From: Lothar Waßmann <LW@KARO-electronics.de>
Date: Mon, 25 Aug 2014 12:30:23 +0000 (+0200)
Subject: karo: tx48: make sure I2C pads are high upon boot
X-Git-Tag: KARO-TX-2014-08-27~2
X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-uboot.git;a=commitdiff_plain;h=a868814ccbf18795d069d0c038ed95a573ce357c

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 10b939095d..81103cefc6 100644
--- 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;
 }