linux-kernel - Re: [PATCH] pinctrl: at91-pio4: handle suspend to ram

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Message-ID: <20170407124546.r3vwjjb5tqg624x5@rfolt0960.corp.atmel.com>
Date:   Fri, 7 Apr 2017 14:45:46 +0200
From:   Ludovic Desroches <ludovic.desroches@...rochip.com>
To:     Alexandre Belloni <alexandre.belloni@...e-electrons.com>
CC:     Linus Walleij <linus.walleij@...aro.org>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl: at91-pio4: handle suspend to ram

On Thu, Apr 06, 2017 at 03:36:23PM +0200, Alexandre Belloni wrote:
> When suspending to RAM, the power to the core is cut and the register
> values are lost. Save and restore more registers than just IMR.
> 
> Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
> ---
>  drivers/pinctrl/pinctrl-at91-pio4.c | 34 ++++++++++++++++++++++++++++------
>  1 file changed, 28 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pinctrl/pinctrl-at91-pio4.c b/drivers/pinctrl/pinctrl-at91-pio4.c
> index 28bbc1bb9e6c..dc8591543dee 100644
> --- a/drivers/pinctrl/pinctrl-at91-pio4.c
> +++ b/drivers/pinctrl/pinctrl-at91-pio4.c
> @@ -126,7 +126,11 @@ struct atmel_pioctrl {
>  	struct irq_domain	*irq_domain;
>  	int			*irqs;
>  	unsigned		*pm_wakeup_sources;
> -	unsigned		*pm_suspend_backup;
> +	struct {
> +		u32		imr;
> +		u32		odsr;
> +		u32		cfgr[ATMEL_PIO_NPINS_PER_BANK];
> +	} *pm_suspend_backup;
>  	struct device		*dev;
>  	struct device_node	*node;
>  };
> @@ -830,17 +834,26 @@ static int __maybe_unused atmel_pctrl_suspend(struct device *dev)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct atmel_pioctrl *atmel_pioctrl = platform_get_drvdata(pdev);
> -	int i;
> +	int i, j;
>  
>  	/*
>  	 * For each bank, save IMR to restore it later and disable all GPIO
>  	 * interrupts excepting the ones marked as wakeup sources.
>  	 */
>  	for (i = 0; i < atmel_pioctrl->nbanks; i++) {
> -		atmel_pioctrl->pm_suspend_backup[i] =
> +		atmel_pioctrl->pm_suspend_backup[i].imr =
>  			atmel_gpio_read(atmel_pioctrl, i, ATMEL_PIO_IMR);
>  		atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_IDR,
>  				 ~atmel_pioctrl->pm_wakeup_sources[i]);
> +		atmel_pioctrl->pm_suspend_backup[i].odsr =
> +			atmel_gpio_read(atmel_pioctrl, i, ATMEL_PIO_ODSR);
> +		for (j = 0; j < ATMEL_PIO_NPINS_PER_BANK; j++) {
> +			atmel_gpio_write(atmel_pioctrl, i,
> +					 ATMEL_PIO_MSKR, BIT(j));
> +			atmel_pioctrl->pm_suspend_backup[i].cfgr[j] =
> +				atmel_gpio_read(atmel_pioctrl, i,
> +						ATMEL_PIO_CFGR);
> +		}
>  	}
>  
>  	return 0;
> @@ -850,11 +863,20 @@ static int __maybe_unused atmel_pctrl_resume(struct device *dev)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct atmel_pioctrl *atmel_pioctrl = platform_get_drvdata(pdev);
> -	int i;
> +	int i, j;
>  
> -	for (i = 0; i < atmel_pioctrl->nbanks; i++)
> +	for (i = 0; i < atmel_pioctrl->nbanks; i++) {
>  		atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_IER,
> -				 atmel_pioctrl->pm_suspend_backup[i]);
> +				 atmel_pioctrl->pm_suspend_backup[i].imr);
> +		atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_SODR,
> +				 atmel_pioctrl->pm_suspend_backup[i].odsr);

I would also configure CODR to be sure to be in the same state.

Otherwise: Acked-by: Ludovic Desroches <ludovic.desroches@...rochip.com>

> +		for (j = 0; j < ATMEL_PIO_NPINS_PER_BANK; j++) {
> +			atmel_gpio_write(atmel_pioctrl, i,
> +					 ATMEL_PIO_MSKR, BIT(j));
> +			atmel_gpio_write(atmel_pioctrl, i, ATMEL_PIO_CFGR,
> +					 atmel_pioctrl->pm_suspend_backup[i].cfgr[j]);
> +		}
> +	}
>  
>  	return 0;
>  }
> -- 
> 2.11.0
>