[PATCH] gpio: pl061: add DT binding support

On 10/24/2011 05:26 PM, Grant Likely wrote:

On Wed, Aug 03, 2011 at 06:18:45PM -0500, Rob Herring wrote:

quoted

Grant,

On 08/03/2011 05:22 PM, Grant Likely wrote:

quoted

On Wed, Aug 3, 2011 at 7:54 PM, Rob Herring [off-list ref] wrote:

quoted

From: Rob Herring <redacted>

This adds devicetree binding support to the ARM pl061 driver removing the
platform_data dependency. When DT binding is used, the gpio numbering is
assigned dynamically. The interrupt assignment is converted to use the
irq_domain infrastructure.

Signed-off-by: Rob Herring <redacted>
Cc: Grant Likely <redacted>
---
 drivers/gpio/gpio-pl061.c |   32 +++++++++++++++++++++++---------
 1 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c
index 2c5a18f..7ea74ff 100644
--- a/drivers/gpio/gpio-pl061.c
+++ b/drivers/gpio/gpio-pl061.c

@@ -23,6 +23,7 @@
 #include <linux/amba/bus.h>
 #include <linux/amba/pl061.h>
 #include <linux/slab.h>
+#include <linux/of_irq.h>

 #define GPIODIR 0x400
 #define GPIOIS  0x404

@@ -246,6 +247,20 @@ static int pl061_probe(struct amba_device *dev, const struct amba_id *id)
       if (chip == NULL)
               return -ENOMEM;

+       pdata = dev->dev.platform_data;
+       if (pdata) {
+               chip->gc.base = pdata->gpio_base;
+               chip->irq_base = pdata->irq_base;
+       } else if (dev->dev.of_node) {
+               u32 intspec = 0;
+               chip->gc.base = -1;
+               chip->irq_base = irq_create_of_mapping(dev->dev.of_node,
+                                                      &intspec, 1);

This looks wrong.  intspec is always 0 here, when I would assume you
would want the value of the interrupts property from this device's
node.  Is this the cascade irq number?  Or is it supposed to be the
starting interrupt number for the gpios?  If it is starting interrupt
number, then it should actually be dynamically assigned.  If it is the
cascade, then platform_get_irq() should work.

It's the latter case that I need to retrieve. I have this platform code
assigning the linux irq numbers:

        struct device_node *node;
        int n = 0;

        node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-gic");
        if (!node)
                panic("missing gic devicetree node\n");
        irq_domain_add_simple(node, 0);

        for_each_compatible_node(node, NULL, "arm,pl061") {
                irq_domain_add_simple(node, 160 + (8 * n));
                n++;
        }

In this case with simple translation, intspec is really a don't care.
irq_create_of_mapping just finds the domain that matches the gpio
ctrlr's node and returns the domain's irq_base (+ 0) as the translate
function will just return the intspec value for the hw_irq.

Have I missed something? There is not yet any dynamic assignment of
linux irq numbers?

Yes, the kernel does support dynamic irq number assignment, but the
interrupt controller still needs to manage it.  I've not yet decided
what the best way to integrate it into irq_domain is.

I had since figured that out with the GIC series. We should discuss at
Connect. My plan here is to make generic-irq-chip use domains and
irq_alloc_descs, then convert pl061 to use generic-irq-chip.

Rob