gpio: Drop the chained IRQ handler assign function

gpiochip_set_chained_irqchip() would assign a chained handler
to a GPIO chip. We now populate struct gpio_irq_chip for all
chained GPIO irqchips so drop this function.

Cc: Andy Shevchenko <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/driver-api/gpio/driver.rst

···
   cascaded irq has to be handled by a threaded interrupt handler.
   Apart from that it works exactly like the chained 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
   explicitly requested by the driver, this does very little more than

drivers/gpio/gpio-mt7621.c

···
 
 		/*
 		 * Directly request the irq here instead of passing
-		 * a flow-handler to gpiochip_set_chained_irqchip,
-		 * because the irq is shared.
+		 * a flow-handler because the irq is shared.
 		 */
 		ret = devm_request_irq(dev, mtk->gpio_irq,
 				       mediatek_gpio_irq_handler, IRQF_SHARED,

drivers/gpio/gpio-xgs-iproc.c

···
 
 		/*
 		 * Directly request the irq here instead of passing
-		 * a flow-handler to gpiochip_set_chained_irqchip,
-		 * because the irq is shared.
+		 * a flow-handler because the irq is shared.
 		 */
 		ret = devm_request_irq(dev, irq, iproc_gpio_irq_handler,
 				       IRQF_SHARED, chip->gc.label, &chip->gc);

drivers/gpio/gpiolib.c

···
  * gpiochip_set_cascaded_irqchip() - connects a cascaded irqchip to a gpiochip
  * @gc: the gpiochip to set the irqchip chain to
  * @parent_irq: the irq number corresponding to the parent IRQ for this
- * chained irqchip
+ * cascaded irqchip
  * @parent_handler: the parent interrupt handler for the accumulated IRQ
  * coming out of the gpiochip. If the interrupt is nested rather than
  * cascaded, pass NULL in this handler argument
···
 						 gc);
 	}
 }
-
-/**
- * gpiochip_set_chained_irqchip() - connects a chained irqchip to a gpiochip
- * @gpiochip: the gpiochip to set the irqchip chain to
- * @irqchip: the irqchip to chain to the gpiochip
- * @parent_irq: the irq number corresponding to the parent IRQ for this
- * chained irqchip
- * @parent_handler: the parent interrupt handler for the accumulated IRQ
- * coming out of the gpiochip.
- */
-void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
-				  struct irq_chip *irqchip,
-				  unsigned int parent_irq,
-				  irq_flow_handler_t parent_handler)
-{
-	if (gpiochip->irq.threaded) {
-		chip_err(gpiochip, "tried to chain a threaded gpiochip\n");
-		return;
-	}
-
-	gpiochip_set_cascaded_irqchip(gpiochip, parent_irq, parent_handler);
-}
-EXPORT_SYMBOL_GPL(gpiochip_set_chained_irqchip);
 
 /**
  * gpiochip_set_nested_irqchip() - connects a nested irqchip to a gpiochip

include/linux/gpio/driver.h

···
 void gpiochip_irq_domain_deactivate(struct irq_domain *domain,
 				    struct irq_data *data);
 
-void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
-		struct irq_chip *irqchip,
-		unsigned int parent_irq,
-		irq_flow_handler_t parent_handler);
-
 void gpiochip_set_nested_irqchip(struct gpio_chip *gpiochip,
 		struct irq_chip *irqchip,
 		unsigned int parent_irq);