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parport: daisy: use new parport device model

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Modify parport daisy driver to use the new parallel port device model.

Last attempt was '1aec4211204d ("parport: daisy: use new parport device
model")' which failed as daisy was also trying to load the low level
driver and that resulted in a deadlock.

Cc: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20191016144540.18810-4-sudipm.mukherjee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sudip Mukherjee 2019-10-16 15:45:40 +01:00 committed by Greg Kroah-Hartman
parent 231ec2f24d
commit 60f8a59ddc
1 changed files with 39 additions and 1 deletions
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40
drivers/parport/daisy.c
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@ -45,6 +45,7 @@ static struct daisydev {
static DEFINE_SPINLOCK(topology_lock);
static int numdevs;
static bool daisy_init_done;
/* Forward-declaration of lower-level functions. */
static int mux_present(struct parport *port);
@ -87,6 +88,24 @@ static struct parport *clone_parport(struct parport *real, int muxport)
return extra;
}
static int daisy_drv_probe(struct pardevice *par_dev)
{
struct device_driver *drv = par_dev->dev.driver;
if (strcmp(drv->name, "daisy_drv"))
return -ENODEV;
if (strcmp(par_dev->name, daisy_dev_name))
return -ENODEV;
return 0;
}
static struct parport_driver daisy_driver = {
.name = "daisy_drv",
.probe = daisy_drv_probe,
.devmodel = true,
};
/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
* Return value is number of devices actually detected. */
int parport_daisy_init(struct parport *port)
@ -98,6 +117,23 @@ int parport_daisy_init(struct parport *port)
int i;
int last_try = 0;
if (!daisy_init_done) {
/*
* flag should be marked true first as
* parport_register_driver() might try to load the low
* level driver which will lead to announcing new ports
* and which will again come back here at
* parport_daisy_init()
*/
daisy_init_done = true;
i = parport_register_driver(&daisy_driver);
if (i) {
pr_err("daisy registration failed\n");
daisy_init_done = false;
return i;
}
}
again:
/* Because this is called before any other devices exist,
* we don't have to claim exclusive access. */
@ -213,10 +249,12 @@ void parport_daisy_fini(struct parport *port)
struct pardevice *parport_open(int devnum, const char *name)
{
struct daisydev *p = topology;
struct pardev_cb par_cb;
struct parport *port;
struct pardevice *dev;
int daisy;
memset(&par_cb, 0, sizeof(par_cb));
spin_lock(&topology_lock);
while (p && p->devnum != devnum)
p = p->next;
@ -230,7 +268,7 @@ struct pardevice *parport_open(int devnum, const char *name)
port = parport_get_port(p->port);
spin_unlock(&topology_lock);
dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
dev = parport_register_dev_model(port, name, &par_cb, devnum);
parport_put_port(port);
if (!dev)
return NULL;