On 08.08.2018 14:10, Greg KH wrote:
On Mon, Aug 06, 2018 at 12:03:10PM +0200, Christian Gromm wrote:
The channel attribute dbr_size is only relevant for the DIM2 interface. So
is the packets_per_xact for USB. Currently, all attrs are shown by default
in sysfs for any channel. To get a clean content of a channel directory,
this patch makes the attributes show up only on the channel they belong to.
Signed-off-by: Christian Gromm <christian.gromm@xxxxxxxxxxxxx>
---
drivers/staging/most/core.c | 12 +++++++++---
drivers/staging/most/core.h | 5 +++++
drivers/staging/most/dim2/dim2.c | 1 +
drivers/staging/most/usb/usb.c | 1 +
4 files changed, 16 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/most/core.c b/drivers/staging/most/core.c
index f4c4646..19694a1 100644
--- a/drivers/staging/most/core.c
+++ b/drivers/staging/most/core.c
@@ -25,6 +25,7 @@
#define MAX_CHANNELS 64
#define STRING_SIZE 80
+#define MAX_NUM_ATTRS 14
static struct ida mdev_id;
static int dummy_num_buffers;
@@ -459,7 +460,7 @@ static DEVICE_ATTR_RW(set_subbuffer_size);
static DEVICE_ATTR_RW(set_packets_per_xact);
static DEVICE_ATTR_RW(set_dbr_size);
-static struct attribute *channel_attrs[] = {
+static struct attribute *channel_attrs[MAX_NUM_ATTRS] = {
Oh, this is ripe for abuse :)
DEV_ATTR(available_directions),
DEV_ATTR(available_datatypes),
DEV_ATTR(number_of_packet_buffers),
@@ -472,8 +473,6 @@ static struct attribute *channel_attrs[] = {
DEV_ATTR(set_direction),
DEV_ATTR(set_datatype),
DEV_ATTR(set_subbuffer_size),
- DEV_ATTR(set_packets_per_xact),
- DEV_ATTR(set_dbr_size),
NULL,
};
@@ -1416,6 +1415,13 @@ int most_register_interface(struct most_interface *iface)
iface->dev.init_name = iface->p->name;
iface->dev.bus = &mc.bus;
iface->dev.parent = &mc.dev;
+ if (iface->extra_attrs == XACT_ATTRS) {
+ channel_attrs[12] = DEV_ATTR(set_packets_per_xact);
+ channel_attrs[13] = NULL;
+ } else if (iface->extra_attrs == DBR_ATTRS) {
+ channel_attrs[12] = DEV_ATTR(set_dbr_size);
+ channel_attrs[13] = NULL;
+ }
No, please use the proper way of doing this. Your attribute can have a
callback when it is being created to test if it should be created or
not. Use that, this is exactly what it is there for.
Hmm, I don't see how to hook a custom callback to a device attribute
as its structure does not provide any pointer to do so.
I went down the rabbit hole staring at "device_register", but
I couldn't find any code that checks for such a function before
adding the attributes to sysfs.
Can you please point out some driver code that makes use of such
a callback you are talking about? That would be nice.
all the best,
Chris
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