i2c: qup: change completion timeout according to transfer length

Currently the completion timeout is being taken according to
maximum transfer length which is too high if SCL is operating in
high frequency. This patch calculates timeout on the basis of
one-byte transfer time and uses the same for completion timeout.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Reviewed-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index bf1b7eec8a4ce387e2175990e66fc1b32a487322..13c751e2dd9a915213ea8576ea41583bd470f22c 100644 (file)
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -121,8 +121,12 @@
 #define MX_TX_RX_LEN                   SZ_64K
 #define MX_BLOCKS                      (MX_TX_RX_LEN / QUP_READ_LIMIT)
 
-/* Max timeout in ms for 32k bytes */
-#define TOUT_MAX                       300
+/*
+ * Minimum transfer timeout for i2c transfers in seconds. It will be added on
+ * the top of maximum transfer time calculated from i2c bus speed to compensate
+ * the overheads.
+ */
+#define TOUT_MIN                       2
 
 /* Default values. Use these if FW query fails */
 #define DEFAULT_CLK_FREQ 100000
@@ -163,6 +167,7 @@ struct qup_i2c_dev {
        int                     in_blk_sz;
 
        unsigned long           one_byte_t;
+       unsigned long           xfer_timeout;
        struct qup_i2c_block    blk;
 
        struct i2c_msg          *msg;
@@ -849,7 +854,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg,
                dma_async_issue_pending(qup->brx.dma);
        }
 
-       if (!wait_for_completion_timeout(&qup->xfer, TOUT_MAX * HZ)) {
+       if (!wait_for_completion_timeout(&qup->xfer, qup->xfer_timeout)) {
                dev_err(qup->dev, "normal trans timed out\n");
                ret = -ETIMEDOUT;
        }
@@ -1605,6 +1610,8 @@ static int qup_i2c_probe(struct platform_device *pdev)
         */
        one_bit_t = (USEC_PER_SEC / clk_freq) + 1;
        qup->one_byte_t = one_bit_t * 9;
+       qup->xfer_timeout = TOUT_MIN * HZ +
+                           usecs_to_jiffies(MX_TX_RX_LEN * qup->one_byte_t);
 
        dev_dbg(qup->dev, "IN:block:%d, fifo:%d, OUT:block:%d, fifo:%d\n",
                qup->in_blk_sz, qup->in_fifo_sz,