On 09/07/07 09:53 -0600, Grant Likely wrote: > On 7/9/07, Domen Puncer <[EMAIL PROTECTED]> wrote: > >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. > > > >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 > >@@ -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(); > > } > > Are the mb() calls necessary? The writeccr path includes eieio; is > that not sufficient?
Right, v2: 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 boards by Matthias and me. Signed-off-by: Domen Puncer <[EMAIL PROTECTED]> --- drivers/i2c/busses/i2c-mpc.c | 17 +++++++++++++++++ 1 file changed, 17 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 +167,7 @@ static void mpc_i2c_start(struct mpc_i2c static void mpc_i2c_stop(struct mpc_i2c *i2c) { writeccr(i2c, CCR_MEN); + writeccr(i2c, 0); } static int mpc_write(struct mpc_i2c *i2c, int target, @@ -245,6 +260,8 @@ 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(); _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded
