[RFC PATCH 2/3] serial: uartps: Move register to probe based on run time detection

From: Michal Simek
Date: Thu Apr 26 2018 - 10:08:56 EST


Find out the highest serial alias and allocate that amount of
structures/minor numbers to be able to handle all of them.
Origin setting that there are two prealocated CDNS_UART_NR_PORTS is kept
there.

Signed-off-by: Michal Simek <michal.simek@xxxxxxxxxx>
---

Discussed here: https://patchwork.kernel.org/patch/9738445/

The same solution is done in pl011 driver.
---
drivers/tty/serial/xilinx_uartps.c | 32 ++++++++++++++++--------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 0fc9de20843c..ffb5b66a05b5 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1432,6 +1432,22 @@ static int cdns_uart_probe(struct platform_device *pdev)
struct cdns_uart *cdns_uart_data;
const struct of_device_id *match;

+ if (!cdns_uart_uart_driver.state) {
+ rc = of_alias_get_highest_id("serial");
+ if (rc >= CDNS_UART_NR_PORTS) {
+ /* serial2 means 3 ports that's why rc(2) + 1 here */
+ rc += 1;
+ /* Rewrite default setup which is using 2 ports */
+ cdns_uart_uart_driver.nr = rc;
+ }
+
+ rc = uart_register_driver(&cdns_uart_uart_driver);
+ if (rc < 0) {
+ dev_err(&pdev->dev, "Failed to register driver\n");
+ return rc;
+ }
+ }
+
cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data),
GFP_KERNEL);
if (!cdns_uart_data)
@@ -1622,28 +1638,14 @@ static struct platform_driver cdns_uart_platform_driver = {

static int __init cdns_uart_init(void)
{
- int retval = 0;
-
- /* Register the cdns_uart driver with the serial core */
- retval = uart_register_driver(&cdns_uart_uart_driver);
- if (retval)
- return retval;
-
/* Register the platform driver */
- retval = platform_driver_register(&cdns_uart_platform_driver);
- if (retval)
- uart_unregister_driver(&cdns_uart_uart_driver);
-
- return retval;
+ return platform_driver_register(&cdns_uart_platform_driver);
}

static void __exit cdns_uart_exit(void)
{
/* Unregister the platform driver */
platform_driver_unregister(&cdns_uart_platform_driver);
-
- /* Unregister the cdns_uart driver */
- uart_unregister_driver(&cdns_uart_uart_driver);
}

arch_initcall(cdns_uart_init);
--
2.17.0