gpio: mcp23s08: Add option to configure IRQ output polarity as active high

Default is active low, but if property is specified in DT set INTPOL flag.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
index c306a2d..f3332b9 100644 (file)
--- a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
@@ -57,6 +57,8 @@ Optional device specific properties:
         occurred on. If it is not set, the interrupt are only generated for the
         bank they belong to.
         On devices with only one interrupt output this property is useless.
+- microchip,irq-active-high: Sets the INTPOL flag in the IOCON register. This
+        configures the IRQ output polarity as active high.
 
 Example I2C (with interrupt):
 gpiom1: gpio@20 {

diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 0d58440..93ee7da 100644 (file)
--- a/drivers/gpio/gpio-mcp23s08.c
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -65,6 +65,7 @@ struct mcp23s08_ops {
 
 struct mcp23s08 {
        u8                      addr;
+       bool                    irq_active_high;
 
        u16                     cache[11];
        u16                     irq_rise;
@@ -476,6 +477,7 @@ static int mcp23s08_irq_setup(struct mcp23s08 *mcp)
 {
        struct gpio_chip *chip = &mcp->chip;
        int err, irq, j;
+       unsigned long irqflags = IRQF_ONESHOT | IRQF_SHARED;
 
        mutex_init(&mcp->irq_lock);
 
@@ -484,10 +486,13 @@ static int mcp23s08_irq_setup(struct mcp23s08 *mcp)
        if (!mcp->irq_domain)
                return -ENODEV;
 
+       if (mcp->irq_active_high)
+               irqflags |= IRQF_TRIGGER_HIGH;
+       else
+               irqflags |= IRQF_TRIGGER_LOW;
+
        err = devm_request_threaded_irq(chip->dev, mcp->irq, NULL, mcp23s08_irq,
-                                       IRQF_TRIGGER_LOW | IRQF_ONESHOT |
-                                       IRQF_SHARED,
-                                       dev_name(chip->dev), mcp);
+                                       irqflags, dev_name(chip->dev), mcp);
        if (err != 0) {
                dev_err(chip->dev, "unable to request IRQ#%d: %d\n",
                        mcp->irq, err);
@@ -589,6 +594,7 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
 
        mcp->data = data;
        mcp->addr = addr;
+       mcp->irq_active_high = false;
 
        mcp->chip.direction_input = mcp23s08_direction_input;
        mcp->chip.get = mcp23s08_get;
@@ -648,14 +654,24 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
                goto fail;
 
        mcp->irq_controller = pdata->irq_controller;
-       if (mcp->irq && mcp->irq_controller && (type == MCP_TYPE_017))
-               mirror = pdata->mirror;
+       if (mcp->irq && mcp->irq_controller) {
+               mcp->irq_active_high = of_property_read_bool(mcp->chip.of_node,
+                               "microchip,irq-active-high");
 
-       if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN) || mirror) {
+               if (type == MCP_TYPE_017)
+                       mirror = pdata->mirror;
+       }
+
+       if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN) || mirror ||
+            mcp->irq_active_high) {
                /* mcp23s17 has IOCON twice, make sure they are in sync */
                status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
                status |= IOCON_HAEN | (IOCON_HAEN << 8);
-               status &= ~(IOCON_INTPOL | (IOCON_INTPOL << 8));
+               if (mcp->irq_active_high)
+                       status |= IOCON_INTPOL | (IOCON_INTPOL << 8);
+               else
+                       status &= ~(IOCON_INTPOL | (IOCON_INTPOL << 8));
+
                if (mirror)
                        status |= IOCON_MIRROR | (IOCON_MIRROR << 8);