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

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Message-ID: <51369b07-dade-7b56-bc9c-bc21b161916e@foss.st.com>
Date:   Tue, 12 Jul 2022 12:01:35 +0200
From:   Fabrice Gasnier <fabrice.gasnier@...s.st.com>
To:     Heikki Krogerus <heikki.krogerus@...ux.intel.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

On 7/12/22 10:56, Heikki Krogerus wrote:
> 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?

Hi Heikki,

There's no dependency. I did a separate patch mainly to ease the review.

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

Ok, I'll merge this into the first patches as you suggest, and add your
Acked-by.

Thanks for reviewing,
Best Regards,
Fabrice

> 
> 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
>