[PATCH 4.19 106/118] tty: serial: 8250_mtk: always resume the device in probe.

[Greg Kroah-Hartman]

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Shih <pih...@chromium.org>

commit 100bc3e2bebf95506da57cbdf5f26b25f6da4c81 upstream.

serial8250_register_8250_port calls uart_config_port, which calls
config_port on the port before it tries to power on the port. So we need
the port to be on before calling serial8250_register_8250_port. Change
the code to always do a runtime resume in probe before registering port,
and always do a runtime suspend in remove.

This basically reverts the change in commit 68e5fc4a255a ("tty: serial:
8250_mtk: use pm_runtime callbacks for enabling"), but still use
pm_runtime callbacks.

Fixes: 68e5fc4a255a ("tty: serial: 8250_mtk: use pm_runtime callbacks for 
enabling")
Signed-off-by: Peter Shih <pih...@chromium.org>
Cc: stable <sta...@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/tty/serial/8250/8250_mtk.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -213,17 +213,17 @@ static int mtk8250_probe(struct platform
 
        platform_set_drvdata(pdev, data);
 
-       pm_runtime_enable(&pdev->dev);
-       if (!pm_runtime_enabled(&pdev->dev)) {
-               err = mtk8250_runtime_resume(&pdev->dev);
-               if (err)
-                       return err;
-       }
+       err = mtk8250_runtime_resume(&pdev->dev);
+       if (err)
+               return err;
 
        data->line = serial8250_register_8250_port(&uart);
        if (data->line < 0)
                return data->line;
 
+       pm_runtime_set_active(&pdev->dev);
+       pm_runtime_enable(&pdev->dev);
+
        return 0;
 }
 
@@ -234,13 +234,11 @@ static int mtk8250_remove(struct platfor
        pm_runtime_get_sync(&pdev->dev);
 
        serial8250_unregister_port(data->line);
+       mtk8250_runtime_suspend(&pdev->dev);
 
        pm_runtime_disable(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
 
-       if (!pm_runtime_status_suspended(&pdev->dev))
-               mtk8250_runtime_suspend(&pdev->dev);
-
        return 0;
 }