Browse Source

i2c: Enable i2c and perform bus clear procedure

Help the boot loader and perform a bus clear. U-Boot will try to
read the MAC from the EEPROM and barebox has the complex boot
state stored in it.

In the past we have seen U-boot failing to read from the EEPROM
and let's have one place to initialize it.
master
Holger Hans Peter Freyther 5 years ago
parent
commit
910bd284c3
  1. 2
      board.h
  2. 39
      davinci.c

2
board.h

@ -39,7 +39,7 @@
#if defined(board_sysmobts_v2)
# define PINMUX0_DEFAULT 0x0000000F
# define PINMUX1_DEFAULT PINMUX1_UART0 | PINMUX1_UART1
# define PINMUX1_DEFAULT PINMUX1_UART0 | PINMUX1_UART1 | PINMUX1_I2C
# define NAND_nWP_GPIO 33
#endif

39
davinci.c

@ -217,6 +217,39 @@ lpsc_tansition(uint8_t module, uint8_t domain, uint8_t state)
;
}
static void
i2c_init(void)
{
int i;
// Perform a bus clear. That is the best we can do to
// unlock I2C devices that do not have reset signal
SYSTEM->PINMUX[1] &= ~PINMUX1_I2C;
gpio_direction_in(43); // SCL High
waitloop(450);
gpio_direction_in(44); // SDA High
waitloop(450);
gpio_direction_out(43, 0); // SCL Low
waitloop(450);
gpio_direction_out(44, 0); // SDA Low
waitloop(450);
for (i=0; i<9; i++) {
gpio_direction_in(43); // SCL High
waitloop(450);
gpio_direction_out(43, 0); // SCL Low
waitloop(450);
}
gpio_direction_in(43); // SCL High
waitloop(450);
gpio_direction_in(44); // SDA High
SYSTEM->PINMUX[1] |= PINMUX1_I2C;
}
static void
ivt_init(void)
{
@ -716,6 +749,12 @@ davinci_platform_init(char *version, int *nwp_nand)
gpio_direction_out(HDD_ENA, 1);
#endif
/* Init/Reset I2C */
#ifdef PINMUX1_DEFAULT
if ((PINMUX1_DEFAULT) & PINMUX1_I2C)
i2c_init();
#endif
/* IRQ Vector Table Setup */
ivt_init();

Loading…
Cancel
Save