// SPDX-License-Identifier: GPL-2.0-only // // GPIO Aggregator // // Copyright (C) 2019-2020 Glider bv #define DRV_NAME "gpio-aggregator" #define pr_fmt(fmt) DRV_NAME ": " fmt #include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/ctype.h> #include <linux/gpio.h> #include <linux/gpio/consumer.h> #include <linux/gpio/driver.h> #include <linux/gpio/machine.h> #include <linux/idr.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/overflow.h> #include <linux/platform_device.h> #include <linux/spinlock.h> #include <linux/string.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 int aggr_add_gpio(struct gpio_aggregator *aggr, const char *key, 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] = GPIO_LOOKUP_IDX(key, hwnum, NULL, *n, 0); (*n)++; memset(&lookups->table[*n], 0, sizeof(lookups->table[*n])); aggr->lookups = lookups; return 0; } static int aggr_parse(struct gpio_aggregator *aggr) { char *args = skip_spaces(aggr->args); char *name, *offsets, *p; unsigned long *bitmap; unsigned int i, n = 0; int error = 0; bitmap = bitmap_alloc(ARCH_NR_GPIOS, GFP_KERNEL); if (!bitmap) return -ENOMEM; args = next_arg(args, &name, &p); while (*args) { args = next_arg(args, &offsets, &p); p = get_options(offsets, 0, &error); if (error == 0 || *p) { /* Named GPIO line */ error = aggr_add_gpio(aggr, name, U16_MAX, &n); if (error) goto free_bitmap; name = offsets; continue; } /* GPIO chip + offset(s) */ error = bitmap_parselist(offsets, bitmap, ARCH_NR_GPIOS); if (error) { pr_err("Cannot parse %s: %d\n", offsets, error); goto free_bitmap; } for_each_set_bit(i, bitmap, ARCH_NR_GPIOS) { error = aggr_add_gpio(aggr, name, i, &n); if (error) goto free_bitmap; } args = next_arg(args, &name, &p); } if (!n) { pr_err("No GPIOs specified\n"); error = -EINVAL; } free_bitmap: bitmap_free(bitmap); return error; } 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->dev_id) { 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); } /* * 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 */ }; #define fwd_tmp_values(fwd) &(fwd)->tmp[0] #define fwd_tmp_descs(fwd) (void *)&(fwd)->tmp[BITS_TO_LONGS((fwd)->chip.ngpio)] #define fwd_tmp_size(ngpios) (BITS_TO_LONGS((ngpios)) + (ngpios)) 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 chip->can_sleep ? gpiod_get_value_cansleep(fwd->descs[offset]) : gpiod_get_value(fwd->descs[offset]); } static int gpio_fwd_get_multiple(struct gpiochip_fwd *fwd, unsigned long *mask, unsigned long *bits) { struct gpio_desc **descs = fwd_tmp_descs(fwd); unsigned long *values = fwd_tmp_values(fwd); unsigned int i, j = 0; int error; bitmap_clear(values, 0, fwd->chip.ngpio); for_each_set_bit(i, mask, fwd->chip.ngpio) descs[j++] = fwd->descs[i]; if (fwd->chip.can_sleep) error = gpiod_get_array_value_cansleep(j, descs, NULL, values); else error = gpiod_get_array_value(j, descs, NULL, values); if (error) return error; j = 0; for_each_set_bit(i, mask, fwd->chip.ngpio) __assign_bit(i, bits, test_bit(j++, values)); return 0; } static int gpio_fwd_get_multiple_locked(struct gpio_chip *chip, unsigned long *mask, unsigned long *bits) { struct gpiochip_fwd *fwd = gpiochip_get_data(chip); unsigned long flags; int error; if (chip->can_sleep) { mutex_lock(&fwd->mlock); error = gpio_fwd_get_multiple(fwd, mask, bits); mutex_unlock(&fwd->mlock); } else { spin_lock_irqsave(&fwd->slock, flags); error = gpio_fwd_get_multiple(fwd, mask, bits); 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); if (chip->can_sleep) gpiod_set_value_cansleep(fwd->descs[offset], value); else gpiod_set_value(fwd->descs[offset], value); } static void gpio_fwd_set_multiple(struct gpiochip_fwd *fwd, unsigned long *mask, unsigned long *bits) { struct gpio_desc **descs = fwd_tmp_descs(fwd); unsigned long *values = fwd_tmp_values(fwd); unsigned int i, j = 0; for_each_set_bit(i, mask, fwd->chip.ngpio) { __assign_bit(j, values, test_bit(i, bits)); descs[j++] = fwd->descs[i]; } if (fwd->chip.can_sleep) gpiod_set_array_value_cansleep(j, descs, NULL, values); else gpiod_set_array_value(j, descs, NULL, values); } static void gpio_fwd_set_multiple_locked(struct gpio_chip *chip, unsigned long *mask, unsigned long *bits) { struct gpiochip_fwd *fwd = gpiochip_get_data(chip); unsigned long flags; if (chip->can_sleep) { mutex_lock(&fwd->mlock); gpio_fwd_set_multiple(fwd, mask, bits); mutex_unlock(&fwd->mlock); } else { spin_lock_irqsave(&fwd->slock, flags); gpio_fwd_set_multiple(fwd, mask, bits); 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); return gpiod_set_config(fwd->descs[offset], config); } static int gpio_fwd_to_irq(struct gpio_chip *chip, unsigned int offset) { struct gpiochip_fwd *fwd = gpiochip_get_data(chip); return gpiod_to_irq(fwd->descs[offset]); } /** * 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, fwd_tmp_size(ngpios)), GFP_KERNEL); if (!fwd) return ERR_PTR(-ENOMEM); chip = &fwd->chip; /* * If any of the GPIO lines are sleeping, then the entire forwarder * will be sleeping. * If any of the chips support .set_config(), then the forwarder will * support setting configs. */ for (i = 0; i < ngpios; i++) { struct gpio_chip *parent = gpiod_to_chip(descs[i]); dev_dbg(dev, "%u => gpio %d irq %d\n", i, desc_to_gpio(descs[i]), gpiod_to_irq(descs[i])); if (gpiod_cansleep(descs[i])) chip->can_sleep = true; if (parent && parent->set_config) chip->set_config = gpio_fwd_set_config; } 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_locked; chip->set = gpio_fwd_set; chip->set_multiple = gpio_fwd_set_multiple_locked; chip->to_irq = gpio_fwd_to_irq; 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; } /* * GPIO Aggregator 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[] = { /* * 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 <geert+renesas@glider.be>"); MODULE_DESCRIPTION("GPIO Aggregator"); MODULE_LICENSE("GPL v2");