Author: ian
Date: Fri Dec 6 22:32:06 2019
New Revision: 355467
URL: https://svnweb.freebsd.org/changeset/base/355467
Log:
Implement bus_rescan for gpiobus(4). This allows on-the-fly reconfiguration
of gpio devices by using kenv to add hints for a new device and then do
'devctl rescan gpiobus4' to make the new device(s) attach.
It's not particularly easy to detect whether the 'at' hint has been deleted
for a child device that's currently attached, so this doesn't handle that.
But the user can use devctl commands to manually detach an existing device.
Modified:
head/sys/dev/gpio/gpiobus.c
Modified: head/sys/dev/gpio/gpiobus.c
==============================================================================
--- head/sys/dev/gpio/gpiobus.c Fri Dec 6 22:20:26 2019 (r355466)
+++ head/sys/dev/gpio/gpiobus.c Fri Dec 6 22:32:06 2019 (r355467)
@@ -716,6 +716,21 @@ gpiobus_add_child(device_t dev, u_int order, const cha
return (child);
}
+static int
+gpiobus_rescan(device_t dev)
+{
+
+ /*
+ * Re-scan is supposed to remove and add children, but if someone has
+ * deleted the hints for a child we attached earlier, we have no easy
+ * way to handle that. So this just attaches new children for whom new
+ * hints or drivers have arrived since we last tried.
+ */
+ bus_enumerate_hinted_children(dev);
+ bus_generic_attach(dev);
+ return (0);
+}
+
static void
gpiobus_hinted_child(device_t bus, const char *dname, int dunit)
{
@@ -725,6 +740,10 @@ gpiobus_hinted_child(device_t bus, const char *dname,
const char *pins;
int irq, pinmask;
+ if (device_find_child(bus, dname, dunit) != NULL) {
+ return;
+ }
+
child = BUS_ADD_CHILD(bus, 0, dname, dunit);
devi = GPIOBUS_IVAR(child);
if (resource_int_value(dname, dunit, "pins", &pinmask) == 0) {
@@ -1077,6 +1096,7 @@ static device_method_t gpiobus_methods[] = {
DEVMETHOD(bus_deactivate_resource,
bus_generic_deactivate_resource),
DEVMETHOD(bus_get_resource_list, gpiobus_get_resource_list),
DEVMETHOD(bus_add_child, gpiobus_add_child),
+ DEVMETHOD(bus_rescan, gpiobus_rescan),
DEVMETHOD(bus_probe_nomatch, gpiobus_probe_nomatch),
DEVMETHOD(bus_print_child, gpiobus_print_child),
DEVMETHOD(bus_child_pnpinfo_str, gpiobus_child_pnpinfo_str),
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