Hello Hans,

Am 14.01.2016 um 14:06 schrieb Hans de Goede:
On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1,
rather then a normal r/w bit which is cleared by writing 0.

Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
  drivers/i2c/mvtwsi.c | 19 +++++++++++++++----
  1 file changed, 15 insertions(+), 4 deletions(-)

Thanks!

Applied to u-boot-i2c.git with fixing 3 checkpatch
errors/warnings.

bye,
Heiko

diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c
index f20d1b2..698bfc1 100644
--- a/drivers/i2c/mvtwsi.c
+++ b/drivers/i2c/mvtwsi.c
@@ -73,6 +73,17 @@ struct  mvtwsi_registers {
  #define       MVTWSI_CONTROL_INTEN    0x00000080

  /*
+ * On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1,
+ * on other platforms it is a normal r/w bit which is cleared by writing 0.
+ */
+
+#ifdef CONFIG_SUNXI_GEN_SUN6I
+#define        MVTWSI_CONTROL_CLEAR_IFLG       0x00000008
+#else
+#define        MVTWSI_CONTROL_CLEAR_IFLG       0x00000000
+#endif
+
+/*
   * Status register values -- only those expected in normal master
   * operation on non-10-bit-address devices; whatever status we don't
   * expect in nominal conditions (bus errors, arbitration losses,
@@ -189,7 +200,7 @@ static int twsi_start(struct i2c_adapter *adap, int 
expected_status)
        /* globally set TWSIEN in case it was not */
        twsi_control_flags |= MVTWSI_CONTROL_TWSIEN;
        /* assert START */
-       writel(twsi_control_flags | MVTWSI_CONTROL_START, &twsi->control);
+       writel(twsi_control_flags | MVTWSI_CONTROL_START | MVTWSI_CONTROL_CLEAR_IFLG, 
&twsi->control);
        /* wait for controller to process START */
        return twsi_wait(adap, expected_status);
  }
@@ -204,7 +215,7 @@ static int twsi_send(struct i2c_adapter *adap, u8 byte, int 
expected_status)
        /* put byte in data register for sending */
        writel(byte, &twsi->data);
        /* clear any pending interrupt -- that'll cause sending */
-       writel(twsi_control_flags, &twsi->control);
+        writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
        /* wait for controller to receive byte and check ACK */
        return twsi_wait(adap, expected_status);
  }
@@ -224,7 +235,7 @@ static int twsi_recv(struct i2c_adapter *adap, u8 *byte)
        else
                expected_status = MVTWSI_STATUS_DATA_R_NAK;
        /* acknowledge *previous state* and launch receive */
-       writel(twsi_control_flags, &twsi->control);
+       writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
        /* wait for controller to receive byte and assert ACK or NAK */
        status = twsi_wait(adap, expected_status);
        /* if we did receive expected byte then store it */
@@ -246,7 +257,7 @@ static int twsi_stop(struct i2c_adapter *adap, int status)

        /* assert STOP */
        control = MVTWSI_CONTROL_TWSIEN | MVTWSI_CONTROL_STOP;
-       writel(control, &twsi->control);
+       writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
        /* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */
        do {
                stop_status = readl(&twsi->status);


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