linux-kernel - Re: [RFC 1/2] i2c: designware: Add missing locks

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Message-ID: <YcSaqmlI7l4H1lsN@smile.fi.intel.com>
Date:   Thu, 23 Dec 2021 17:50:02 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Jan Dabros <jsd@...ihalf.com>
Cc:     linux-kernel@...r.kernel.org, linux-i2c@...r.kernel.org,
        jarkko.nikula@...ux.intel.com, mika.westerberg@...ux.intel.com,
        wsa@...nel.org, rrangel@...omium.org, mw@...ihalf.com,
        jaz@...ihalf.com, upstream@...ihalf.com
Subject: Re: [RFC 1/2] i2c: designware: Add missing locks

On Wed, Dec 22, 2021 at 10:45:57AM +0100, Jan Dabros wrote:
> All accesses to controller's registers should be protected on
> probe, disable and xfer paths. This is needed for i2c bus controllers
> that are shared with but not controlled by kernel.

...

> +	ret = i2c_dw_acquire_lock(dev);
> +	if (ret)
> +		return ret;
> +
>  	ret = regmap_read(dev->map, DW_IC_COMP_PARAM_1, &param);
>  	if (ret)
>  		return ret;
> +	i2c_dw_release_lock(dev);

Not sure this part is fully correct. Please, fix the leakage.

...

> +	ret = i2c_dw_acquire_lock(dev);
> +	if (ret)
> +		return;
>  
>  	/* Disable controller */
>  	__i2c_dw_disable(dev);
> @@ -614,6 +624,8 @@ void i2c_dw_disable(struct dw_i2c_dev *dev)
>  	/* Disable all interrupts */
>  	regmap_write(dev->map, DW_IC_INTR_MASK, 0);
>  	regmap_read(dev->map, DW_IC_CLR_INTR, &dummy);

> +	i2c_dw_release_lock(dev);

Not enough context here, bu I believe there is the same issue(s).

-- 
With Best Regards,
Andy Shevchenko