basic_mmio_gpio: allow overriding number of gpio

Some platforms may have a number of GPIO that is less than the register
width of the peripheral.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 13 insertions, 6 deletions

diff --git a/drivers/gpio/basic_mmio_gpio.c b/drivers/gpio/basic_mmio_gpio.c
index 5db5de43832..2b2d3845446 100644
--- a/drivers/gpio/basic_mmio_gpio.c
+++ b/drivers/gpio/basic_mmio_gpio.c
@@ -239,6 +239,7 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
         resource_size_t dat_sz;
         int bits;
         int ret;
+        int ngpio;
 
         res_dat = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
         if (!res_dat)
@@ -249,6 +250,7 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
                 return -EINVAL;
 
         bits = dat_sz * 8;
+        ngpio = bits;
         if (bits > BITS_PER_LONG)
                 return -EINVAL;
 
@@ -277,13 +279,22 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
 
         spin_lock_init(&bgc->lock);
 
+        if (pdata) {
+                bgc->gc.base = pdata->base;
+                if (pdata->ngpio > 0)
+                        ngpio = pdata->ngpio;
+        } else {
+                bgc->gc.base = -1;
+        }
+
         bgc->bits = bits;
         ret = bgpio_setup_accessors(pdev, bgc);
         if (ret)
                 return ret;
 
         bgc->data = bgc->read_reg(bgc->reg_dat);
-        bgc->gc.ngpio = bits;
+
+        bgc->gc.ngpio = ngpio;
         bgc->gc.direction_input = bgpio_dir_in;
         bgc->gc.direction_output = bgpio_dir_out;
         bgc->gc.get = bgpio_get;
@@ -291,11 +302,6 @@ static int __devinit bgpio_probe(struct platform_device *pdev)
         bgc->gc.dev = dev;
         bgc->gc.label = dev_name(dev);
 
-        if (pdata)
-                bgc->gc.base = pdata->base;
-        else
-                bgc->gc.base = -1;
-
         platform_set_drvdata(pdev, bgc);
 
         ret = gpiochip_add(&bgc->gc);
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index 198087a16fc..f23ec73b944 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -15,6 +15,7 @@
 
 struct bgpio_pdata {
         int base;
+        int ngpio;
 };
 
 #endif /* __BASIC_MMIO_GPIO_H */