From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christophe Leroy <christophe.leroy@c-s.fr>
Subject: [PATCH] Adding proper request of GPIO used by cpm_uart driver
Date: Wed, 21 Aug 2013 17:59:24 +0200
Message-ID: <201308211559.r7LFxOBV025845@localhost.localdomain>
Return-path: <linux-kernel-owner@vger.kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
List-Id: linux-serial@vger.kernel.org

cpm_uart serial driver uses GPIO for control signals. In order to be used
properly, GPIOs have to be reserved. Comment in gpiolib.c considers illegal
the use of GPIOs without requesting them. In addition, the direction of the
GPIO has to be set properly.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

diff -ur linux-3.8.13/drivers/tty/serial/cpm_uart/cpm_uart_core.c linux/drivers/tty/serial/cpm_uart/cpm_uart_core.c
--- linux-3.8.13/drivers/tty/serial/cpm_uart/cpm_uart_core.c	2013-08-21 05:34:03.000000000 +0200
+++ linux/drivers/tty/serial/cpm_uart/cpm_uart_core.c	2013-08-21 05:30:04.000000000 +0200
@@ -1213,8 +1213,32 @@
 		goto out_pram;
 	}
 
-	for (i = 0; i < NUM_GPIOS; i++)
-		pinfo->gpios[i] = of_get_gpio(np, i);
+	for (i = 0; i < NUM_GPIOS; i++) {
+		int gpio;
+
+		pinfo->gpios[i] = -1;
+
+		gpio = of_get_gpio(np, i);
+
+		if (gpio_is_valid(gpio)) {
+			ret = gpio_request(gpio, "cpm_uart");
+			if (ret) {
+				pr_err("can't request gpio #%d: %d\n", i, ret);
+				continue;
+			}
+			if (i == GPIO_RTS || i == GPIO_DTR)
+				ret = gpio_direction_output(gpio, 0);
+			else
+				ret = gpio_direction_input(gpio);
+			if (ret) {
+				pr_err("can't set direction for gpio #%d: %d\n",
+					i, ret);
+				gpio_free(gpio);
+				continue;
+			}
+			pinfo->gpios[i] = gpio;
+		}
+	}
 
 #ifdef CONFIG_PPC_EARLY_DEBUG_CPM
 	udbg_putc = NULL;