1 files changed, 99 insertions, 0 deletions
diff --git a/fw/fe310/eos/i2c.c b/fw/fe310/eos/i2c.c
new file mode 100644
index 0000000..122a1b2
--- /dev/null
+++ b/fw/fe310/eos/i2c.c
@@ -0,0 +1,99 @@
+#include <stdlib.h>
+#include <stdint.h>
+
+#include "encoding.h"
+#include "platform.h"
+#include "prci_driver.h"
+
+#include "eos.h"
+#include "i2c.h"
+
+void eos_i2c_start(uint32_t baud_rate) {
+    eos_i2c_set_baud_rate(baud_rate);
+    GPIO_REG(GPIO_IOF_SEL)      &= ~IOF0_I2C0_MASK;
+    GPIO_REG(GPIO_IOF_EN)       |=  IOF0_I2C0_MASK;
+}
+
+void eos_i2c_stop(void) {
+    GPIO_REG(GPIO_IOF_EN)       &=  ~IOF0_I2C0_MASK;
+}
+
+void eos_i2c_set_baud_rate(uint32_t baud_rate) {
+    unsigned long clock_rate = PRCI_get_cpu_freq();
+    uint16_t prescaler = (clock_rate / (baud_rate * 5)) - 1;
+
+    I2C0_REGB(I2C_CONTROL) &= ~I2C_CONTROL_EN;
+    I2C0_REGB(I2C_PRESCALE_LOW) = prescaler & 0xFF;
+    I2C0_REGB(I2C_PRESCALE_HIGH) = (prescaler >> 8) & 0xFF;
+    I2C0_REGB(I2C_CONTROL) |= I2C_CONTROL_EN;
+}
+
+
+static int i2c_read(uint8_t cmd) {
+    I2C0_REGB(I2C_COMMAND) = I2C_CMD_READ | cmd;
+    while (I2C0_REGB(I2C_STATUS) & I2C_STATUS_TIP);
+
+    return I2C0_REGB(I2C_RECEIVE);
+}
+
+static int i2c_write(uint8_t cmd, uint8_t b) {
+    I2C0_REGB(I2C_TRANSMIT) = b;
+    I2C0_REGB(I2C_COMMAND) = I2C_CMD_WRITE | cmd;
+    while (I2C0_REGB(I2C_STATUS) & I2C_STATUS_TIP);
+
+    if (I2C0_REGB(I2C_STATUS) & I2C_STATUS_RXACK) return EOS_ERR;
+    return EOS_OK;
+}
+
+static int i2c_addr(uint8_t addr, uint8_t rw_flag) {
+    return i2c_write(I2C_CMD_START, ((addr & 0x7F) << 1) | (rw_flag & 0x1));
+}
+
+int eos_i2c_read(uint8_t addr, uint8_t reg, uint8_t *buffer, uint16_t len) {
+    int rv;
+    int i;
+
+    rv = i2c_addr(addr, I2C_WRITE);
+    if (rv) return rv;
+
+    rv = i2c_write(0, reg);
+    if (rv) return rv;
+
+    rv = i2c_addr(addr, I2C_READ);
+    if (rv) return rv;
+
+    for (i=0; i<len; i++) {
+        rv = i2c_read(i == (len - 1) ? (I2C_CMD_ACK | I2C_CMD_STOP) : 0);  /* Set NACK to end read, and generate STOP condition */
+        if (rv < 0) return rv;
+
+        buffer[i] = (uint8_t)rv;
+    }
+
+    return EOS_OK;
+}
+
+int eos_i2c_write(uint8_t addr, uint8_t reg, uint8_t *buffer, uint16_t len) {
+    int rv;
+    int i;
+
+    rv = i2c_addr(addr, I2C_WRITE);
+    if (rv) return rv;
+
+    rv = i2c_write(0, reg);
+    if (rv) return rv;
+
+    for (i=0; i<len; i++) {
+        rv = i2c_write(i == (len - 1) ? I2C_CMD_STOP : 0, buffer[i]);
+        if (rv) return rv;
+    }
+
+    return EOS_OK;
+}
+
+int eos_i2c_read8(uint8_t addr, uint8_t reg, uint8_t *data) {
+    return eos_i2c_read(addr, reg, data, 1);
+}
+
+int eos_i2c_write8(uint8_t addr, uint8_t reg, uint8_t data) {
+    return eos_i2c_write(addr, reg, &data, 1);
+}