fdt: expose GPIO decoder to public interface

fdt_decode module is able to decode GPIO configurations (GPIO number,
I/O direction, and polarity). But the GPIO decoder was kept private to
fdt_decode module because GPIOs were generally used to control a larger
device (LCD, for example) and so considering a single GPIO in isolation
usually did not make much sense.

However, we are aware that there are cases that a GPIO is not a part of
any other larger device, but a standalone prober of hardware status. In
these cases, decoding a single GPIO does make sense. Thus, we expose the
GPIO decoder to public interface.

As this patch only changes functions from static to non-static and
function names, I only tested it builds or not.

BUG=none
TEST=build for Aebl successfully

Change-Id: Ic5f19b64f0cf3f64c56adead7c57e480ef24cab8
Reviewed-on: http://gerrit.chromium.org/gerrit/5725
Tested-by: Che-Liang Chiou <clchiou@chromium.org>
Reviewed-by: Anton Staaf <robotboy@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/fdt_decode.h b/include/fdt_decode.h
index 3ca140bb46..28776d0580 100644
--- a/include/fdt_decode.h
+++ b/include/fdt_decode.h
@@ -314,6 +314,34 @@ int fdt_decode_next_alias(const void *blob, const char *name,
 int fdt_decode_get_spi_switch(const void *blob, struct fdt_spi_uart *config);
 
 /**
+ * Decode a single GPIOs from an FDT.
+ *
+ * @param blob		FDT blob to use
+ * @param node		Node to look at
+ * @param property	Node property name
+ * @param gpio		gpio elements to fill from FDT
+ * @return 0 if ok, -FDT_ERR_MISSING if the property is missing.
+ */
+int fdt_decode_gpio(const void *blob, int node, const char *property,
+		struct fdt_gpio_state *gpio);
+
+/**
+ * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
+ * terminating item.
+ *
+ * @param blob		FDT blob to use
+ * @param node		Node to look at
+ * @param property	Node property name
+ * @param gpio		Array of gpio elements to fill from FDT. This will be
+ *			untouched if either 0 or an error is returned
+ * @param max_count	Maximum number of elements allowed
+ * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
+ * be exceeded, or -FDT_ERR_MISSING if the property is missing.
+ */
+int fdt_decode_gpios(const void *blob, int node, const char *property,
+		struct fdt_gpio_state *gpio, int max_count);
+
+/**
  * Set up a GPIO pin according to the provided gpio. This sets it to either
  * input or output. If an output, then the defined value is assigned.
  *