gpio: add userspace ABI for GPIO line information

[deliverable/linux.git] / drivers / gpio / gpiolib.c

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 797c790aa7506c42ea748e2c030b5f692f82f2e8..3580c0de9d5a8d51209ab4889025d8c599181400 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -331,14 +331,15 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
        struct gpio_device *gdev = filp->private_data;
        struct gpio_chip *chip = gdev->chip;
        int __user *ip = (int __user *)arg;
-       struct gpiochip_info chipinfo;
 
        /* We fail any subsequent ioctl():s when the chip is gone */
        if (!chip)
                return -ENODEV;
 
+       /* Fill in the struct and pass to userspace */
        if (cmd == GPIO_GET_CHIPINFO_IOCTL) {
-               /* Fill in the struct and pass to userspace */
+               struct gpiochip_info chipinfo;
+
                strncpy(chipinfo.name, dev_name(&gdev->dev),
                        sizeof(chipinfo.name));
                chipinfo.name[sizeof(chipinfo.name)-1] = '\0';
@@ -349,6 +350,52 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                if (copy_to_user(ip, &chipinfo, sizeof(chipinfo)))
                        return -EFAULT;
                return 0;
+       } else if (cmd == GPIO_GET_LINEINFO_IOCTL) {
+               struct gpioline_info lineinfo;
+               struct gpio_desc *desc;
+
+               if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
+                       return -EFAULT;
+               if (lineinfo.line_offset > gdev->ngpio)
+                       return -EINVAL;
+
+               desc = &gdev->descs[lineinfo.line_offset];
+               if (desc->name) {
+                       strncpy(lineinfo.name, desc->name,
+                               sizeof(lineinfo.name));
+                       lineinfo.name[sizeof(lineinfo.name)-1] = '\0';
+               } else {
+                       lineinfo.name[0] = '\0';
+               }
+               if (desc->label) {
+                       strncpy(lineinfo.label, desc->label,
+                               sizeof(lineinfo.label));
+                       lineinfo.label[sizeof(lineinfo.label)-1] = '\0';
+               } else {
+                       lineinfo.label[0] = '\0';
+               }
+
+               /*
+                * Userspace only need to know that the kernel is using
+                * this GPIO so it can't use it.
+                */
+               lineinfo.flags = 0;
+               if (desc->flags & (FLAG_REQUESTED | FLAG_IS_HOGGED |
+                                  FLAG_USED_AS_IRQ | FLAG_EXPORT |
+                                  FLAG_SYSFS))
+                       lineinfo.flags |= GPIOLINE_FLAG_KERNEL;
+               if (desc->flags & FLAG_IS_OUT)
+                       lineinfo.flags |= GPIOLINE_FLAG_IS_OUT;
+               if (desc->flags & FLAG_ACTIVE_LOW)
+                       lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW;
+               if (desc->flags & FLAG_OPEN_DRAIN)
+                       lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN;
+               if (desc->flags & FLAG_OPEN_SOURCE)
+                       lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE;
+
+               if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
+                       return -EFAULT;
+               return 0;
        }
        return -EINVAL;
 }