linux-kernel - Re: [PATCH V3 1/2] i2c-designware: Add i2c bus locking support

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Message-ID: <5480144F.2040506@linux.intel.com>
Date:	Thu, 04 Dec 2014 09:59:11 +0200
From:	Jarkko Nikula <jarkko.nikula@...ux.intel.com>
To:	"David E. Box" <david.e.box@...ux.intel.com>, wsa@...-dreams.de
CC:	jdelvare@...e.de, arnd@...db.de, maxime.ripard@...e-electrons.com,
	dianders@...omium.org, u.kleine-koenig@...gutronix.de,
	laurent.pinchart+renesas@...asonboard.com,
	boris.brezillon@...e-electrons.com, andrew@...n.ch,
	sjg@...omium.org, markus.mayer@...aro.org,
	jacob.jun.pan@...ux.intel.com, max.schwarz@...ine.de,
	mika.westerberg@...ux.intel.com, skuribay@...ox.com,
	Romain.Baeriswyl@...lis.com, wenkai.du@...el.com,
	chiau.ee.chew@...el.com, alan@...ux.intel.com,
	linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org
Subject: Re: [PATCH V3 1/2] i2c-designware: Add i2c bus locking support

Hi

On 12/02/2014 02:09 AM, David E. Box wrote:
> Adds support for acquiring and releasing a hardware bus lock in the i2c
> designware core transfer function. This is needed for i2c bus controllers
> that are shared with but not controlled by the kernel.
>
> Signed-off-by: David E. Box <david.e.box@...ux.intel.com>
> ---
>   drivers/i2c/busses/i2c-designware-core.c    | 11 +++++++++++
>   drivers/i2c/busses/i2c-designware-core.h    |  6 ++++++
>   drivers/i2c/busses/i2c-designware-platdrv.c | 18 +++++++++++++-----
>   3 files changed, 30 insertions(+), 5 deletions(-)
>
...
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index a743115..afdff3b 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -261,10 +261,16 @@ static int dw_i2c_probe(struct platform_device *pdev)
>   		return r;
>   	}
>   
> -	pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> -	pm_runtime_use_autosuspend(&pdev->dev);
> -	pm_runtime_set_active(&pdev->dev);
> -	pm_runtime_enable(&pdev->dev);
> +	i2c_dw_eval_lock_support(dev);
i2c_dw_eval_lock_support() is added in the next patch.
> +
> +	if (dev->pm_runtime_disabled) {
> +		pm_runtime_forbid(&pdev->dev);
> +	} else {
> +		pm_runtime_set_autosuspend_delay(&pdev->dev, 1000);
> +		pm_runtime_use_autosuspend(&pdev->dev);
> +		pm_runtime_set_active(&pdev->dev);
> +		pm_runtime_enable(&pdev->dev);
> +	}
>   
>   	return 0;
>   }
> @@ -314,7 +320,9 @@ static int dw_i2c_resume(struct device *dev)
>   	struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev);
>   
>   	clk_prepare_enable(i_dev->clk);
> -	i2c_dw_init(i_dev);
> +
> +	if (!i_dev->pm_runtime_disabled)
> +		i2c_dw_init(i_dev);
>   
Should there be similar conditional call or locking around i2c_dw_init() 
and i2c_dw_disable_int() also in dw_i2c_probe()?

-- 
Jarkko
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