Re: [PATCH v1 1/2] i2c: spacemit: Avoid sleeping during bus reset in atomic context

From: Aurelien Jarno <aurelien@aurel32.net>
To: Anand Moon <linux.amoon@gmail.com>
Cc: Troy Mitchell <troy.mitchell@linux.spacemit.com>,
	Andi Shyti <andi.shyti@kernel.org>,
	Sebastian Reichel <sre@kernel.org>, Yixun Lan <dlan@kernel.org>,
	"open list:I2C SUBSYSTEM HOST DRIVERS"
	<linux-i2c@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	"open list:SYSTEM RESET/SHUTDOWN DRIVERS"
	<linux-pm@vger.kernel.org>,
	"open list:RISC-V SPACEMIT SoC Support"
	<linux-riscv@lists.infradead.org>,
	"open list:RISC-V SPACEMIT SoC Support"
	<spacemit@lists.linux.dev>, Alex Elder <elder@riscstar.com>
Subject: Re: [PATCH v1 1/2] i2c: spacemit: Avoid sleeping during bus reset in atomic context
Date: Tue, 10 Nov 2026 21:49:02 +0100	[thread overview]
Message-ID: <avODPs8yytWCMxn3@aurel32.net> (raw)
In-Reply-To: <20261110061429.2036-1-linux.amoon@gmail.com>

On 2026-11-10 11:44, Anand Moon wrote:
> The spacemit_i2c_conditionally_reset_bus() function uses usleep_range()
> to wait after triggering a bus reset request. However, this function can
> be invoked during atomic I2C transfers (such as power-off or restart
> handlers running in atomic notifier chains), where sleeping is illegal.
> 
> Replace the sleep operation with the driver's internal helper,
> spacemit_i2c_delay(), which conditionally uses udelay() when running in
> an atomic context, avoiding "scheduling while atomic" bugs.
> 
> Assisted-by: LLM
> Cc: Troy Mitchell <troy.mitchell@linux.spacemit.com>
> Cc: Alex Elder <elder@riscstar.com>
> Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> ---
>  drivers/i2c/busses/i2c-k1.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
> index ff32876e24d3..f4b21d7efaaf 100644
> --- a/drivers/i2c/busses/i2c-k1.c
> +++ b/drivers/i2c/busses/i2c-k1.c
> @@ -332,7 +332,7 @@ static void spacemit_i2c_conditionally_reset_bus(struct spacemit_i2c_dev *i2c)
>  		writel(FIELD_PREP(SPACEMIT_RCR_FIELD_RST_CYC, 1),
>  		       i2c->base + SPACEMIT_IRCR);
>  		writel(SPACEMIT_CR_RSTREQ, i2c->base + SPACEMIT_ICR);
> -		usleep_range(20, 30);
> +		spacemit_i2c_delay(i2c, 20);
>  	}
>  
>  	/* check sda again here */
> 
> base-commit: b3dfbde62cf1981c4638939c159dfd087b7a72e9

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                     http://aurel32.net