[PATCH] Adding proper request of GPIO used by cpm_uart driver
From: Christophe Leroy <hidden>
Date: 2013-08-21 15:59:33
Also in:
linux-serial, lkml
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 <redacted> 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;