renumber XO-1.75 serial ports

[dsd]

The XO-1.75 has four serial ports.

• ttyS0: quanta's debug connector
• ttyS1: unconnected
• ttyS2: standard serial port used for OFW/kernel messages, runs a getty during Linux operation
• ttyS3: alternate serial port, nothing uses it by default

Paul suggests that we could unravel the mmp2/pxa layers a bit so that we can assign a better numbering scheme. Renaming ttyS2 to ttyS0 would solve a few special cases (bringing it in-line with XO-1/XO-1.5).

[dsd]

See olpc_xo_1_75_init() in olpc-xo-1-75.c for where the serial ports are created (with fixed numbers) at the moment.

[pgf]

for instance, this fixes it. (thanks to jnettlet) may or may not be the right place, layering-wise.

diff --git a/arch/arm/mach-mmp/mmp2.c b/arch/arm/mach-mmp/mmp2.c
index b1f5126..dc09b72 100644
--- a/arch/arm/mach-mmp/mmp2.c
+++ b/arch/arm/mach-mmp/mmp2.c
@@ -382,10 +382,17 @@ struct sys_timer mmp2_timer = {
 };
 
 /* on-chip devices */
+#ifdef CONFIG_MACH_OLPC_XO_1_75
+MMP2_DEVICE(uart1, "pxa2xx-uart", 2, UART1, 0xd4030000, 0x30, 4, 5);
+MMP2_DEVICE(uart2, "pxa2xx-uart", 3, UART2, 0xd4017000, 0x30, 20, 21);
+MMP2_DEVICE(uart3, "pxa2xx-uart", 0, UART3, 0xd4018000, 0x30, 22, 23);
+MMP2_DEVICE(uart4, "pxa2xx-uart", 1, UART4, 0xd4016000, 0x30, 18, 19);
+#else
 MMP2_DEVICE(uart1, "pxa2xx-uart", 0, UART1, 0xd4030000, 0x30, 4, 5);
 MMP2_DEVICE(uart2, "pxa2xx-uart", 1, UART2, 0xd4017000, 0x30, 20, 21);
 MMP2_DEVICE(uart3, "pxa2xx-uart", 2, UART3, 0xd4018000, 0x30, 22, 23);
 MMP2_DEVICE(uart4, "pxa2xx-uart", 3, UART4, 0xd4016000, 0x30, 18, 19);
+#endif
 MMP2_DEVICE(twsi1, "pxa2xx-i2c", 0, TWSI1, 0xd4011000, 0x70);
 MMP2_DEVICE(twsi2, "pxa2xx-i2c", 1, TWSI2, 0xd4031000, 0x70);
 MMP2_DEVICE(twsi3, "pxa2xx-i2c", 2, TWSI3, 0xd4032000, 0x70);

[Quozl]

Documentation may need update; http://wiki.laptop.org/go/Serial_adapters#XO-1.75