summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-designware-core.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/i2c/busses/i2c-designware-core.c')
-rw-r--r--drivers/i2c/busses/i2c-designware-core.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index c41ca6354fc5..ad46616de29e 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -67,9 +67,12 @@
#define DW_IC_STATUS 0x70
#define DW_IC_TXFLR 0x74
#define DW_IC_RXFLR 0x78
+#define DW_IC_SDA_HOLD 0x7c
#define DW_IC_TX_ABRT_SOURCE 0x80
#define DW_IC_ENABLE_STATUS 0x9c
#define DW_IC_COMP_PARAM_1 0xf4
+#define DW_IC_COMP_VERSION 0xf8
+#define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A
#define DW_IC_COMP_TYPE 0xfc
#define DW_IC_COMP_TYPE_VALUE 0x44570140
@@ -332,6 +335,16 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
+ /* Configure SDA Hold Time if required */
+ if (dev->sda_hold_time) {
+ reg = dw_readl(dev, DW_IC_COMP_VERSION);
+ if (reg >= DW_IC_SDA_HOLD_MIN_VERS)
+ dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
+ else
+ dev_warn(dev->dev,
+ "Hardware too old to adjust SDA hold time.");
+ }
+
/* Configure Tx/Rx FIFO threshold levels */
dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL);
dw_writel(dev, 0, DW_IC_RX_TL);
@@ -580,14 +593,23 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
i2c_dw_xfer_init(dev);
/* wait for tx to complete */
- ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);
+ ret = wait_for_completion_timeout(&dev->cmd_complete, HZ);
if (ret == 0) {
dev_err(dev->dev, "controller timed out\n");
+ /* i2c_dw_init implicitly disables the adapter */
i2c_dw_init(dev);
ret = -ETIMEDOUT;
goto done;
- } else if (ret < 0)
- goto done;
+ }
+
+ /*
+ * We must disable the adapter before unlocking the &dev->lock mutex
+ * below. Otherwise the hardware might continue generating interrupts
+ * which in turn causes a race condition with the following transfer.
+ * Needs some more investigation if the additional interrupts are
+ * a hardware bug or this driver doesn't handle them correctly yet.
+ */
+ __i2c_dw_enable(dev, false);
if (dev->msg_err) {
ret = dev->msg_err;
@@ -596,8 +618,6 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
/* no error */
if (likely(!dev->cmd_err)) {
- /* Disable the adapter */
- __i2c_dw_enable(dev, false);
ret = num;
goto done;
}