From: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
Add OF notifier handler needed for creating/destroying spi devices
according to dynamic runtime changes in the DT live tree. This code is
enabled when CONFIG_OF_DYNAMIC is selected.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: <linux-spi@xxxxxxxxxxxxxxx>
---
drivers/spi/spi.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 84 insertions(+)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index a3557c57d4f7..bf1cab0fad66 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2317,6 +2317,86 @@ EXPORT_SYMBOL_GPL(spi_write_then_read);
/*-------------------------------------------------------------------------*/
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+static int __spi_of_device_match(struct device *dev, void *data)
+{
+ return dev->of_node == data;
+}
+
+/* must call put_device() when done with returned spi_device device */
+static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
+{
+ struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
+ __spi_of_device_match);
+ return dev ? to_spi_device(dev) : NULL;
+}
+
+static int __spi_of_master_match(struct device *dev, const void *data)
+{
+ return dev->of_node == data;
+}
+
+/* the spi masters are not using spi_bus, so we find it with another way */
+static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
+{
+ struct device *dev;
+
+ dev = class_find_device(&spi_master_class, NULL, node,
+ __spi_of_master_match);
+ if (!dev)
+ return NULL;
+
+ /* reference got in class_find_device */
+ return container_of(dev, struct spi_master, dev);
+}
+
+static int of_spi_notify(struct notifier_block *nb, unsigned long action,
+ void *arg)
+{
+ struct of_reconfig_data *rd = arg;
+ struct spi_master *master;
+ struct spi_device *spi;
+
+ switch (of_reconfig_get_state_change(action, arg)) {
+ case OF_RECONFIG_CHANGE_ADD:
+ master = of_find_spi_master_by_node(rd->dn->parent);
+ if (master == NULL)
+ return NOTIFY_OK; /* not for us */
+
+ spi = of_register_spi_device(master, rd->dn);
+ put_device(&master->dev);
+
+ if (IS_ERR(spi)) {
+ pr_err("%s: failed to create for '%s'\n",
+ __func__, rd->dn->full_name);
+ return notifier_from_errno(PTR_ERR(spi));
+ }
+ break;
+
+ case OF_RECONFIG_CHANGE_REMOVE:
+ /* find our device by node */
+ spi = of_find_spi_device_by_node(rd->dn);
+ if (spi == NULL)
+ return NOTIFY_OK; /* no? not meant for us */
+
+ /* unregister takes one ref away */
+ spi_unregister_device(spi);
+
+ /* and put the reference of the find */
+ put_device(&spi->dev);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block spi_of_notifier = {
+ .notifier_call = of_spi_notify,
+};
+#else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
+extern struct notifier_block spi_of_notifier;
+#endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
+
static int __init spi_init(void)
{
int status;
@@ -2334,6 +2414,10 @@ static int __init spi_init(void)
status = class_register(&spi_master_class);
if (status < 0)
goto err2;
+
+ if (IS_ENABLED(CONFIG_OF))
+ WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
+
return 0;
err2:
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
