From: Wolfram Sang <wsa@kernel.org>
To: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-i2c@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Tamal Saha <tamal.saha@intel.com>
Subject: Re: [PATCH 1/6] i2c: designware: Do not complete i2c read without RX_FULL interrupt
Date: Thu, 16 Dec 2021 22:17:04 +0100 [thread overview]
Message-ID: <Ybus0MVyyNU+GyeC@kunai> (raw)
In-Reply-To: <20211215151205.584264-1-jarkko.nikula@linux.intel.com>
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On Wed, Dec 15, 2021 at 05:12:00PM +0200, Jarkko Nikula wrote:
> From: Tamal Saha <tamal.saha@intel.com>
>
> Intel Keem Bay platform supports multi-master operations over same i2c
> bus using Synopsys i2c DesignWare IP. When multi-masters initiate i2c
> operation simultaneously in a loop, SCL line is stucked low forever
> after few i2c operations. Following interrupt sequences are observed
> in:
> working case: TX_EMPTY, RX_FULL and STOP_DET
> non working case: TX_EMPTY, STOP_DET, RX_FULL.
>
> DW_apb_i2c stretches the SCL line when the TX FIFO is empty or when
> RX FIFO is full. The DW_apb_i2c master will continue to hold the SCL
> line LOW until RX FIFO is read.
>
> Linux kernel i2c DesignWare driver does not handle above non working
> sequence. TX_EMPTY, RX_FULL and STOP_DET routine execution are required
> in sequence although RX_FULL interrupt is raised after STOP_DET by
> hardware. Clear STOP_DET for the following conditions:
> (STOP_DET ,RX_FULL, rx_outstanding)
> Write Operation: (1, 0, 0)
> Read Operation:
> RX_FULL followed by STOP_DET: (0, 1, 1) -> (1, 0, 0)
> STOP_DET followed by RX_FULL: (1, 0, 1) -> (1, 1, 0)
> RX_FULL and STOP_DET together: (1, 1, 1)
>
> Signed-off-by: Tamal Saha <tamal.saha@intel.com>
> Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Applied to for-next, thanks!
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prev parent reply other threads:[~2021-12-16 21:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-15 15:12 [PATCH 1/6] i2c: designware: Do not complete i2c read without RX_FULL interrupt Jarkko Nikula
2021-12-15 15:12 ` [PATCH 2/6] i2c: designware-pci: Fix to change data types of hcnt and lcnt parameters Jarkko Nikula
2021-12-16 21:17 ` Wolfram Sang
2021-12-15 15:12 ` [PATCH 3/6] i2c: designware-pci: Add a note about struct dw_scl_sda_cfg usage Jarkko Nikula
2021-12-16 21:17 ` Wolfram Sang
2021-12-15 15:12 ` [PATCH 4/6] i2c: designware-pci: Group MODULE_*() macros Jarkko Nikula
2021-12-16 21:18 ` Wolfram Sang
2021-12-17 11:30 ` Andy Shevchenko
2021-12-15 15:12 ` [PATCH 5/6] i2c: designware-pci: use __maybe_unused for PM functions Jarkko Nikula
2021-12-16 21:18 ` Wolfram Sang
2021-12-15 15:12 ` [PATCH 6/6] i2c: designware-pci: Convert to use dev_err_probe() Jarkko Nikula
2021-12-16 21:18 ` Wolfram Sang
2021-12-16 21:17 ` Wolfram Sang [this message]
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