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xtensa/esp32: Adds I2C Bit banging reset

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This commit is contained in:
Sara Souza 2021-06-17 12:07:37 -03:00 committed by Xiang Xiao
parent 1448de4451
commit 00edeee1ff
1 changed files with 101 additions and 1 deletions
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102
arch/xtensa/src/esp32/esp32_i2c.c
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@ -91,6 +91,8 @@
I2C_ARBITRATION_LOST_INT_ENA | \
I2C_RXFIFO_OVF_INT_ENA)
#define I2C_SCL_CYC_NUM_DEF 9
/* I2C event trace logic.
* NOTE: trace uses the internal, non-standard, low-level debug interface
* syslog() but does not require that any other debug is enabled.
@ -1047,6 +1049,100 @@ static int esp32_i2c_transfer(FAR struct i2c_master_s *dev,
return ret;
}
/****************************************************************************
* Name: esp32_i2c_clear_bus
*
* Description:
* Clear I2C bus, when the slave is stuck in a deadlock and keeps pulling
* the bus low, master can control the SCL bus to generate 9 CLKs.
*
* Parameters:
* priv - Pointer to the internal driver state structure.
*
****************************************************************************/
#ifdef CONFIG_I2C_RESET
static int esp32_i2c_clear_bus(struct esp32_i2c_priv_s *priv)
{
uint32_t clock_count;
uint32_t stretch_count;
int ret;
const struct esp32_i2c_config_s *config = priv->config;
/* Use GPIO configuration to un-wedge the bus */
esp32_configgpio(config->scl_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
esp32_gpio_matrix_out(config->scl_pin, SIG_GPIO_OUT_IDX, 0, 0);
esp32_configgpio(config->sda_pin, INPUT_PULLUP | OUTPUT_OPEN_DRAIN);
esp32_gpio_matrix_out(config->sda_pin, SIG_GPIO_OUT_IDX, 0, 0);
/* Set SDA to high */
esp32_gpiowrite(config->sda_pin, 1);
/* Clock the bus until any slaves currently driving it let it go. */
clock_count = 0;
while (!esp32_gpioread(config->sda_pin))
{
/* Give up if we have tried too hard */
if (clock_count++ >= I2C_SCL_CYC_NUM_DEF)
{
ret = -EIO;
goto out;
}
/* Sniff to make sure that clock stretching has finished.
*
* If the bus never relaxes, the reset has failed.
*/
stretch_count = 0;
while (!esp32_gpioread(config->scl_pin))
{
/* Give up if we have tried too hard */
if (stretch_count++ > 10)
{
ret = -EIO;
goto out;
}
up_udelay(10);
}
/* Drive SCL low */
esp32_gpiowrite(config->scl_pin, 0);
up_udelay(10);
/* Drive SCL high again */
esp32_gpiowrite(config->scl_pin, 1);
up_udelay(10);
}
/* Generate a start followed by a stop to reset slave
* state machines.
*/
esp32_gpiowrite(config->sda_pin, 0);
up_udelay(10);
esp32_gpiowrite(config->scl_pin, 0);
up_udelay(10);
esp32_gpiowrite(config->scl_pin, 1);
up_udelay(10);
esp32_gpiowrite(config->sda_pin, 1);
up_udelay(10);
ret = OK;
out:
return ret;
}
#endif
/****************************************************************************
* Name: esp32_i2c_reset
*
@ -1073,7 +1169,11 @@ static int esp32_i2c_reset(FAR struct i2c_master_s *dev)
flags = enter_critical_section();
esp32_i2c_reset_fsmc(priv);
esp32_i2c_deinit(priv);
esp32_i2c_clear_bus(priv);
esp32_i2c_init(priv);
priv->i2cstate = I2CSTATE_IDLE;
priv->msgid = 0;