diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-common.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-common.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c index 183a35038eef..f5d478e54798 100644 --- a/drivers/i2c/busses/i2c-designware-common.c +++ b/drivers/i2c/busses/i2c-designware-common.c @@ -62,6 +62,8 @@ static const char *const abort_sources[] = { "slave lost the bus while transmitting data to a remote master", [ABRT_SLAVE_RD_INTX] = "incorrect slave-transmitter mode configuration", + [ABRT_SLAVE_SDA_STUCK_AT_LOW] = + "SDA stuck at low", }; static int dw_reg_read(void *context, unsigned int reg, unsigned int *val) @@ -361,6 +363,9 @@ static void i2c_dw_adjust_bus_speed(struct dw_i2c_dev *dev) { u32 acpi_speed = i2c_dw_acpi_round_bus_speed(dev->dev); struct i2c_timings *t = &dev->timings; + u32 wanted_speed; + u32 legal_speed = 0; + int i; /* * Find bus speed from the "clock-frequency" device property, ACPI @@ -372,6 +377,30 @@ static void i2c_dw_adjust_bus_speed(struct dw_i2c_dev *dev) t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed); else t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ; + + wanted_speed = t->bus_freq_hz; + + /* For unsupported speeds, scale down the lowest speed which is faster. */ + for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) { + /* supported speeds is in decreasing order */ + if (wanted_speed == supported_speeds[i]) { + legal_speed = 0; + break; + } + if (wanted_speed > supported_speeds[i]) + break; + + legal_speed = supported_speeds[i]; + } + + if (legal_speed) { + /* + * Pretend this was the requested speed, but preserve the preferred + * speed so the clock counts can be scaled. + */ + t->bus_freq_hz = legal_speed; + dev->wanted_bus_speed = wanted_speed; + } } int i2c_dw_fw_parse_and_configure(struct dw_i2c_dev *dev) @@ -649,8 +678,16 @@ int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev) int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) { unsigned long abort_source = dev->abort_source; + unsigned int reg; int i; + if (abort_source & DW_IC_TX_ABRT_SLAVE_SDA_STUCK_AT_LOW) { + regmap_write(dev->map, DW_IC_ENABLE, + DW_IC_ENABLE_ENABLE | DW_IC_ENABLE_BUS_RECOVERY); + regmap_read_poll_timeout(dev->map, DW_IC_ENABLE, reg, + !(reg & DW_IC_ENABLE_BUS_RECOVERY), + 1100, 200000); + } if (abort_source & DW_IC_TX_ABRT_NOACK) { for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources)) dev_dbg(dev->dev, @@ -665,6 +702,8 @@ int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev) return -EAGAIN; if (abort_source & DW_IC_TX_ABRT_GCALL_READ) return -EINVAL; /* wrong msgs[] data */ + if (abort_source & DW_IC_TX_ABRT_SLAVE_SDA_STUCK_AT_LOW) + return -EREMOTEIO; return -EIO; } |