Hi,
I need to read the state of the TX2’s Volume Up button in u-boot. In Linux the Volume Up button is gpio-313.
So far I’ve patched p2771-0000.c as:
#define DEBUG
#include <common.h>
#include <i2c.h>
#include <asm/gpio.h>
#include "../p2571/max77620_init.h"
void read_pin(void)
{
if (gpio_request(313, "GPIO_VOLUME_UP") == -1) {
printf("GPIO request failed for 313\n");
}
else {
printf("GPIO request succeeded for 313");
if (gpio_direction_input(313) == -1) {
printf("Failed to set the input direction for 313\n");
}
else {
printf("Succeeded to set the input direction for 313\n");
udelay(3000000);
int state = gpio_get_value(313);
printf("The status is %s\n", state ? "HIGH" : "LOW");
}
}
}
int tegra_board_init(void)
{
struct udevice *dev;
uchar val;
int ret;
/* Turn on MAX77620 LDO3 to 3.3V for SD card power */
debug("%s: Set LDO3 for VDDIO_SDMMC_AP power to 3.3V\n", __func__);
ret = i2c_get_chip_for_busnum(0, MAX77620_I2C_ADDR_7BIT, 1, &dev);
if (ret) {
printf("%s: Cannot find MAX77620 I2C chip\n", __func__);
return ret;
}
/* 0xF2 for 3.3v, enabled: bit7:6 = 11 = enable, bit5:0 = voltage */
val = 0xF2;
ret = dm_i2c_write(dev, MAX77620_CNFG1_L3_REG, &val, 1);
if (ret) {
printf("i2c_write 0 0x3c 0x27 failed: %d\n", ret);
return ret;
}
read_pin();
return 0;
}
int tegra_pcie_board_init(void)
{
struct udevice *dev;
uchar val;
int ret;
/* Turn on MAX77620 LDO7 to 1.05V for PEX power */
debug("%s: Set LDO7 for PEX power to 1.05V\n", __func__);
ret = i2c_get_chip_for_busnum(0, MAX77620_I2C_ADDR_7BIT, 1, &dev);
if (ret) {
printf("%s: Cannot find MAX77620 I2C chip\n", __func__);
return -1;
}
/* 0xC5 for 1.05v, enabled: bit7:6 = 11 = enable, bit5:0 = voltage */
val = 0xC5;
ret = dm_i2c_write(dev, MAX77620_CNFG1_L7_REG, &val, 1);
if (ret)
printf("i2c_write 0 0x3c 0x31 failed: %d\n", ret);
read_pin();
return 0;
}
But the button state never changes. I’m not sure if the gpio-313 is only for kernel mapping. Where is this defined?
Also the gpio_request, gpio_direction_input and gpio_get_value as marked deprecated in favor of driver model. What is the driver model for Tegra?
I originally tried reading the status from the u-boot shell but couldn’t find the button in the banks. How to map it there?
Thanks,