| Message ID | 1346323204-19210-1-git-send-email-Joakim.Tjernlund@transmode.se (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Thu, Aug 30, 2012 at 5:40 AM, Joakim Tjernlund <Joakim.Tjernlund@transmode.se> wrote: > - mpc_i2c_stop(i2c); > + mpc_i2c_stop(i2c); /* Initiate STOP */ > + orig_jiffies = jiffies; > + /* Wait until STOP is seen, allow up to 1 s */ > + while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { > + if (time_after(jiffies, orig_jiffies + HZ)) { > + u8 status = readb(i2c->base + MPC_I2C_SR); > + > + dev_dbg(i2c->dev, "timeout\n"); > + if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) { > + writeb(status & ~CSR_MAL, > + i2c->base + MPC_I2C_SR); > + mpc_i2c_fixup(i2c); > + } > + return -EIO; > + } > + cond_resched(); > + } Shouldn't the while-loop be inside mpc_i2c_stop() itself?
Tabi Timur-B04825 <B04825@freescale.com> wrote on 2012/09/02 04:48:01: > On Thu, Aug 30, 2012 at 5:40 AM, Joakim Tjernlund > <Joakim.Tjernlund@transmode.se> wrote: > > > - mpc_i2c_stop(i2c); > > + mpc_i2c_stop(i2c); /* Initiate STOP */ > > + orig_jiffies = jiffies; > > + /* Wait until STOP is seen, allow up to 1 s */ > > + while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { > > + if (time_after(jiffies, orig_jiffies + HZ)) { > > + u8 status = readb(i2c->base + MPC_I2C_SR); > > + > > + dev_dbg(i2c->dev, "timeout\n"); > > + if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) { > > + writeb(status & ~CSR_MAL, > > + i2c->base + MPC_I2C_SR); > > + mpc_i2c_fixup(i2c); > > + } > > + return -EIO; > > + } > > + cond_resched(); > > + } > > Shouldn't the while-loop be inside mpc_i2c_stop() itself? Possibly but I choosed to do it this way as there is a similar loop in the beginning of mpc_xfer(). I figured it has better visibility if it is in the same function. Jocke
Joakim Tjernlund/Transmode wrote on 2012/09/02 16:22:00: > > Tabi Timur-B04825 <B04825@freescale.com> wrote on 2012/09/02 04:48:01: > > On Thu, Aug 30, 2012 at 5:40 AM, Joakim Tjernlund > > <Joakim.Tjernlund@transmode.se> wrote: > > > > > - mpc_i2c_stop(i2c); > > > + mpc_i2c_stop(i2c); /* Initiate STOP */ > > > + orig_jiffies = jiffies; > > > + /* Wait until STOP is seen, allow up to 1 s */ > > > + while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { > > > + if (time_after(jiffies, orig_jiffies + HZ)) { > > > + u8 status = readb(i2c->base + MPC_I2C_SR); > > > + > > > + dev_dbg(i2c->dev, "timeout\n"); > > > + if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) { > > > + writeb(status & ~CSR_MAL, > > > + i2c->base + MPC_I2C_SR); > > > + mpc_i2c_fixup(i2c); > > > + } > > > + return -EIO; > > > + } > > > + cond_resched(); > > > + } > > > > Shouldn't the while-loop be inside mpc_i2c_stop() itself? > > Possibly but I choosed to do it this way as there is a similar loop in the beginning of mpc_xfer(). > I figured it has better visibility if it is in the same function. > > Jocke Ping? Anything holding this patch back? Jocke
On Thu, Aug 30, 2012 at 12:40:04PM +0200, Joakim Tjernlund wrote: > mpc_i2c_stop() only initiates STOP but does not wait for it to > hit the I2C bus. This is a problem when using I2C devices which > uses fairly long clock stretching just before STOP if you also > have an i2c-mux which may switch to another bus before STOP has > been processed. > > Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Patch didn't apply, because it was a p0-patch. Checkpatch would have warned you. Fixed that and applied to -next, thanks!
Wolfram Sang <w.sang@pengutronix.de> wrote on 2012/09/14 16:02:34: > > On Thu, Aug 30, 2012 at 12:40:04PM +0200, Joakim Tjernlund wrote: > > mpc_i2c_stop() only initiates STOP but does not wait for it to > > hit the I2C bus. This is a problem when using I2C devices which > > uses fairly long clock stretching just before STOP if you also > > have an i2c-mux which may switch to another bus before STOP has > > been processed. > > > > Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> > > Patch didn't apply, because it was a p0-patch. Checkpatch would have > warned you. Bugger, it is my git config setting: [diff] noprefix = true I always forget to remove that one before generating patches, I will have to remove it. > > Fixed that and applied to -next, thanks! Thanks
diff --git drivers/i2c/busses/i2c-mpc.c drivers/i2c/busses/i2c-mpc.c index 3d31879..c08f287 100644 --- drivers/i2c/busses/i2c-mpc.c +++ drivers/i2c/busses/i2c-mpc.c @@ -574,7 +574,23 @@ static int mpc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) mpc_write(i2c, pmsg->addr, pmsg->buf, pmsg->len, i); } } - mpc_i2c_stop(i2c); + mpc_i2c_stop(i2c); /* Initiate STOP */ + orig_jiffies = jiffies; + /* Wait until STOP is seen, allow up to 1 s */ + while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) { + if (time_after(jiffies, orig_jiffies + HZ)) { + u8 status = readb(i2c->base + MPC_I2C_SR); + + dev_dbg(i2c->dev, "timeout\n"); + if ((status & (CSR_MCF | CSR_MBB | CSR_RXAK)) != 0) { + writeb(status & ~CSR_MAL, + i2c->base + MPC_I2C_SR); + mpc_i2c_fixup(i2c); + } + return -EIO; + } + cond_resched(); + } return (ret < 0) ? ret : num; }
mpc_i2c_stop() only initiates STOP but does not wait for it to hit the I2C bus. This is a problem when using I2C devices which uses fairly long clock stretching just before STOP if you also have an i2c-mux which may switch to another bus before STOP has been processed. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> --- drivers/i2c/busses/i2c-mpc.c | 18 +++++++++++++++++- 1 files changed, 17 insertions(+), 1 deletions(-)