linux-kernel - Re: [PATCH 1/2] media: max9271: Fix GPIO enable/disable

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Date:   Mon, 23 Nov 2020 14:14:36 +0000
From:   Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
To:     Jacopo Mondi <jacopo+renesas@...ndi.org>,
        laurent.pinchart+renesas@...asonboard.com,
        niklas.soderlund+renesas@...natech.se, geert@...ux-m68k.org
Cc:     linux-media@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] media: max9271: Fix GPIO enable/disable

Hi Jacopo,

On 20/11/2020 16:15, Jacopo Mondi wrote:
> Fix GPIO enable/disable operations which wrongly read the 0x0f register
> to obtain the current mask of the enabled lines instead of using
> the correct 0x0e register.
> 
> Also fix access to bit 0 of the register which is marked as reserved.
> 
> Fixes: 34009bffc1c6 ("media: i2c: Add RDACM20 driver")
> Signed-off-by: Jacopo Mondi <jacopo+renesas@...ndi.org>

Took me a few reads of this and the datasheet to be sure :S

But now I am :-D

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@...asonboard.com>

> ---
>  drivers/media/i2c/max9271.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/i2c/max9271.c b/drivers/media/i2c/max9271.c
> index 0f6f7a092a46..c247db569bab 100644
> --- a/drivers/media/i2c/max9271.c
> +++ b/drivers/media/i2c/max9271.c
> @@ -223,12 +223,12 @@ int max9271_enable_gpios(struct max9271_device *dev, u8 gpio_mask)
>  {
>  	int ret;
>  
> -	ret = max9271_read(dev, 0x0f);
> +	ret = max9271_read(dev, 0x0e);
>  	if (ret < 0)
>  		return 0;
>  
>  	/* BIT(0) reserved: GPO is always enabled. */
> -	ret |= gpio_mask | BIT(0);
> +	ret |= (gpio_mask & ~BIT(0));
>  	ret = max9271_write(dev, 0x0e, ret);
>  	if (ret < 0) {
>  		dev_err(&dev->client->dev, "Failed to enable gpio (%d)\n", ret);
> @@ -245,12 +245,12 @@ int max9271_disable_gpios(struct max9271_device *dev, u8 gpio_mask)
>  {
>  	int ret;
>  
> -	ret = max9271_read(dev, 0x0f);
> +	ret = max9271_read(dev, 0x0e);
>  	if (ret < 0)
>  		return 0;
>  
>  	/* BIT(0) reserved: GPO cannot be disabled */
> -	ret &= (~gpio_mask | BIT(0));
> +	ret &= ~(gpio_mask | BIT(0));
>  	ret = max9271_write(dev, 0x0e, ret);
>  	if (ret < 0) {
>  		dev_err(&dev->client->dev, "Failed to disable gpio (%d)\n", ret);
>