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>

1 files changed, 23 insertions, 7 deletions

diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
index 0d58440eb8da..93ee7da2d8b0 100644
--- 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);