On Thu, Aug 21, 2014 at 10:04:31PM +0400, Sergei Shtylyov wrote:

Hello.

On 08/21/2014 09:50 PM, Addy Ke wrote:

quoted

In rk3x SOC, the I2C controller can receive/transmit up to 32 bytes data
in one transaction, so the size of data to be write/read to/from
TXDATAx/RXDATAx must be less than or equal 32 bytes at a time.

quoted

Test on pinky board, elan receive 158 bytes data.

quoted

Signed-off-by: Addy Ke <redacted>
---
 drivers/i2c/busses/i2c-rk3x.c | 3 +++
 1 file changed, 3 insertions(+)

quoted

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 69e1185..dc0aa64 100644
--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c

@@ -323,6 +323,9 @@ static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
 	/* ack interrupt */
 	i2c_writel(i2c, REG_INT_MBRF, REG_IPD);

+	/* Can only handle a maximum of 32 bytes at a time */
+	len = (len > 32) ? 32 : len;

   Why not min(len, 32)? Or even:

	if (len > 32)
		len = 32;

No silent trimming, please. The message should be rejected when the transfer is
set up. We could assign -EOVERFLOW to that type of failures, so users
will know. Sadly, I have seen other controllers having such limits :(

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