Re: [PATCH 2/2] i2c: altera: cleanup spinlock

[Thor Thayer <thor.thayer@linux.intel.com>]

On 5/8/20 8:14 AM, Atsushi Nemoto wrote:
> Protect altr_i2c_int_enable() by the mutex and remove unneeded spinlock.
> 
> Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp>
> ---
>   drivers/i2c/busses/i2c-altera.c | 12 ++++--------
>   1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-altera.c b/drivers/i2c/busses/i2c-altera.c
> index 16ddc26..997434f 100644
> --- a/drivers/i2c/busses/i2c-altera.c
> +++ b/drivers/i2c/busses/i2c-altera.c
> @@ -69,7 +69,6 @@
>    * @fifo_size: size of the FIFO passed in.
>    * @isr_mask: cached copy of local ISR enables.
>    * @isr_status: cached copy of local ISR status.
> - * @lock: spinlock for IRQ synchronization.
>    * @isr_mutex: mutex for IRQ thread.
>    */
>   struct altr_i2c_dev {
> @@ -86,18 +85,14 @@ struct altr_i2c_dev {
>   	u32 fifo_size;
>   	u32 isr_mask;
>   	u32 isr_status;
> -	spinlock_t lock;	/* IRQ synchronization */
>   	struct mutex isr_mutex;
>   };
>   
>   static void
>   altr_i2c_int_enable(struct altr_i2c_dev *idev, u32 mask, bool enable)
>   {
> -	unsigned long flags;
>   	u32 int_en;
>   
> -	spin_lock_irqsave(&idev->lock, flags);
> -
>   	int_en = readl(idev->base + ALTR_I2C_ISER);
>   	if (enable)
>   		idev->isr_mask = int_en | mask;
> @@ -105,8 +100,6 @@ altr_i2c_int_enable(struct altr_i2c_dev *idev, u32 mask, bool enable)
>   		idev->isr_mask = int_en & ~mask;
>   
>   	writel(idev->isr_mask, idev->base + ALTR_I2C_ISER);
> -
> -	spin_unlock_irqrestore(&idev->lock, flags);
>   }
>   
>   static void altr_i2c_int_clear(struct altr_i2c_dev *idev, u32 mask)
> @@ -346,6 +339,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
>   
>   	time_left = wait_for_completion_timeout(&idev->msg_complete,
>   						ALTR_I2C_XFER_TIMEOUT);
> +	mutex_lock(&idev->isr_mutex);
>   	altr_i2c_int_enable(idev, imask, false);
>   
>   	value = readl(idev->base + ALTR_I2C_STATUS) & ALTR_I2C_STAT_CORE;
> @@ -358,6 +352,7 @@ static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
>   	}
>   
>   	altr_i2c_core_disable(idev);
> +	mutex_unlock(&idev->isr_mutex);
>   
>   	return idev->msg_err;
>   }
> @@ -415,7 +410,6 @@ static int altr_i2c_probe(struct platform_device *pdev)
>   
>   	idev->dev = &pdev->dev;
>   	init_completion(&idev->msg_complete);
> -	spin_lock_init(&idev->lock);
>   	mutex_init(&idev->isr_mutex);
>   
>   	ret = device_property_read_u32(idev->dev, "fifo-size",
> @@ -453,7 +447,9 @@ static int altr_i2c_probe(struct platform_device *pdev)
>   		return ret;
>   	}
>   
> +	mutex_lock(&idev->isr_mutex);
>   	altr_i2c_init(idev);
> +	mutex_unlock(&idev->isr_mutex);
>   
>   	i2c_set_adapdata(&idev->adapter, idev);
>   	strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
> 

Reviewed-by: Thor Thayer <thor.thayer@linux.intel.com>