Introduce ZIO_PARAM_{TRIGGER,BUFFER} and use it

This introduces ZIO_PARAM_TRIGGER(_name)  and ZIO_PARAM_BUFFER(_name)
and uses them in zio-zero.  We'd love most software-driven devices
to use the buffer= and trigger= parameters to override the default, thus
the centralized macros.

Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>

drivers/zio-zero.c

@@ -14,10 +14,8 @@
 #include <linux/zio.h>
 #include <linux/zio-buffer.h>
 
-static char *zzero_trigger;
-static char *zzero_buffer;
-module_param_named(trigger, zzero_trigger, charp, 0444);
-module_param_named(buffer, zzero_buffer, charp, 0444);
+ZIO_PARAM_TRIGGER(zzero_trigger);
+ZIO_PARAM_BUFFER(zzero_buffer);
 
 static int zzero_input(struct zio_cset *cset)
 {

include/linux/zio.h

@@ -189,6 +189,14 @@ static inline struct zio_channel *__first_enabled_chan(struct zio_cset *cset,
 		     (cptr = __first_enabled_chan(cset, cptr));	\
 		     cptr++)
 
+/* We suggest all drivers have these options */
+#define ZIO_PARAM_TRIGGER(_name) \
+	char *_name; \
+	module_param_named(trigger, _name, charp, 0444)
+#define ZIO_PARAM_BUFFER(_name) \
+	char *_name; \
+	module_param_named(buffer, _name, charp, 0444)
+
 #ifdef __ZIO_INTERNAL__
 
 /* This list is used in the core to keep track of registered objects */