Work around a problem reported on:
http://ozlabs.org/pipermail/linuxppc-embedded/2005-July/019038.html
Without this patch I2C on mpc5200 becomes unusable after a while.
Tested on mpc5200 based boards by Matthias and me.
Signed-off-by: Domen Puncer <[EMAIL PROTECTED]>
---
drivers/i2c/busses/i2c-mpc.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
Index: work-powerpc.git/drivers/i2c/busses/i2c-mpc.c
===================================================================
--- work-powerpc.git.orig/drivers/i2c/busses/i2c-mpc.c
+++ work-powerpc.git/drivers/i2c/busses/i2c-mpc.c
@@ -74,6 +74,20 @@ static irqreturn_t mpc_i2c_isr(int irq,
return IRQ_HANDLED;
}
+static void mpc_i2c_fixup(struct mpc_i2c *i2c)
+{
+ writeccr(i2c, 0);
+ udelay(30);
+ writeccr(i2c, CCR_MEN);
+ udelay(30);
+ writeccr(i2c, CCR_MSTA | CCR_MTX);
+ udelay(30);
+ writeccr(i2c, CCR_MSTA | CCR_MTX | CCR_MEN);
+ udelay(30);
+ writeccr(i2c, CCR_MEN);
+ udelay(30);
+}
+
static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
{
unsigned long orig_jiffies = jiffies;
@@ -153,6 +167,9 @@ static void mpc_i2c_start(struct mpc_i2c
static void mpc_i2c_stop(struct mpc_i2c *i2c)
{
writeccr(i2c, CCR_MEN);
+ mb();
+ writeccr(i2c, 0);
+ mb();
}
static int mpc_write(struct mpc_i2c *i2c, int target,
@@ -245,6 +262,8 @@ static int mpc_xfer(struct i2c_adapter *
}
if (time_after(jiffies, orig_jiffies + HZ)) {
pr_debug("I2C: timeout\n");
+ if (readb(i2c->base + MPC_I2C_SR) == (CSR_MCF | CSR_MBB
| CSR_RXAK))
+ mpc_i2c_fixup(i2c);
return -EIO;
}
schedule();
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