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-rw-r--r--arch/avr32/mach-at32ap/pio.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/arch/avr32/mach-at32ap/pio.c b/arch/avr32/mach-at32ap/pio.c
index c3f596ce526..9ba5654cde1 100644
--- a/arch/avr32/mach-at32ap/pio.c
+++ b/arch/avr32/mach-at32ap/pio.c
@@ -135,7 +135,28 @@ fail:
dump_stack();
}
-/*--------------------------------------------------------------------------*/
+/* Reserve a pin, preventing anyone else from changing its configuration. */
+void __init at32_reserve_pin(unsigned int pin)
+{
+ struct pio_device *pio;
+ unsigned int pin_index = pin & 0x1f;
+
+ pio = gpio_to_pio(pin);
+ if (unlikely(!pio)) {
+ printk("pio: invalid pin %u\n", pin);
+ goto fail;
+ }
+
+ if (unlikely(test_and_set_bit(pin_index, &pio->pinmux_mask))) {
+ printk("%s: pin %u is busy\n", pio->name, pin_index);
+ goto fail;
+ }
+
+ return;
+
+fail:
+ dump_stack();
+}
/*--------------------------------------------------------------------------*/