uart_register_driver call binds the driver to a specific device
node through tty_register_driver call. This should typically happen
during device probe call.
In a multiplatform scenario, it is possible that multiple serial
drivers are part of the kernel. Currently the driver registration fails
if multiple serial drivers with same default major/minor numbers are
included in the kernel.
A typical case is observed with amba-pl011 and samsung-uart drivers.
Signed-off-by: Tushar Behera <tushar.beh...@linaro.org>
---
drivers/tty/serial/amba-pl011.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index d58783d..d4eda24 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2154,9 +2154,19 @@ static int pl011_probe(struct amba_device *dev, const
struct amba_id *id)
amba_ports[i] = uap;
amba_set_drvdata(dev, uap);
+
+ if (!amba_reg.state) {
+ ret = uart_register_driver(&amba_reg);
+ if (ret < 0) {
+ pr_err("Failed to register AMBA-PL011 driver\n");
+ return ret;
+ }
+ }
+
ret = uart_add_one_port(&amba_reg, &uap->port);
if (ret) {
amba_ports[i] = NULL;
+ uart_unregister_driver(&amba_reg);
pl011_dma_remove(uap);
}
out:
@@ -2175,6 +2185,7 @@ static int pl011_remove(struct amba_device *dev)
amba_ports[i] = NULL;
pl011_dma_remove(uap);
+ uart_unregister_driver(&amba_reg);
return 0;
}
@@ -2230,22 +2241,14 @@ static struct amba_driver pl011_driver = {
static int __init pl011_init(void)
{
- int ret;
printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
- ret = uart_register_driver(&amba_reg);
- if (ret == 0) {
- ret = amba_driver_register(&pl011_driver);
- if (ret)
- uart_unregister_driver(&amba_reg);
- }
- return ret;
+ return amba_driver_register(&pl011_driver);
}
static void __exit pl011_exit(void)
{
amba_driver_unregister(&pl011_driver);
- uart_unregister_driver(&amba_reg);
}
/*
--
1.7.9.5
--
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