If the WM8903 is hooked up to an interrupt, set the irq_active_low flag
in the default platform data based on the IRQ's IRQ_TYPE. Map IRQ_TYPE_NONE
(a lack of explicit configuration/restriction) to irq_active_low = false;
the previous default.

This code is mainly added to support device tree interrupt bindings,
although will work perfectly well in a non device tree system too.

Any interrupt controller that supports only a single IRQ_TYPE could
set each IRQ's type based on that restriction. This applies equally
with and without device tree. To cater for interrupt controllers
that don't do this, for which irqd_get_trigger_type() will return
IRQ_TYPE_NONE, the platform data irq_active_low field may be used
in systems that don't use device tree.

With device tree, every IRQ must have some IRQ_TYPE set.

Controllers that support DT and multiple IRQ_TYPEs must define the
interrupts property (as used in interrupt source nodes) such that it
defines the IRQ_TYPE to use. When the core DT setup code initializes
wm8903->irq, the interrupts property will be parsed, and as a side-
effect, set the IRQ's IRQ_TYPE for the WM8903 probe() function to read.

Controllers that support DT and a single IRQ_TYPE could arrange to
set the IRQ_TYPE somehow during their initialization, or hard-code
it during the processing of the child interrupts property.

Signed-off-by: Stephen Warren <[email protected]>
---
 sound/soc/codecs/wm8903.c |   28 ++++++++++++++++++++++++++++
 1 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/sound/soc/codecs/wm8903.c b/sound/soc/codecs/wm8903.c
index 38e1137..6797b0a 100644
--- a/sound/soc/codecs/wm8903.c
+++ b/sound/soc/codecs/wm8903.c
@@ -24,6 +24,7 @@
 #include <linux/pm.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
+#include <linux/irq.h>
 #include <sound/core.h>
 #include <sound/jack.h>
 #include <sound/pcm.h>
@@ -1937,6 +1938,33 @@ static int wm8903_probe(struct snd_soc_codec *codec)
        defpdata.gpio_base = -1;
        for (i = 0; i < ARRAY_SIZE(defpdata.gpio_cfg); i++)
                defpdata.gpio_cfg[i] = 0xffffffff;
+       if (wm8903->irq) {
+               struct irq_data *irq_data = irq_get_irq_data(wm8903->irq);
+               if (!irq_data) {
+                       dev_err(codec->dev, "Invalid IRQ: %d\n",
+                               wm8903->irq);
+                       return -EINVAL;
+               }
+               switch (irqd_get_trigger_type(irq_data)) {
+               case IRQ_TYPE_NONE:
+                       /*
+                        * We assume the controller imposes no restrictions,
+                        * so we are able to select active-high
+                        */
+                       /* Fall-through */
+               case IRQ_TYPE_LEVEL_HIGH:
+                       defpdata.irq_active_low = false;
+                       break;
+               case IRQ_TYPE_LEVEL_LOW:
+                       defpdata.irq_active_low = true;
+                       break;
+               default:
+                       dev_err(codec->dev,
+                               "Unsupported IRQ_TYPE %x\n",
+                               irqd_get_trigger_type(irq_data));
+                       return -EINVAL;
+               }
+       }
 
        /* If no platform data was supplied, use the defaults */
        if (!pdata)
-- 
1.7.0.4

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