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Date:   Wed, 9 Feb 2022 17:23:05 +0200
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Jan Dabros <jsd@semihalf.com>
Cc:     linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
        jarkko.nikula@linux.intel.com, mika.westerberg@linux.intel.com,
        hdegoede@redhat.com, wsa@kernel.org, rrangel@chromium.org,
        mw@semihalf.com, jaz@semihalf.com, upstream@semihalf.com,
        thomas.lendacky@amd.com, alexander.deucher@amd.com,
        Nimesh.Easow@amd.com, mario.limonciello@amd.com
Subject: Re: [PATCH v4 1/2] i2c: designware: Add missing locks
Message-ID: <YgPcWRsaW52Cgii0@smile.fi.intel.com>
References: <20220208141218.2049591-1-jsd@semihalf.com>
 <20220208141218.2049591-2-jsd@semihalf.com>
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Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
Precedence: bulk

On Tue, Feb 08, 2022 at 03:12:17PM +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 controller by kernel.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Jan Dabros <jsd@semihalf.com>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/i2c/busses/i2c-designware-common.c | 12 ++++++++++++
>  drivers/i2c/busses/i2c-designware-master.c |  6 ++++++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
> index bf2a4920638a..9f8574320eb2 100644
> --- a/drivers/i2c/busses/i2c-designware-common.c
> +++ b/drivers/i2c/busses/i2c-designware-common.c
> @@ -578,7 +578,12 @@ int i2c_dw_set_fifo_size(struct dw_i2c_dev *dev)
>  	 * Try to detect the FIFO depth if not set by interface driver,
>  	 * the depth could be from 2 to 256 from HW spec.
>  	 */
> +	ret = i2c_dw_acquire_lock(dev);
> +	if (ret)
> +		return ret;
> +
>  	ret = regmap_read(dev->map, DW_IC_COMP_PARAM_1, &param);
> +	i2c_dw_release_lock(dev);
>  	if (ret)
>  		return ret;
>  
> @@ -607,6 +612,11 @@ u32 i2c_dw_func(struct i2c_adapter *adap)
>  void i2c_dw_disable(struct dw_i2c_dev *dev)
>  {
>  	u32 dummy;
> +	int ret;
> +
> +	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);
>  }
>  
>  void i2c_dw_disable_int(struct dw_i2c_dev *dev)
> diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
> index 9177463c2cbb..1a4b23556db3 100644
> --- a/drivers/i2c/busses/i2c-designware-master.c
> +++ b/drivers/i2c/busses/i2c-designware-master.c
> @@ -905,7 +905,13 @@ int i2c_dw_probe_master(struct dw_i2c_dev *dev)
>  		irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND;
>  	}
>  
> +	ret = i2c_dw_acquire_lock(dev);
> +	if (ret)
> +		return ret;
> +
>  	i2c_dw_disable_int(dev);
> +	i2c_dw_release_lock(dev);
> +
>  	ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, irq_flags,
>  			       dev_name(dev->dev), dev);
>  	if (ret) {
> -- 
> 2.35.0.263.gb82422642f-goog
> 

-- 
With Best Regards,
Andy Shevchenko