diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c index 35f762872b8a..58562700c85e 100644 --- a/drivers/i2c/busses/i2c-designware-common.c +++ b/drivers/i2c/busses/i2c-designware-common.c @@ -441,6 +441,7 @@ err_release_lock: void __i2c_dw_disable(struct dw_i2c_dev *dev) { + struct i2c_timings *t = &dev->timings; unsigned int raw_intr_stats; unsigned int enable; int timeout = 100; @@ -453,6 +454,19 @@ void __i2c_dw_disable(struct dw_i2c_dev *dev) abort_needed = raw_intr_stats & DW_IC_INTR_MST_ON_HOLD; if (abort_needed) { + if (!(enable & DW_IC_ENABLE_ENABLE)) { + regmap_write(dev->map, DW_IC_ENABLE, DW_IC_ENABLE_ENABLE); + /* + * Wait 10 times the signaling period of the highest I2C + * transfer supported by the driver (for 400KHz this is + * 25us) to ensure the I2C ENABLE bit is already set + * as described in the DesignWare I2C databook. + */ + fsleep(DIV_ROUND_CLOSEST_ULL(10 * MICRO, t->bus_freq_hz)); + /* Set ENABLE bit before setting ABORT */ + enable |= DW_IC_ENABLE_ENABLE; + } + regmap_write(dev->map, DW_IC_ENABLE, enable | DW_IC_ENABLE_ABORT); ret = regmap_read_poll_timeout(dev->map, DW_IC_ENABLE, enable, !(enable & DW_IC_ENABLE_ABORT), 10, diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index ae835000fd32..99d8c6bbc032 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -109,6 +109,7 @@ DW_IC_INTR_RX_UNDER | \ DW_IC_INTR_RD_REQ) +#define DW_IC_ENABLE_ENABLE BIT(0) #define DW_IC_ENABLE_ABORT BIT(1) #define DW_IC_STATUS_ACTIVITY BIT(0) diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c index 85dbd0eb5392..579c668cb78a 100644 --- a/drivers/i2c/busses/i2c-designware-master.c +++ b/drivers/i2c/busses/i2c-designware-master.c @@ -253,6 +253,34 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev) regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_MASTER_MASK); } +/* + * This function waits for the controller to be idle before disabling I2C + * When the controller is not in the IDLE state, the MST_ACTIVITY bit + * (IC_STATUS[5]) is set. + * + * Values: + * 0x1 (ACTIVE): Controller not idle + * 0x0 (IDLE): Controller is idle + * + * The function is called after completing the current transfer. + * + * Returns: + * False when the controller is in the IDLE state. + * True when the controller is in the ACTIVE state. + */ +static bool i2c_dw_is_controller_active(struct dw_i2c_dev *dev) +{ + u32 status; + + regmap_read(dev->map, DW_IC_STATUS, &status); + if (!(status & DW_IC_STATUS_MASTER_ACTIVITY)) + return false; + + return regmap_read_poll_timeout(dev->map, DW_IC_STATUS, status, + !(status & DW_IC_STATUS_MASTER_ACTIVITY), + 1100, 20000) != 0; +} + static int i2c_dw_check_stopbit(struct dw_i2c_dev *dev) { u32 val; @@ -694,6 +722,16 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) goto done; } + /* + * This happens rarely (~1:500) and is hard to reproduce. Debug trace + * showed that IC_STATUS had value of 0x23 when STOP_DET occurred, + * if disable IC_ENABLE.ENABLE immediately that can result in + * IC_RAW_INTR_STAT.MASTER_ON_HOLD holding SCL low. Check if + * controller is still ACTIVE before disabling I2C. + */ + if (i2c_dw_is_controller_active(dev)) + dev_err(dev->dev, "controller active\n"); + /* * We must disable the adapter before returning and signaling the end * of the current transfer. Otherwise the hardware might continue