[PATCH 3.16 044/357] i2c: rk3x: fix bug that cause transfer fails in master receive mode

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: addy ke <addy.ke@xxxxxxxxxxxxxx>

commit 5da4309f9e1b4de9c2b69e917912fbb84006d44e upstream.

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

Tested on rk3288-pinky board, elan receive 158 bytes data.

Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx>
Acked-by: Max Schwarz <max.schwarz@xxxxxxxxx>
Reviewed-by: Doug Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/i2c/busses/i2c-rk3x.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/i2c/busses/i2c-rk3x.c
+++ b/drivers/i2c/busses/i2c-rk3x.c
@@ -323,6 +323,10 @@ static void rk3x_i2c_handle_read(struct
 	/* ack interrupt */
 	i2c_writel(i2c, REG_INT_MBRF, REG_IPD);
 
+	/* Can only handle a maximum of 32 bytes at a time */
+	if (len > 32)
+		len = 32;
+
 	/* read the data from receive buffer */
 	for (i = 0; i < len; ++i) {
 		if (i % 4 == 0)


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