[PATCH, v2] serial: tegra: Add missing clk_disable_unprepare() in tegra_uart_hw_init()

[Yi Yang]

Add the missing clk_disable_unprepare() before return from
tegra_uart_hw_init() in the error handling path.
When request_irq() fails in tegra_uart_startup(), 'tup->uart_clk'
has been enabled, fix it by adding clk_disable_unprepare().

Fixes: cc9ca4d95846 ("serial: tegra: Only print FIFO error message when an error occurs")
Fixes: d781ec21bae6 ("serial: tegra: report clk rate errors")
Signed-off-by: Yi Yang <yiyang13@xxxxxxxxxx>
---
v2:
- it is also missing in tegra_uart_startup() if an error occurs
after a successful tegra_uart_hw_init() call, fix it.
 drivers/tty/serial/serial-tegra.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index e5b9773db5e3..1cf08b33456c 100644
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -1046,6 +1046,7 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
 	if (tup->cdata->fifo_mode_enable_status) {
 		ret = tegra_uart_wait_fifo_mode_enabled(tup);
 		if (ret < 0) {
+			clk_disable_unprepare(tup->uart_clk);
 			dev_err(tup->uport.dev,
 				"Failed to enable FIFO mode: %d\n", ret);
 			return ret;
@@ -1067,6 +1068,7 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
 	 */
 	ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
 	if (ret < 0) {
+		clk_disable_unprepare(tup->uart_clk);
 		dev_err(tup->uport.dev, "Failed to set baud rate\n");
 		return ret;
 	}
@@ -1226,10 +1228,13 @@ static int tegra_uart_startup(struct uart_port *u)
 				dev_name(u->dev), tup);
 	if (ret < 0) {
 		dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
-		goto fail_hw_init;
+		goto fail_request_irq;
 	}
 	return 0;
 
+fail_request_irq:
+	/* tup->uart_clk is already enabled in tegra_uart_hw_init */
+	clk_disable_unprepare(tup->uart_clk);
 fail_hw_init:
 	if (!tup->use_rx_pio)
 		tegra_uart_dma_channel_free(tup, true);
-- 
2.17.1