serial: 8250_bcm2835aux: add PM suspend/resume support

This adds suspend/resume support for the 8250_bcm2835aux
driver to provide power management support on attached
devices.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240728130029.78279-7-wahrenst@gmx.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
index 121a5ce8605089ae2e1877b56bfc4190c808355d..36e2bb34d82bd9aaac7559df211eb2d5ad4c18f2 100644 (file)
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -13,6 +13,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/console.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -213,11 +214,47 @@ static const struct acpi_device_id bcm2835aux_serial_acpi_match[] = {
 };
 MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match);
 
+static int bcm2835aux_suspend(struct device *dev)
+{
+       struct bcm2835aux_data *data = dev_get_drvdata(dev);
+       struct uart_8250_port *up = serial8250_get_port(data->line);
+
+       serial8250_suspend_port(data->line);
+
+       if (device_may_wakeup(dev))
+               return 0;
+
+       if (uart_console(&up->port) && !console_suspend_enabled)
+               return 0;
+
+       clk_disable_unprepare(data->clk);
+       return 0;
+}
+
+static int bcm2835aux_resume(struct device *dev)
+{
+       struct bcm2835aux_data *data = dev_get_drvdata(dev);
+       int ret;
+
+       ret = clk_prepare_enable(data->clk);
+       if (ret)
+               return ret;
+
+       serial8250_resume_port(data->line);
+
+       return 0;
+}
+
+static const struct dev_pm_ops bcm2835aux_dev_pm_ops = {
+       SYSTEM_SLEEP_PM_OPS(bcm2835aux_suspend, bcm2835aux_resume)
+};
+
 static struct platform_driver bcm2835aux_serial_driver = {
        .driver = {
                .name = "bcm2835-aux-uart",
                .of_match_table = bcm2835aux_serial_match,
                .acpi_match_table = bcm2835aux_serial_acpi_match,
+               .pm = pm_ptr(&bcm2835aux_dev_pm_ops),
        },
        .probe  = bcm2835aux_serial_probe,
        .remove_new = bcm2835aux_serial_remove,