| Message ID | 20230724105546.1964059-1-carlos.song@nxp.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/3] i2c: imx-lpi2c: directly return ISR when detect a NACK | expand |
Hi Carlos, On Mon, Jul 24, 2023 at 06:55:44PM +0800, carlos.song@nxp.com wrote: > From: Gao Pan <pandy.gao@nxp.com> > > A NACK flag in ISR means i2c bus error. In such codition, > there is no need to do read/write operation. It's better > to return ISR directly and then stop i2c transfer. > > Fixes: a55fa9d0e42e ("i2c: imx-lpi2c: add low power i2c bus driver") > Signed-off-by: Gao Pan <pandy.gao@nxp.com> > Signed-off-by: Carlos Song <carlos.song@nxp.com> > --- > drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++++------ > 1 file changed, 5 insertions(+), 6 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c > index c3287c887c6f..158de0b7f030 100644 > --- a/drivers/i2c/busses/i2c-imx-lpi2c.c > +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c > @@ -514,15 +514,14 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id) > temp = readl(lpi2c_imx->base + LPI2C_MSR); > temp &= enabled; > > - if (temp & MSR_RDF) > + if (temp & MSR_NDF) { > + complete(&lpi2c_imx->complete); > + return IRQ_HANDLED; you can actually remove the return here if (temp & MSR_NDF) complete(); else if (temp & MSR_RDF) exfifo(); else if (temp & MSR_TDF) txfifo(); return IRQ_HANDLED; BTW, the logic here is changing, as well and it's not described in the commit log. This patch is not only stopping when a nack is received (MSR_NDF), but it's also making mutually exclusive read/write (which I guess are MSR_RDF and MSR_TDF). Is this what you want? If so, can you please describe it in the commit log or add a comment describing that the three states are all mutually exclusive. Thanks, Andi > + } else if (temp & MSR_RDF) > lpi2c_imx_read_rxfifo(lpi2c_imx); > - > - if (temp & MSR_TDF) > + else if (temp & MSR_TDF) > lpi2c_imx_write_txfifo(lpi2c_imx); > > - if (temp & MSR_NDF) > - complete(&lpi2c_imx->complete); > - > return IRQ_HANDLED; > } > > -- > 2.34.1 >
Hi, Andi > -----Original Message----- > From: Andi Shyti <andi.shyti@kernel.org> > Sent: Wednesday, July 26, 2023 7:55 AM > To: Carlos Song <carlos.song@nxp.com> > Cc: Aisheng Dong <aisheng.dong@nxp.com>; shawnguo@kernel.org; > s.hauer@pengutronix.de; kernel@pengutronix.de; festevam@gmail.com; Clark > Wang <xiaoning.wang@nxp.com>; Bough Chen <haibo.chen@nxp.com>; > dl-linux-imx <linux-imx@nxp.com>; linux-i2c@vger.kernel.org; > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org > Subject: [EXT] Re: [PATCH v2 1/3] i2c: imx-lpi2c: directly return ISR when detect > a NACK > > Caution: This is an external email. Please take care when clicking links or > opening attachments. When in doubt, report the message using the 'Report this > email' button > > > Hi Carlos, > > On Mon, Jul 24, 2023 at 06:55:44PM +0800, carlos.song@nxp.com wrote: > > From: Gao Pan <pandy.gao@nxp.com> > > > > A NACK flag in ISR means i2c bus error. In such codition, there is no > > need to do read/write operation. It's better to return ISR directly > > and then stop i2c transfer. > > > > Fixes: a55fa9d0e42e ("i2c: imx-lpi2c: add low power i2c bus driver") > > Signed-off-by: Gao Pan <pandy.gao@nxp.com> > > Signed-off-by: Carlos Song <carlos.song@nxp.com> > > --- > > drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++++------ > > 1 file changed, 5 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c > > b/drivers/i2c/busses/i2c-imx-lpi2c.c > > index c3287c887c6f..158de0b7f030 100644 > > --- a/drivers/i2c/busses/i2c-imx-lpi2c.c > > +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c > > @@ -514,15 +514,14 @@ static irqreturn_t lpi2c_imx_isr(int irq, void > *dev_id) > > temp = readl(lpi2c_imx->base + LPI2C_MSR); > > temp &= enabled; > > > > - if (temp & MSR_RDF) > > + if (temp & MSR_NDF) { > > + complete(&lpi2c_imx->complete); > > + return IRQ_HANDLED; > > you can actually remove the return here > > if (temp & MSR_NDF) > complete(); > else if (temp & MSR_RDF) > exfifo(); > else if (temp & MSR_TDF) > txfifo(); > > return IRQ_HANDLED; > > > BTW, the logic here is changing, as well and it's not described in the commit log. > This patch is not only stopping when a nack is received (MSR_NDF), but it's also > making mutually exclusive read/write (which I guess are MSR_RDF and > MSR_TDF). > > Is this what you want? If so, can you please describe it in the commit log or add > a comment describing that the three states are all mutually exclusive. > Yes. That is ok. I will fix the commit log and send V3 patch. > Thanks, > Andi > > > > + } else if (temp & MSR_RDF) > > lpi2c_imx_read_rxfifo(lpi2c_imx); > > - > > - if (temp & MSR_TDF) > > + else if (temp & MSR_TDF) > > lpi2c_imx_write_txfifo(lpi2c_imx); > > > > - if (temp & MSR_NDF) > > - complete(&lpi2c_imx->complete); > > - > > return IRQ_HANDLED; > > } > > > > -- > > 2.34.1 > >
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c index c3287c887c6f..158de0b7f030 100644 --- a/drivers/i2c/busses/i2c-imx-lpi2c.c +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -514,15 +514,14 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id) temp = readl(lpi2c_imx->base + LPI2C_MSR); temp &= enabled; - if (temp & MSR_RDF) + if (temp & MSR_NDF) { + complete(&lpi2c_imx->complete); + return IRQ_HANDLED; + } else if (temp & MSR_RDF) lpi2c_imx_read_rxfifo(lpi2c_imx); - - if (temp & MSR_TDF) + else if (temp & MSR_TDF) lpi2c_imx_write_txfifo(lpi2c_imx); - if (temp & MSR_NDF) - complete(&lpi2c_imx->complete); - return IRQ_HANDLED; }