PROCESSOR-SDK-AM65X: GPIO APIs in U-boot

Hi Pavel,

I tried to call APIs from the file  u-boot-2019.01/board/ti/am65x/evm.c

But i am not able to see any result.

The source code which i added in the file is below:

static void request_and_set_gpio(int gpio, char *name, int val)
{
int ret;

ret = gpio_request(gpio, name);
if (ret < 0) {
printf("%s: Unable to request %s\n", __func__, name);
return;
}

ret = gpio_direction_output(gpio, 0);
if (ret < 0) {
printf("%s: Unable to set %s  as output\n", __func__, name);
goto err_free_gpio;
}

gpio_set_value(gpio, val);

return;

err_free_gpio:
gpio_free(gpio);
}
#define REQUEST_AND_SET_GPIO(N) request_and_set_gpio(N, #N, 1);
#define REQUEST_AND_CLR_GPIO(N) request_and_set_gpio(N, #N, 0);

After that i am calling these function  as below :

void spl_board_init(void)
{

 probe_daughtercards();

request_and_set_gpio(88, "gpio1", 1);
   
}

Shadab,

In u-boot-2019.01/board/ti/am57xx/board.c we have:

#define GPIO_DDR_VTT_EN 203 //gpio7_11

gpio_request(GPIO_DDR_VTT_EN, "ddr_vtt_en");
gpio_direction_output(GPIO_DDR_VTT_EN, 1);

For AM65x gpio1_88, you need to use

gpio_request(184,"custom_gpio");

gpio_direction_output(184, 1);

Regards,
Pavel

Hi Pavel,

I tried what you have suggested me in your reply  as below :

void spl_board_init(void)
{
    probe_daughtercards();
 

gpio_request(184,"custom_gpio");

gpio_direction_output(184, 1);

   
}

 But i didn't get any expected result .Kindly suggest me if i am making any mistake.

Regards,

Shadab

Shadab,

Md Shadab said:

I tried what you have suggested me in your reply  as below :

void spl_board_init(void)
{
    probe_daughtercards();
 

gpio_request(184,"custom_gpio");

gpio_direction_output(184, 1);

   
}

 But i didn't get any expected result .Kindly suggest me if i am making any mistake.

I would suggest you to explore the result returned from these GPIO functions.

ret = gpio_request(184,"custom_gpio");

if (ret < 0) {
        printf("%s: gpio %d request failed %d\n", __func__,
                            184, ret);
        return;
    }

ret = gpio_direction_output(184, 1);
    if (ret < 0) {
        printf("%s: Unable to set %s  as output\n", __func__, 184);
        goto err_free_gpio;
    }

gpio_set_value(184, 1);

Then I would suggest you to print and explore GPIO1 module registers, check if these has the correct and expected values.

Regards,
Pavel

Thank you Pavel for the reply .

I tried to debug the response of GPIO functions in U-boot  but getting failure response.

spl_board_init : gpio : 184  request failed -2

Regards,

Shadab

Shadab,

Seems that gpio_request() is NOT working fine for AM65x u-boot. I would suggest you to try with other similar functions:

1. dm_gpio_request()

2. gpio_request_by_name()

Regards,
Pavel

Thank you for the reply Pavel.

I am not able to understand how to call these APIs that you have mentioned in the last post

1. dm_gpio_request()

2. gpio_request_by_name()

Can you provide me  some examples ?

Regards,

Shadab

Shadab,

Using GPIO API in AM65x u-boot is a bit challenging.

You can use direct approach instead. You can directly write in the GPIO registers to toggle pin gpio1_88. You need to use use below registers:

#define DIR_REG *((unsigned int *) 0x00601060)    //GPIO1.GPIO_DIR45
 
#define MUX_REG *((unsigned int *) 0x0011C300) //SOC_PADCONFIG_192
 
#define SET_REG *((unsigned int *) 0x00601068)  //GPIO1.GPIO_SET_DATA45
 
#define CLEAR_REG *((unsigned int *) 0x0060106C)  //GPIO1.GPIO_CLR_DATA45

Then you can write below values:

CLEAR_REG |= 0x01000000;

MUX_REG = 0x08050007;
 
DIR_REG &= ~0x01000000;

        SET_REG |= 0x01000000;
 
        sdelay(2);
 
        CLEAR_REG |= 0x01000000;
 
        sdelay(1);

Hi povel,

We have to write these values in  board/ti/am65x/evm.c ? or any other file?

Varun,

If you need to configure GPIO module registers in uboot, then you can do this in

1. u-boot/board/ti/am65x/evm.c

or

2. u-boot/arch/arm/mach-k3/am6_init.c

Regards,
Pavel