On 2013-04-17 19:16, H Hartley Sweeten wrote:
This function is intended to be used by the comedi legacy (ISA) drivers
either directly as the (*detach) function or as a helper in the drivers
private (*detach) function.
Modify the __comedi_request_region() helper so that it stores the first
struct resource returned by request_region() in the comedi_device.
The comedi_legacy_detach() function will then automatically release the
region during the detach of the driver.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/comedidev.h | 2 ++
drivers/staging/comedi/drivers.c | 29 ++++++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h
index ce509d0..48dfe16 100644
--- a/drivers/staging/comedi/comedidev.h
+++ b/drivers/staging/comedi/comedidev.h
@@ -215,6 +215,7 @@ struct comedi_device {
struct comedi_subdevice *subdevices;
/* dumb */
+ struct resource *res;
unsigned long iobase;
unsigned int irq;
@@ -354,6 +355,7 @@ int __comedi_request_region(struct comedi_device *,
unsigned long start, unsigned long len);
int comedi_request_region(struct comedi_device *,
unsigned long start, unsigned long len);
+void comedi_legacy_detach(struct comedi_device *);
int comedi_auto_config(struct device *, struct comedi_driver *,
unsigned long context);
diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c
index 2a28f64..cb5f0d5 100644
--- a/drivers/staging/comedi/drivers.c
+++ b/drivers/staging/comedi/drivers.c
@@ -121,6 +121,7 @@ static void cleanup_device(struct comedi_device *dev)
dev->driver = NULL;
dev->board_name = NULL;
dev->board_ptr = NULL;
+ dev->res = NULL;
dev->iobase = 0;
dev->ioenabled = false;
dev->irq = 0;
@@ -358,6 +359,8 @@ static void comedi_report_boards(struct comedi_driver *driv)
int __comedi_request_region(struct comedi_device *dev,
unsigned long start, unsigned long len)
{
+ struct resource *res;
+
if (!start) {
dev_warn(dev->class_dev,
"%s: a I/O base address must be specified\n",
@@ -365,12 +368,23 @@ int __comedi_request_region(struct comedi_device *dev,
return -EINVAL;
}
- if (!request_region(start, len, dev->board_name)) {
+ res = request_region(start, len, dev->board_name);
+ if (!res) {
dev_warn(dev->class_dev, "%s: I/O port conflict (%#lx,%lu)\n",
dev->board_name, start, len);
return -EIO;
}
+ /*
+ * Save the resource of the first region requested by a driver.
+ * comedi_legacy_detach() will automatically release that region.
+ *
+ * If a driver request additional regions, it must release those
+ * regions during the (*detach).
+ */
+ if (!dev->res)
+ dev->res = res;
+
return 0;
}
EXPORT_SYMBOL_GPL(__comedi_request_region);
@@ -394,6 +408,19 @@ int comedi_request_region(struct comedi_device *dev,
}
EXPORT_SYMBOL_GPL(comedi_request_region);
+/**
+ * comedi_legacy_detach() - A generic (*detach) function for legacy drivers.
+ * @dev: comedi_device struct
+ */
+void comedi_legacy_detach(struct comedi_device *dev)
+{
+ if (dev->res) {
+ release_region(dev->res->start, resource_size(dev->res));
+ dev->res = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(comedi_legacy_detach);
+
int comedi_device_attach(struct comedi_device *dev, struct comedi_devconfig *it)
{
struct comedi_driver *driv;
An alternative implementation would be to leave
__comedi_request_region() alone, but change comedi_request_region() to
record the length in a new member dev->iolen at the same time that it
records the start address in dev->iobase. Then your
comedi_legacy_detach() could do something like:
if (dev->iolen) {
release_region(dev->iobase, dev->iolen);
dev->iolen = 0;
}
I think it seems slightly simpler and shouldn't affect your other
patches. Any thoughts?
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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