From: "Sverdlin, Alexander (Nokia - DE/Ulm)" <alexander.sverdlin@nokia.com>
To: "Adamski,
Krzysztof (Nokia - PL/Wroclaw)" <krzysztof.adamski@nokia.com>,
Wolfram Sang <wsa@the-dreams.de>
Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Guenter Roeck <linux@roeck-us.net>,
Tobias Jordan <Tobias.Jordan@elektrobit.com>,
Peter Rosin <peda@axentia.se>
Subject: Re: [PATCH 2/3] i2c-axxia: check for error conditions first
Date: Tue, 11 Dec 2018 12:02:32 +0000 [thread overview]
Message-ID: <bb305008-f552-b7d0-49f6-daf76a827e1f@nokia.com> (raw)
In-Reply-To: <d9a8070357973b5078dc897a18f319cba1df5de0.1544453688.git.krzysztof.adamski@nokia.com>
Hi!
On 10/12/2018 16:01, Adamski, Krzysztof (Nokia - PL/Wroclaw) wrote:
> It was observed that when using seqentional mode contrary to the
^^^^^^^^^^^
> documentation, the SS bit (which is supposed to only be set if
> automatic/sequence command completed normally), is sometimes set
> together with NA (NAK in address phase) causing transfer to falsely be
> considered successful.
>
> My assumption is that this does not happen during manual mode since the
> controller is stopping its work the moment it sets NA/ND bit in status
> register. This is not the case in Automatic/Sequentional mode where it
^^^^^^^^^^^^
> is still working to send STOP condition and the actual status we get
> depends on the time when the ISR is run.
>
> This patch changes the order of checking status bits in ISR - error
> conditions are checked first and only if none of them occurred, the
> transfer may be considered successful. This is required to introduce
> using of sequentional mode in next patch.
^^^^^^^^^^^^
sequential
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
> Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
> ---
> drivers/i2c/busses/i2c-axxia.c | 32 ++++++++++++++++----------------
> 1 file changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
> index d37caf694fbf..35258321e81b 100644
> --- a/drivers/i2c/busses/i2c-axxia.c
> +++ b/drivers/i2c/busses/i2c-axxia.c
> @@ -296,22 +296,7 @@ static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
> i2c_int_disable(idev, MST_STATUS_TFL);
> }
>
> - if (status & MST_STATUS_SCC) {
> - /* Stop completed */
> - i2c_int_disable(idev, ~MST_STATUS_TSS);
> - complete(&idev->msg_complete);
> - } else if (status & MST_STATUS_SNS) {
> - /* Transfer done */
> - i2c_int_disable(idev, ~MST_STATUS_TSS);
> - if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
> - axxia_i2c_empty_rx_fifo(idev);
> - complete(&idev->msg_complete);
> - } else if (status & MST_STATUS_TSS) {
> - /* Transfer timeout */
> - idev->msg_err = -ETIMEDOUT;
> - i2c_int_disable(idev, ~MST_STATUS_TSS);
> - complete(&idev->msg_complete);
> - } else if (unlikely(status & MST_STATUS_ERR)) {
> + if (unlikely(status & MST_STATUS_ERR)) {
> /* Transfer error */
> i2c_int_disable(idev, ~0);
> if (status & MST_STATUS_AL)
> @@ -328,6 +313,21 @@ static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
> readl(idev->base + MST_TX_BYTES_XFRD),
> readl(idev->base + MST_TX_XFER));
> complete(&idev->msg_complete);
> + } else if (status & MST_STATUS_SCC) {
> + /* Stop completed */
> + i2c_int_disable(idev, ~MST_STATUS_TSS);
> + complete(&idev->msg_complete);
> + } else if (status & MST_STATUS_SNS) {
> + /* Transfer done */
> + i2c_int_disable(idev, ~MST_STATUS_TSS);
> + if (i2c_m_rd(idev->msg) && idev->msg_xfrd < idev->msg->len)
> + axxia_i2c_empty_rx_fifo(idev);
> + complete(&idev->msg_complete);
> + } else if (status & MST_STATUS_TSS) {
> + /* Transfer timeout */
> + idev->msg_err = -ETIMEDOUT;
> + i2c_int_disable(idev, ~MST_STATUS_TSS);
> + complete(&idev->msg_complete);
> }
>
> out:
>
--
Best regards,
Alexander Sverdlin.
next prev parent reply other threads:[~2018-12-11 12:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-10 15:00 [PATCH 0/3] i2c-axxia: support Sequence command Adamski, Krzysztof (Nokia - PL/Wroclaw)
2018-12-10 15:00 ` [PATCH 1/3] i2c-axxia: dedicated function to set client addr Adamski, Krzysztof (Nokia - PL/Wroclaw)
2018-12-11 12:00 ` Sverdlin, Alexander (Nokia - DE/Ulm)
2018-12-11 20:05 ` Wolfram Sang
2018-12-10 15:01 ` [PATCH 2/3] i2c-axxia: check for error conditions first Adamski, Krzysztof (Nokia - PL/Wroclaw)
2018-12-11 12:02 ` Sverdlin, Alexander (Nokia - DE/Ulm) [this message]
2018-12-11 20:05 ` Wolfram Sang
2018-12-10 15:05 ` [PATCH 3/3] i2c-axxia: support sequence command mode Adamski, Krzysztof (Nokia - PL/Wroclaw)
2018-12-11 12:05 ` Sverdlin, Alexander (Nokia - DE/Ulm)
2018-12-11 20:04 ` Wolfram Sang
2018-12-13 12:09 ` [PATCH v2] i2c: axxia: " Adamski, Krzysztof (Nokia - PL/Wroclaw)
2018-12-13 12:45 ` Sverdlin, Alexander (Nokia - DE/Ulm)
2018-12-17 22:31 ` Wolfram Sang
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