + lookups->table[*n].chip_hwnum = hwnum; + lookups->table[*n].idx = *n; + + (*n)++; + memset(&lookups->table[*n], 0, sizeof(lookups->table[*n])); + + aggr->lookups = lookups; + return 0; +} + +static int aggr_parse(struct gpio_aggregator *aggr) +{ + char *name, *offsets, *first, *last, *next; + unsigned int a, b, i, n = 0; + char *args = aggr->args; + int error; + + for (name = get_arg(&args), offsets = get_arg(&args); name; + offsets = get_arg(&args)) { + if (IS_ERR(name)) { + pr_err("Cannot get GPIO specifier: %ld\n", + PTR_ERR(name)); + return PTR_ERR(name); + } + + if (!isrange(offsets)) { + /* Named GPIO line */ + error = aggr_add_gpio(aggr, name, -1, &n); + if (error) + return error; + + name = offsets; + continue; + } + + /* GPIO chip + offset(s) */ + for (first = offsets; *first; first = next) { + next = strchrnul(first, ','); + if (*next) + *next++ = '\0'; + + last = strchr(first, '-'); + if (last) + *last++ = '\0'; + + if (kstrtouint(first, 10, &a)) { + pr_err("Cannot parse GPIO index %s\n", first); + return -EINVAL; + } + + if (!last) { + b = a; + } else if (kstrtouint(last, 10, &b)) { + pr_err("Cannot parse GPIO index %s\n", last); + return -EINVAL; + } + + for (i = a; i <= b; i++) { + error = aggr_add_gpio(aggr, name, i, &n); + if (error) + return error; + } + } + + name = get_arg(&args); + } + + if (!n) { + pr_err("No GPIOs specified\n"); + return -EINVAL; + } + + return 0; +} + +static ssize_t new_device_store(struct device_driver *driver, const char *buf, + size_t count) +{ + struct gpio_aggregator *aggr; + struct platform_device *pdev; + int res, id; + + /* kernfs guarantees string termination, so count + 1 is safe */ + aggr = kzalloc(sizeof(*aggr) + count + 1, GFP_KERNEL); + if (!aggr) + return -ENOMEM; + + memcpy(aggr->args, buf, count + 1); + + aggr->lookups = kzalloc(struct_size(aggr->lookups, table, 1), + GFP_KERNEL); + if (!aggr->lookups) { + res = -ENOMEM; + goto free_ga; + } + + mutex_lock(&gpio_aggregator_lock); + id = idr_alloc(&gpio_aggregator_idr, aggr, 0, 0, GFP_KERNEL); + mutex_unlock(&gpio_aggregator_lock); + + if (id < 0) { + res = id; + goto free_table; + } + + aggr->lookups->dev_id = kasprintf(GFP_KERNEL, "%s.%d", DRV_NAME, id); + if (!aggr->lookups) { + res = -ENOMEM; + goto remove_idr; + } + + res = aggr_parse(aggr); + if (res) + goto free_dev_id; + + gpiod_add_lookup_table(aggr->lookups); + + pdev = platform_device_register_simple(DRV_NAME, id, NULL, 0); + if (IS_ERR(pdev)) { + res = PTR_ERR(pdev); + goto remove_table; + } + + aggr->pdev = pdev; + return count; + +remove_table: + gpiod_remove_lookup_table(aggr->lookups); +free_dev_id: + kfree(aggr->lookups->dev_id); +remove_idr: + mutex_lock(&gpio_aggregator_lock); + idr_remove(&gpio_aggregator_idr, id); + mutex_unlock(&gpio_aggregator_lock); +free_table: + kfree(aggr->lookups); +free_ga: + kfree(aggr); + return res; +} + +static DRIVER_ATTR_WO(new_device); + +static void gpio_aggregator_free(struct gpio_aggregator *aggr) +{ + platform_device_unregister(aggr->pdev); + gpiod_remove_lookup_table(aggr->lookups); + kfree(aggr->lookups->dev_id); + kfree(aggr->lookups); + kfree(aggr); +} + +static ssize_t delete_device_store(struct device_driver *driver, + const char *buf, size_t count) +{ + struct gpio_aggregator *aggr; + unsigned int id; + int error; + + if (!str_has_prefix(buf, DRV_NAME ".")) + return -EINVAL; + + error = kstrtouint(buf + strlen(DRV_NAME "."), 10, &id); + if (error) + return error; + + mutex_lock(&gpio_aggregator_lock); + aggr = idr_remove(&gpio_aggregator_idr, id); + mutex_unlock(&gpio_aggregator_lock); + if (!aggr) + return -ENOENT; + + gpio_aggregator_free(aggr); + return count; +} +static DRIVER_ATTR_WO(delete_device); + +static struct attribute *gpio_aggregator_attrs[] = { + &driver_attr_new_device.attr, + &driver_attr_delete_device.attr, + NULL, +}; +ATTRIBUTE_GROUPS(gpio_aggregator); + +static int __exit gpio_aggregator_idr_remove(int id, void *p, void *data) +{ + gpio_aggregator_free(p); + return 0; +} + +static void __exit gpio_aggregator_remove_all(void) +{ + mutex_lock(&gpio_aggregator_lock); + idr_for_each(&gpio_aggregator_idr, gpio_aggregator_idr_remove, NULL); + idr_destroy(&gpio_aggregator_idr); + mutex_unlock(&gpio_aggregator_lock); +} + + + /* + * Common GPIO Forwarder + */ + +struct gpiochip_fwd { + struct gpio_chip chip; + struct gpio_desc **descs; + union { + struct mutex mlock; /* protects tmp[] if can_sleep */ + spinlock_t slock; /* protects tmp[] if !can_sleep */ + }; + unsigned long tmp[]; /* values and descs for multiple ops */ +}; + +static int gpio_fwd_get_direction(struct gpio_chip *chip, unsigned int offset) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + return gpiod_get_direction(fwd->descs[offset]); +} + +static int gpio_fwd_direction_input(struct gpio_chip *chip, unsigned int offset) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + return gpiod_direction_input(fwd->descs[offset]); +} + +static int gpio_fwd_direction_output(struct gpio_chip *chip, + unsigned int offset, int value) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + return gpiod_direction_output(fwd->descs[offset], value); +} + +static int gpio_fwd_get(struct gpio_chip *chip, unsigned int offset) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + return gpiod_get_value(fwd->descs[offset]); +} + +static int gpio_fwd_get_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + unsigned long *values, flags; + struct gpio_desc **descs; + unsigned int i, j = 0; + int error; + + if (chip->can_sleep) + mutex_lock(&fwd->mlock); + else + spin_lock_irqsave(&fwd->slock, flags); + + values = &fwd->tmp[0]; + bitmap_clear(values, 0, fwd->chip.ngpio); + descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)]; + + for_each_set_bit(i, mask, fwd->chip.ngpio) + descs[j++] = fwd->descs[i]; + + error = gpiod_get_array_value(j, descs, NULL, values); + if (!error) { + j = 0; + for_each_set_bit(i, mask, fwd->chip.ngpio) + __assign_bit(i, bits, test_bit(j++, values)); + } + + if (chip->can_sleep) + mutex_unlock(&fwd->mlock); + else + spin_unlock_irqrestore(&fwd->slock, flags); + + return error; +} + +static void gpio_fwd_set(struct gpio_chip *chip, unsigned int offset, int value) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + gpiod_set_value(fwd->descs[offset], value); +} + +static void gpio_fwd_set_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + unsigned long *values, flags; + struct gpio_desc **descs; + unsigned int i, j = 0; + + if (chip->can_sleep) + mutex_lock(&fwd->mlock); + else + spin_lock_irqsave(&fwd->slock, flags); + + values = &fwd->tmp[0]; + descs = (void *)&fwd->tmp[BITS_TO_LONGS(fwd->chip.ngpio)]; + + for_each_set_bit(i, mask, fwd->chip.ngpio) { + __assign_bit(j, values, test_bit(i, bits)); + descs[j++] = fwd->descs[i]; + } + + gpiod_set_array_value(j, descs, NULL, values); + + if (chip->can_sleep) + mutex_unlock(&fwd->mlock); + else + spin_unlock_irqrestore(&fwd->slock, flags); +} + +static int gpio_fwd_set_config(struct gpio_chip *chip, unsigned int offset, + unsigned long config) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + + chip = fwd->descs[offset]->gdev->chip; + if (chip->set_config) + return chip->set_config(chip, offset, config); + + return -ENOTSUPP; +} + +static int gpio_fwd_init_valid_mask(struct gpio_chip *chip, + unsigned long *valid_mask, + unsigned int ngpios) +{ + struct gpiochip_fwd *fwd = gpiochip_get_data(chip); + unsigned int i; + + for (i = 0; i < ngpios; i++) { + if (!gpiochip_line_is_valid(fwd->descs[i]->gdev->chip, + gpio_chip_hwgpio(fwd->descs[i]))) + clear_bit(i, valid_mask); + } + + return 0; +} + +/** + * gpiochip_fwd_create() - Create a new GPIO forwarder + * @dev: Parent device pointer + * @ngpios: Number of GPIOs in the forwarder. + * @descs: Array containing the GPIO descriptors to forward to. + * This array must contain @ngpios entries, and must not be deallocated + * before the forwarder has been destroyed again. + * + * This function creates a new gpiochip, which forwards all GPIO operations to + * the passed GPIO descriptors. + * + * Return: An opaque object pointer, or an ERR_PTR()-encoded negative error + * code on failure. + */ +static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev, + unsigned int ngpios, + struct gpio_desc *descs[]) +{ + const char *label = dev_name(dev); + struct gpiochip_fwd *fwd; + struct gpio_chip *chip; + unsigned int i; + int error; + + fwd = devm_kzalloc(dev, struct_size(fwd, tmp, + BITS_TO_LONGS(ngpios) + ngpios), GFP_KERNEL); + if (!fwd) + return ERR_PTR(-ENOMEM); + + chip = &fwd->chip; + + for (i = 0; i < ngpios; i++) { + dev_dbg(dev, "gpio %u => gpio-%d (%s)\n", i, + desc_to_gpio(descs[i]), descs[i]->label ? : "?"); + + if (gpiod_cansleep(descs[i])) + chip->can_sleep = true; + if (descs[i]->gdev->chip->set_config) + chip->set_config = gpio_fwd_set_config; + if (descs[i]->gdev->chip->init_valid_mask) + chip->init_valid_mask = gpio_fwd_init_valid_mask; + } + + chip->label = label; + chip->parent = dev; + chip->owner = THIS_MODULE; + chip->get_direction = gpio_fwd_get_direction; + chip->direction_input = gpio_fwd_direction_input; + chip->direction_output = gpio_fwd_direction_output; + chip->get = gpio_fwd_get; + chip->get_multiple = gpio_fwd_get_multiple; + chip->set = gpio_fwd_set; + chip->set_multiple = gpio_fwd_set_multiple; + chip->base = -1; + chip->ngpio = ngpios; + fwd->descs = descs; + + if (chip->can_sleep) + mutex_init(&fwd->mlock); + else + spin_lock_init(&fwd->slock); + + error = devm_gpiochip_add_data(dev, chip, fwd); + if (error) + return ERR_PTR(error); + + return fwd; +} + + + /* + * Common GPIO Aggregator/Repeater platform device + */ + +static int gpio_aggregator_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct gpio_desc **descs; + struct gpiochip_fwd *fwd; + int i, n; + + n = gpiod_count(dev, NULL); + if (n < 0) + return n; + + descs = devm_kmalloc_array(dev, n, sizeof(*descs), GFP_KERNEL); + if (!descs) + return -ENOMEM; + + for (i = 0; i < n; i++) { + descs[i] = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS); + if (IS_ERR(descs[i])) + return PTR_ERR(descs[i]); + } + + fwd = gpiochip_fwd_create(dev, n, descs); + if (IS_ERR(fwd)) + return PTR_ERR(fwd); + + platform_set_drvdata(pdev, fwd); + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id gpio_aggregator_dt_ids[] = { + { .compatible = "gpio-repeater" }, + /* + * Add GPIO-operated devices controlled from userspace below, + * or use "driver_override" in sysfs + */ + {}, +}; +MODULE_DEVICE_TABLE(of, gpio_aggregator_dt_ids); +#endif + +static struct platform_driver gpio_aggregator_driver = { + .probe = gpio_aggregator_probe, + .driver = { + .name = DRV_NAME, + .groups = gpio_aggregator_groups, + .of_match_table = of_match_ptr(gpio_aggregator_dt_ids), + }, +}; + +static int __init gpio_aggregator_init(void) +{ + return platform_driver_register(&gpio_aggregator_driver); +} +module_init(gpio_aggregator_init); + +static void __exit gpio_aggregator_exit(void) +{ + gpio_aggregator_remove_all(); + platform_driver_unregister(&gpio_aggregator_driver); +} +module_exit(gpio_aggregator_exit); + +MODULE_AUTHOR("Geert Uytterhoeven "); +MODULE_DESCRIPTION("GPIO Aggregator/Repeater"); +MODULE_LICENSE("GPL v2"); -- 2.17.1