add new board and app for gpio testing on octsimtest board

Change-Id: I01243044002f51b34e8dc12c1b1f565bbf1740a2

firmware/libboard/octsimtest/source/i2c.c

@@ -0,0 +1,225 @@
+/* I2C EEPROM memory read and write utilities
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307, USA
+ */
+#include "board.h"
+#include <stdbool.h>
+
+/* Low-Level I2C Routines */
+
+static const Pin pin_sda = {PIO_PA30, PIOA, ID_PIOA, PIO_OUTPUT_1, PIO_OPENDRAIN };
+static const Pin pin_sda_in = {PIO_PA30, PIOA, ID_PIOA, PIO_INPUT, PIO_DEFAULT };
+static const Pin pin_scl = {PIO_PA31, PIOA, ID_PIOA, PIO_OUTPUT_1, PIO_OPENDRAIN };
+
+static void i2c_delay()
+{
+	volatile int v;
+	int i;
+
+	/* 100 cycles results in SCL peak length of 44us, so it's about
+	 * 440ns per cycle here */
+	for (i = 0; i < 14; i++) {
+		v = 0;
+	}
+}
+
+void i2c_pin_init(void)
+{
+	PIO_Configure(&pin_scl, PIO_LISTSIZE(pin_scl));
+	PIO_Configure(&pin_sda, PIO_LISTSIZE(pin_sda));
+}
+
+static void set_scl(void)
+{
+	PIO_Set(&pin_scl);
+	i2c_delay();
+}
+
+static void set_sda(void)
+{
+	PIO_Set(&pin_sda);
+	i2c_delay();
+}
+
+static void clear_scl(void)
+{
+	PIO_Clear(&pin_scl);
+	i2c_delay();
+}
+
+static void clear_sda(void)
+{
+	PIO_Clear(&pin_sda);
+	i2c_delay();
+}
+
+static bool read_sda(void)
+{
+	bool ret;
+
+	PIO_Configure(&pin_sda_in, PIO_LISTSIZE(pin_sda_in));
+	if (PIO_Get(&pin_sda_in))
+		ret = true;
+	else
+		ret = false;
+	PIO_Configure(&pin_sda, PIO_LISTSIZE(pin_sda));
+
+	return ret;
+}
+
+/* Core I2C Routines */
+
+static bool i2c_started = false;
+
+static void i2c_start_cond(void)
+{
+	if (i2c_started) {
+		set_sda();
+		set_scl();
+	}
+
+	clear_sda();
+	i2c_delay();
+	clear_scl();
+	i2c_started = true;
+}
+
+static void i2c_stop_cond(void)
+{
+	clear_sda();
+	set_scl();
+	set_sda();
+	i2c_delay();
+	i2c_started = false;
+}
+
+static void i2c_write_bit(bool bit)
+{
+	if (bit)
+		set_sda();
+	else
+		clear_sda();
+	i2c_delay(); // ?
+	set_scl();
+	clear_scl();
+}
+
+static bool i2c_read_bit(void)
+{
+	bool bit;
+
+	set_sda();
+	set_scl();
+	bit = read_sda();
+	clear_scl();
+
+	return bit;
+}
+
+bool i2c_write_byte(bool send_start, bool send_stop, uint8_t byte)
+{
+	uint8_t bit;
+	bool nack;
+
+	if (send_start)
+		i2c_start_cond();
+
+	for (bit = 0; bit < 8; bit++) {
+		i2c_write_bit((byte & 0x80) != 0);
+		byte <<= 1;
+	}
+
+	nack = i2c_read_bit();
+
+	if (send_stop)
+		i2c_stop_cond();
+
+	return nack;
+}
+
+uint8_t i2c_read_byte(bool nack, bool send_stop)
+{
+	uint8_t byte = 0;
+	uint8_t bit;
+
+	for (bit = 0; bit < 8; bit++) {
+		byte = (byte << 1) | i2c_read_bit();
+	}
+
+	i2c_write_bit(nack);
+
+	if (send_stop)
+		i2c_stop_cond();
+
+	return byte;
+}
+
+
+/* EEPROM related code */
+
+int eeprom_write_byte(uint8_t slave, uint8_t addr, uint8_t byte)
+{
+	bool nack;
+
+	WDT_Restart(WDT);
+
+	/* Write slave address */
+	nack = i2c_write_byte(true, false, slave << 1);
+	if (nack)
+		goto out_stop;
+	nack = i2c_write_byte(false, false, addr);
+	if (nack)
+		goto out_stop;
+	nack = i2c_write_byte(false, true, byte);
+	if (nack)
+		goto out_stop;
+	/* Wait tWR time to ensure EEPROM is writing correctly (tWR = 5 ms for AT24C02) */
+	mdelay(5);
+
+out_stop:
+	i2c_stop_cond();
+	if (nack)
+		return -1;
+	else
+		return 0;
+}
+
+int eeprom_read_byte(uint8_t slave, uint8_t addr)
+{
+	bool nack;
+
+	WDT_Restart(WDT);
+
+	/* dummy write cycle */
+	nack = i2c_write_byte(true, false, slave << 1);
+	if (nack)
+		goto out_stop;
+	nack = i2c_write_byte(false, false, addr);
+	if (nack)
+		goto out_stop;
+	/* Re-start with read */
+	nack = i2c_write_byte(true, false, (slave << 1) | 1);
+	if (nack)
+		goto out_stop;
+
+	return i2c_read_byte(true, true);
+
+out_stop:
+	i2c_stop_cond();
+	if (nack)
+		return -1;
+	else
+		return 0;
+}