tools/gpio: add gpio basic opereations

Add basic gpio operations. User could get/set gpio value for specific
line of gpiochip.

Reference "tools/gpio/gpio-hammer.c" or
"tools/testing/selftest/gpio/gpio-mockup-chardev.c" for how to use it.

Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Reviewed-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/tools/gpio/gpio-utils.h b/tools/gpio/gpio-utils.h
index 5f57133..344ea04 100644
--- a/tools/gpio/gpio-utils.h
+++ b/tools/gpio/gpio-utils.h
@@ -24,4 +24,20 @@ static inline int check_prefix(const char *str, const char *prefix)
 		strncmp(str, prefix, strlen(prefix)) == 0;
 }
 
+int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,
+				 unsigned int nlines, unsigned int flag,
+				 struct gpiohandle_data *data,
+				 const char *consumer_label);
+int gpiotools_set_values(const int fd, struct gpiohandle_data *data);
+int gpiotools_get_values(const int fd, struct gpiohandle_data *data);
+int gpiotools_release_linehandle(const int fd);
+
+int gpiotools_get(const char *device_name, unsigned int line);
+int gpiotools_gets(const char *device_name, unsigned int *lines,
+		   unsigned int nlines, struct gpiohandle_data *data);
+int gpiotools_set(const char *device_name, unsigned int line,
+		  unsigned int value);
+int gpiotools_sets(const char *device_name, unsigned int *lines,
+		   unsigned int nlines, struct gpiohandle_data *data);
+
 #endif /* _GPIO_UTILS_H_ */