Add i2c capability for AVR

src/arch/avr/i2c.c

@@ -0,0 +1,163 @@
+#include <stdio.h>
+#include <avr/io.h>
+#include <util/twi.h>
+
+#include <arch/i2c.h>
+#include <board/cpu.h>
+
+#define TIMEOUT (F_CPU/1000)
+
+#define I2C_READ 0x01
+#define I2C_WRITE 0x00
+
+uint8_t i2c_start(uint8_t addr, uint8_t rw) {
+	uint32_t count;
+
+	// reset TWI control register
+	TWCR = 0;
+	// transmit START condition
+	TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+	// wait for end of transmission
+	count = TIMEOUT;
+	while(!(TWCR & (1<<TWINT)) && count > 0) count -= 1;
+	if (count == 0) {
+		printf("i2c_start timed out waiting to send start to 0x%X\n", addr);
+		return 1;
+	}
+
+	// check if the start condition was successfully transmitted
+	if((TWSR & 0xF8) != TW_START){
+		printf("i2c_start failed to send start condition to 0x%X\n", addr);
+		return 1;
+	}
+
+	// load slave addr into data register
+	TWDR = ((addr << 1) | rw);
+	// start transmission of addr
+	TWCR = (1<<TWINT) | (1<<TWEN);
+	// wait for end of transmission
+	count = TIMEOUT;
+	while(!(TWCR & (1<<TWINT)) && count > 0) count -= 1;
+	if (count == 0) {
+		printf("i2c_start timed out waiting to send addr to 0x%X\n", addr);
+		return 1;
+	}
+
+	// check if the device has acknowledged the READ / WRITE mode
+	uint8_t twst = TW_STATUS & 0xF8;
+	if ((twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK)) {
+		printf("i2c_start failed to receive ack from 0x%X\n", addr);
+		return 1;
+	}
+
+	return 0;
+}
+
+void i2c_stop() {
+	// transmit STOP condition
+	TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+}
+
+uint8_t i2c_write(uint8_t data) {
+	uint32_t count;
+
+	// load data into data register
+	TWDR = data;
+	// start transmission of data
+	TWCR = (1<<TWINT) | (1<<TWEN);
+	// wait for end of transmission
+	count = TIMEOUT;
+	while(!(TWCR & (1<<TWINT)) && count > 0) count -= 1;
+	if (count == 0) {
+		printf("i2c_write timed out waiting to send 0x%X\n", data);
+		return 1;
+	}
+
+	if( (TWSR & 0xF8) != TW_MT_DATA_ACK ){
+		printf("i2c_write failed to receive ack for 0x%X\n", data);
+		return 1;
+	}
+
+	return 0;
+}
+
+uint8_t i2c_read_ack() {
+	// start TWI module and acknowledge data after reception
+	TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+	// wait for end of transmission
+	while( !(TWCR & (1<<TWINT)) );
+	// return received data from TWDR
+	return TWDR;
+}
+
+uint8_t i2c_read_nack() {
+	// start receiving without acknowledging reception
+	TWCR = (1<<TWINT) | (1<<TWEN);
+	// wait for end of transmission
+	while( !(TWCR & (1<<TWINT)) );
+	// return received data from TWDR
+	return TWDR;
+}
+
+uint8_t i2c_recv(uint8_t addr, uint8_t* data, uint16_t length) {
+	if (i2c_start(addr, I2C_READ)) return 1;
+
+	uint16_t i;
+	for (i = 0; i < (length-1); i++)
+	{
+		data[i] = i2c_read_ack();
+	}
+	data[(length-1)] = i2c_read_nack();
+
+	i2c_stop();
+
+	return 0;
+}
+
+uint8_t i2c_send(uint8_t addr, uint8_t* data, uint16_t length) {
+	if (i2c_start(addr, I2C_WRITE)) return 1;
+
+	uint16_t i;
+	for (i = 0; i < length; i++) {
+		if (i2c_write(data[i])) return 1;
+	}
+
+	i2c_stop();
+
+	return 0;
+}
+
+uint8_t i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length) {
+	if (i2c_start(addr, I2C_WRITE)) return 1;
+
+	if (i2c_write(reg)) return 1;
+
+	if (i2c_start(addr, I2C_READ)) return 1;
+
+	uint16_t i;
+	for (i = 0; i < (length-1); i++)
+	{
+		data[i] = i2c_read_ack();
+	}
+	data[(length-1)] = i2c_read_nack();
+
+	i2c_stop();
+
+	return 0;
+}
+
+uint8_t i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length) {
+	if (i2c_start(addr, I2C_WRITE)) return 1;
+
+	if(i2c_write(reg)) return 1;
+
+	uint16_t i;
+	for (i = 0; i < length; i++)
+	{
+		if (i2c_write(data[i])) return 1;
+	}
+
+	i2c_stop();
+
+	return 0;
+}

src/arch/avr/include/arch/i2c.h

@@ -0,0 +1,10 @@
+#ifndef _ARCH_I2C_H
+#define _ARCH_I2C_H
+
+uint8_t i2c_recv(uint8_t addr, uint8_t* data, uint16_t length);
+uint8_t i2c_send(uint8_t addr, uint8_t* data, uint16_t length);
+
+uint8_t i2c_get(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length);
+uint8_t i2c_set(uint8_t addr, uint8_t reg, uint8_t* data, uint16_t length);
+
+#endif // _ARCH_I2C_H

src/board/arduino/mega2560/battery.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+
+#include <board/i2c.h>
+
+uint8_t smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
+    return i2c_get(address, command, (uint8_t *)data, 2);
+}
+
+void battery_debug(void) {
+    uint16_t data = 0;
+    uint8_t err = 0;
+
+    #define command(N, A, V) { \
+        printf(#N ": "); \
+        err = smbus_read(A, V, &data); \
+        if (err) { \
+            printf("ERROR %02X\n", err); \
+            return; \
+        } \
+        printf("%04X\n", data); \
+    }
+
+    printf("Battery:\n");
+    command(Temperature, 0x0B, 0x08);
+    command(Voltage, 0x0B, 0x09);
+    command(Current, 0x0B, 0x0A);
+    command(Charge, 0x0B, 0x0D);
+
+    printf("Charger:\n");
+    command(ChargeOption0, 0x09, 0x12);
+    command(ChargeOption1, 0x09, 0x3B);
+    command(ChargeOption2, 0x09, 0x38);
+    command(ChargeOption3, 0x09, 0x37);
+    command(ChargeCurrent, 0x09, 0x14);
+    command(ChargeVoltage, 0x09, 0x15);
+    command(DishargeCurrent, 0x09, 0x39);
+    command(InputCurrent, 0x09, 0x3F);
+    command(ProchotOption0, 0x09, 0x3C);
+    command(ProchotOption1, 0x09, 0x3D);
+    command(ProchotStatus, 0x09, 0x3A);
+
+    #undef command
+}

src/board/arduino/mega2560/i2c.c

@@ -0,0 +1,10 @@
+#include <avr/io.h>
+
+#include <board/cpu.h>
+#include <board/i2c.h>
+
+void i2c_init(unsigned long baud) {
+	TWAR = 0;
+	TWBR = (uint8_t)(((F_CPU / baud) - 16 ) / 2);
+	TWCR = 0;
+}

src/board/arduino/mega2560/include/board/battery.h

@@ -0,0 +1,6 @@
+#ifndef _BOARD_BATTERY_H
+#define _BOARD_BATTERY_H
+
+void battery_debug(void);
+
+#endif // _BOARD_BATTERY_H

src/board/arduino/mega2560/include/board/i2c.h

@@ -0,0 +1,6 @@
+#ifndef _BOARD_I2C_H
+#define _BOARD_I2C_H
+
+void i2c_init(unsigned long baud);
+
+#endif // _BOARD_I2C_H

src/board/arduino/mega2560/main.c

@@ -2,9 +2,12 @@
 
 #include <arch/gpio.h>
 #include <arch/uart.h>
+#include <board/battery.h>
+#include <board/i2c.h>
 
 void init(void) {
     uart_stdio_init(0, __CONSOLE_BAUD__);
+    i2c_init(50000);
 }
 
 struct Gpio LED = GPIO(B, 7);
@@ -15,10 +18,14 @@ int main(void) {
     gpio_set_dir(&LED, true);
     gpio_set(&LED, false);
     printf("Hello from System76 EC for the Arduino Mega 2560!\n");
+
+    battery_debug();
+
     for (;;) {
         int c = getchar();
         if (c == '\r') {
             putchar('\n');
+            battery_debug();
         } else if (c > 0) {
             putchar(c);
         }