Re: [PATCH] i2c: imx: make controller available until system suspend_noirq() and from resume_noirq()

[Frank Li <Frank.li@nxp.com>]

On Mon, Nov 25, 2024 at 10:21:08PM +0800, carlos.song@nxp.com wrote:
> From: Carlos Song <carlos.song@nxp.com>
>
> Put runtime pm to resume state between suspend() and suspend_noirq(),
> resume_noirq() and resume(), because some I2C devices need controller
> on to do communication during this period.
>
> The controller can't be wakeup once runtime pm is disabled and in
> runtime autosuspended state.
>
> The problem can be easily reproduced on the I.MX8MQ platform:
> PMIC needs to be used to enable regular when the system resumes.
> When PMIC uses I2C controller, I2C runtime pm has not been enabled,
> so in i2c xfer(), pm_runtime_resume_and_get() will return error,
> which causes data transfer failed. Therefore, regulars can not
> be enabled and hang system resumes.
> Here is resume error log:
> [   53.888902] galcore 38000000.gpu3d: PM: calling genpd_resume_noirq @ 529, parent: platform
> [   53.897203] i2c_imx_xfer, pm_runtime_resume_and_get is -13
> [   53.902713] imx-pgc imx-pgc-domain.5: failed to enable regulator: -EACCES
> [   53.909518] galcore 38000000.gpu3d: PM: genpd_resume_noirq returned 0 after 12331 usecs
> [   53.917545] mxc_hantro 38300000.vpu: PM: calling genpd_resume_noirq @ 529, parent: soc@0
> [   53.925659] i2c_imx_xfer, pm_runtime_resume_and_get is -13
> [   53.931157] imx-pgc imx-pgc-domain.6: failed to enable regulator: -EACCES
>
> I.MX8MQ system resume normally after applying the fix. Here is resume log:
> [   71.068807] galcore 38000000.gpu3d: PM: calling genpd_resume_noirq @ 530, parent: platform
> [   71.077103] i2c_imx_xfer, pm_runtime_resume_and_get is 0
> [   71.083578] galcore 38000000.gpu3d: PM: genpd_resume_noirq returned 0 after 6490 usecs
> [   71.091526] mxc_hantro 38300000.vpu: PM: calling genpd_resume_noirq @ 530, parent: soc@0
> [   71.099638] i2c_imx_xfer, pm_runtime_resume_and_get is 0
> [   71.106091] mxc_hantro 38300000.vpu: PM: genpd_resume_noirq returned 0 after 6458 usecs
>
> Signed-off-by: Carlos Song <carlos.song@nxp.com>
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/i2c/busses/i2c-imx.c | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index ee7070ee9e6e..c35092726465 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1770,7 +1770,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  		goto rpm_disable;
>
>  	/* Request IRQ */
> -	ret = request_irq(irq, i2c_imx_isr, IRQF_SHARED, pdev->name, i2c_imx);
> +	ret = request_irq(irq, i2c_imx_isr, IRQF_SHARED | IRQF_NO_SUSPEND,
> +			  pdev->name, i2c_imx);
>  	if (ret) {
>  		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
>  		goto rpm_disable;
> @@ -1894,7 +1895,36 @@ static int i2c_imx_runtime_resume(struct device *dev)
>  	return ret;
>  }
>
> +static int i2c_imx_suspend(struct device *dev)
> +{
> +	/*
> +	 * Some I2C devices may need I2C controller up during resume_noirq()
> +	 * or suspend_noirq(), if the controller is autosuspended, there is
> +	 * no way to wakeup it once runtime pm is disabled (in suspend_late()).
> +	 * When system resume, I2C controller will be available until runtime pm
> +	 * is enabled(in_resume_early()). But it is too late for some devices.
> +	 * Wakeup the controller in suspend() callback while runtime pm is enabled,
> +	 * I2C controller will be available until suspend_noirq() callback
> +	 * (pm_runtime_force_suspend()) is called. During the resume, I2C controller
> +	 * can be restored by resume_noirq() callback (pm_runtime_force_resume()).
> +	 * Then resume() callback enables autosuspend. It will make I2C controller
> +	 * available until system suspend_noirq() and from resume_noirq().
> +	 */
> +	return pm_runtime_resume_and_get(dev);
> +}
> +
> +static int i2c_imx_resume(struct device *dev)
> +{
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_put_autosuspend(dev);
> +
> +	return 0;
> +}
> +
>  static const struct dev_pm_ops i2c_imx_pm_ops = {
> +	NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +				  pm_runtime_force_resume)
> +	SYSTEM_SLEEP_PM_OPS(i2c_imx_suspend, i2c_imx_resume)
>  	RUNTIME_PM_OPS(i2c_imx_runtime_suspend, i2c_imx_runtime_resume, NULL)
>  };
>
> --
> 2.34.1
>