From mboxrd@z Thu Jan 1 00:00:00 1970 From: jbrunet@baylibre.com (Jerome Brunet) Date: Wed, 08 Mar 2017 10:50:36 +0100 Subject: [PATCH 07/12] i2c: meson: improve interrupt handler and detect spurious interrupts In-Reply-To: References: Message-ID: <1488966636.2514.16.camel@baylibre.com> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org On Wed, 2017-03-08 at 07:47 +0100, Heiner Kallweit wrote: > If state is STATE_IDLE no interrupt should occur. Detect this case and > warn. > In addition move resetting REG_CTRL_START bit to the start of the > interrupt handler and remove a unneeded REG_CTRL_START bit reset > in meson_i2c_xfer_msg. > > Signed-off-by: Heiner Kallweit > --- > ?drivers/i2c/busses/i2c-meson.c | 16 +++++++++------- > ?1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c > index 81304840..b3b881f9 100644 > --- a/drivers/i2c/busses/i2c-meson.c > +++ b/drivers/i2c/busses/i2c-meson.c > @@ -233,7 +233,15 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id) > ? dev_dbg(i2c->dev, "irq: state %d, pos %d, count %d, ctrl %08x\n", > ? i2c->state, i2c->pos, i2c->count, ctrl); > ? > - if (ctrl & REG_CTRL_ERROR && i2c->state != STATE_IDLE) { > + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); > + > + if (i2c->state == STATE_IDLE) { > + dev_notice(i2c->dev, "spurious interrupt detected\n"); > + spin_unlock(&i2c->lock); > + return IRQ_NONE; > + } Does it really happen ? Did you see any specific issue you'd like to share ? If not, I'm not a big fan of this change. In any case, if it can be handled gracefully, I'd drop the trace in the interrupt handler. > + > + if (ctrl & REG_CTRL_ERROR) { > ? /* > ? ?* The bit is set when the IGNORE_NAK bit is cleared > ? ?* and the device didn't respond. In this case, the > @@ -276,15 +284,12 @@ static irqreturn_t meson_i2c_irq(int irqno, void > *dev_id) > ? i2c->state = STATE_IDLE; > ? complete(&i2c->done); > ? break; > - case STATE_IDLE: > - break; > ? } > ? > ?out: > ? if (i2c->state != STATE_IDLE) { > ? /* Restart the processing */ > ? meson_i2c_write_tokens(i2c); > - meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); > ? meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, > ? ???REG_CTRL_START); > ? } > @@ -344,9 +349,6 @@ static int meson_i2c_xfer_msg(struct meson_i2c *i2c, > struct i2c_msg *msg, > ? ?*/ > ? spin_lock_irqsave(&i2c->lock, flags); > ? > - /* Abort any active operation */ > - meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); > - > ? if (!time_left) { > ? i2c->state = STATE_IDLE; > ? ret = -ETIMEDOUT; From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerome Brunet Subject: Re: [PATCH 07/12] i2c: meson: improve interrupt handler and detect spurious interrupts Date: Wed, 08 Mar 2017 10:50:36 +0100 Message-ID: <1488966636.2514.16.camel@baylibre.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wm0-f48.google.com ([74.125.82.48]:34551 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751291AbdCHKux (ORCPT ); Wed, 8 Mar 2017 05:50:53 -0500 Received: by mail-wm0-f48.google.com with SMTP id 196so29333418wmm.1 for ; Wed, 08 Mar 2017 02:50:52 -0800 (PST) In-Reply-To: Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Heiner Kallweit , Wolfram Sang Cc: linux-amlogic@lists.infradead.org, "linux-i2c@vger.kernel.org" On Wed, 2017-03-08 at 07:47 +0100, Heiner Kallweit wrote: > If state is STATE_IDLE no interrupt should occur. Detect this case and > warn. > In addition move resetting REG_CTRL_START bit to the start of the > interrupt handler and remove a unneeded REG_CTRL_START bit reset > in meson_i2c_xfer_msg. > > Signed-off-by: Heiner Kallweit > --- >  drivers/i2c/busses/i2c-meson.c | 16 +++++++++------- >  1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c > index 81304840..b3b881f9 100644 > --- a/drivers/i2c/busses/i2c-meson.c > +++ b/drivers/i2c/busses/i2c-meson.c > @@ -233,7 +233,15 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id) >   dev_dbg(i2c->dev, "irq: state %d, pos %d, count %d, ctrl %08x\n", >   i2c->state, i2c->pos, i2c->count, ctrl); >   > - if (ctrl & REG_CTRL_ERROR && i2c->state != STATE_IDLE) { > + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); > + > + if (i2c->state == STATE_IDLE) { > + dev_notice(i2c->dev, "spurious interrupt detected\n"); > + spin_unlock(&i2c->lock); > + return IRQ_NONE; > + } Does it really happen ? Did you see any specific issue you'd like to share ? If not, I'm not a big fan of this change. In any case, if it can be handled gracefully, I'd drop the trace in the interrupt handler. > + > + if (ctrl & REG_CTRL_ERROR) { >   /* >    * The bit is set when the IGNORE_NAK bit is cleared >    * and the device didn't respond. In this case, the > @@ -276,15 +284,12 @@ static irqreturn_t meson_i2c_irq(int irqno, void > *dev_id) >   i2c->state = STATE_IDLE; >   complete(&i2c->done); >   break; > - case STATE_IDLE: > - break; >   } >   >  out: >   if (i2c->state != STATE_IDLE) { >   /* Restart the processing */ >   meson_i2c_write_tokens(i2c); > - meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); >   meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, >      REG_CTRL_START); >   } > @@ -344,9 +349,6 @@ static int meson_i2c_xfer_msg(struct meson_i2c *i2c, > struct i2c_msg *msg, >    */ >   spin_lock_irqsave(&i2c->lock, flags); >   > - /* Abort any active operation */ > - meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0); > - >   if (!time_left) { >   i2c->state = STATE_IDLE; >   ret = -ETIMEDOUT;