i2c: img-scb: do dummy writes before fifo access

Move scb_wr_rd_fence to before reading from fifo and writing to
fifo to make sure the the first read/write is done after the required
number of cycles.

Fixes: commit 27bce457d588 ("i2c: img-scb: Add Imagination Technologies I2C SCB driver")
Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Acked-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: James Hartley <james.hartley@imgtec.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-img-scb.c b/drivers/i2c/busses/i2c-img-scb.c
index 5c3c615..0368d91 100644 (file)
--- a/drivers/i2c/busses/i2c-img-scb.c
+++ b/drivers/i2c/busses/i2c-img-scb.c
@@ -534,6 +534,7 @@ static void img_i2c_read_fifo(struct img_i2c *i2c)
                u32 fifo_status;
                u8 data;
 
+               img_i2c_wr_rd_fence(i2c);
                fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
                if (fifo_status & FIFO_READ_EMPTY)
                        break;
@@ -542,7 +543,6 @@ static void img_i2c_read_fifo(struct img_i2c *i2c)
                *i2c->msg.buf = data;
 
                img_i2c_writel(i2c, SCB_READ_FIFO_REG, 0xff);
-               img_i2c_wr_rd_fence(i2c);
                i2c->msg.len--;
                i2c->msg.buf++;
        }
@@ -554,12 +554,12 @@ static void img_i2c_write_fifo(struct img_i2c *i2c)
        while (i2c->msg.len) {
                u32 fifo_status;
 
+               img_i2c_wr_rd_fence(i2c);
                fifo_status = img_i2c_readl(i2c, SCB_FIFO_STATUS_REG);
                if (fifo_status & FIFO_WRITE_FULL)
                        break;
 
                img_i2c_writel(i2c, SCB_WRITE_DATA_REG, *i2c->msg.buf);
-               img_i2c_wr_rd_fence(i2c);
                i2c->msg.len--;
                i2c->msg.buf++;
        }