TTY: serial, handle platform_get_irq retval properly

platform_get_irq can fail, so we should handle negative value when
returned.

[v2]

platform_get_irq can actually return zero on some platforms. So do not
remove checks for irq == 0 there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/amba-pl011.c

@@ -2553,11 +2553,17 @@ static int sbsa_uart_probe(struct platform_device *pdev)
 	if (!uap)
 		return -ENOMEM;
 
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "cannot obtain irq\n");
+		return ret;
+	}
+	uap->port.irq	= ret;
+
 	uap->reg_offset	= vendor_sbsa.reg_offset;
 	uap->vendor	= &vendor_sbsa;
 	uap->fifosize	= 32;
 	uap->port.iotype = vendor_sbsa.access_32b ? UPIO_MEM32 : UPIO_MEM;
-	uap->port.irq	= platform_get_irq(pdev, 0);
 	uap->port.ops	= &sbsa_uart_pops;
 	uap->fixed_baud = baudrate;
 

drivers/tty/serial/fsl_lpuart.c

@@ -1830,7 +1830,13 @@ static int lpuart_probe(struct platform_device *pdev)
 	sport->port.dev = &pdev->dev;
 	sport->port.type = PORT_LPUART;
 	sport->port.iotype = UPIO_MEM;
-	sport->port.irq = platform_get_irq(pdev, 0);
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "cannot obtain irq\n");
+		return ret;
+	}
+	sport->port.irq = ret;
+
 	if (sport->lpuart32)
 		sport->port.ops = &lpuart32_pops;
 	else

drivers/tty/serial/pmac_zilog.c

@@ -1720,7 +1720,7 @@ static int __init pmz_init_port(struct uart_pmac_port *uap)
 
 	r_ports = platform_get_resource(uap->pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_irq(uap->pdev, 0);
-	if (!r_ports || !irq)
+	if (!r_ports || irq <= 0)
 		return -ENODEV;
 
 	uap->port.mapbase  = r_ports->start;

drivers/tty/serial/serial-tegra.c

@@ -1317,7 +1317,12 @@ static int tegra_uart_probe(struct platform_device *pdev)
 	}
 
 	u->iotype = UPIO_MEM32;
-	u->irq = platform_get_irq(pdev, 0);
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Couldn't get IRQ\n");
+		return ret;
+	}
+	u->irq = ret;
 	u->regshift = 2;
 	ret = uart_add_one_port(&tegra_uart_driver, u);
 	if (ret < 0) {