[PATCH 2/6] serial: 8250: update .pm callbacks to return int

[Praveen Talari <praveen.talari@oss.qualcomm.com>]

The uart_ops.pm and uart_port.pm callback signatures have been changed
from void to int. Update all 8250 .pm implementations to match.

serial8250_do_pm() is the core 8250 power management helper, exported
for use by sub-drivers. Change its return type from void to int and
update its declaration in include/linux/serial_8250.h accordingly.
serial8250_do_pm() always returns 0.

serial8250_pm() is the uart_ops.pm entry point for the 8250 driver. It
delegates to a per-port pm function stored in uart_port.pm or falls back
to serial8250_do_pm(). Both paths are called for their side effects and
the function returns 0.

The remaining sub-driver callbacks perform their PM work through
platform-specific helpers (clocks, runtime PM, GPIO) and currently have
no error paths of their own. Update them to return 0 to satisfy the new
signature; individual error propagation can be added per-driver as
needed.

  8250_exar: exar_pm()
  8250_mtk:  mtk8250_do_pm()
  8250_omap: omap_8250_pm()
  8250_pxa:  serial_pxa_pm()

No functional change intended.

Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
---
 drivers/tty/serial/8250/8250_dw.c   | 3 ++-
 drivers/tty/serial/8250/8250_exar.c | 4 +++-
 drivers/tty/serial/8250/8250_mtk.c  | 4 +++-
 drivers/tty/serial/8250/8250_omap.c | 6 ++++--
 drivers/tty/serial/8250/8250_port.c | 9 ++++++---
 drivers/tty/serial/8250/8250_pxa.c  | 6 ++++--
 include/linux/serial_8250.h         | 6 +++---
 7 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 5fba913f3301..7d5fa11d685f 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -458,7 +458,7 @@ static int dw8250_handle_irq(struct uart_port *p)
 	return 1;
 }
 
-static void
+static int
 dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
 {
 	if (!state)
@@ -468,6 +468,7 @@ dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
 
 	if (state)
 		pm_runtime_put_sync_suspend(port->dev);
+	return 0;
 }
 
 static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index c682c0d0dffa..0d0026ea155f 100644
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -419,7 +419,7 @@ static const struct serial_rs485 generic_rs485_supported = {
 	.flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND,
 };
 
-static void exar_pm(struct uart_port *port, unsigned int state, unsigned int old)
+static int exar_pm(struct uart_port *port, unsigned int state, unsigned int old)
 {
 	/*
 	 * Exar UARTs have a SLEEP register that enables or disables each UART
@@ -428,6 +428,8 @@ static void exar_pm(struct uart_port *port, unsigned int state, unsigned int old
 	 * the UART channel may only write to the corresponding bit.
 	 */
 	serial_port_out(port, UART_EXAR_SLEEP, state ? 0xff : 0);
+
+	return 0;
 }
 
 /*
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index e6a56cf54ae0..9184b1eeddd7 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -452,7 +452,7 @@ static int __maybe_unused mtk8250_runtime_resume(struct device *dev)
 	return 0;
 }
 
-static void
+static int
 mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
 {
 	if (!state)
@@ -462,6 +462,8 @@ mtk8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
 
 	if (state)
 		pm_runtime_put_sync_suspend(port->dev);
+
+	return 0;
 }
 
 #ifdef CONFIG_SERIAL_8250_DMA
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c
index c552c6b9a037..8f099afd6ff8 100644
--- a/drivers/tty/serial/8250/8250_omap.c
+++ b/drivers/tty/serial/8250/8250_omap.c
@@ -527,8 +527,8 @@ static void omap_8250_set_termios(struct uart_port *port,
 }
 
 /* same as 8250 except that we may have extra flow bits set in EFR */
-static void omap_8250_pm(struct uart_port *port, unsigned int state,
-			 unsigned int oldstate)
+static int omap_8250_pm(struct uart_port *port, unsigned int state,
+			unsigned int oldstate)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	u8 efr;
@@ -546,6 +546,8 @@ static void omap_8250_pm(struct uart_port *port, unsigned int state,
 	serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 	serial_out(up, UART_EFR, efr);
 	serial_out(up, UART_LCR, 0);
+
+	return 0;
 }
 
 static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 630deb7dd344..315e0a2fcc14 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2848,16 +2848,18 @@ serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
 		serial8250_do_set_ldisc(port, termios);
 }
 
-void serial8250_do_pm(struct uart_port *port, unsigned int state,
-		      unsigned int oldstate)
+int serial8250_do_pm(struct uart_port *port, unsigned int state,
+		     unsigned int oldstate)
 {
 	struct uart_8250_port *p = up_to_u8250p(port);
 
 	serial8250_set_sleep(p, state != 0);
+
+	return 0;
 }
 EXPORT_SYMBOL(serial8250_do_pm);
 
-static void
+static int
 serial8250_pm(struct uart_port *port, unsigned int state,
 	      unsigned int oldstate)
 {
@@ -2865,6 +2867,7 @@ serial8250_pm(struct uart_port *port, unsigned int state,
 		port->pm(port, state, oldstate);
 	else
 		serial8250_do_pm(port, state, oldstate);
+	return 0;
 }
 
 static unsigned int serial8250_port_size(struct uart_8250_port *pt)
diff --git a/drivers/tty/serial/8250/8250_pxa.c b/drivers/tty/serial/8250/8250_pxa.c
index 6dd0190b4843..02f0037e0a31 100644
--- a/drivers/tty/serial/8250/8250_pxa.c
+++ b/drivers/tty/serial/8250/8250_pxa.c
@@ -76,8 +76,8 @@ static void serial_pxa_dl_write(struct uart_8250_port *up, u32 value)
 }
 
 
-static void serial_pxa_pm(struct uart_port *port, unsigned int state,
-	      unsigned int oldstate)
+static int serial_pxa_pm(struct uart_port *port, unsigned int state,
+			 unsigned int oldstate)
 {
 	struct pxa8250_data *data = port->private_data;
 
@@ -85,6 +85,8 @@ static void serial_pxa_pm(struct uart_port *port, unsigned int state,
 		clk_prepare_enable(data->clk);
 	else
 		clk_disable_unprepare(data->clk);
+
+	return 0;
 }
 
 static int serial_pxa_probe(struct platform_device *pdev)
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index a95b2d143d24..12916189c20c 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -57,7 +57,7 @@ struct plat_serial8250_port {
 				     struct ktermios *);
 	unsigned int	(*get_mctrl)(struct uart_port *);
 	int		(*handle_irq)(struct uart_port *);
-	void		(*pm)(struct uart_port *, unsigned int state,
+	int		(*pm)(struct uart_port *port, unsigned int state,
 			      unsigned old);
 	void		(*handle_break)(struct uart_port *);
 };
@@ -189,8 +189,8 @@ void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios);
 unsigned int serial8250_do_get_mctrl(struct uart_port *port);
 int serial8250_do_startup(struct uart_port *port);
 void serial8250_do_shutdown(struct uart_port *port);
-void serial8250_do_pm(struct uart_port *port, unsigned int state,
-		      unsigned int oldstate);
+int serial8250_do_pm(struct uart_port *port, unsigned int state,
+		     unsigned int oldstate);
 void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl);
 void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
 			       unsigned int quot);

-- 
2.34.1