tty: serial: qcom_geni_serial: Add comments for clarification

* Document reason for newline character counting in console_write
* Document reason for disabling IRQ in the system resume operation

Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index c3eb87c028a6..dcd22ca33485 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -286,6 +286,10 @@ __qcom_geni_serial_console_write(struct uart_port *uport, const char *s,
         u32 bytes_to_send = count;
 
         for (i = 0; i < count; i++) {
+                /*
+                 * uart_console_write() adds a carriage return for each newline.
+                 * Account for additional bytes to be written.
+                 */
                 if (s[i] == '\n')
                         bytes_to_send++;
         }
@@ -1101,6 +1105,14 @@ static int __maybe_unused qcom_geni_serial_sys_resume_noirq(struct device *dev)
 
         if (console_suspend_enabled && uport->suspended) {
                 uart_resume_port(uport->private_data, uport);
+                /*
+                 * uart_suspend_port() invokes port shutdown which in turn
+                 * frees the irq. uart_resume_port invokes port startup which
+                 * performs request_irq. The request_irq auto-enables the IRQ.
+                 * In addition, resume_noirq implicitly enables the IRQ and
+                 * leads to an unbalanced IRQ enable warning. Disable the IRQ
+                 * before returning so that the warning is suppressed.
+                 */
                 disable_irq(uport->irq);
         }
         return 0;