target/linux/brcm2708/patches-4.9/950-0108-i2c-bcm2835-Use-dev_dbg-logging-on-transfer-errors.patch

   1 From bff25210b88dc7b71ee9c2626e42a939072dec64 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
   3 Date: Mon, 19 Sep 2016 17:19:41 +0200
   4 Subject: [PATCH] i2c: bcm2835: Use dev_dbg logging on transfer errors
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   8
   9 Writing to an AT24C32 generates on average 2x i2c transfer errors per
  10 32-byte page write. Which amounts to a lot for a 4k write. This is due
  11 to the fact that the chip doesn't respond during it's internal write
  12 cycle when the at24 driver tries and retries the next write.
  13 Only a handful drivers use dev_err() on transfer error, so switch to
  14 dev_dbg() instead.
  15
  16 Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
  17 Reviewed-by: Eric Anholt <eric@anholt.net>
  18 ---
  19  drivers/i2c/busses/i2c-bcm2835.c | 2 +-
  20  1 file changed, 1 insertion(+), 1 deletion(-)
  21
  22 --- a/drivers/i2c/busses/i2c-bcm2835.c
  23 +++ b/drivers/i2c/busses/i2c-bcm2835.c
  24 @@ -218,7 +218,7 @@ static int bcm2835_i2c_xfer_msg(struct b
  25             (msg->flags & I2C_M_IGNORE_NAK))
  26                 return 0;
  27
  28 -       dev_err(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
  29 +       dev_dbg(i2c_dev->dev, "i2c transfer failed: %x\n", i2c_dev->msg_err);
  30
  31         if (i2c_dev->msg_err & BCM2835_I2C_S_ERR)
  32                 return -EREMOTEIO;