gpio: handle also nested irqchips in the chained handler set-up

To unify how we connect cascaded IRQ chips to parent IRQs, if
NULL us passed as handler to the gpiochip_set_chained_irqchip()
function, assume the chips is nested rather than chained, and
we still get the parent set up correctly by way of this function
call.

Alter the drivers for tc3589x and stmpe to use this to set up
their chained handlers as a demonstration of the usage.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/gpio/driver.txt b/Documentation/gpio/driver.txt
index 23b751a10d7b0850ce0a8aee23da026be01222ce..31e0b5db55d89a1e1d9e8da5e9f3fef2a4694450 100644 (file)
--- a/Documentation/gpio/driver.txt
+++ b/Documentation/gpio/driver.txt
@@ -124,7 +124,8 @@ symbol:
 * gpiochip_set_chained_irqchip(): sets up a chained irq handler for a
   gpio_chip from a parent IRQ and passes the struct gpio_chip* as handler
   data. (Notice handler data, since the irqchip data is likely used by the
-  parent irqchip!) This is for the chained type of chip.
+  parent irqchip!) This is for the chained type of chip. This is also used
+  to set up a nested irqchip if NULL is passed as handler.
 
 To use the helpers please keep the following in mind:
 

diff --git a/drivers/gpio/gpio-stmpe.c b/drivers/gpio/gpio-stmpe.c
index 845025a57240ac3517c7401c3bbe7c0f7c4ebe8a..b0b342787c375d185ee6c1b58c958fa5d3c36a6a 100644 (file)
--- a/drivers/gpio/gpio-stmpe.c
+++ b/drivers/gpio/gpio-stmpe.c
@@ -308,6 +308,12 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
        if (ret)
                goto out_free;
 
+       ret = gpiochip_add(&stmpe_gpio->chip);
+       if (ret) {
+               dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
+               goto out_disable;
+       }
+
        if (irq > 0) {
                ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
                                stmpe_gpio_irq, IRQF_ONESHOT,
@@ -324,14 +330,13 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
                if (ret) {
                        dev_err(&pdev->dev,
                                "could not connect irqchip to gpiochip\n");
-                       return ret;
+                       goto out_disable;
                }
-       }
 
-       ret = gpiochip_add(&stmpe_gpio->chip);
-       if (ret) {
-               dev_err(&pdev->dev, "unable to add gpiochip: %d\n", ret);
-               goto out_disable;
+               gpiochip_set_chained_irqchip(&stmpe_gpio->chip,
+                                            &stmpe_gpio_irq_chip,
+                                            irq,
+                                            NULL);
        }
 
        if (pdata && pdata->setup)
@@ -343,6 +348,7 @@ static int stmpe_gpio_probe(struct platform_device *pdev)
 
 out_disable:
        stmpe_disable(stmpe, STMPE_BLOCK_GPIO);
+       gpiochip_remove(&stmpe_gpio->chip);
 out_free:
        kfree(stmpe_gpio);
        return ret;

diff --git a/drivers/gpio/gpio-tc3589x.c b/drivers/gpio/gpio-tc3589x.c
index 7324869c38e0a01d82444da901ecaef719b8469e..ae0f6466eb09bf60e941b14966c62e0fbe7d1b77 100644 (file)
--- a/drivers/gpio/gpio-tc3589x.c
+++ b/drivers/gpio/gpio-tc3589x.c
@@ -300,6 +300,11 @@ static int tc3589x_gpio_probe(struct platform_device *pdev)
                return ret;
        }
 
+       gpiochip_set_chained_irqchip(&tc3589x_gpio->chip,
+                                    &tc3589x_gpio_irq_chip,
+                                    irq,
+                                    NULL);
+
        if (pdata && pdata->setup)
                pdata->setup(tc3589x, tc3589x_gpio->chip.base);
 

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 9362b5b817af150597ee5edebce5e70fe4e08bd8..6e00c82be1421e7a4dec378b1ea305fa8304a0d6 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -385,13 +385,14 @@ static struct gpio_chip *find_chip_by_name(const char *name)
  */
 
 /**
- * gpiochip_add_chained_irqchip() - adds a chained irqchip to a gpiochip
- * @gpiochip: the gpiochip to add the irqchip to
- * @irqchip: the irqchip to add to the gpiochip
+ * gpiochip_set_chained_irqchip() - sets 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
+ * coming out of the gpiochip. If the interrupt is nested rather than
+ * cascaded, pass NULL in this handler argument
  */
 void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
                                  struct irq_chip *irqchip,
@@ -400,23 +401,26 @@ void gpiochip_set_chained_irqchip(struct gpio_chip *gpiochip,
 {
        unsigned int offset;
 
-       if (gpiochip->can_sleep) {
-               chip_err(gpiochip, "you cannot have chained interrupts on a chip that may sleep\n");
-               return;
-       }
        if (!gpiochip->irqdomain) {
                chip_err(gpiochip, "called %s before setting up irqchip\n",
                         __func__);
                return;
        }
 
-       irq_set_chained_handler(parent_irq, parent_handler);
-
-       /*
-        * The parent irqchip is already using the chip_data for this
-        * irqchip, so our callbacks simply use the handler_data.
-        */
-       irq_set_handler_data(parent_irq, gpiochip);
+       if (parent_handler) {
+               if (gpiochip->can_sleep) {
+                       chip_err(gpiochip,
+                                "you cannot have chained interrupts on a "
+                                "chip that may sleep\n");
+                       return;
+               }
+               irq_set_chained_handler(parent_irq, parent_handler);
+               /*
+                * The parent irqchip is already using the chip_data for this
+                * irqchip, so our callbacks simply use the handler_data.
+                */
+               irq_set_handler_data(parent_irq, gpiochip);
+       }
 
        /* Set the parent IRQ for all affected IRQs */
        for (offset = 0; offset < gpiochip->ngpio; offset++)