[PATCH v8 11/24] drivers/fsi: Add master unscan

From: Christopher Bostic
Date: Tue Jun 06 2017 - 17:09:42 EST


Allow a master to undo a previous scan. Should a master scan a bus
twice it will need to ensure it doesn't double register any
previously detected device.

Signed-off-by: Christopher Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
----
v7 - Unscan when unregistering master
- Remove leading '__'s from function names
- Return fail state for sysfs rescan file
---
drivers/fsi/fsi-core.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)

diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index d7a6e76..fcb0c81 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -71,6 +71,7 @@ struct fsi_slave {
uint32_t size; /* size of slave address space */
};

+#define to_fsi_master(d) container_of(d, struct fsi_master, dev)
#define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)

static int fsi_master_read(struct fsi_master *master, int link,
@@ -488,6 +489,40 @@ static int fsi_master_scan(struct fsi_master *master)
return 0;
}

+static int fsi_slave_remove_device(struct device *dev, void *arg)
+{
+ device_unregister(dev);
+ return 0;
+}
+
+static int fsi_master_remove_slave(struct device *dev, void *arg)
+{
+ device_for_each_child(dev, NULL, fsi_slave_remove_device);
+ device_unregister(dev);
+ return 0;
+}
+
+static void fsi_master_unscan(struct fsi_master *master)
+{
+ device_for_each_child(&master->dev, NULL, fsi_master_remove_slave);
+}
+
+static ssize_t master_rescan_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct fsi_master *master = to_fsi_master(dev);
+ int rc;
+
+ fsi_master_unscan(master);
+ rc = fsi_master_scan(master);
+ if (rc < 0)
+ return rc;
+
+ return count;
+}
+
+static DEVICE_ATTR(rescan, 0200, NULL, master_rescan_store);
+
int fsi_master_register(struct fsi_master *master)
{
int rc;
@@ -504,7 +539,15 @@ int fsi_master_register(struct fsi_master *master)
return rc;
}

+ rc = device_create_file(&master->dev, &dev_attr_rescan);
+ if (rc) {
+ device_unregister(&master->dev);
+ ida_simple_remove(&master_ida, master->idx);
+ return rc;
+ }
+
fsi_master_scan(master);
+
return 0;
}
EXPORT_SYMBOL_GPL(fsi_master_register);
@@ -516,6 +559,7 @@ void fsi_master_unregister(struct fsi_master *master)
master->idx = -1;
}

+ fsi_master_unscan(master);
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(fsi_master_unregister);
--
1.8.2.2