The driver core supports the ability to handle the creation and removal
of device-specific sysfs files in a race-free manner. Moreover, it can
guarantee the success of creation. Therefore, it should be better to
convert to use dev_groups.
Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
---
Changelog:
v4 -> v5:
1. Use a forward declaration for ftdi_sio_groups.
2. Correct ftdi_sio_attr_is_visible() implementation.
v3 -> v4:
1. Move the code and remove the pre-definitions.
v2 -> v3:
1. Add is_visible to filter the unneeded files.
v1 -> v2:
1. Change the title.
2. Switch to use an attribute group.
---
drivers/usb/serial/ftdi_sio.c | 60 +++++++++++++++++------------------
1 file changed, 29 insertions(+), 31 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index d5a3986dfee7..660181064cda 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1108,10 +1108,13 @@ static u32 ftdi_232bm_baud_to_divisor(int baud);
static u32 ftdi_2232h_baud_base_to_divisor(int baud, int base);
static u32 ftdi_2232h_baud_to_divisor(int baud);
+extern const struct attribute_group *ftdi_sio_groups[];
+
static struct usb_serial_driver ftdi_sio_device = {
.driver = {
.owner = THIS_MODULE,
.name = "ftdi_sio",
+ .dev_groups = ftdi_sio_groups,
},
.description = "FTDI USB Serial Device",
.id_table = id_table_combined,
@@ -1729,38 +1732,19 @@ static ssize_t event_char_store(struct device *dev,
}
static DEVICE_ATTR_WO(event_char);
-static int create_sysfs_attrs(struct usb_serial_port *port)
+static umode_t ftdi_sio_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int idx)
{
+ struct device *dev = kobj_to_dev(kobj);
+ struct usb_serial_port *port = container_of(dev, struct usb_serial_port, dev);
struct ftdi_private *priv = usb_get_serial_port_data(port);
- int retval = 0;
+ umode_t mode = attr->mode;
/* XXX I've no idea if the original SIO supports the event_char
* sysfs parameter, so I'm playing it safe. */
if (priv->chip_type != SIO) {
- dev_dbg(&port->dev, "sysfs attributes for %s\n", ftdi_chip_name[priv->chip_type]);
- retval = device_create_file(&port->dev, &dev_attr_event_char);
- if ((!retval) &&
- (priv->chip_type == FT232BM ||
- priv->chip_type == FT2232C ||
- priv->chip_type == FT232RL ||
- priv->chip_type == FT2232H ||
- priv->chip_type == FT4232H ||
- priv->chip_type == FT232H ||
- priv->chip_type == FTX)) {
- retval = device_create_file(&port->dev,
- &dev_attr_latency_timer);
- }
- }
- return retval;
-}
-
-static void remove_sysfs_attrs(struct usb_serial_port *port)
-{
- struct ftdi_private *priv = usb_get_serial_port_data(port);
-
- /* XXX see create_sysfs_attrs */
- if (priv->chip_type != SIO) {
- device_remove_file(&port->dev, &dev_attr_event_char);
+ if (attr == &dev_attr_event_char.attr)
+ return mode;
if (priv->chip_type == FT232BM ||
priv->chip_type == FT2232C ||
priv->chip_type == FT232RL ||
@@ -1768,12 +1752,29 @@ static void remove_sysfs_attrs(struct usb_serial_port *port)
priv->chip_type == FT4232H ||
priv->chip_type == FT232H ||
priv->chip_type == FTX) {
- device_remove_file(&port->dev, &dev_attr_latency_timer);
+ if (attr == &dev_attr_latency_timer.attr)
+ return mode;
}
}
-
+ return 0;
}
+static struct attribute *ftdi_sio_attrs[] = {
+ &dev_attr_event_char.attr,
+ &dev_attr_latency_timer.attr,
+ NULL,
+};
+
+static const struct attribute_group ftdi_sio_group = {
+ .attrs = ftdi_sio_attrs,
+ .is_visible = ftdi_sio_attr_is_visible,
+};
+
+const struct attribute_group *ftdi_sio_groups[] = {
+ &ftdi_sio_group,
+ NULL
+};
+
#ifdef CONFIG_GPIOLIB
static int ftdi_set_bitmode(struct usb_serial_port *port, u8 mode)
@@ -2251,7 +2252,6 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
if (read_latency_timer(port) < 0)
priv->latency = 16;
write_latency_timer(port);
- create_sysfs_attrs(port);
result = ftdi_gpio_init(port);
if (result < 0) {
@@ -2377,8 +2377,6 @@ static void ftdi_sio_port_remove(struct usb_serial_port *port)
ftdi_gpio_remove(port);
- remove_sysfs_attrs(port);
-
kfree(priv);
}
--
2.25.1
