[PATCH] [RFC] Allow configs from choice blocks to be selected.

[John Stultz <john.stultz@linaro.org>]

In looking at trying to replace defconfigs with kconfig fragments,
one limitation identified is that config items in choice blocks
cannot be selected by other config options.

One way to doge this would be to create non-visible meta options
that change the choice block's default, but that would require
additional meta-configs per-choice config, plus a conditional
default per meta-config. That just seemed too ugly.

So I looked into how to allow the choice default to be overrided
by a select statment, and the following patch is the result.

I'm very new to kconfig code, so I expect that my changes are
probably broken in some subtle way, but in my limited testing it
seems to work. The select only chagnes the default, which can be
overrided by the user via the menu. This allows kconfig fragments
to work for make defconfig, while not restricting user
customization.

Thoughts and feedback (or alternate approaches) would be appreciated.

thanks
-john

CC: Roman Zippel <zippel@linux-m68k.org>
CC: Grant Likely <grant.likely@secretlab.ca>
CC: linux-kbuild@vger.kernel.org
CC: Jason Hui <jason.hui@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
 scripts/kconfig/symbol.c |   16 ++++++++++++++--
 1 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/scripts/kconfig/symbol.c b/scripts/kconfig/symbol.c
index a796c95..284b223 100644
--- a/scripts/kconfig/symbol.c
+++ b/scripts/kconfig/symbol.c
@@ -203,8 +203,6 @@ static void sym_calc_visibility(struct symbol *sym)
 		sym->visible = tri;
 		sym_set_changed(sym);
 	}
-	if (sym_is_choice_value(sym))
-		return;
 	/* defaulting to "yes" if no explicit "depends on" are given */
 	tri = yes;
 	if (sym->dir_dep.expr)
@@ -235,9 +233,23 @@ static void sym_calc_visibility(struct symbol *sym)
 struct symbol *sym_choice_default(struct symbol *sym)
 {
 	struct symbol *def_sym;
+	struct symbol *ret = NULL;
 	struct property *prop;
 	struct expr *e;
 
+	/* check to see if any are selected */
+	prop = sym_get_choice_prop(sym);
+	expr_list_for_each_sym(prop->expr, e, def_sym)
+		if (def_sym->rev_dep.tri != no) {
+			if (ret)
+				fprintf(stderr, "warning: conflicting selects "
+					"on choice block: %s\n", sym->name);
+			else
+				ret = def_sym;
+		}
+	if (ret)
+		return ret;
+
 	/* any of the defaults visible? */
 	for_all_defaults(sym, prop) {
 		prop->visible.tri = expr_calc_value(prop->visible.expr);
-- 
1.7.3.2.146.gca209