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stmhal/i2c: Reset the I2C peripheral if there was an error on the bus. 

If an I2C send/recv fails then the peripheral is now checked to see if
it's in a "stuck" state waiting for the stop bit, and if so then it is
reset so that the next I2C transaction can proceed.

This patch also de-inits the I2C peripheral in the init() method, before
init'ing it again.
This commit is contained in:
Damien George 2016-11-11 17:38:52 +11:00
parent c4e58eaa98
commit 74fb5d6932
1 changed files with 19 additions and 0 deletions
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19
stmhal/i2c.c
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@ -283,6 +283,20 @@ void i2c_deinit(I2C_HandleTypeDef *i2c) {
}
}
STATIC void i2c_reset_after_error(I2C_HandleTypeDef *i2c) {
// wait for bus-busy flag to be cleared, with a timeout
for (int timeout = 50; timeout > 0; --timeout) {
if (!__HAL_I2C_GET_FLAG(i2c, I2C_FLAG_BUSY)) {
// stop bit was generated and bus is back to normal
return;
}
HAL_Delay(1);
}
// bus was/is busy, need to reset the peripheral to get it to work again
i2c_deinit(i2c);
i2c_init(i2c);
}
STATIC HAL_StatusTypeDef i2c_wait_dma_finished(I2C_HandleTypeDef *i2c, uint32_t timeout) {
// Note: we can't use WFI to idle in this loop because the DMA completion
// interrupt may occur before the WFI. Hence we miss it and have to wait
@ -369,6 +383,7 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
*self->use_dma = args[4].u_bool;
// init the I2C bus
i2c_deinit(self->i2c);
i2c_init(self->i2c);
return mp_const_none;
@ -562,6 +577,7 @@ STATIC mp_obj_t pyb_i2c_send(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
}
if (status != HAL_OK) {
i2c_reset_after_error(self->i2c);
mp_hal_raise(status);
}
@ -635,6 +651,7 @@ STATIC mp_obj_t pyb_i2c_recv(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_
}
if (status != HAL_OK) {
i2c_reset_after_error(self->i2c);
mp_hal_raise(status);
}
@ -709,6 +726,7 @@ STATIC mp_obj_t pyb_i2c_mem_read(mp_uint_t n_args, const mp_obj_t *pos_args, mp_
}
if (status != HAL_OK) {
i2c_reset_after_error(self->i2c);
mp_hal_raise(status);
}
@ -776,6 +794,7 @@ STATIC mp_obj_t pyb_i2c_mem_write(mp_uint_t n_args, const mp_obj_t *pos_args, mp
}
if (status != HAL_OK) {
i2c_reset_after_error(self->i2c);
mp_hal_raise(status);
}