From: Carlos Song <carlos.song@nxp.com>

Mark the I2C adapter as suspended during system suspend to block further
transfers, and resume it on system resume. This prevents potential hangs
when the hardware is powered down but clients still attempt I2C transfers.

Fixes: 358025ac091e ("i2c: imx: make controller available until system suspend_noirq() and from resume_noirq()")
Cc: stable@vger.kernel.org
Signed-off-by: Carlos Song <carlos.song@nxp.com>
---
Change for v3:
  - Add hrtimer_cancel in i2c_imx_suspend_noirq to cancel slave_timer for
    safe suspend in i2c slave mode.
Change for v2:
  - Call i2c_mark_adapter_suspended() before pm_runtime_force_suspend()
    to prevent potential deadlock if a transfer is active during suspend.
  - Roll back with i2c_mark_adapter_resumed() if pm_runtime_force_suspend()
    fails.
---
 drivers/i2c/busses/i2c-imx.c | 41 ++++++++++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index a208fefd3c3b..d651ade86267 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1913,6 +1913,43 @@ static int i2c_imx_runtime_resume(struct device *dev)
 	return ret;
 }
 
+static int __maybe_unused i2c_imx_suspend_noirq(struct device *dev)
+{
+	struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
+	int ret;
+
+	i2c_mark_adapter_suspended(&i2c_imx->adapter);
+
+	/*
+	 * Cancel the slave timer before powering down to prevent
+	 * i2c_imx_slave_timeout() from accessing hardware registers
+	 * while the clock is disabled.
+	 */
+	hrtimer_cancel(&i2c_imx->slave_timer);
+
+	ret = pm_runtime_force_suspend(dev);
+	if (ret) {
+		i2c_mark_adapter_resumed(&i2c_imx->adapter);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int __maybe_unused i2c_imx_resume_noirq(struct device *dev)
+{
+	struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret)
+		return ret;
+
+	i2c_mark_adapter_resumed(&i2c_imx->adapter);
+
+	return 0;
+}
+
 static int i2c_imx_suspend(struct device *dev)
 {
 	/*
@@ -1946,8 +1983,8 @@ static int i2c_imx_resume(struct device *dev)
 }
 
 static const struct dev_pm_ops i2c_imx_pm_ops = {
-	NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
-				  pm_runtime_force_resume)
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(i2c_imx_suspend_noirq,
+				  i2c_imx_resume_noirq)
 	SYSTEM_SLEEP_PM_OPS(i2c_imx_suspend, i2c_imx_resume)
 	RUNTIME_PM_OPS(i2c_imx_runtime_suspend, i2c_imx_runtime_resume, NULL)
 };
-- 
2.43.0

Hi Carlos,

On 5/20/2026 3:45 PM, Carlos Song (OSS) wrote:
> From: Carlos Song <carlos.song@nxp.com>
> 
> Mark the I2C adapter as suspended during system suspend to block further
> transfers, and resume it on system resume. This prevents potential hangs
> when the hardware is powered down but clients still attempt I2C transfers.
> 
Code changes looks fine to me but have comment on commit log.

It seems, you are adding support of _noirq() callbacks to allow 
transfers during suspend/resume noirq phase of PM.

Would it make sense if you can write "Replace system PM callbacks with 
noirq PM callbacks" OR "Allow transfers during _noirq phase of the PM 
ops" instead of "mark I2C adapter when hardware is powered down" ?

> Fixes: 358025ac091e ("i2c: imx: make controller available until system suspend_noirq() and from resume_noirq()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Carlos Song <carlos.song@nxp.com>
> ---
> Change for v3:
>    - Add hrtimer_cancel in i2c_imx_suspend_noirq to cancel slave_timer for
>      safe suspend in i2c slave mode.
> Change for v2:
>    - Call i2c_mark_adapter_suspended() before pm_runtime_force_suspend()
>      to prevent potential deadlock if a transfer is active during suspend.
>    - Roll back with i2c_mark_adapter_resumed() if pm_runtime_force_suspend()
>      fails.
> ---

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