linux-kernel - Re: [PATCH v1 3/5] drivers: media: bcm2835-unicam: Disable trigger mode operation

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Message-ID: <qylnmgwawjmzuzkawku7ti6orj4a7ju6bckie25ion5ii5satz@slyawn2rm7gm>
Date: Fri, 22 Nov 2024 12:18:11 +0100
From: Jacopo Mondi <jacopo.mondi@...asonboard.com>
To: Naushir Patuck <naush@...pberrypi.com>
Cc: Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>, 
	Mauro Carvalho Chehab <mchehab@...nel.org>, Florian Fainelli <florian.fainelli@...adcom.com>, 
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>, Ray Jui <rjui@...adcom.com>, 
	Scott Branden <sbranden@...adcom.com>, linux-media@...r.kernel.org, 
	linux-rpi-kernel@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, jacopo.mondi@...asonboard.com, 
	Dave Stevenson <dave.stevenson@...pberrypi.com>
Subject: Re: [PATCH v1 3/5] drivers: media: bcm2835-unicam: Disable trigger
 mode operation

Hi Naush

On Fri, Nov 22, 2024 at 08:41:50AM +0000, Naushir Patuck wrote:
> The imx219/imx708 sensors frequently generate a single corrupt frame
> (image or embedded data) when the sensor first starts. This can either
> be a missing line, or invalid samples within the line. This only occurrs
> using the upstream Unicam kernel driver.

I think the last statement can b dropped.

>
> Disabling trigger mode elimiates this corruption. Since trigger mode is
> a legacy feature copied from the firmware driver and not expected to be
> needed, remove it. Tested on the Raspberry Pi cameras and shows no ill
> effects.
>
> Signed-off-by: Naushir Patuck <naush@...pberrypi.com>

Reviewed-by: Jacopo Mondi <jacopo.mondi@...asonboard.com>

Thanks
  j

> ---
>  drivers/media/platform/broadcom/bcm2835-unicam.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/drivers/media/platform/broadcom/bcm2835-unicam.c b/drivers/media/platform/broadcom/bcm2835-unicam.c
> index d573d4d89881..550eb1b064f1 100644
> --- a/drivers/media/platform/broadcom/bcm2835-unicam.c
> +++ b/drivers/media/platform/broadcom/bcm2835-unicam.c
> @@ -834,11 +834,6 @@ static irqreturn_t unicam_isr(int irq, void *dev)
>  		}
>  	}
>
> -	if (unicam_reg_read(unicam, UNICAM_ICTL) & UNICAM_FCM) {
> -		/* Switch out of trigger mode if selected */
> -		unicam_reg_write_field(unicam, UNICAM_ICTL, 1, UNICAM_TFC);
> -		unicam_reg_write_field(unicam, UNICAM_ICTL, 0, UNICAM_FCM);
> -	}
>  	return IRQ_HANDLED;
>  }
>
> @@ -1002,8 +997,7 @@ static void unicam_start_rx(struct unicam_device *unicam,
>
>  	unicam_reg_write_field(unicam, UNICAM_ANA, 0, UNICAM_DDL);
>
> -	/* Always start in trigger frame capture mode (UNICAM_FCM set) */
> -	val = UNICAM_FSIE | UNICAM_FEIE | UNICAM_FCM | UNICAM_IBOB;
> +	val = UNICAM_FSIE | UNICAM_FEIE | UNICAM_IBOB;
>  	line_int_freq = max(fmt->height >> 2, 128);
>  	unicam_set_field(&val, line_int_freq, UNICAM_LCIE_MASK);
>  	unicam_reg_write(unicam, UNICAM_ICTL, val);
> --
> 2.34.1
>
>