tres: fix I2C hang on fake siren init (#2069)

* fix i2c hang

* misra fix

---------

Co-authored-by: Comma Device <device@comma.ai>

board/boards/tres.h

@@ -69,7 +69,6 @@ static void tres_init(void) {
   set_gpio_alternate(GPIOC, 10, GPIO_AF4_I2C5);
   set_gpio_alternate(GPIOC, 11, GPIO_AF4_I2C5);
   register_set_bits(&(GPIOC->OTYPER), GPIO_OTYPER_OT10 | GPIO_OTYPER_OT11); // open drain
-  fake_siren_init();
 
   // Clock source
   clock_source_init();

board/drivers/fake_siren.h

@@ -2,6 +2,8 @@
 
 #define CODEC_I2C_ADDR 0x10
 
+void fake_siren_init(void);
+
 void fake_siren_codec_enable(bool enabled) {
   if (enabled) {
     bool success = true;
@@ -28,8 +30,14 @@ void fake_siren_codec_enable(bool enabled) {
 
 
 void fake_siren_set(bool enabled) {
+  static bool initialized = false;
   static bool fake_siren_enabled = false;
 
+  if (!initialized) {
+    fake_siren_init();
+    initialized = true;
+  }
+
   if (enabled != fake_siren_enabled) {
     fake_siren_codec_enable(enabled);
   }

board/main.c

@@ -325,12 +325,13 @@ int main(void) {
   // panda has an FPU, let's use it!
   enable_fpu();
 
+  microsecond_timer_init();
+
+  current_board->set_siren(false);
   if (current_board->fan_max_rpm > 0U) {
     fan_init();
   }
 
-  microsecond_timer_init();
-
   // init to SILENT and can silent
   set_safety_mode(SAFETY_SILENT, 0U);
 

board/stm32h7/lli2c.h

@@ -1,20 +1,27 @@
-
 // TODO: this driver relies heavily on polling,
 // if we want it to be more async, we should use interrupts
 
+#define I2C_RETRY_COUNT 10U
 #define I2C_TIMEOUT_US 100000U
 
-// cppcheck-suppress misra-c2012-2.7; not sure why it triggers here?
 bool i2c_status_wait(const volatile uint32_t *reg, uint32_t mask, uint32_t val) {
   uint32_t start_time = microsecond_timer_get();
   while(((*reg & mask) != val) && (get_ts_elapsed(microsecond_timer_get(), start_time) < I2C_TIMEOUT_US));
   return ((*reg & mask) == val);
 }
 
+void i2c_reset(I2C_TypeDef *I2C) {
+  // peripheral reset
+  register_clear_bits(&I2C->CR1, I2C_CR1_PE);
+  while ((I2C->CR1 & I2C_CR1_PE) != 0U);
+  register_set_bits(&I2C->CR1, I2C_CR1_PE);
+}
+
 bool i2c_write_reg(I2C_TypeDef *I2C, uint8_t addr, uint8_t reg, uint8_t value) {
-  // Setup transfer and send START + addr
   bool ret = false;
-  for(uint32_t i=0U; i<10U; i++) {
+
+  // Setup transfer and send START + addr
+  for (uint32_t i = 0U; i < I2C_RETRY_COUNT; i++) {
     register_clear_bits(&I2C->CR2, I2C_CR2_ADD10);
     I2C->CR2 = ((uint32_t)addr << 1U) & I2C_CR2_SADD_Msk;
     register_clear_bits(&I2C->CR2, I2C_CR2_RD_WRN);
@@ -57,9 +64,10 @@ end:
 }
 
 bool i2c_read_reg(I2C_TypeDef *I2C, uint8_t addr, uint8_t reg, uint8_t *value) {
-  // Setup transfer and send START + addr
   bool ret = false;
-  for(uint32_t i=0U; i<10U; i++) {
+
+  // Setup transfer and send START + addr
+  for (uint32_t i = 0U; i < I2C_RETRY_COUNT; i++) {
     register_clear_bits(&I2C->CR2, I2C_CR2_ADD10);
     I2C->CR2 = ((uint32_t)addr << 1U) & I2C_CR2_SADD_Msk;
     register_clear_bits(&I2C->CR2, I2C_CR2_RD_WRN);
@@ -116,6 +124,11 @@ bool i2c_read_reg(I2C_TypeDef *I2C, uint8_t addr, uint8_t reg, uint8_t *value) {
   I2C->CR2 |= I2C_CR2_STOP;
 
 end:
+
+  if (!ret) {
+    i2c_reset(I2C);
+  }
+
   return ret;
 }
 
@@ -131,7 +144,7 @@ bool i2c_set_reg_bits(I2C_TypeDef *I2C, uint8_t address, uint8_t regis, uint8_t
 bool i2c_clear_reg_bits(I2C_TypeDef *I2C, uint8_t address, uint8_t regis, uint8_t bits) {
   uint8_t value;
   bool ret = i2c_read_reg(I2C, address, regis, &value);
-  if(ret) {
+  if (ret) {
     ret = i2c_write_reg(I2C, address, regis, value & (uint8_t) (~bits));
   }
   return ret;
@@ -149,5 +162,6 @@ bool i2c_set_reg_mask(I2C_TypeDef *I2C, uint8_t address, uint8_t regis, uint8_t
 void i2c_init(I2C_TypeDef *I2C) {
   // 100kHz clock speed
   I2C->TIMINGR = 0x107075B0;
-  I2C->CR1 = I2C_CR1_PE;
-}
+
+  i2c_reset(I2C);
+}

python/__init__.py

@@ -252,7 +252,6 @@ class Panda:
       return None
     if len(pandas) == 1:
       print(f"INFO: connecting to panda {pandas[0]}")
-      time.sleep(1)
       return pandas[0]
     while True:
       print("Multiple pandas available:")