karo: tx48: make sure I2C pads are high upon boot

The LTC3589 PMIC may leave the SDA line pulled low when the module is
reset during an I2C transfer with the chip, blocking the I2C bus.

Reconfigure the I2C pads as GPIO upon boot and drive them HIGH, when
they are initially LOW.

diff --git a/board/karo/tx48/tx48.c b/board/karo/tx48/tx48.c
index 10b939095d350b63c1715946430fc8525f29f08c..81103cefc612ad91c05474294a75a97655d2dcc9 100644 (file)
--- a/board/karo/tx48/tx48.c
+++ b/board/karo/tx48/tx48.c
@@ -325,6 +325,21 @@ static u32 prm_rstst __attribute__((section(".data")));
 /*
  * Basic board specific setup
  */
+static const struct pin_mux tx48_pads[] = {
+       { OFFSET(i2c0_sda), MODE(7) | RXACTIVE | PULLUDEN | PULLUP_EN, },
+       { OFFSET(i2c0_scl), MODE(7) | RXACTIVE | PULLUDEN | PULLUP_EN, },
+};
+
+static const struct pin_mux tx48_i2c_pads[] = {
+       { OFFSET(i2c0_sda), MODE(0) | RXACTIVE | PULLUDEN | PULLUP_EN, },
+       { OFFSET(i2c0_scl), MODE(0) | RXACTIVE | PULLUDEN | PULLUP_EN, },
+};
+
+static const struct gpio tx48_gpios[] = {
+       { AM33XX_GPIO_NR(3, 5), GPIOF_INPUT, "I2C1_SDA", },
+       { AM33XX_GPIO_NR(3, 6), GPIOF_INPUT, "I2C1_SCL", },
+};
+
 static const struct pin_mux stk5_pads[] = {
        /* heartbeat LED */
        { OFFSET(gpmc_a10), MODE(7) | PULLUDEN, },
@@ -819,6 +834,8 @@ static void stk5v5_board_init(void)
 /* called with default environment! */
 int board_init(void)
 {
+       int i;
+
        /* mach type passed to kernel */
 #ifdef CONFIG_OF_LIBFDT
        gd->bd->bi_arch_number = -1;
@@ -829,6 +846,17 @@ int board_init(void)
        if (ctrlc())
                printf("CTRL-C detected\n");
 
+       gpio_request_array(tx48_gpios, ARRAY_SIZE(tx48_gpios));
+       tx48_set_pin_mux(tx48_pads, ARRAY_SIZE(tx48_pads));
+
+       for (i = 0; i < ARRAY_SIZE(tx48_gpios); i++) {
+               int gpio = tx48_gpios[i].gpio;
+
+               if (gpio_get_value(gpio) == 0)
+                       gpio_direction_output(gpio, 1);
+       }
+
+       tx48_set_pin_mux(tx48_pads, ARRAY_SIZE(tx48_i2c_pads));
        return 0;
 }