linux-kernel - Re: [PATCH v6 02/23] mfd: max77686: Add power management support

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Date:	Fri, 04 Jul 2014 12:51:12 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Cc:	Lee Jones <lee.jones@...aro.org>, Mark Brown <broonie@...nel.org>,
	Mike Turquette <mturquette@...aro.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Doug Anderson <dianders@...omium.org>,
	Olof Johansson <olof@...om.net>,
	Tomeu Vizoso <tomeu.vizoso@...labora.com>,
	Yadwinder Singh Brar <yadi.brar01@...il.com>,
	Tushar Behera <trblinux@...il.com>,
	Andreas Farber <afaerber@...e.de>,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 02/23] mfd: max77686: Add power management support

On pią, 2014-07-04 at 11:55 +0200, Javier Martinez Canillas wrote:
> The driver doesn't have PM operations defined so add a suspend
> and resume function handlers to allow the PMIC IRQ to wakeup
> the system when it is put into a sleep state.
> 
> Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
> ---
>  drivers/mfd/max77686.c | 40 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 40 insertions(+)

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@...sung.com>

Best regards,
Krzysztof


> diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c
> index 3cb41d0..a38e9ee 100644
> --- a/drivers/mfd/max77686.c
> +++ b/drivers/mfd/max77686.c
> @@ -240,10 +240,50 @@ static const struct i2c_device_id max77686_i2c_id[] = {
>  };
>  MODULE_DEVICE_TABLE(i2c, max77686_i2c_id);
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int max77686_suspend(struct device *dev)
> +{
> +	struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
> +	struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
> +
> +	if (device_may_wakeup(dev))
> +		enable_irq_wake(max77686->irq);
> +
> +	/*
> +	 * IRQ must be disabled during suspend because if it happens
> +	 * while suspended it will be handled before resuming I2C.
> +	 *
> +	 * When device is woken up from suspend (e.g. by RTC wake alarm),
> +	 * an interrupt occurs before resuming I2C bus controller.
> +	 * Interrupt handler tries to read registers but this read
> +	 * will fail because I2C is still suspended.
> +	 */
> +	disable_irq(max77686->irq);
> +
> +	return 0;
> +}
> +
> +static int max77686_resume(struct device *dev)
> +{
> +	struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
> +	struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
> +
> +	if (device_may_wakeup(dev))
> +		disable_irq_wake(max77686->irq);
> +
> +	enable_irq(max77686->irq);
> +
> +	return 0;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
> +static SIMPLE_DEV_PM_OPS(max77686_pm, max77686_suspend, max77686_resume);
> +
>  static struct i2c_driver max77686_i2c_driver = {
>  	.driver = {
>  		   .name = "max77686",
>  		   .owner = THIS_MODULE,
> +		   .pm = &max77686_pm,
>  		   .of_match_table = of_match_ptr(max77686_pmic_dt_match),
>  	},
>  	.probe = max77686_i2c_probe,

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