7688/7628的GPIO一共有47个，GPIO0-GPIO46，这些GPIO有复用的功能，按功能模块进行配置，比如I2C有两根线，将其设置为GPIO模式，则两根就都是GPIO模式了，不可为别的功能。
一般有两种方法配置
1.通过寄存器进行配置
下面的使用前提不要被DTS或者驱动什么占用，如switch芯片的network配置
功能的定义由两个地址寄存器。
GPIO1_MODE = 0x10000060
image.png
GPIO2_MODE = 0x10000064
image.png
可以看到两个寄存器覆盖了所有的复用引脚，举个例子，如要将GPIO0/1设置成GPIO模式：
先查看GPIO0/1引脚的默认功能如下，为I2S的引脚。
image.png
所以需要找到I2S的配置寄存器，以下为部分GPIO1_MODE寄存器的含义：
image.png
可看到I2C为GPIO1_MODE的第20:21位。
所以需要做的就是将原本GPIO1_MODE寄存器的值都出来，然后将7:6位设置成01即可。
comnIoctlRegOption(GPIO1_MODE, 0x1 << 6, 0x3 << 6); //I2S,GPIO0-4
000000001
0x1 << 6即 val = 001000000
00000011
0x3 << 6即 mask = 011000000
reg_val[2] = {0, 0};有两个值，一个是传进去的addr，一个该地址返回的val
reg_val[0] = add;
read(fd, reg_val, 8); //reg_val[0]为传入的addr,reg_val[1]为val
reg_val[1] &= ~mask; //A &= ~B,将A值的B位清0，即011000000，第6、7位清0
reg_val[1] |= (val & mask); //A |= B,将A值的B位置1，即001000000，第6位置1
_INT32 comnIoctlRegOption(_UINT32 add, _UINT32 val, _UINT32 mask)
{
int fd = -1;
_UINT32 reg_val[2] = {0, 0};
fd = open(REG_DEV_NAME , O_RDWR|O_NOCTTY|O_NDELAY);
if(fd < 0)
{
printf("comnIoctl(RegOption) Cann't Open %s\r\n", REG_DEV_NAME);
return EOS_ERROR;
}
//set Reset IO Output
reg_val[0] = add;
read(fd, reg_val, 8);
reg_val[1] &= ~mask;
reg_val[1] |= (val & mask);
write(fd, reg_val, 8);
close(fd);
return EOS_OK;
}
comnIoctlRegOption(GPIO1_MODE, 0x1 << 10, 0x3 << 10); //SD,GPIO22-29
comnIoctlRegOption(GPIO1_MODE, 0x1 << 2, 0x3 << 2); //SPIS,GPIO14-17
comnIoctlRegOption(GPIO1_MODE, 0x1 << 26, 0x3 << 26); //UART2,GPIO20-21
comnIoctlGpioInit(GPIO_SIM_CP, GPIO_DIR_OUT, 1);
comnIoctlGpioInit(GPIO_SIM_PL, GPIO_DIR_OUT, 1);
comnIoctlGpioInit(GPIO_SIM_DET0, GPIO_DIR_IN, 1);
comnIoctlGpioInit(GPIO_SIM_DET1, GPIO_DIR_IN, 1);
#define GPIO1_MODE_ADD 0x10000060
#define GPIO2_MODE_ADD 0x10000064
#define GPIO0_CTRL_ADD 0X10000600
#define GPIO0_DATA_ADD 0X10000620 //read or write data
#define GPIO1_CTRL_ADD 0X10000604
#define GPIO1_DATA_ADD 0X10000624
下面给出几个已经封装好的函数，以前后期直接使用
1、寄存器配置
_INT32 comnIoctlRegOption(_UINT32 add, _UINT32 val, _UINT32 mask)
{
int fd = -1;
_UINT32 reg_val[2] = {0, 0};
fd = open(REG_DEV_NAME , O_RDWR|O_NOCTTY|O_NDELAY);
if(fd < 0)
{
printf("comnIoctl(RegOption) Cann't Open %s\r\n", REG_DEV_NAME);
return EOS_ERROR;
}
//set Reset IO Output
reg_val[0] = add;
read(fd, reg_val, 8);
reg_val[1] &= ~mask;
reg_val[1] |= (val & mask);
write(fd, reg_val, 8);
close(fd);
return EOS_OK;
}
2、输入输出模式配置
_INT32 comnIoctlGpioInit(_UCHAR8 gpio, _UCHAR8 dir, _UCHAR8 val)
{
_INT32 fd = -1;
_UINT32 reg_val[2] = {0, 0};
_UINT32 gpio_ctrl_reg_add = 0;
_UINT32 gpio_data_reg_add = 0;
if(gpio < 32)
{
gpio_ctrl_reg_add = REG_GPIO_CTRL0;
gpio_data_reg_add = REG_GPIO_DATA0;
}
else if(gpio >= 32)
{
gpio_ctrl_reg_add = REG_GPIO_CTRL1;
gpio_data_reg_add = REG_GPIO_DATA1;
gpio -= 32;
}
fd = open(REG_DEV_NAME , O_RDWR|O_NOCTTY|O_NDELAY);
if(fd < 0)
{
printf("comnIoctl(GpioInit) Cann't Open %s\r\n", REG_DEV_NAME);
return EOS_ERROR;
}
//set the io port,out or in
reg_val[0] = gpio_ctrl_reg_add;
read(fd, reg_val, 8);
if(dir == GPIO_DIR_OUT)
{
reg_val[1] |= 1 << gpio;
}
else if(dir == GPIO_DIR_IN)
{
reg_val[1] &= ~(1 << gpio);
}
write(fd, reg_val, 8);
//set the val
reg_val[0] = gpio_data_reg_add;
read(fd, reg_val, 8);
if(val > 0)
{
reg_val[1] |= 1 << gpio;
}
else
{
reg_val[1] &= ~(1 << gpio);
}
write(fd, reg_val, 8);
close(fd);
return EOS_OK;
}
3、输出高低
_INT32 comnIoctlGpioSetValue(_UCHAR8 gpio, _UCHAR8 val)
{
_INT32 fd = -1;
_UINT32 reg_val[2] = {0, 0};
_UINT32 gpio_data_reg_add = 0;
if((gpio > 63) || (val > 1))
{
printf("comnIoctl(GpioSetValue) paramer is wrong!\n");
return EOS_ERROR;
}
if(gpio < 32)
{
gpio_data_reg_add = REG_GPIO_DATA0;
}
else if(gpio >= 32)
{
gpio_data_reg_add = REG_GPIO_DATA1;
gpio -= 32;
}
fd = open(REG_DEV_NAME , O_RDWR|O_NOCTTY|O_NDELAY);
if(fd < 0)
{
//printf("comnIoctl(GpioSetValue) Cann't Open %s\r\n", REG_DEV_NAME);
return EOS_ERROR;
}
//输出0/1
reg_val[0] = gpio_data_reg_add;
read(fd, reg_val, 8);
if(val == 0)
{
reg_val[1] &= ~(1 << gpio);
}
else if(val == 1)
{
reg_val[1] |= 1 << gpio;
}
write(fd, reg_val, 8);
close(fd);
return EOS_OK;
}
4、读IO电平
_INT32 comnIoctlGpioGetValue(_UCHAR8 gpio)
{
_INT32 fd = -1;
_UINT32 reg_val[2] = {0, 0};
_UINT32 gpio_data_reg_add = 0;
if(gpio > 63)
{
printf("comnIoctl(GpioGetValue) paramer is wrong!\n");
return EOS_ERROR;
}
if(gpio < 32)
{
gpio_data_reg_add = REG_GPIO_DATA0;
}
else if(gpio >= 32)
{
gpio_data_reg_add = REG_GPIO_DATA1;
gpio -= 32;
}
fd = open(REG_DEV_NAME , O_RDWR|O_NOCTTY|O_NDELAY);
if(fd < 0)
{
//printf("comnIoctl(GpioGetValue) Cann't Open %s\r\n", REG_DEV_NAME);
return EOS_ERROR;
}
//输出0/1
reg_val[0] = gpio_data_reg_add;
read(fd, reg_val, 8);
close(fd);
return ((reg_val[1] >> gpio) & 1);
}
2.多寄存器控制的GPIO
image.png
如上图，SD卡由EPHY_AGPIO_AIO_EN(非EPHY_APGIO_AIO_EN)和SD_MODE两个寄存器控制，都要置1才可以
image.png
对于SD_MODE置1比较容易，上面已经给出方法，如下：
comnIoctlRegOption(GPIO1_MODE, 0x1 << 10, 0x3 << 10); //SD,GPIO22-29
EPHY_AGPIO_AIO_EN即AGPIO_CFG的17-29位置1，为了通用comnIoctlRegOption函数，做如下设置。
comnIoctlRegOption(AGPIO_CFG, 0xF << 17, 0xF << 17); //EPHY_AGPIO_AIO_EN[4:1],GPIO14-29
000001111
0xF << 6即 val = 00001111 00000000 000000000
00001111
0xF << 6即 mask = 00001111 00000000 000000000
reg_val[2] = {0, 0};有两个值，一个是传进去的addr，一个该地址返回的val
reg_val[0] = add;
read(fd, reg_val, 8); //reg_val[0]为传入的addr,reg_val[1]为val
reg_val[1] &= ~mask; //A &= ~B,将A值的B位清0，第17-20位清0
reg_val[1] |= (val & mask); //A |= B,将A值的B位置1，第17-20位置1
3.通过DTS进行配置
http://wiki.wrtnode.cc/index.php?title=GPIO%E8%B5%84%E6%BA%90
DTS格式有点类似Json，一般系统都会有两个dts，一个芯片的dtsi,如：$(TOPDIR)/target/linux/ramips/dts/mt7628an.dts另一个板子的配置dts，如：$(TOPDIR)/target/linux/ramips/dts/WRTNODE2P.dts。板子配置的dts会include芯片的dtsi,如下：
/dts-v1/;
/include/ "mt7628an.dtsi"
1、MT7620
mt7620a.dtsi
结合mt7620的datasheet里GPIO pin share schemes以及在mt7620n.dtsi里我们看到有，将GPIO#0到GPIO#72（中间有仅仅做GPO或GPI的）分为四组GPIO0-GPIO3；
- 对应GPIO0是从GPIO#0开始到GPIO#23，一共有24个；
- 对应GPIO1是从GPIO#24开始到GPIO#39，一共有16个；
- 对应GPIO2是从GPIO#40开始到GPIO#71，一共有32个；
- 对应GPIO3对应的是GPIO#72，仅有一个。
gpio0: gpio@600 {
compatible = "ralink,mt7620a-gpio", "ralink,rt2880-gpio";
reg = <0x600 0x34>;
resets = <&rstctrl 13>;
reset-names = "pio";
interrupt-parent = <&intc>;
interrupts = <6>;
gpio-controller;
#gpio-cells = <2>;
ralink,gpio-base = <0>;
ralink,num-gpios = <24>;
ralink,register-map = [ 00 04 08 0c
20 24 28 2c
30 34 ];
};
gpio1: gpio@638 {
compatible = "ralink,mt7620a-gpio", "ralink,rt2880-gpio";
reg = <0x638 0x24>;
interrupt-parent = <&intc>;
interrupts = <6>;
gpio-controller;
#gpio-cells = <2>;
ralink,gpio-base = <24>;
ralink,num-gpios = <16>;
ralink,register-map = [ 00 04 08 0c
10 14 18 1c
20 24 ];
status = "disabled";
};
gpio2: gpio@660 {
compatible = "ralink,mt7620a-gpio", "ralink,rt2880-gpio";
reg = <0x660 0x24>;
interrupt-parent = <&intc>;
interrupts = <6>;
gpio-controller;
#gpio-cells = <2>;
ralink,gpio-base = <40>;
ralink,num-gpios = <32>;
ralink,register-map = [ 00 04 08 0c
10 14 18 1c
20 24 ];
status = "disabled";
};
gpio3: gpio@688 {
compatible = "ralink,mt7620a-gpio", "ralink,rt2880-gpio";
reg = <0x688 0x24>;
interrupt-parent = <&intc>;
interrupts = <6>;
gpio-controller;
#gpio-cells = <2>;
ralink,gpio-base = <72>;
ralink,num-gpios = <1>;
ralink,register-map = [ 00 04 08 0c
10 14 18 1c
20 24 ];
status = "disabled";
};
上面的gpio1/2/3的status = "disabled"，默认是关闭的，如果要使用需要在dts里面打开，如下：
palmbus@10000000 {
gpio1: gpio@638 {
status = "okay";
};
gpio2: gpio@660 {
status = "okay";
};
gpio3: gpio@688 {
status = "okay";
};
}
如果引脚的功能有被复用到的，也需要把复用引脚释放，添加到ralink,group里面，如下：
pinctrl {
state_default: pinctrl0 {
default {
ralink,group = "ephy", "wled", "pa", "i2c", "wdt", "uartf", "spi refclk";
ralink,function = "gpio";
};
};
};
上面的ephy/i2c/spi refclk等名称在build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7628/linux-3.18.29/arch/mips/ralink/mt7620.c里面有定义，如下：
static struct rt2880_pmx_group mt7620a_pinmux_data[] = {
GRP("i2c", i2c_grp, 1, MT7620_GPIO_MODE_I2C),
GRP("uartf", uartf_grp, MT7620_GPIO_MODE_UART0_MASK,
MT7620_GPIO_MODE_UART0_SHIFT),
GRP("spi", spi_grp, 1, MT7620_GPIO_MODE_SPI),
GRP("uartlite", uartlite_grp, 1, MT7620_GPIO_MODE_UART1),
GRP_G("wdt", wdt_grp, MT7620_GPIO_MODE_WDT_MASK,
MT7620_GPIO_MODE_WDT_GPIO, MT7620_GPIO_MODE_WDT_SHIFT),
GRP("mdio", mdio_grp, 1, MT7620_GPIO_MODE_MDIO),
GRP("rgmii1", rgmii1_grp, 1, MT7620_GPIO_MODE_RGMII1),
GRP("spi refclk", refclk_grp, 1, MT7620_GPIO_MODE_SPI_REF_CLK),
GRP_G("pcie", pcie_rst_grp, MT7620_GPIO_MODE_PCIE_MASK,
MT7620_GPIO_MODE_PCIE_GPIO, MT7620_GPIO_MODE_PCIE_SHIFT),
GRP_G("nd_sd", nd_sd_grp, MT7620_GPIO_MODE_ND_SD_MASK,
MT7620_GPIO_MODE_ND_SD_GPIO, MT7620_GPIO_MODE_ND_SD_SHIFT),
GRP("rgmii2", rgmii2_grp, 1, MT7620_GPIO_MODE_RGMII2),
GRP("wled", wled_grp, 1, MT7620_GPIO_MODE_WLED),
GRP("ephy", ephy_grp, 1, MT7620_GPIO_MODE_EPHY),
GRP("pa", pa_grp, 1, MT7620_GPIO_MODE_PA),
{ 0 }
};
第一个参数就是名称，第二个参数，对应该组引脚的解析个数，如：
static struct rt2880_pmx_func i2c_grp[] = { FUNC("i2c", 0, 1, 2) };
static struct rt2880_pmx_func spi_grp[] = { FUNC("spi", 0, 3, 4) };
static struct rt2880_pmx_func uartlite_grp[] = { FUNC("uartlite", 0, 15, 2) };
static struct rt2880_pmx_func mdio_grp[] = { FUNC("mdio", 0, 22, 2) };
static struct rt2880_pmx_func rgmii1_grp[] = { FUNC("rgmii1", 0, 24, 12) };
static struct rt2880_pmx_func refclk_grp[] = { FUNC("spi refclk", 0, 37, 3) };
i2c后面的1，2，代表从gpio1开始，占用2个引脚；spi refclk的37，3，代表从gpio37开始，占用3个引脚；这些跟功能引脚的定义其实是对应的，如下：
image
gpio-leds {
compatible = "gpio-leds";
indicator {
label = "wrtnode:blue:indicator";
gpios = <&gpio1 14 0>;
};
};
2、MT7688
mt7628an.dtsi
mt7628an.dtsi里有对gpio的注册,一共将GPIO分为三组，分别为gpio0、gpio1、gpio2
每组gpio包含32个gpio；在WRTnode2R/2P上只用到了gpio0和gpio1两组。
gpio@600 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "mtk,mt7628-gpio", "mtk,mt7621-gpio";
reg = <0x600 0x100>;
interrupt-parent = <&intc>;
interrupts = <6>;
gpio0: bank@0 {
reg = <0>;
compatible = "mtk,mt7621-gpio-bank";
gpio-controller;
#gpio-cells = <2>;
};
gpio1: bank@1 {
reg = <1>;
compatible = "mtk,mt7621-gpio-bank";
gpio-controller;
#gpio-cells = <2>;
};
gpio2: bank@2 {
reg = <2>;
compatible = "mtk,mt7621-gpio-bank";
gpio-controller;
#gpio-cells = <2>;
};
};
与MT7620不同的是，这三组gpio都是开启的，在dts中就不用在操作。
与MT7620相同的是，如果引脚的功能有被复用到的，也需要把复用引脚释放，添加到ralink,group里面，如下：
pinctrl {
state_default: pinctrl0 {
gpio {
ralink,group = "i2c", "gpio", "jtag";
ralink,function = "gpio";
};
};
};
不过MT7620个MT7628的引脚功能分布式不一样的，所以在build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7628/linux-3.18.29/arch/mips/ralink/mt7620.c里定义也是不一样的，如下：
static struct rt2880_pmx_group mt7628an_pinmux_data[] = {
GRP_G("pwm1", pwm1_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_PWM1),
GRP_G("pwm0", pwm0_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_PWM0),
GRP_G("uart2", uart2_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_UART2),
GRP_G("uart1", uart1_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_UART1),
GRP_G("i2c", i2c_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_I2C),
GRP("refclk", refclk_grp_mt7628, 1, MT7628_GPIO_MODE_REFCLK),
GRP("perst", perst_grp_mt7628, 1, MT7628_GPIO_MODE_PERST),
GRP("wdt", wdt_grp_mt7628, 1, MT7628_GPIO_MODE_WDT),
GRP("spi", spi_grp_mt7628, 1, MT7628_GPIO_MODE_SPI),
GRP_G("sdmode", sd_mode_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_SDMODE),
GRP_G("uart0", uart0_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_UART0),
GRP_G("i2s", i2s_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_I2S),
GRP_G("spi cs1", spi_cs1_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_CS1),
GRP_G("spis", spis_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_SPIS),
GRP_G("gpio", gpio_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_GPIO),
GRP_G("wled_an", wled_an_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_WLED_AN),
GRP_G("wled_kn", wled_kn_grp_mt7628, MT7628_GPIO_MODE_MASK, 1, MT7628_GPIO_MODE_WLED_KN),
{ 0 }
};
第二个参数，对应该组引脚的解析个数，如：
static struct rt2880_pmx_func i2c_grp_mt7628[] = {
FUNC("-", 3, 4, 2),
FUNC("debug", 2, 4, 2),
FUNC("gpio", 1, 4, 2),
FUNC("i2c", 0, 4, 2),
};
i2c后面的4，2，代表从gpio4开始，占用2个引脚；与MT7620的gpio1-2是不一样的。
image
gpio_export {
compatible = "gpio-export";
#size-cells = <0>;
lte4power {
gpio-export,name = "G4Power";
gpio-export,output = <0>;
gpios = <&gpio0 29 0>; //GPIO_ACTIVE_HIGH
};
lte4reset {
gpio-export,name = "G4Reset";
gpio-export,output = <0>;
gpios = <&gpio0 28 0>;
};
lte4status {
gpio-export,name = "G4Status";
gpio-export,input = <0>;
gpios = <&gpio0 22 0>; //GPIO_ACTIVE_HIGH
};
}
gpio-leds {
compatible = "gpio-leds";
indicator {
label = "wrtnode:blue:indicator";
gpios = <&gpio1 9 1>;
};
};
gpio-keys-polled {
compatible = "gpio-keys-polled";
#address-cells = <1>;
#size-cells = <0>;
poll-interval = <20>;
reset {
label = "reset";
gpios = <&gpio0 5 1>;
linux,code = <0x198>;
};
};
root@OpenWrt:/sys/class/leds# ls
wrtnode:blue:indicator