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

[Addy Ke]

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.

Test on pinky board, elan receive 158 bytes data.

Signed-off-by: Addy Ke <addy.ke at rock-chips.com>
---
 drivers/i2c/busses/i2c-rk3x.c | 3 +++
 1 file changed, 3 insertions(+)

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;
+
 	/* read the data from receive buffer */
 	for (i = 0; i < len; ++i) {
 		if (i % 4 == 0)
-- 
1.8.3.2