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libraries/Wire: Add support for target mode.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
1 parent 045ae9d commit 00ddf31

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+184
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2 files changed

+184
-72
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‎libraries/Wire/Wire.cpp‎

Lines changed: 163 additions & 64 deletions
Original file line numberDiff line numberDiff line change
@@ -5,104 +5,147 @@
55
*/
66

77
#include <Wire.h>
8+
#include <stddef.h>
89
#include <zephyr/sys/util_macro.h>
910

10-
arduino::ZephyrI2C::ZephyrI2C(const struct device *i2c) : i2c_dev(i2c)
11-
{
11+
// Helper function to get ZephyrI2C instance from config pointer.
12+
static arduino::ZephyrI2C* getInstance(struct i2c_target_config *config) {
13+
return reinterpret_cast<arduino::ZephyrI2C*>(
14+
reinterpret_cast<char*>(config) - offsetof(arduino::ZephyrI2C, i2c_cfg)
15+
);
16+
}
17+
18+
static int i2c_target_stop_cb(struct i2c_target_config *config) {
19+
arduino::ZephyrI2C *instance = getInstance(config);
20+
return instance->stopCallback(config);
21+
}
22+
23+
static int i2c_target_write_requested_cb(struct i2c_target_config *config) {
24+
arduino::ZephyrI2C *instance = getInstance(config);
25+
return instance->writeRequestedCallback(config);
26+
}
27+
28+
static int i2c_target_write_received_cb(struct i2c_target_config *config, uint8_t val) {
29+
arduino::ZephyrI2C *instance = getInstance(config);
30+
return instance->writeReceivedCallback(config, val);
31+
}
32+
33+
static int i2c_target_read_requested_cb(struct i2c_target_config *config, uint8_t *val) {
34+
arduino::ZephyrI2C *instance = getInstance(config);
35+
return instance->readRequestedCallback(config, val);
36+
}
37+
38+
static int i2c_target_read_processed_cb(struct i2c_target_config *config, uint8_t *val) {
39+
arduino::ZephyrI2C *instance = getInstance(config);
40+
return instance->readProcessedCallback(config, val);
41+
}
42+
43+
// I2C target callback structure.
44+
static struct i2c_target_callbacks target_callbacks = {
45+
.write_requested = i2c_target_write_requested_cb,
46+
.read_requested = i2c_target_read_requested_cb,
47+
.write_received = i2c_target_write_received_cb,
48+
.read_processed = i2c_target_read_processed_cb,
49+
.stop = i2c_target_stop_cb,
50+
};
51+
52+
arduino::ZephyrI2C::ZephyrI2C(const struct device *i2c) : i2c_dev(i2c), i2c_cfg({0}) {
53+
ring_buf_init(&txRingBuffer.rb, sizeof(txRingBuffer.buffer), txRingBuffer.buffer);
54+
ring_buf_init(&rxRingBuffer.rb, sizeof(rxRingBuffer.buffer), rxRingBuffer.buffer);
55+
1256
}
1357

1458
void arduino::ZephyrI2C::begin() {
15-
ring_buf_init(&rxRingBuffer.rb, sizeof(rxRingBuffer.buffer), rxRingBuffer.buffer);
59+
1660
}
1761

1862
void arduino::ZephyrI2C::begin(uint8_t slaveAddr) {
19-
63+
i2c_cfg.address = slaveAddr;
64+
i2c_cfg.callbacks = &target_callbacks;
65+
66+
// Register I2C target
67+
i2c_target_register(i2c_dev, &i2c_cfg);
2068
}
2169

22-
void arduino::ZephyrI2C::end() {}
70+
void arduino::ZephyrI2C::end() {
71+
// Unregister I2C target
72+
if (i2c_cfg.address) {
73+
i2c_target_unregister(i2c_dev, &i2c_cfg);
74+
memset(&i2c_cfg, 0, sizeof(i2c_cfg));
75+
}
76+
}
2377

2478
void arduino::ZephyrI2C::setClock(uint32_t freq) {
25-
uint8_t speed = I2C_SPEED_STANDARD;
26-
if(freq > 0x06u ) {
27-
if(freq == 100000) {
28-
speed = I2C_SPEED_STANDARD;
29-
} else if(freq == 400000) {
30-
speed = I2C_SPEED_FAST;
31-
} else if(freq == 1000000) {
32-
speed = I2C_SPEED_FAST_PLUS;
33-
} else {
34-
speed = I2C_SPEED_STANDARD;
35-
}
36-
} else {
37-
speed = (uint8_t) freq;
38-
}
39-
uint32_t i2c_cfg = I2C_MODE_CONTROLLER |
40-
I2C_SPEED_SET(speed);
41-
42-
if (i2c_configure(i2c_dev, i2c_cfg)) {
43-
//Serial.println("Failed to configure i2c interface.");
44-
}
45-
}
46-
47-
void arduino::ZephyrI2C::beginTransmission(uint8_t address) { // TODO for ADS1115
79+
uint8_t speed;
80+
81+
if (freq == 100000) {
82+
speed = I2C_SPEED_STANDARD;
83+
} else if (freq == 400000) {
84+
speed = I2C_SPEED_FAST;
85+
} else if (freq == 1000000) {
86+
speed = I2C_SPEED_FAST_PLUS;
87+
} else {
88+
speed = I2C_SPEED_STANDARD;
89+
}
90+
91+
i2c_configure(i2c_dev, I2C_SPEED_SET(speed) | I2C_MODE_CONTROLLER);
92+
}
93+
94+
void arduino::ZephyrI2C::beginTransmission(uint8_t address) {
4895
_address = address;
49-
usedTxBuffer = 0;
96+
ring_buf_reset(&txRingBuffer.rb);
97+
ring_buf_reset(&rxRingBuffer.rb);
5098
}
5199

52100
uint8_t arduino::ZephyrI2C::endTransmission(bool stopBit) {
53-
int ret = i2c_write(i2c_dev, txBuffer, usedTxBuffer, _address);
54-
if (ret) {
55-
return 1; // fail
101+
int ret = 0;
102+
uint8_t *data = NULL;
103+
size_t max = ring_buf_capacity_get(&txRingBuffer.rb);
104+
size_t len = ring_buf_get_claim(&txRingBuffer.rb, &data, max);
105+
106+
if (len) {
107+
ret = i2c_write(i2c_dev, data, len, _address);
56108
}
57-
return 0;
109+
110+
// Must be called even if 0 bytes claimed.
111+
ring_buf_get_finish(&txRingBuffer.rb, len);
112+
113+
return ret ? 1 : 0;
58114
}
59115

60-
uint8_t arduino::ZephyrI2C::endTransmission(void) { // TODO for ADS1115
116+
uint8_t arduino::ZephyrI2C::endTransmission(void) {
61117
return endTransmission(true);
62118
}
63119

64-
size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len,
65-
bool stopBit) {
120+
size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len, bool stopBit) {
66121
uint8_t buf[len];
67-
int ret = i2c_read(i2c_dev, buf, len, address);
68-
if (ret != 0)
69-
{
122+
if (i2c_read(i2c_dev, buf, len, address)) {
70123
return 0;
71124
}
72-
ret = ring_buf_put(&rxRingBuffer.rb, buf, len);
73-
if (ret == 0)
74-
{
125+
if (!ring_buf_put(&rxRingBuffer.rb, buf, len)) {
75126
return 0;
76127
}
77128
return len;
78129
}
79130

80-
size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len) { // TODO for ADS1115
131+
size_t arduino::ZephyrI2C::requestFrom(uint8_t address, size_t len) {
81132
return requestFrom(address, len, true);
82133
}
83134

84-
size_t arduino::ZephyrI2C::write(uint8_t data) { // TODO for ADS1115
85-
txBuffer[usedTxBuffer++] = data;
86-
return 1;
135+
size_t arduino::ZephyrI2C::write(uint8_t data) {
136+
return ring_buf_put(&txRingBuffer.rb, &data, 1);
87137
}
88138

89139
size_t arduino::ZephyrI2C::write(const uint8_t *buffer, size_t size) {
90-
if (usedTxBuffer + size > 256) {
91-
size = 256 - usedTxBuffer;
92-
}
93-
memcpy(txBuffer + usedTxBuffer, buffer, size);
94-
usedTxBuffer += size;
95-
return size;
140+
return ring_buf_put(&txRingBuffer.rb, buffer, size);
96141
}
97142

98143
int arduino::ZephyrI2C::read() {
99144
uint8_t buf[1];
100145
if (ring_buf_size_get(&rxRingBuffer.rb)) {
101-
int ret = ring_buf_get(&rxRingBuffer.rb, buf, 1);
102-
if (ret == 0) {
103-
return -1;
104-
}
105-
return (int)buf[0];
146+
if (ring_buf_get(&rxRingBuffer.rb, buf, 1)) {
147+
return (int) buf[0];
148+
}
106149
}
107150
return -1;
108151
}
@@ -113,17 +156,73 @@ int arduino::ZephyrI2C::available() {
113156

114157
int arduino::ZephyrI2C::peek() {
115158
uint8_t buf[1];
116-
int bytes_read = ring_buf_peek(&rxRingBuffer.rb, buf, 1);
117-
if (bytes_read == 0){
118-
return 0;
159+
if (!ring_buf_peek(&rxRingBuffer.rb, buf, 1)) {
160+
return -1;
119161
}
120-
return (int)buf[0];
162+
return (int) buf[0];
121163
}
122164

123-
void arduino::ZephyrI2C::flush() {}
165+
void arduino::ZephyrI2C::flush() {
124166

125-
void arduino::ZephyrI2C::onReceive(voidFuncPtrParamInt cb) {}
126-
void arduino::ZephyrI2C::onRequest(voidFuncPtr cb) {}
167+
}
168+
169+
void arduino::ZephyrI2C::onReceive(voidFuncPtrParamInt cb) {
170+
onReceiveCb = cb;
171+
}
172+
173+
void arduino::ZephyrI2C::onRequest(voidFuncPtr cb) {
174+
onRequestCb = cb;
175+
}
176+
177+
int arduino::ZephyrI2C::writeRequestedCallback(struct i2c_target_config *config) {
178+
// Reset the buffer on write requests.
179+
ring_buf_reset(&rxRingBuffer.rb);
180+
return 0;
181+
}
182+
183+
int arduino::ZephyrI2C::writeReceivedCallback(struct i2c_target_config *config, uint8_t val) {
184+
size_t len = ring_buf_size_get(&rxRingBuffer.rb);
185+
size_t max = ring_buf_capacity_get(&rxRingBuffer.rb);
186+
187+
// If the buffer is about to overflow, invoke the callback
188+
// with the current length.
189+
if (onReceiveCb && ((len + 1) > max)) {
190+
onReceiveCb(len);
191+
}
192+
193+
return ring_buf_put(&rxRingBuffer.rb, &val, 1) ? 0 : -1;
194+
}
195+
196+
int arduino::ZephyrI2C::readRequestedCallback(struct i2c_target_config *config, uint8_t *val) {
197+
// Reset the buffer on read requests.
198+
ring_buf_reset(&txRingBuffer.rb);
199+
200+
if (onRequestCb) {
201+
onRequestCb();
202+
}
203+
204+
return readProcessedCallback(config, val);
205+
}
206+
207+
int arduino::ZephyrI2C::readProcessedCallback(struct i2c_target_config *config, uint8_t *val) {
208+
*val = 0xFF;
209+
ring_buf_get(&txRingBuffer.rb, val, 1);
210+
// Returning a negative value here is not handled gracefully and
211+
// causes the target/board to stop responding (at least with ST).
212+
return 0;
213+
}
214+
215+
int arduino::ZephyrI2C::stopCallback(struct i2c_target_config *config) {
216+
// If the RX buffer is not empty invoke the callback with the
217+
// remaining data length.
218+
if (onReceiveCb) {
219+
size_t len = ring_buf_size_get(&rxRingBuffer.rb);
220+
if (len) {
221+
onReceiveCb(len);
222+
}
223+
}
224+
return 0;
225+
}
127226

128227
#if DT_NODE_HAS_PROP(DT_PATH(zephyr_user), i2cs)
129228
#if (DT_PROP_LEN(DT_PATH(zephyr_user), i2cs) > 1)

‎libraries/Wire/Wire.h‎

Lines changed: 21 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -15,6 +15,11 @@ typedef void (*voidFuncPtrParamInt)(int);
1515

1616
namespace arduino {
1717

18+
struct i2c_ring {
19+
struct ring_buf rb;
20+
uint8_t buffer[256];
21+
};
22+
1823
class ZephyrI2C : public HardwareI2C {
1924
public:
2025
ZephyrI2C(const struct device* i2c);
@@ -43,16 +48,24 @@ class ZephyrI2C : public HardwareI2C {
4348
virtual void flush();
4449
virtual int available();
4550

51+
// I2C target callbacks
52+
int writeRequestedCallback(struct i2c_target_config *config);
53+
int writeReceivedCallback(struct i2c_target_config *config, uint8_t val);
54+
int readRequestedCallback(struct i2c_target_config *config, uint8_t *val);
55+
int readProcessedCallback(struct i2c_target_config *config, uint8_t *val);
56+
int stopCallback(struct i2c_target_config *config);
57+
58+
struct i2c_target_config i2c_cfg;
59+
4660
private:
4761
int _address;
48-
uint8_t txBuffer[256];
49-
uint32_t usedTxBuffer;
50-
struct rx_ring_buf{
51-
struct ring_buf rb;
52-
uint8_t buffer[256];
53-
};
54-
struct rx_ring_buf rxRingBuffer;
55-
const struct device* i2c_dev;
62+
63+
struct i2c_ring txRingBuffer;
64+
struct i2c_ring rxRingBuffer;
65+
const struct device *i2c_dev;
66+
67+
voidFuncPtr onRequestCb = NULL;
68+
voidFuncPtrParamInt onReceiveCb = NULL;
5669
};
5770

5871
} // namespace arduino

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