serial: samsung: enable clock before accessing interrupt mask resister

남영민 · gregkh · commit a8a1781b8726 · 2017-02-03T10:12:16.000+01:00
Ensure that the uart clock is enabled prior to writing to the
interrupt mask register in s3c24xx_serial_resume_noirq function.
Without enabing the uart clock, the uart register cannot be accessed.

Signed-off-by: Youngmin Nam &lt;youngmin.nam@samsung.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
@@ -1916,6 +1916,7 @@ static int s3c24xx_serial_resume(struct device *dev)
 static int s3c24xx_serial_resume_noirq(struct device *dev)
 {
 	struct uart_port *port = s3c24xx_dev_to_port(dev);
+	struct s3c24xx_uart_port *ourport = to_ourport(port);
 
 	if (port) {
 		/* restore IRQ mask */
@@ -1925,7 +1926,9 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)
 				uintm &= ~S3C64XX_UINTM_TXD_MSK;
 			if (rx_enabled(port))
 				uintm &= ~S3C64XX_UINTM_RXD_MSK;
+			clk_prepare_enable(ourport->clk);
 			wr_regl(port, S3C64XX_UINTM, uintm);
+			clk_disable_unprepare(ourport->clk);
 		}
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -1916,6 +1916,7 @@ static int s3c24xx_serial_resume(struct device *dev)`
`1916`	`1916`	`static int s3c24xx_serial_resume_noirq(struct device *dev)`
`1917`	`1917`	`{`
`1918`	`1918`	`struct uart_port *port = s3c24xx_dev_to_port(dev);`
	`1919`	`+ struct s3c24xx_uart_port *ourport = to_ourport(port);`
`1919`	`1920`
`1920`	`1921`	`if (port) {`
`1921`	`1922`	`/* restore IRQ mask */`
`@@ -1925,7 +1926,9 @@ static int s3c24xx_serial_resume_noirq(struct device *dev)`
`1925`	`1926`	`uintm &= ~S3C64XX_UINTM_TXD_MSK;`
`1926`	`1927`	`if (rx_enabled(port))`
`1927`	`1928`	`uintm &= ~S3C64XX_UINTM_RXD_MSK;`
	`1929`	`+ clk_prepare_enable(ourport->clk);`
`1928`	`1930`	`wr_regl(port, S3C64XX_UINTM, uintm);`
	`1931`	`+ clk_disable_unprepare(ourport->clk);`
`1929`	`1932`	`}`
`1930`	`1933`	`}`
`1931`	`1934`