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

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@rock-chips.com>
Acked-by: Max Schwarz <max.schwarz@online.de>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
index 69e1185..e637c32 100644 (file)
--- 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 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 */
+       if (len > 32)
+               len = 32;
+
        /* read the data from receive buffer */
        for (i = 0; i < len; ++i) {
                if (i % 4 == 0)