[PATCH] serial: lantiq: Make driver modular and console configurable

From: Rahul Tanwar
Date: Fri May 08 2020 - 07:20:57 EST


Add changes so Lantiq serial driver can be compiled as a module.
Also, make this driver's use as console selectable/configurable.

Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/Kconfig | 13 +++++++++++--
drivers/tty/serial/lantiq.c | 43 ++++++++++++++++++++++++++++++++++++++++---
2 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 4b0a7b98f8c7..996782247174 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1034,13 +1034,22 @@ config SERIAL_SIFIVE_CONSOLE
boot time.)

config SERIAL_LANTIQ
- bool "Lantiq serial driver"
+ tristate "Lantiq serial driver"
depends on (LANTIQ || X86) || COMPILE_TEST
select SERIAL_CORE
+ help
+ Support for UART on Lantiq and Intel SoCs.
+ To compile this driver as a module, choose M here, the
+ module will be called lantiq.
+
+config SERIAL_LANTIQ_CONSOLE
+ bool "Console on Lantiq UART"
+ depends on SERIAL_LANTIQ=y
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
help
- Support for console and UART on Lantiq SoCs.
+ Select this option if you would like to use a Lantiq UART as the
+ system console.

config SERIAL_QE
tristate "Freescale QUICC Engine serial port support"
diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c
index c5e46ff972e4..93ed59bccd11 100644
--- a/drivers/tty/serial/lantiq.c
+++ b/drivers/tty/serial/lantiq.c
@@ -15,6 +15,7 @@
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/lantiq.h>
+#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
@@ -597,6 +598,13 @@ static const struct uart_ops lqasc_pops = {
.verify_port = lqasc_verify_port,
};

+
+/*
+ * Linux console interface
+ */
+
+#ifdef CONFIG_SERIAL_LANTIQ_CONSOLE
+
static void
lqasc_console_putchar(struct uart_port *port, int ch)
{
@@ -705,6 +713,14 @@ lqasc_serial_early_console_setup(struct earlycon_device *device,
OF_EARLYCON_DECLARE(lantiq, "lantiq,asc", lqasc_serial_early_console_setup);
OF_EARLYCON_DECLARE(lantiq, "intel,lgm-asc", lqasc_serial_early_console_setup);

+#define LANTIQ_SERIAL_CONSOLE (&lqasc_console)
+
+#else
+
+#define LANTIQ_SERIAL_CONSOLE NULL
+
+#endif
+
static struct uart_driver lqasc_reg = {
.owner = THIS_MODULE,
.driver_name = DRVNAME,
@@ -712,7 +728,7 @@ static struct uart_driver lqasc_reg = {
.major = 0,
.minor = 0,
.nr = MAXPORTS,
- .cons = &lqasc_console,
+ .cons = LANTIQ_SERIAL_CONSOLE,
};

static int fetch_irq_lantiq(struct device *dev, struct ltq_uart_port *ltq_port)
@@ -899,6 +915,13 @@ lqasc_probe(struct platform_device *pdev)
return ret;
}

+static int lqasc_remove(struct platform_device *pdev)
+{
+ struct uart_port *port = platform_get_drvdata(pdev);
+
+ return uart_remove_one_port(&lqasc_reg, port);
+}
+
static const struct ltq_soc_data soc_data_lantiq = {
.fetch_irq = fetch_irq_lantiq,
.request_irq = request_irq_lantiq,
@@ -916,8 +939,11 @@ static const struct of_device_id ltq_asc_match[] = {
{ .compatible = "intel,lgm-asc", .data = &soc_data_intel },
{},
};
+MODULE_DEVICE_TABLE(of, ltq_asc_match);

static struct platform_driver lqasc_driver = {
+ .probe = lqasc_probe,
+ .remove = lqasc_remove,
.driver = {
.name = DRVNAME,
.of_match_table = ltq_asc_match,
@@ -933,10 +959,21 @@ init_lqasc(void)
if (ret != 0)
return ret;

- ret = platform_driver_probe(&lqasc_driver, lqasc_probe);
+ ret = platform_driver_register(&lqasc_driver);
if (ret != 0)
uart_unregister_driver(&lqasc_reg);

return ret;
}
-device_initcall(init_lqasc);
+
+static void __exit exit_lqasc(void)
+{
+ platform_driver_unregister(&lqasc_driver);
+ uart_unregister_driver(&lqasc_reg);
+}
+
+module_init(init_lqasc);
+module_exit(exit_lqasc);
+
+MODULE_DESCRIPTION("Serial driver for Lantiq & Intel gateway SoCs");
+MODULE_LICENSE("GPL v2");
--
2.11.0