diff options
| -rw-r--r-- | Documentation/driver-api/gpio/driver.rst | 122 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib.c | 320 | ||||
| -rw-r--r-- | include/linux/gpio/driver.h | 111 |
3 files changed, 527 insertions, 26 deletions
diff --git a/Documentation/driver-api/gpio/driver.rst b/Documentation/driver-api/gpio/driver.rst index 921c71a3d683..5e96dbc7f4e7 100644 --- a/Documentation/driver-api/gpio/driver.rst +++ b/Documentation/driver-api/gpio/driver.rst @@ -259,7 +259,7 @@ most often cascaded off a parent interrupt controller, and in some special cases the GPIO logic is melded with a SoC's primary interrupt controller. The IRQ portions of the GPIO block are implemented using an irq_chip, using -the header <linux/irq.h>. So basically such a driver is utilizing two sub- +the header <linux/irq.h>. So this combined driver is utilizing two sub- systems simultaneously: gpio and irq. It is legal for any IRQ consumer to request an IRQ from any irqchip even if it @@ -391,25 +391,119 @@ Infrastructure helpers for GPIO irqchips ---------------------------------------- To help out in handling the set-up and management of GPIO irqchips and the -associated irqdomain and resource allocation callbacks, the gpiolib has -some helpers that can be enabled by selecting the GPIOLIB_IRQCHIP Kconfig -symbol: - -- gpiochip_irqchip_add(): adds a chained cascaded irqchip to a gpiochip. It - will pass the struct gpio_chip* for the chip to all IRQ callbacks, so the - callbacks need to embed the gpio_chip in its state container and obtain a - pointer to the container using container_of(). - (See Documentation/driver-api/driver-model/design-patterns.rst) +associated irqdomain and resource allocation callbacks. These are activated +by selecting the Kconfig symbol GPIOLIB_IRQCHIP. If the symbol +IRQ_DOMAIN_HIERARCHY is also selected, hierarchical helpers will also be +provided. A big portion of overhead code will be managed by gpiolib, +under the assumption that your interrupts are 1-to-1-mapped to the +GPIO line index: + + GPIO line offset Hardware IRQ + 0 0 + 1 1 + 2 2 + ... ... + ngpio-1 ngpio-1 + +If some GPIO lines do not have corresponding IRQs, the bitmask valid_mask +and the flag need_valid_mask in gpio_irq_chip can be used to mask off some +lines as invalid for associating with IRQs. + +The preferred way to set up the helpers is to fill in the +struct gpio_irq_chip inside struct gpio_chip before adding the gpio_chip. +If you do this, the additional irq_chip will be set up by gpiolib at the +same time as setting up the rest of the GPIO functionality. The following +is a typical example of a cascaded interrupt handler using gpio_irq_chip: + + /* Typical state container with dynamic irqchip */ + struct my_gpio { + struct gpio_chip gc; + struct irq_chip irq; + }; + + int irq; /* from platform etc */ + struct my_gpio *g; + struct gpio_irq_chip *girq; + + /* Set up the irqchip dynamically */ + g->irq.name = "my_gpio_irq"; + g->irq.irq_ack = my_gpio_ack_irq; + g->irq.irq_mask = my_gpio_mask_irq; + g->irq.irq_unmask = my_gpio_unmask_irq; + g->irq.irq_set_type = my_gpio_set_irq_type; + + /* Get a pointer to the gpio_irq_chip */ + girq = &g->gc.irq; + girq->chip = &g->irq; + girq->parent_handler = ftgpio_gpio_irq_handler; + girq->num_parents = 1; + girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents), + GFP_KERNEL); + if (!girq->parents) + return -ENOMEM; + girq->default_type = IRQ_TYPE_NONE; + girq->handler = handle_bad_irq; + girq->parents[0] = irq; + + return devm_gpiochip_add_data(dev, &g->gc, g); + +The helper support using hierarchical interrupt controllers as well. +In this case the typical set-up will look like this: + + /* Typical state container with dynamic irqchip */ + struct my_gpio { + struct gpio_chip gc; + struct irq_chip irq; + struct fwnode_handle *fwnode; + }; + + int irq; /* from platform etc */ + struct my_gpio *g; + struct gpio_irq_chip *girq; + + /* Set up the irqchip dynamically */ + g->irq.name = "my_gpio_irq"; + g->irq.irq_ack = my_gpio_ack_irq; + g->irq.irq_mask = my_gpio_mask_irq; + g->irq.irq_unmask = my_gpio_unmask_irq; + g->irq.irq_set_type = my_gpio_set_irq_type; + + /* Get a pointer to the gpio_irq_chip */ + girq = &g->gc.irq; + girq->chip = &g->irq; + girq->default_type = IRQ_TYPE_NONE; + girq->handler = handle_bad_irq; + girq->fwnode = g->fwnode; + girq->parent_domain = parent; + girq->child_to_parent_hwirq = my_gpio_child_to_parent_hwirq; + + return devm_gpiochip_add_data(dev, &g->gc, g); + +As you can see pretty similar, but you do not supply a parent handler for +the IRQ, instead a parent irqdomain, an fwnode for the hardware and +a funcion .child_to_parent_hwirq() that has the purpose of looking up +the parent hardware irq from a child (i.e. this gpio chip) hardware irq. +As always it is good to look at examples in the kernel tree for advice +on how to find the required pieces. + +The old way of adding irqchips to gpiochips after registration is also still +available but we try to move away from this: + +- DEPRECATED: gpiochip_irqchip_add(): adds a chained cascaded irqchip to a + gpiochip. It will pass the struct gpio_chip* for the chip to all IRQ + callbacks, so the callbacks need to embed the gpio_chip in its state + container and obtain a pointer to the container using container_of(). + (See Documentation/driver-model/design-patterns.txt) - gpiochip_irqchip_add_nested(): adds a nested cascaded irqchip to a gpiochip, as discussed above regarding different types of cascaded irqchips. The cascaded irq has to be handled by a threaded interrupt handler. Apart from that it works exactly like the chained irqchip. -- gpiochip_set_chained_irqchip(): sets up a chained cascaded irq handler for a - gpio_chip from a parent IRQ and passes the struct gpio_chip* as handler - data. Notice that we pass is as the handler data, since the irqchip data is - likely used by the parent irqchip. +- DEPRECATED: gpiochip_set_chained_irqchip(): sets up a chained cascaded irq + handler for a gpio_chip from a parent IRQ and passes the struct gpio_chip* + as handler data. Notice that we pass is as the handler data, since the + irqchip data is likely used by the parent irqchip. - gpiochip_set_nested_irqchip(): sets up a nested cascaded irq handler for a gpio_chip from a parent IRQ. As the parent IRQ has usually been diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 537a37a89891..5277b8f1ff7c 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1720,6 +1720,273 @@ void gpiochip_set_nested_irqchip(struct gpio_chip *gpiochip, } EXPORT_SYMBOL_GPL(gpiochip_set_nested_irqchip); +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + +/** + * gpiochip_set_hierarchical_irqchip() - connects a hierarchical irqchip + * to a gpiochip + * @gc: the gpiochip to set the irqchip hierarchical handler to + * @irqchip: the irqchip to handle this level of the hierarchy, the interrupt + * will then percolate up to the parent + */ +static void gpiochip_set_hierarchical_irqchip(struct gpio_chip *gc, + struct irq_chip *irqchip) +{ + /* DT will deal with mapping each IRQ as we go along */ + if (is_of_node(gc->irq.fwnode)) + return; + + /* + * This is for legacy and boardfile "irqchip" fwnodes: allocate + * irqs upfront instead of dynamically since we don't have the + * dynamic type of allocation that hardware description languages + * provide. Once all GPIO drivers using board files are gone from + * the kernel we can delete this code, but for a transitional period + * it is necessary to keep this around. + */ + if (is_fwnode_irqchip(gc->irq.fwnode)) { + int i; + int ret; + + for (i = 0; i < gc->ngpio; i++) { + struct irq_fwspec fwspec; + unsigned int parent_hwirq; + unsigned int parent_type; + struct gpio_irq_chip *girq = &gc->irq; + + /* + * We call the child to parent translation function + * only to check if the child IRQ is valid or not. + * Just pick the rising edge type here as that is what + * we likely need to support. + */ + ret = girq->child_to_parent_hwirq(gc, i, + IRQ_TYPE_EDGE_RISING, + &parent_hwirq, + &parent_type); + if (ret) { + chip_err(gc, "skip set-up on hwirq %d\n", + i); + continue; + } + + fwspec.fwnode = gc->irq.fwnode; + /* This is the hwirq for the GPIO line side of things */ + fwspec.param[0] = girq->child_offset_to_irq(gc, i); + /* Just pick something */ + fwspec.param[1] = IRQ_TYPE_EDGE_RISING; + fwspec.param_count = 2; + ret = __irq_domain_alloc_irqs(gc->irq.domain, + /* just pick something */ + -1, + 1, + NUMA_NO_NODE, + &fwspec, + false, + NULL); + if (ret < 0) { + chip_err(gc, + "can not allocate irq for GPIO line %d parent hwirq %d in hierarchy domain: %d\n", + i, parent_hwirq, + ret); + } + } + } + + chip_err(gc, "%s unknown fwnode type proceed anyway\n", __func__); + + return; +} + +static int gpiochip_hierarchy_irq_domain_translate(struct irq_domain *d, + struct irq_fwspec *fwspec, + unsigned long *hwirq, + unsigned int *type) +{ + /* We support standard DT translation */ + if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) { + return irq_domain_translate_twocell(d, fwspec, hwirq, type); + } + + /* This is for board files and others not using DT */ + if (is_fwnode_irqchip(fwspec->fwnode)) { + int ret; + + ret = irq_domain_translate_twocell(d, fwspec, hwirq, type); + if (ret) + return ret; + WARN_ON(*type == IRQ_TYPE_NONE); + return 0; + } + return -EINVAL; +} + +static int gpiochip_hierarchy_irq_domain_alloc(struct irq_domain *d, + unsigned int irq, + unsigned int nr_irqs, + void *data) +{ + struct gpio_chip *gc = d->host_data; + irq_hw_number_t hwirq; + unsigned int type = IRQ_TYPE_NONE; + struct irq_fwspec *fwspec = data; + struct irq_fwspec parent_fwspec; + unsigned int parent_hwirq; + unsigned int parent_type; + struct gpio_irq_chip *girq = &gc->irq; + int ret; + + /* + * The nr_irqs parameter is always one except for PCI multi-MSI + * so this should not happen. + */ + WARN_ON(nr_irqs != 1); + + ret = gc->irq.child_irq_domain_ops.translate(d, fwspec, &hwirq, &type); + if (ret) + return ret; + + chip_info(gc, "allocate IRQ %d, hwirq %lu\n", irq, hwirq); + + ret = girq->child_to_parent_hwirq(gc, hwirq, type, + &parent_hwirq, &parent_type); + if (ret) { + chip_err(gc, "can't look up hwirq %lu\n", hwirq); + return ret; + } + chip_info(gc, "found parent hwirq %u\n", parent_hwirq); + + /* + * We set handle_bad_irq because the .set_type() should + * always be invoked and set the right type of handler. + */ + irq_domain_set_info(d, + irq, + hwirq, + gc->irq.chip, + gc, + girq->handler, + NULL, NULL); + irq_set_probe(irq); + + /* + * Create a IRQ fwspec to send up to the parent irqdomain: + * specify the hwirq we address on the parent and tie it + * all together up the chain. + */ + parent_fwspec.fwnode = d->parent->fwnode; + /* This parent only handles asserted level IRQs */ + girq->populate_parent_fwspec(gc, &parent_fwspec, parent_hwirq, + parent_type); + chip_info(gc, "alloc_irqs_parent for %d parent hwirq %d\n", + irq, parent_hwirq); + ret = irq_domain_alloc_irqs_parent(d, irq, 1, &parent_fwspec); + if (ret) + chip_err(gc, + "failed to allocate parent hwirq %d for hwirq %lu\n", + parent_hwirq, hwirq); + + return ret; +} + +static unsigned int gpiochip_child_offset_to_irq_noop(struct gpio_chip *chip, + unsigned int offset) +{ + return offset; +} + +static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops) +{ + ops->activate = gpiochip_irq_domain_activate; + ops->deactivate = gpiochip_irq_domain_deactivate; + ops->alloc = gpiochip_hierarchy_irq_domain_alloc; + ops->free = irq_domain_free_irqs_common; + + /* + * We only allow overriding the translate() function for + * hierarchical chips, and this should only be done if the user + * really need something other than 1:1 translation. + */ + if (!ops->translate) + ops->translate = gpiochip_hierarchy_irq_domain_translate; +} + +static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc) +{ + if (!gc->irq.child_to_parent_hwirq || + !gc->irq.fwnode) { + chip_err(gc, "missing irqdomain vital data\n"); + return -EINVAL; + } + + if (!gc->irq.child_offset_to_irq) + gc->irq.child_offset_to_irq = gpiochip_child_offset_to_irq_noop; + + if (!gc->irq.populate_parent_fwspec) + gc->irq.populate_parent_fwspec = + gpiochip_populate_parent_fwspec_twocell; + + gpiochip_hierarchy_setup_domain_ops(&gc->irq.child_irq_domain_ops); + + gc->irq.domain = irq_domain_create_hierarchy( + gc->irq.parent_domain, + 0, + gc->ngpio, + gc->irq.fwnode, + &gc->irq.child_irq_domain_ops, + gc); + + if (!gc->irq.domain) + return -ENOMEM; + + gpiochip_set_hierarchical_irqchip(gc, gc->irq.chip); + + return 0; +} + +static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc) +{ + return !!gc->irq.parent_domain; +} + +void gpiochip_populate_parent_fwspec_twocell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type) +{ + fwspec->param_count = 2; + fwspec->param[0] = parent_hwirq; + fwspec->param[1] = parent_type; +} +EXPORT_SYMBOL_GPL(gpiochip_populate_parent_fwspec_twocell); + +void gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type) +{ + fwspec->param_count = 4; + fwspec->param[0] = 0; + fwspec->param[1] = parent_hwirq; + fwspec->param[2] = 0; + fwspec->param[3] = parent_type; +} +EXPORT_SYMBOL_GPL(gpiochip_populate_parent_fwspec_fourcell); + +#else + +static int gpiochip_hierarchy_add_domain(struct gpio_chip *gc) +{ + return -EINVAL; +} + +static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc) +{ + return false; +} + +#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */ + /** * gpiochip_irq_map() - maps an IRQ into a GPIO irqchip * @d: the irqdomain used by this irqchip @@ -1788,6 +2055,11 @@ static const struct irq_domain_ops gpiochip_domain_ops = { .xlate = irq_domain_xlate_twocell, }; +/* + * TODO: move these activate/deactivate in under the hierarchicial + * irqchip implementation as static once SPMI and SSBI (all external + * users) are phased over. + */ /** * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ * @domain: The IRQ domain used by this IRQ chip @@ -1827,10 +2099,25 @@ EXPORT_SYMBOL_GPL(gpiochip_irq_domain_deactivate); static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset) { + struct irq_domain *domain = chip->irq.domain; + if (!gpiochip_irqchip_irq_valid(chip, offset)) return -ENXIO; - return irq_create_mapping(chip->irq.domain, offset); +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + if (irq_domain_is_hierarchy(domain)) { + struct irq_fwspec spec; + + spec.fwnode = domain->fwnode; + spec.param_count = 2; + spec.param[0] = chip->irq.child_offset_to_irq(chip, offset); + spec.param[1] = IRQ_TYPE_NONE; + + return irq_create_fwspec_mapping(&spec); + } +#endif + + return irq_create_mapping(domain, offset); } static int gpiochip_irq_reqres(struct irq_data *d) @@ -1907,7 +2194,7 @@ static int gpiochip_add_irqchip(struct gpio_chip *gpiochip, struct lock_class_key *request_key) { struct irq_chip *irqchip = gpiochip->irq.chip; - const struct irq_domain_ops *ops; + const struct irq_domain_ops *ops = NULL; struct device_node *np; unsigned int type; unsigned int i; @@ -1943,16 +2230,25 @@ static int gpiochip_add_irqchip(struct gpio_chip *gpiochip, gpiochip->irq.lock_key = lock_key; gpiochip->irq.request_key = request_key; - if (gpiochip->irq.domain_ops) - ops = gpiochip->irq.domain_ops; - else - ops = &gpiochip_domain_ops; - - gpiochip->irq.domain = irq_domain_add_simple(np, gpiochip->ngpio, - gpiochip->irq.first, - ops, gpiochip); - if (!gpiochip->irq.domain) - return -EINVAL; + /* If a parent irqdomain is provided, let's build a hierarchy */ + if (gpiochip_hierarchy_is_hierarchical(gpiochip)) { + int ret = gpiochip_hierarchy_add_domain(gpiochip); + if (ret) + return ret; + } else { + /* Some drivers provide custom irqdomain ops */ + if (gpiochip->irq.domain_ops) + ops = gpiochip->irq.domain_ops; + + if (!ops) + ops = &gpiochip_domain_ops; + gpiochip->irq.domain = irq_domain_add_simple(np, + gpiochip->ngpio, + gpiochip->irq.first, + ops, gpiochip); + if (!gpiochip->irq.domain) + return -EINVAL; + } if (gpiochip->irq.parent_handler) { void *data = gpiochip->irq.parent_handler_data ?: gpiochip; diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 6a0e420915a3..0e6d3b0c0211 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -23,6 +23,9 @@ enum gpio_lookup_flags; #ifdef CONFIG_GPIOLIB #ifdef CONFIG_GPIOLIB_IRQCHIP + +struct gpio_chip; + /** * struct gpio_irq_chip - GPIO interrupt controller */ @@ -49,6 +52,84 @@ struct gpio_irq_chip { */ const struct irq_domain_ops *domain_ops; +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + /** + * @fwnode: + * + * Firmware node corresponding to this gpiochip/irqchip, necessary + * for hierarchical irqdomain support. + */ + struct fwnode_handle *fwnode; + + /** + * @parent_domain: + * + * If non-NULL, will be set as the parent of this GPIO interrupt + * controller's IRQ domain to establish a hierarchical interrupt + * domain. The presence of this will activate the hierarchical + * interrupt support. + */ + struct irq_domain *parent_domain; + + /** + * @child_to_parent_hwirq: + * + * This callback translates a child hardware IRQ offset to a parent + * hardware IRQ offset on a hierarchical interrupt chip. The child + * hardware IRQs correspond to the GPIO index 0..ngpio-1 (see the + * ngpio field of struct gpio_chip) and the corresponding parent + * hardware IRQ and type (such as IRQ_TYPE_*) shall be returned by + * the driver. The driver can calculate this from an offset or using + * a lookup table or whatever method is best for this chip. Return + * 0 on successful translation in the driver. + * + * If some ranges of hardware IRQs do not have a corresponding parent + * HWIRQ, return -EINVAL, but also make sure to fill in @valid_mask and + * @need_valid_mask to make these GPIO lines unavailable for + * translation. + */ + int (*child_to_parent_hwirq)(struct gpio_chip *chip, + unsigned int child_hwirq, + unsigned int child_type, + unsigned int *parent_hwirq, + unsigned int *parent_type); + + /** + * @populate_parent_fwspec: + * + * This optional callback populates the &struct irq_fwspec for the + * parent's IRQ domain. If this is not specified, then + * &gpiochip_populate_parent_fwspec_twocell will be used. A four-cell + * variant named &gpiochip_populate_parent_fwspec_fourcell is also + * available. + */ + void (*populate_parent_fwspec)(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type); + + /** + * @child_offset_to_irq: + * + * This optional callback is used to translate the child's GPIO line + * offset on the GPIO chip to an IRQ number for the GPIO to_irq() + * callback. If this is not specified, then a default callback will be + * provided that returns the line offset. + */ + unsigned int (*child_offset_to_irq)(struct gpio_chip *chip, + unsigned int pin); + + /** + * @child_irq_domain_ops: + * + * The IRQ domain operations that will be used for this GPIO IRQ + * chip. If no operations are provided, then default callbacks will + * be populated to setup the IRQ hierarchy. Some drivers need to + * supply their own translate function. + */ + struct irq_domain_ops child_irq_domain_ops; +#endif + /** * @handler: * @@ -449,6 +530,36 @@ struct bgpio_pdata { int ngpio; }; +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY + +void gpiochip_populate_parent_fwspec_twocell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type); +void gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type); + +#else + +static void gpiochip_populate_parent_fwspec_twocell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type) +{ +} + +static void gpiochip_populate_parent_fwspec_fourcell(struct gpio_chip *chip, + struct irq_fwspec *fwspec, + unsigned int parent_hwirq, + unsigned int parent_type) +{ +} + +#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */ + + #if IS_ENABLED(CONFIG_GPIO_GENERIC) int bgpio_init(struct gpio_chip *gc, struct device *dev, |