[DM814x笔记]引脚复用配置

在TI814x设备中，复位时，默认的引脚复用配置被设置为Mode0（FUNCTION 1）。如果想将某些引脚配置成其他的功能而不是Mode0，或者说重载在U-Boot中已经设置好的引脚配置，内核需要重新配置。

       引脚配置可以有两种方法：

1、在arch/arm/mach-omap2/board-ti8148evm.c中的board_mux数组中添加特定的复用入口。比如在board_mux中添加

TI814X_MUX(MTSI_DCLK, OMAP_MUX_MODE1|OMAP_PULL_UP)或TI814X_MUX(MTSI_DCLK, OMAP_MUX_MODE1)，要注意必须放在{.reg_offset=OMAP_MUX_TERMINATOR}之前。

2、在arch/arm/mach-omap2/devices.c中的初始化omap2_init_devices()函数中调用函数omap_mux_init_signal()。比如：omap_mux_init_signal("gmiil_rxclk",OMAP_PULL_UP)或omap_mux_init_signal("gmiil_rxclk",0)。

       其中引脚复用信号的名字及其使用的模式种类在内核源码目录中的arch/arm/mach-omap2/mux814x.c中的muxmodes[]数组指定。

       查看引脚的复用情况，可以使用debugfs。

# mount -t debugfs none /sys/kernel/debug

# cat /sys/kernel/debug/omap_mux/clkin32

       关于引脚复用有比较特殊的几个IO需要注意。比如GP0[1]、GP1[7]~GP1[10]，要使用其GPIO的功能，需要做如下配置。

       首先，使能时钟：

//enable GP0 GP1 Clock，见TMS320DM816x Technical Reference Manual.pdf中的RCM_ALWON_GPIO_0_CLKCTRL Register

/* PRCM Base Address */

#define PRCM_BASE 0x48180000

#define CM_ALWON_GPIO_0_CLKCTRL (PRCM_BASE + 0x155c)

#define CM_ALWON_GPIO_1_CLKCTRL (PRCM_BASE + 0x1560)

__raw_write(0x102,CM_ALWON_GPIO_0_CLKCTRL);

while((__raw_read(CM_ALWON_GPIO_0_CLKCTRL)&0x03)!=0x2);

__raw_write(0x102,CM_ALWON_GPIO_1_CLKCTRL);

while((__raw_read(CM_ALWON_GPIO_1_CLKCTRL)&0x03)!=0x2);

//GP0_1 Mode7

__raw_write(0x00040080,0x4818081c);

       其次，在U-Boot中定义如下变量：

#define MLBP_SIG_IO_CTRL_FOR_GPb7b8  0x48140E18

#define MLBP_SIG_IO_CTRL_FOR_GPb9b10 0x48140E1C

#define MLBP_SIG_IO_CTRL_VAL 0x3F //set 3LB to enable;2 lvcmos buffer, padn receiver, padp receiver

#define GPIO1_OE 0x4804C134

#define GPIO1_SETDATAOUT 0x4804C194

#define GPIO1_CLEARDATAOUT 0x4804C190

#define GPIO1_DATAOUT 0x4804C13C

#define WR_MEM_32(addr,data) *(unsigned int *)(addr)=(unsigned int)(data)

#define RD_MEM_32(addr) *(unsigned int *)addr

WR_MEM_32(MLBP_SIG_IO_CTRL_FOR_GPb7b8, MLBP_SIG_IO_CTRL_VAL);

WR_MEM_32(MLBP_SIG_IO_CTRL_FOR_GPb9b10, MLBP_SIG_IO_CTRL_VAL);

//将引脚配置成GPIO功能并上拉

(*(volatile unsigned int *)(0x481408F4))=(volatile unsigned int)((1<<19)|(1<<18)|(1<<17)|(1<<7)); //GP1_7

(*(volatile unsigned int *)(0x481408F8))=(volatile unsigned int)((1<<19)|(1<<18)|(1<<17)|(1<<7)); //GP1_8

(*(volatile unsigned int *)(0x481408FC))=(volatile unsigned int)((1<<19)|(1<<18)|(1<<17)|(1<<7)); //GP1_9

//输出使能

val=__raw_readl(GPIO1_OE);

val&=(~((1<<7)|(1<<8)|(1<<9)));

__raw_writel(val, GPIO1_OE);

//置位

val=__raw_readl(GPIO1_SETDATAOUT);

val|=((1<<7)|(1<<8)|(1<<9));

__raw_writel(val, GPIO1_SETDATAOUT);

//清零

val=__raw_readl(GPIO1_CLEARDATAOUT);

val|=((1<<7)|(1<<8)|(1<<9));

__raw_writel(val, GPIO1_CLEARDATAOUT);

Reference:

http://repository.timesys.com/buildsources/u/u-boot/u-boot-2010.06/u-boot-2010.06-ti81xx-201202011623.patch

http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/153934.aspx

转载地址:http://weimenlove.blog.163.com/blog/static/177754732012101311230450/