[PATCH 03/12] component: Support binding with no matches

[Paul Cercueil]

Support binding the master even though no components have been
registered.

This permits to support cases where components are optional.

Signed-off-by: Paul Cercueil <p...@crapouillou.net>
---
 drivers/base/component.c | 35 ++++++++++++++++++++++++++---------
 1 file changed, 26 insertions(+), 9 deletions(-)

diff --git a/drivers/base/component.c b/drivers/base/component.c
index e97704104784..a9de7ee1677f 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -100,7 +100,7 @@ static int component_devices_show(struct seq_file *s, void 
*data)
 
        seq_printf(s, "%-40s %20s\n", "device name", "status");
        seq_puts(s, 
"-------------------------------------------------------------\n");
-       for (i = 0; i < match->num; i++) {
+       for (i = 0; !!match && i < match->num; i++) {
                struct component *component = match->compare[i].component;
 
                seq_printf(s, "%-40s %20s\n",
@@ -184,6 +184,11 @@ static int find_components(struct master *master)
        size_t i;
        int ret = 0;
 
+       if (!match) {
+               dev_dbg(master->dev, "No components\n");
+               return 0;
+       }
+
        /*
         * Scan the array of match functions and attach
         * any components which are found to this master.
@@ -218,10 +223,12 @@ static void remove_component(struct master *master, 
struct component *c)
 {
        size_t i;
 
-       /* Detach the component from this master. */
-       for (i = 0; i < master->match->num; i++)
-               if (master->match->compare[i].component == c)
-                       master->match->compare[i].component = NULL;
+       if (master->match) {
+               /* Detach the component from this master. */
+               for (i = 0; i < master->match->num; i++)
+                       if (master->match->compare[i].component == c)
+                               master->match->compare[i].component = NULL;
+       }
 }
 
 /*
@@ -470,10 +477,12 @@ int component_master_add_with_match(struct device *dev,
        struct master *master;
        int ret;
 
-       /* Reallocate the match array for its true size */
-       ret = component_match_realloc(dev, match, match->num);
-       if (ret)
-               return ret;
+       if (match) {
+               /* Reallocate the match array for its true size */
+               ret = component_match_realloc(dev, match, match->num);
+               if (ret)
+                       return ret;
+       }
 
        master = kzalloc(sizeof(*master), GFP_KERNEL);
        if (!master)
@@ -557,6 +566,10 @@ void component_unbind_all(struct device *master_dev, void 
*data)
        if (!master)
                return;
 
+       /* No match, nothing to unbind */
+       if (!master->match)
+               return;
+
        /* Unbind components in reverse order */
        for (i = master->match->num; i--; )
                if (!master->match->compare[i].duplicate) {
@@ -640,6 +653,10 @@ int component_bind_all(struct device *master_dev, void 
*data)
        if (!master)
                return -EINVAL;
 
+       /* No match, nothing to bind */
+       if (!master->match)
+               return 0;
+
        /* Bind components in match order */
        for (i = 0; i < master->match->num; i++)
                if (!master->match->compare[i].duplicate) {
-- 
2.26.2