linux-kernel - Re: [PATCH v2 8/9] atmel_flexcom: Support backup mode

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Message-ID: <53aa7783-0ecf-1e68-1bf9-c470ba2f79eb@microchip.com>
Date:   Tue, 19 Sep 2017 11:29:12 +0200
From:   Nicolas Ferre <nicolas.ferre@...rochip.com>
To:     Romain Izard <romain.izard.pro@...il.com>,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>,
        Wenyou Yang <wenyou.yang@...el.com>,
        Josh Wu <rainyfeeling@...look.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Cyrille Pitchen <cyrille.pitchen@...ev4u.fr>,
        Thierry Reding <thierry.reding@...il.com>,
        Richard Genoud <richard.genoud@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Lee Jones <lee.jones@...aro.org>
CC:     <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-mtd@...ts.infradead.org>, <linux-pwm@...r.kernel.org>,
        <linux-serial@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 8/9] atmel_flexcom: Support backup mode

On 15/09/2017 at 16:04, Romain Izard wrote:
> The controller used by a flexcom module is configured at boot, and left
> alone after this. As the configuration will be lost after backup mode,
> restore the state of the flexcom driver on resume.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@...il.com>

Tested-by: Nicolas Ferre <nicolas.ferre@...rochip.com>
On sama5d2 Xplained board (i2c0 from flexcom 4).
and obviously:
Acked-by: Nicolas Ferre <nicolas.ferre@...rochip.com>

Thanks Romain!

Regards,

> ---
>  drivers/mfd/atmel-flexcom.c | 65 ++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 50 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
> index 064bde9cff5a..ef1235c4a179 100644
> --- a/drivers/mfd/atmel-flexcom.c
> +++ b/drivers/mfd/atmel-flexcom.c
> @@ -39,34 +39,44 @@
>  #define FLEX_MR_OPMODE(opmode)	(((opmode) << FLEX_MR_OPMODE_OFFSET) &	\
>  				 FLEX_MR_OPMODE_MASK)
>  
> +struct atmel_flexcom {
> +	void __iomem *base;
> +	u32 opmode;
> +	struct clk *clk;
> +};
>  
>  static int atmel_flexcom_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> -	struct clk *clk;
>  	struct resource *res;
> -	void __iomem *base;
> -	u32 opmode;
> +	struct atmel_flexcom *afc;
>  	int err;
> +	u32 val;
> +
> +	afc = devm_kzalloc(&pdev->dev, sizeof(*afc), GFP_KERNEL);
> +	if (!afc)
> +		return -ENOMEM;
>  
> -	err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
> +	platform_set_drvdata(pdev, afc);
> +
> +	err = of_property_read_u32(np, "atmel,flexcom-mode", &afc->opmode);
>  	if (err)
>  		return err;
>  
> -	if (opmode < ATMEL_FLEXCOM_MODE_USART ||
> -	    opmode > ATMEL_FLEXCOM_MODE_TWI)
> +	if (afc->opmode < ATMEL_FLEXCOM_MODE_USART ||
> +	    afc->opmode > ATMEL_FLEXCOM_MODE_TWI)
>  		return -EINVAL;
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	base = devm_ioremap_resource(&pdev->dev, res);
> -	if (IS_ERR(base))
> -		return PTR_ERR(base);
> +	afc->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(afc->base))
> +		return PTR_ERR(afc->base);
>  
> -	clk = devm_clk_get(&pdev->dev, NULL);
> -	if (IS_ERR(clk))
> -		return PTR_ERR(clk);
> +	afc->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(afc->clk))
> +		return PTR_ERR(afc->clk);
>  
> -	err = clk_prepare_enable(clk);
> +	err = clk_prepare_enable(afc->clk);
>  	if (err)
>  		return err;
>  
> @@ -76,9 +86,10 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
>  	 * inaccessible and are read as zero. Also the external I/O lines of the
>  	 * Flexcom are muxed to reach the selected device.
>  	 */
> -	writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR);
> +	val = FLEX_MR_OPMODE(afc->opmode);
> +	writel(val, afc->base + FLEX_MR);
>  
> -	clk_disable_unprepare(clk);
> +	clk_disable_unprepare(afc->clk);
>  
>  	return devm_of_platform_populate(&pdev->dev);
>  }
> @@ -89,10 +100,34 @@ static const struct of_device_id atmel_flexcom_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int atmel_flexcom_resume(struct device *dev)
> +{
> +	struct atmel_flexcom *afc = dev_get_drvdata(dev);
> +	int err;
> +	u32 val;
> +
> +	err = clk_prepare_enable(afc->clk);
> +	if (err)
> +		return err;
> +
> +	val = FLEX_MR_OPMODE(afc->opmode),
> +	writel(val, afc->base + FLEX_MR);
> +
> +	clk_disable_unprepare(afc->clk);
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL,
> +			 atmel_flexcom_resume);
> +
>  static struct platform_driver atmel_flexcom_driver = {
>  	.probe	= atmel_flexcom_probe,
>  	.driver	= {
>  		.name		= "atmel_flexcom",
> +		.pm		= &atmel_flexcom_pm_ops,
>  		.of_match_table	= atmel_flexcom_of_match,
>  	},
>  };
> 


-- 
Nicolas Ferre