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[PATCH 2/2] drivers: i2c: qup: Fix error handling

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  [PATCH 2/2] drivers: i2c: qup: Fix error handling Sricharan R <sricharan@codeaurora.org> - 2016-05-02 07:30 +0200
    Re: [PATCH 2/2] drivers: i2c: qup: Fix error handling Andy Gross <andy.gross@linaro.org> - 2016-05-05 19:30 +0200
      RE: [PATCH 2/2] drivers: i2c: qup: Fix error handling "Sricharan" <sricharan@codeaurora.org> - 2016-05-06 06:10 +0200

#1391984 — [PATCH 2/2] drivers: i2c: qup: Fix error handling

Among the bus errors reported from the QUP_MASTER_STATUS register
only NACK is considered and transfer gets suspended, while
other errors are ignored. Correct this and suspend the transfer
for other errors as well. This avoids unnessecary 'timeouts' which
happens when waiting for events that would never happen when there
is already an error condition on the bus.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
 drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c
index 8620e99..8afb733 100644
--- a/drivers/i2c/busses/i2c-qup.c
+++ b/drivers/i2c/busses/i2c-qup.c
@@ -310,6 +310,7 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 	u32 opflags;
 	u32 status;
 	u32 shift = __ffs(op);
+	int ret = 0;
 
 	len *= qup->one_byte_t;
 	/* timeout after a wait of twice the max time */
@@ -321,18 +322,31 @@ static int qup_i2c_wait_ready(struct qup_i2c_dev *qup, int op, bool val,
 
 		if (((opflags & op) >> shift) == val) {
 			if ((op == QUP_OUT_NOT_EMPTY) && qup->is_last) {
-				if (!(status & I2C_STATUS_BUS_ACTIVE))
-					return 0;
+				if (!(status & I2C_STATUS_BUS_ACTIVE)) {
+					ret = 0;
+					goto done;
+				}
 			} else {
-				return 0;
+				ret = 0;
+				goto done;
 			}
 		}
 
-		if (time_after(jiffies, timeout))
-			return -ETIMEDOUT;
-
+		if (time_after(jiffies, timeout)) {
+			ret = -ETIMEDOUT;
+			goto done;
+		}
 		usleep_range(len, len * 2);
 	}
+
+done:
+	if (qup->bus_err || qup->qup_err) {
+		if (qup->bus_err & QUP_I2C_NACK_FLAG)
+			dev_err(qup->dev, "NACK from %x\n", qup->msg->addr);
+		ret = -EIO;
+	}
+
+	return ret;
 }
 
 static void qup_i2c_set_write_mode_v2(struct qup_i2c_dev *qup,
@@ -882,10 +896,9 @@ static int qup_i2c_wait_for_complete(struct qup_i2c_dev *qup,
 	}
 
 	if (qup->bus_err || qup->qup_err) {
-		if (qup->bus_err & QUP_I2C_NACK_FLAG) {
+		if (qup->bus_err & QUP_I2C_NACK_FLAG)
 			dev_err(qup->dev, "NACK from %x\n", msg->addr);
-			ret = -EIO;
-		}
+		ret = -EIO;
 	}
 
 	return ret;
@@ -1227,6 +1240,9 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
 	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
 	int ret, len, idx = 0, use_dma = 0;
 
+	qup->bus_err = 0;
+	qup->qup_err = 0;
+
 	ret = pm_runtime_get_sync(qup->dev);
 	if (ret < 0)
 		goto out;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation

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#1395245

On Mon, May 02, 2016 at 10:53:57AM +0530, Sricharan R wrote:
> Among the bus errors reported from the QUP_MASTER_STATUS register
> only NACK is considered and transfer gets suspended, while
> other errors are ignored. Correct this and suspend the transfer
> for other errors as well. This avoids unnessecary 'timeouts' which
> happens when waiting for events that would never happen when there
> is already an error condition on the bus.
> 
> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> ---
>  drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)

Reviewed-by: Andy Gross <andy.gross@linaro.org>

<snip>

> @@ -1227,6 +1240,9 @@ static int qup_i2c_xfer_v2(struct i2c_adapter *adap,
>  	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
>  	int ret, len, idx = 0, use_dma = 0;
>  
> +	qup->bus_err = 0;
> +	qup->qup_err = 0;
> +

What about the initial setting of these?  Does this need to be removed from the
main xfer function?

>  	ret = pm_runtime_get_sync(qup->dev);
>  	if (ret < 0)
>  		goto out;

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#1395594

Hi Andy,

> -----Original Message-----
> From: Andy Gross [mailto:andy.gross@linaro.org]
> Sent: Thursday, May 05, 2016 10:52 PM
> To: Sricharan R <sricharan@codeaurora.org>
> Cc: devicetree@vger.kernel.org; architt@codeaurora.org; linux-arm-
> msm@vger.kernel.org; ntelkar@codeaurora.org; galak@codeaurora.org;
> linux-kernel@vger.kernel.org; linux-i2c@vger.kernel.org; iivanov@mm-
> sol.com; agross@codeaurora.org; dmaengine@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org
> Subject: Re: [PATCH 2/2] drivers: i2c: qup: Fix error handling
> 
> On Mon, May 02, 2016 at 10:53:57AM +0530, Sricharan R wrote:
> > Among the bus errors reported from the QUP_MASTER_STATUS register
> only
> > NACK is considered and transfer gets suspended, while other errors are
> > ignored. Correct this and suspend the transfer for other errors as
> > well. This avoids unnessecary 'timeouts' which happens when waiting
> > for events that would never happen when there is already an error
> > condition on the bus.
> >
> > Signed-off-by: Sricharan R <sricharan@codeaurora.org>
> > ---
> >  drivers/i2c/busses/i2c-qup.c | 34 +++++++++++++++++++++++++---------
> >  1 file changed, 25 insertions(+), 9 deletions(-)
> 
> Reviewed-by: Andy Gross <andy.gross@linaro.org>
> 
 Thanks.
> <snip>
> 
> > @@ -1227,6 +1240,9 @@ static int qup_i2c_xfer_v2(struct i2c_adapter
> *adap,
> >  	struct qup_i2c_dev *qup = i2c_get_adapdata(adap);
> >  	int ret, len, idx = 0, use_dma = 0;
> >
> > +	qup->bus_err = 0;
> > +	qup->qup_err = 0;
> > +
> 
> What about the initial setting of these?  Does this need to be removed
from
> the main xfer function?
  Thanks for the catch. Will remove in bam_xfer , redundant.
  Now that there are i2x_xfer_v2 and i2c_xfer, 
   its not set in the old i2c_xfer call, where as it should be set there
   as well. I will change this and resend.

Regards,
 Sricharan

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