linux-kernel - Re: [PATCH v2 4/4] usb: typec: ucsi: stm32g0: add support for power management

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Date:   Tue, 12 Jul 2022 11:56:34 +0300
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Fabrice Gasnier <fabrice.gasnier@...s.st.com>
Cc:     krzysztof.kozlowski+dt@...aro.org, robh+dt@...nel.org,
        gregkh@...uxfoundation.org, christophe.jaillet@...adoo.fr,
        devicetree@...r.kernel.org, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        amelie.delaunay@...s.st.com, alexandre.torgue@...s.st.com
Subject: Re: [PATCH v2 4/4] usb: typec: ucsi: stm32g0: add support for power
 management

Hi,

Mon, Jul 11, 2022 at 02:01:22PM +0200, Fabrice Gasnier kirjoitti:
> Type-C connector can be used as a wakeup source (typically to detect
> changes on the port, attach or detach...).
> Add suspend / resume routines to enable wake irqs, and signal a wakeup
> event in case the IRQ has fired while in suspend.
> The i2c core is doing the necessary initialization when the "wakeup-source"
> flag is provided.
> Note: the interrupt handler shouldn't be called before the i2c bus resumes.
> So, the interrupts are disabled during suspend period, and re-enabled
> upon resume, to avoid i2c transfer while suspended, from the irq handler.
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>

Does this really need a separate patch? Does the support depend on the
second patch somehow?

If not, then just merge this into the first patch. That
g0->in_bootloader check you can add in the second patch.

Acked-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
>  drivers/usb/typec/ucsi/ucsi_stm32g0.c | 52 +++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_stm32g0.c b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
> index b1d891c9a92c0..061551d464f12 100644
> --- a/drivers/usb/typec/ucsi/ucsi_stm32g0.c
> +++ b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
> @@ -66,6 +66,8 @@ struct ucsi_stm32g0 {
>  	unsigned long flags;
>  	const char *fw_name;
>  	struct ucsi *ucsi;
> +	bool suspended;
> +	bool wakeup_event;
>  };
>  
>  /*
> @@ -416,6 +418,9 @@ static irqreturn_t ucsi_stm32g0_irq_handler(int irq, void *data)
>  	u32 cci;
>  	int ret;
>  
> +	if (g0->suspended)
> +		g0->wakeup_event = true;
> +
>  	ret = ucsi_stm32g0_read(g0->ucsi, UCSI_CCI, &cci, sizeof(cci));
>  	if (ret)
>  		return IRQ_NONE;
> @@ -696,6 +701,52 @@ static int ucsi_stm32g0_remove(struct i2c_client *client)
>  	return 0;
>  }
>  
> +static int ucsi_stm32g0_suspend(struct device *dev)
> +{
> +	struct ucsi_stm32g0 *g0 = dev_get_drvdata(dev);
> +	struct i2c_client *client = g0->client;
> +
> +	if (g0->in_bootloader)
> +		return 0;
> +
> +	/* Keep the interrupt disabled until the i2c bus has been resumed */
> +	disable_irq(client->irq);
> +
> +	g0->suspended = true;
> +	g0->wakeup_event = false;
> +
> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> +		enable_irq_wake(client->irq);
> +
> +	return 0;
> +}
> +
> +static int ucsi_stm32g0_resume(struct device *dev)
> +{
> +	struct ucsi_stm32g0 *g0 = dev_get_drvdata(dev);
> +	struct i2c_client *client = g0->client;
> +
> +	if (g0->in_bootloader)
> +		return 0;
> +
> +	if (device_may_wakeup(dev) || device_wakeup_path(dev))
> +		disable_irq_wake(client->irq);
> +
> +	enable_irq(client->irq);
> +
> +	/* Enforce any pending handler gets called to signal a wakeup_event */
> +	synchronize_irq(client->irq);
> +
> +	if (g0->wakeup_event)
> +		pm_wakeup_event(g0->dev, 0);
> +
> +	g0->suspended = false;
> +
> +	return 0;
> +}
> +
> +static DEFINE_SIMPLE_DEV_PM_OPS(ucsi_stm32g0_pm_ops, ucsi_stm32g0_suspend, ucsi_stm32g0_resume);
> +
>  static const struct of_device_id __maybe_unused ucsi_stm32g0_typec_of_match[] = {
>  	{ .compatible = "st,stm32g0-typec" },
>  	{},
> @@ -712,6 +763,7 @@ static struct i2c_driver ucsi_stm32g0_i2c_driver = {
>  	.driver = {
>  		.name = "ucsi-stm32g0-i2c",
>  		.of_match_table = of_match_ptr(ucsi_stm32g0_typec_of_match),
> +		.pm = pm_sleep_ptr(&ucsi_stm32g0_pm_ops),
>  	},
>  	.probe = ucsi_stm32g0_probe,
>  	.remove = ucsi_stm32g0_remove,
> -- 
> 2.25.1

-- 
heikki