From: Aurelien Jarno <aurelien@aurel32.net>
To: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Cc: Andi Shyti <andi.shyti@kernel.org>, Yixun Lan <dlan@gentoo.org>,
Alex Elder <elder@riscstar.com>,
Troy Mitchell <troymitchell988@gmail.com>,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org, spacemit@lists.linux.dev
Subject: Re: [PATCH v2 2/6] i2c: spacemit: remove stop function to avoid bus error
Date: Thu, 25 Sep 2025 22:11:41 +0200 [thread overview]
Message-ID: <aNWh_dfyfCsqZ8av@aurel32.net> (raw)
In-Reply-To: <20250925-k1-i2c-atomic-v2-2-46dc13311cda@linux.spacemit.com>
On 2025-09-25 10:02, Troy Mitchell wrote:
> Previously, STOP handling was split into two separate steps:
> 1) clear TB/STOP/START/ACK bits
> 2) issue STOP by calling spacemit_i2c_stop()
>
> This left a small window where the control register was updated
> twice, which can confuse the controller. While this race has not
> been observed with interrupt-driven transfers, it reliably causes
> bus errors in PIO mode.
>
> Inline the STOP sequence into the IRQ handler and ensure that
> control register bits are updated atomically in a single writel().
>
> Fixes: 5ea558473fa31 ("i2c: spacemit: add support for SpacemiT K1 SoC")
> Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
> ---
> drivers/i2c/busses/i2c-k1.c | 26 +++++++-------------------
> 1 file changed, 7 insertions(+), 19 deletions(-)
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://aurel32.net
next prev parent reply other threads:[~2025-09-25 20:12 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-25 2:02 [PATCH v2 0/6] i2c: spacemit: fix and introduce pio Troy Mitchell
2025-09-25 2:02 ` [PATCH v2 1/6] i2c: spacemit: ensure bus release check runs when wait_bus_idle() fails Troy Mitchell
2025-09-25 2:02 ` [PATCH v2 2/6] i2c: spacemit: remove stop function to avoid bus error Troy Mitchell
2025-09-25 20:11 ` Aurelien Jarno [this message]
2025-09-25 2:02 ` [PATCH v2 3/6] i2c: spacemit: disable SDA glitch fix to avoid restart delay Troy Mitchell
2025-09-25 2:02 ` [PATCH v2 4/6] i2c: spacemit: check SDA instead of SCL after bus reset Troy Mitchell
2025-09-25 2:02 ` [PATCH v2 5/6] i2c: spacemit: ensure SDA is released " Troy Mitchell
2025-09-25 20:43 ` Aurelien Jarno
2025-09-25 2:02 ` [PATCH v2 6/6] i2c: spacemit: introduce pio for k1 Troy Mitchell
2025-09-26 11:10 ` Yixun Lan
2025-09-26 13:13 ` Troy Mitchell
2025-09-26 14:28 ` Wolfram Sang
2025-09-27 1:24 ` Yixun Lan
2025-09-27 3:57 ` Troy Mitchell
2025-09-28 6:06 ` Troy Mitchell
2025-09-26 16:47 ` Aurelien Jarno
2025-09-27 4:05 ` Troy Mitchell
2025-09-27 1:45 ` Yixun Lan
2025-09-27 4:04 ` Troy Mitchell
2025-09-27 10:16 ` Yixun Lan
2025-09-27 10:24 ` Troy Mitchell
2025-09-27 10:56 ` Yixun Lan
2025-09-28 1:17 ` Troy Mitchell
2025-09-28 2:54 ` Yixun Lan
2025-09-28 8:09 ` Troy Mitchell
2025-09-28 11:22 ` Yixun Lan
2025-09-25 21:50 ` [PATCH v2 0/6] i2c: spacemit: fix and introduce pio Wolfram Sang
2025-09-26 1:47 ` Troy Mitchell
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