Add amp control library using i2c

demo/Makefile

@@ -3,7 +3,7 @@ BUILD_DIR?=../build/gsd_orangecrab/
 include $(BUILD_DIR)/software/include/generated/variables.mak
 include $(SOC_DIRECTORY)/software/common.mak
 
-OBJECTS = audio.o can.o crt0.o donut.o isr.o led.o main.o
+OBJECTS = amp.o audio.o can.o crt0.o donut.o isr.o led.o main.o
 CFLAGS += -DWITH_CXX
 
 

demo/amp

@@ -0,0 +1,33 @@
+#include <generated/csr.h>
+#include <libbase/i2c.h>
+#include <stdint.h>
+
+#pragma once
+
+// Struct Definition
+
+struct amp_i2c {
+	uint8_t pot0;
+	uint8_t pot1;
+	uint8_t conf;
+};
+
+// Function Declarations
+
+bool amp_init(void);
+
+bool amp_read(amp_i2c &);
+
+bool amp_read_pot0(uint8_t &);
+
+bool amp_read_pot1(uint8_t &);
+
+bool amp_read_conf(uint8_t &);
+
+bool amp_write(amp_i2c value);
+
+bool amp_write_pot0(uint8_t value);
+
+bool amp_write_pot1(uint8_t value);
+
+bool amp_write_conf(uint8_t value);

demo/amp.cpp

@@ -0,0 +1,178 @@
+#include "amp"
+#include <generated/csr.h>
+#include <libbase/i2c.h>
+#include <stdint.h>
+
+#ifdef CONFIG_HAS_I2C
+#define I2C_DELAY(n) busy_wait_us(n * (250000 / I2C_FREQ_HZ))
+
+static inline void i2c_oe_scl_sda(bool oe, bool scl, bool sda) {
+	i2c_w_write(
+		((oe & 1) << CSR_I2C_W_OE_OFFSET) |
+		((scl & 1) << CSR_I2C_W_SCL_OFFSET) |
+		((sda & 1) << CSR_I2C_W_SDA_OFFSET));
+}
+
+// START condition: 1-to-0 transition of SDA when SCL is 1
+static void i2c_start(void) {
+	i2c_oe_scl_sda(1, 1, 1);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(1, 1, 0);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(1, 0, 0);
+	I2C_DELAY(1);
+}
+
+// STOP condition: 0-to-1 transition of SDA when SCL is 1
+static void i2c_stop(void) {
+	i2c_oe_scl_sda(1, 0, 0);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(1, 1, 0);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(1, 1, 1);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(0, 1, 1);
+}
+
+// Call when in the middle of SCL low, advances one clk period
+static void i2c_transmit_bit(int value) {
+	i2c_oe_scl_sda(1, 0, value);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(1, 1, value);
+	I2C_DELAY(2);
+	i2c_oe_scl_sda(1, 0, value);
+	I2C_DELAY(1);
+}
+
+// Call when in the middle of SCL low, advances one clk period
+static int i2c_receive_bit(void) {
+	int value;
+	i2c_oe_scl_sda(0, 0, 0);
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(0, 1, 0);
+	I2C_DELAY(1);
+	// read in the middle of SCL high
+	value = i2c_r_read() & 1;
+	I2C_DELAY(1);
+	i2c_oe_scl_sda(0, 0, 0);
+	I2C_DELAY(1);
+	return value;
+}
+
+// Send data byte and return 1 if slave sends ACK
+static bool i2c_transmit_byte(unsigned char data) {
+	int i;
+	int ack;
+
+	// SCL should have already been low for 1/4 cycle
+	// Keep SDA low to avoid short spikes from the pull-ups
+	i2c_oe_scl_sda(1, 0, 0);
+	for (i = 0; i < 8; ++i) {
+		// MSB first
+		i2c_transmit_bit((data & (1 << 7)) != 0);
+		data <<= 1;
+	}
+	i2c_oe_scl_sda(0, 0, 0); // release line
+	ack = i2c_receive_bit();
+
+	// 0 from slave means ack
+	return ack == 0;
+}
+
+// Read data byte and send ACK if ack=1
+static unsigned char i2c_receive_byte(bool ack) {
+	int i;
+	unsigned char data = 0;
+
+	for (i = 0; i < 8; ++i) {
+		data <<= 1;
+		data |= i2c_receive_bit();
+	}
+	i2c_transmit_bit(!ack);
+	i2c_oe_scl_sda(0, 0, 0); // release line
+
+	return data;
+}
+
+bool amp_init(void) {
+	return amp_write({0x00, 0x00, 0x07});
+}
+
+bool amp_read(amp_i2c &rcv) {
+	i2c_start();
+	if (!i2c_transmit_byte(I2C_ADDR_RD(0x28))) {
+		i2c_stop();
+		return false;
+	}
+	rcv.pot0 = i2c_receive_byte(true) & 0x3F;
+	rcv.pot1 = i2c_receive_byte(true) & 0x3F;
+	rcv.conf = i2c_receive_byte(false) & 0x3F;
+	i2c_stop();
+	return true;
+}
+
+bool amp_read_pot0(uint8_t &pot0) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	pot0 = temp.pot0;
+	return success;
+}
+
+bool amp_read_pot1(uint8_t &pot1) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	pot1 = temp.pot1;
+	return success;
+}
+
+bool amp_read_conf(uint8_t &conf) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	conf = temp.conf;
+	return success;
+}
+
+bool amp_write(amp_i2c value) {
+	i2c_start();
+	if (!i2c_transmit_byte(I2C_ADDR_WR(0x28))) {
+		i2c_stop();
+		return true;
+	}
+	if (!i2c_transmit_byte(value.pot0)) {
+		i2c_stop();
+		return false;
+	}
+	if (!i2c_transmit_byte(value.pot1 | 0x40)) {
+		i2c_stop();
+		return false;
+	}
+	if (!i2c_transmit_byte(value.conf | 0x80)) {
+		i2c_stop();
+		return false;
+	}
+	i2c_stop();
+	return true;
+}
+
+bool amp_write_pot0(uint8_t value) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	temp.pot0 = value;
+	return success & amp_write(temp);
+}
+
+bool amp_write_pot1(uint8_t value) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	temp.pot1 = value;
+	return success & amp_write(temp);
+}
+
+bool amp_write_conf(uint8_t value) {
+	amp_i2c temp;
+	bool success = amp_read(temp);
+	temp.conf = value;
+	return success & amp_write(temp);
+}
+
+#endif