Adding proper request of GPIO used by cpm_uart driver

Submitted by Christophe Leroy on Aug. 21, 2013, 3:59 p.m.

Details

Message ID 201308211559.r7LFxOBV025845@localhost.localdomain
State Not Applicable
Headers show

Commit Message

Christophe Leroy Aug. 21, 2013, 3:59 p.m.
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>

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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;