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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 27bce457d5 ("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>
This commit is contained in:
Sifan Naeem 2015-09-10 15:50:02 +01:00 committed by Wolfram Sang
parent 0e59378bc0
commit 2aefb1bd41
1 changed files with 2 additions and 2 deletions
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4
drivers/i2c/busses/i2c-img-scb.c
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@ -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++;
}