[ARM] OpenRD: Enable SD/UART selection for serial port 1

This patch enables users to choose either the SDIO interface or UART1
(RS232/RS485). The selection can be done through kernel parameter.

By default the port would be used for SDIO interface. Passing the string
"kw_openrd_init_uart1=232" or "kw_openrd_init_uart1=485" enables either
the RS-232 or RS-485 port respectively; disabling the SDIO interface.
Anything else selects the default SDIO interface.

"kw_openrd_init_uart1=485" is ignored on OpenRD-Base as it doesn't
have RS485 port.

Signed-off-by: Tanmay Upadhyay <tanmay.upadhyay@einfochips.com>
Acked-by: Alexander Clouter <alex@digriz.org.uk>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>

1 files changed, 100 insertions, 1 deletions

diff --git a/arch/arm/mach-kirkwood/openrd-setup.c b/arch/arm/mach-kirkwood/openrd-setup.c
index fd06be618815..38017c8ac43f 100644
--- a/arch/arm/mach-kirkwood/openrd-setup.c
+++ b/arch/arm/mach-kirkwood/openrd-setup.c
@@ -16,6 +16,7 @@
 #include <linux/ata_platform.h>
 #include <linux/mv643xx_eth.h>
 #include <linux/i2c.h>
+#include <linux/gpio.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
 #include <mach/kirkwood.h>
@@ -57,7 +58,22 @@ static struct mvsdio_platform_data openrd_mvsdio_data = {
 };
 
 static unsigned int openrd_mpp_config[] __initdata = {
+        MPP12_SD_CLK,
+        MPP13_SD_CMD,
+        MPP14_SD_D0,
+        MPP15_SD_D1,
+        MPP16_SD_D2,
+        MPP17_SD_D3,
+        MPP28_GPIO,
         MPP29_GPIO,
+        MPP34_GPIO,
+        0
+};
+
+/* Configure MPP for UART1 */
+static unsigned int openrd_uart1_mpp_config[] __initdata = {
+        MPP13_UART1_TXD,
+        MPP14_UART1_RXD,
         0
 };
 
@@ -67,6 +83,68 @@ static struct i2c_board_info i2c_board_info[] __initdata = {
         },
 };
 
+static int __initdata uart1;
+
+static int __init sd_uart_selection(char *str)
+{
+        uart1 = -EINVAL;
+
+        /* Default is SD. Change if required, for UART */
+        if (!str)
+                return 0;
+
+        if (!strncmp(str, "232", 3)) {
+                uart1 = 232;
+        } else if (!strncmp(str, "485", 3)) {
+                /* OpenRD-Base doesn't have RS485. Treat is as an
+                 * unknown argument & just have default setting -
+                 * which is SD */
+                if (machine_is_openrd_base()) {
+                        uart1 = -ENODEV;
+                        return 1;
+                }
+
+                uart1 = 485;
+        }
+        return 1;
+}
+/* Parse boot_command_line string kw_openrd_init_uart1=232/485 */
+__setup("kw_openrd_init_uart1=", sd_uart_selection);
+
+static int __init uart1_mpp_config(void)
+{
+        kirkwood_mpp_conf(openrd_uart1_mpp_config);
+
+        if (gpio_request(34, "SD_UART1_SEL")) {
+                printk(KERN_ERR "GPIO request failed for SD/UART1 selection"
+                                ", gpio: 34\n");
+                return -EIO;
+        }
+
+        if (gpio_request(28, "RS232_RS485_SEL")) {
+                printk(KERN_ERR "GPIO request failed for RS232/RS485 selection"
+                                ", gpio# 28\n");
+                gpio_free(34);
+                return -EIO;
+        }
+
+        /* Select UART1
+         * Pin # 34: 0 => UART1, 1 => SD */
+        gpio_direction_output(34, 0);
+
+        /* Select RS232 OR RS485
+         * Pin # 28: 0 => RS232, 1 => RS485 */
+        if (uart1 == 232)
+                gpio_direction_output(28, 0);
+        else
+                gpio_direction_output(28, 1);
+
+        gpio_free(34);
+        gpio_free(28);
+
+        return 0;
+}
+
 static void __init openrd_init(void)
 {
         /*
@@ -90,7 +168,6 @@ static void __init openrd_init(void)
                 kirkwood_ge01_init(&openrd_ge01_data);
 
         kirkwood_sata_init(&openrd_sata_data);
-        kirkwood_sdio_init(&openrd_mvsdio_data);
 
         kirkwood_i2c_init();
 
@@ -99,6 +176,28 @@ static void __init openrd_init(void)
                         ARRAY_SIZE(i2c_board_info));
                 kirkwood_audio_init();
         }
+
+        if (uart1 <= 0) {
+                if (uart1 < 0)
+                        printk(KERN_ERR "Invalid kernel parameter to select "
+                                "UART1. Defaulting to SD. ERROR CODE: %d\n",
+                                uart1);
+
+                /* Select SD
+                 * Pin # 34: 0 => UART1, 1 => SD */
+                if (gpio_request(34, "SD_UART1_SEL")) {
+                        printk(KERN_ERR "GPIO request failed for SD/UART1 "
+                                        "selection, gpio: 34\n");
+                } else {
+
+                        gpio_direction_output(34, 1);
+                        gpio_free(34);
+                        kirkwood_sdio_init(&openrd_mvsdio_data);
+                }
+        } else {
+                if (!uart1_mpp_config())
+                        kirkwood_uart1_init();
+        }
 }
 
 static int __init openrd_pci_init(void)