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-rw-r--r--libmaple/i2c.c271
1 files changed, 269 insertions, 2 deletions
diff --git a/libmaple/i2c.c b/libmaple/i2c.c
index 9c93d3f..bbbf123 100644
--- a/libmaple/i2c.c
+++ b/libmaple/i2c.c
@@ -28,9 +28,11 @@
/**
* @file libmaple/i2c.c
* @author Perry Hung <perry@leaflabs.com>
+ * @author Barry Carter <barry.carter@gmail.com>
* @brief Inter-Integrated Circuit (I2C) support.
*
- * Currently, only master mode is supported.
+ * Master and Slave supported
+ * Slave code added Barry Carter 2012
*/
#include "i2c_private.h"
@@ -154,6 +156,7 @@ void i2c_bus_reset(const i2c_dev *dev) {
void i2c_init(i2c_dev *dev) {
rcc_reset_dev(dev->clk_id);
rcc_clk_enable(dev->clk_id);
+ _i2c_irq_priority_fixup(dev);
}
/* Hack for deprecated bit of STM32F1 functionality */
@@ -198,13 +201,51 @@ void i2c_master_enable(i2c_dev *dev, uint32 flags) {
nvic_irq_enable(dev->er_nvic_line);
i2c_enable_irq(dev, I2C_IRQ_EVENT | I2C_IRQ_BUFFER | I2C_IRQ_ERROR);
+ /* Configure the slave unit */
+ if (flags & I2C_SLAVE_DUAL_ADDRESS) {
+ i2c_slave_dual_address_enable(dev);
+ }
+
+ if (flags & I2C_SLAVE_GENERAL_CALL) {
+ i2c_slave_general_call_enable(dev);
+ }
+
+ /* store all of the flags */
+ dev->config_flags = flags;
+
/* Make it go! */
i2c_peripheral_enable(dev);
+ i2c_enable_ack(dev);
dev->state = I2C_STATE_IDLE;
}
/**
+ * @brief Initialize an I2C device as slave (and master)
+ * @param dev Device to enable
+ * @param flags Bitwise or of the following I2C options:
+ * I2C_FAST_MODE: 400 khz operation,
+ * I2C_DUTY_16_9: 16/9 Tlow/Thigh duty cycle (only applicable for
+ * fast mode),
+ * I2C_BUS_RESET: Reset the bus and clock out any hung slaves on
+ * initialization,
+ * I2C_10BIT_ADDRESSING: Enable 10-bit addressing,
+ * I2C_REMAP: (deprecated, STM32F1 only) Remap I2C1 to SCL/PB8
+ * SDA/PB9.
+ * I2C_SLAVE_DUAL_ADDRESS: Slave can respond on 2 i2C addresses
+ * I2C_SLAVE_GENERAL_CALL: SLA+W broadcast to all general call
+ * listeners on bus. Addr 0x00
+ * I2C_SLAVE_USE_RX_BUFFER: Use a buffer to receive the incoming
+ * data. Callback at end of recv
+ * I2C_SLAVE_USE_TX_BUFFER: Use a buffer to transmit data.
+ * Callback will be called before tx
+ */
+void i2c_slave_enable(i2c_dev *dev, uint32 flags) {
+ i2c_disable(dev);
+ i2c_master_enable(dev, dev->config_flags | flags);
+}
+
+/**
* @brief Process an i2c transaction.
*
* Transactions are composed of one or more i2c_msg's, and may be read
@@ -304,6 +345,164 @@ void _i2c_irq_handler(i2c_dev *dev) {
dev->timestamp = systick_uptime();
/*
+ * Add Slave support
+ */
+
+ /* Check to see if MSL master slave bit is set */
+ if ((sr2 & I2C_SR2_MSL) != I2C_SR2_MSL) { /* 0 = slave mode 1 = master */
+
+ /* Check for address match */
+ if (sr1 & I2C_SR1_ADDR) {
+ /* Find out which address was matched */
+ /* Check the general call address first */
+ if (sr2 & I2C_SR2_GENCALL) {
+ dev->i2c_slave_msg->addr = 0;
+ }
+ /* We matched the secondary address */
+ else if (sr2 & I2C_SR2_DUALF) {
+ dev->i2c_slave_msg->addr = dev->regs->OAR2 & 0xFE;
+ }
+ /* We matched the primary address */
+ else if ((sr2 & I2C_SR2_DUALF) != I2C_SR2_DUALF) {
+ dev->i2c_slave_msg->addr = dev->regs->OAR1 & 0xFE;
+ }
+ /* Shouldn't get here */
+ else {
+ dev->i2c_slave_msg->addr = -1; /* uh oh */
+ }
+
+ /* if we have buffered io */
+ if ((dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) ||
+ (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) {
+
+ /* if receiving then this would be a repeated start
+ *
+ *if we have some bytes already
+ */
+ if ((dev->state == I2C_STATE_SL_RX) &&
+ (dev->i2c_slave_msg->xferred > 0) &&
+ (dev->config_flags & I2C_SLAVE_USE_RX_BUFFER)) {
+ /* Call the callback with the contents of the data */
+ if (dev->i2c_slave_recv_callback != NULL) {
+ (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg);
+ }
+ }
+
+ /* Reset the message back to defaults.
+ * We are starting a new message
+ */
+ dev->i2c_slave_msg->flags = 0;
+ dev->i2c_slave_msg->length = 0;
+ dev->i2c_slave_msg->xferred = 0;
+ dev->msgs_left = 0;
+ dev->timestamp = systick_uptime();
+
+ /* We have been addressed with SLA+R so
+ * the master wants us to transmit
+ */
+ if ((sr1 & I2C_SR1_TXE) &&
+ (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) {
+ /* Call the transmit callback so it can populate the msg
+ * data with the bytes to go
+ */
+ if (dev->i2c_slave_transmit_callback != NULL) {
+ (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg);
+ }
+ }
+ dev->state = I2C_STATE_BUSY;
+ }
+
+ sr1 = sr2 = 0;
+ }
+
+ /* EV3: Master requesting data from slave. Transmit a byte*/
+ if (sr1 & I2C_SR1_TXE) {
+ if (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER) {
+ if (dev->i2c_slave_msg->xferred >= dev->i2c_slave_msg->length) {
+ /* End of the transmit buffer? If so we NACK */
+ i2c_disable_ack(dev);
+ /* We have to either issue a STOP or write something here.
+ * STOP here seems to screw up some masters,
+ * For now padding with 0
+ */
+ i2c_write(dev, 0);
+ /*i2c_stop_condition(dev); // This is causing bus lockups way more than it should !? Seems some I2C master devices freak out here*/
+ }
+ else
+ {
+ /* NACk the last byte */
+ if (dev->i2c_slave_msg->xferred == dev->i2c_slave_msg->length-1) {
+ i2c_disable_ack(dev);
+ }
+ else {
+ i2c_enable_ack(dev);
+ }
+ i2c_write(dev, dev->i2c_slave_msg->data[dev->i2c_slave_msg->xferred++]);
+ }
+ }
+ else
+ {
+ /* Call the callback to get the data we need.
+ * The callback is expected to write using i2c_write(...)
+ * If the slave is going to terminate the transfer, this function should
+ * also do a NACK on the last byte!
+ */
+ if (dev->i2c_slave_transmit_callback != NULL) (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg);
+ }
+
+ dev->state = I2C_STATE_BUSY;
+ sr1 = sr2 = 0;
+ }
+
+ /* EV2: Slave received data from a master. Get from DR */
+ if (sr1 & I2C_SR1_RXNE) {
+ if (dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) {
+ /* Fill the buffer with the contents of the data register */
+ /* These is potential for buffer overflow here, so we should
+ * really store the size of the array. This is expensive in
+ * the ISR so left out for now. We must trust the implementor!
+ */
+ dev->i2c_slave_msg->data[dev->i2c_slave_msg->xferred++] = dev->regs->DR;
+ dev->i2c_slave_msg->length++;
+ }
+ else {
+ /* Call the callback with the contents of the data */
+ dev->i2c_slave_msg->data[0] = dev->regs->DR;
+ if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg);
+ }
+ dev->state = I2C_STATE_SL_RX;
+ sr1 = sr2 = 0;
+ }
+
+ /* EV4: Slave has detected a STOP condition on the bus */
+ if (sr1 & I2C_SR1_STOPF) {
+ dev->regs->CR1 |= I2C_CR1_PE;
+
+ if ((dev->config_flags & I2C_SLAVE_USE_RX_BUFFER) ||
+ (dev->config_flags & I2C_SLAVE_USE_TX_BUFFER)) {
+
+ /* The callback with the data will happen on a NACK of the last data byte.
+ * This is handled in the error IRQ (AF bit)
+ */
+ /* Handle the case where the master misbehaves by sending no NACK */
+ if (dev->state != I2C_STATE_IDLE) {
+ if (dev->state == I2C_STATE_SL_RX) {
+ if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg);
+ }
+ else {
+ if (dev->i2c_slave_transmit_callback != NULL) (*(dev->i2c_slave_transmit_callback))(dev->i2c_slave_msg);
+ }
+ }
+ }
+
+ sr1 = sr2 = 0;
+ dev->state = I2C_STATE_IDLE;
+ }
+
+ return;
+ }
+
+ /*
* EV5: Start condition sent
*/
if (sr1 & I2C_SR1_SB) {
@@ -447,6 +646,7 @@ void _i2c_irq_handler(i2c_dev *dev) {
}
}
}
+
}
/*
@@ -456,10 +656,49 @@ void _i2c_irq_handler(i2c_dev *dev) {
void _i2c_irq_error_handler(i2c_dev *dev) {
I2C_CRUMB(ERROR_ENTRY, dev->regs->SR1, dev->regs->SR2);
- dev->error_flags = dev->regs->SR2 & (I2C_SR1_BERR |
+ dev->error_flags = dev->regs->SR1 & (I2C_SR1_BERR |
I2C_SR1_ARLO |
I2C_SR1_AF |
I2C_SR1_OVR);
+
+ /* Are we in slave mode? */
+ if ((dev->regs->SR2 & I2C_SR2_MSL) != I2C_SR2_MSL) {
+ /* Check to see if the master device did a NAK on the last bit
+ * This is perfectly valid for a master to do this on the bus.
+ * We ignore this. Any further error processing takes us into dead
+ * loop waiting for the stop condition that will never arrive
+ */
+ if (dev->regs->SR1 & I2C_SR1_AF) {
+ /* Clear flags */
+ dev->regs->SR1 = 0;
+ dev->regs->SR2 = 0;
+ /* We need to write something to CR1 to clear the flag.
+ * This isn't really mentioned but seems important */
+ i2c_enable_ack(dev);
+
+ if (dev->state == I2C_STATE_SL_RX &&
+ dev->config_flags & I2C_SLAVE_USE_RX_BUFFER &&
+ dev->i2c_slave_msg->xferred > 0) {
+ /* Call the callback with the contents of the data */
+ if (dev->i2c_slave_recv_callback != NULL) (*(dev->i2c_slave_recv_callback))(dev->i2c_slave_msg);
+ }
+
+ dev->state = I2C_STATE_IDLE;
+ return;
+ }
+ /* Catch any other strange errors while in slave mode.
+ * I have seen BERR caused by an over fast master device
+ * as well as several overflows and arbitration failures.
+ * We are going to reset SR flags and carry on at this point which
+ * is not the best thing to do, but stops the bus locking up completely
+ * If we carry on below and send the stop bit, the code spins forever */
+ /* Clear flags */
+ dev->regs->SR1 = 0;
+ dev->regs->SR2 = 0;
+ dev->state = I2C_STATE_IDLE;
+ return;
+ }
+
/* Clear flags */
dev->regs->SR1 = 0;
dev->regs->SR2 = 0;
@@ -507,3 +746,31 @@ static void set_ccr_trise(i2c_dev *dev, uint32 flags) {
i2c_set_clk_control(dev, ccr);
i2c_set_trise(dev, trise);
}
+
+
+/**
+ * @brief callback for when the device acts as a slave. If using an rx buffer, this is triggered
+ * after the last byte, otherwise it is called for every incoming packet.
+ * @param dev I2C device
+ * @param msg The dev_msg to pass to the slave init code
+ * @param func The function pointer to call
+ */
+void i2c_slave_attach_recv_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_recv_callback_func func) {
+ dev->i2c_slave_recv_callback = func;
+ dev->i2c_slave_msg = msg;
+ msg->xferred = 0;
+}
+
+
+/**
+ * @brief callback for when the device acts as a slave. If using a tx buffer, this is triggered
+ * after the device is successsfully addressed with SLA+R.
+ * @param dev I2C device
+ * @param msg The dev_msg to pass to the slave init code
+ * @param func The function pointer to call
+ */
+void i2c_slave_attach_transmit_handler(i2c_dev *dev, i2c_msg *msg, i2c_slave_transmit_callback_func func) {
+ dev->i2c_slave_transmit_callback = func;
+ dev->i2c_slave_msg = msg;
+ msg->xferred = 0;
+}