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Date:   Thu, 15 Apr 2021 02:13:23 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc:     kieran.bingham+renesas@ideasonboard.com,
        niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 10/17] media: i2c: rdacm21: Power up OV10640 before
 OV490
Message-ID: <YHd3E+931vcmv/MS@pendragon.ideasonboard.com>
References: <20210412093451.14198-1-jacopo+renesas@jmondi.org>
 <20210412093451.14198-11-jacopo+renesas@jmondi.org>
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In-Reply-To: <20210412093451.14198-11-jacopo+renesas@jmondi.org>
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Hi Jacopo,

Thank you for the patch.

On Mon, Apr 12, 2021 at 11:34:44AM +0200, Jacopo Mondi wrote:
> The current RDACM21 initialization routine powers up the OV10640 image
> sensor after the OV490 ISP. The ISP is programmed with a firmare loaded
> from an embedded serial flash that (most probably) tries to interact and
> program also the image sensor connected to the ISP.
> 
> As described in commit ("media: i2c: rdacm21: Fix OV10640 powerup") the

s/[()]//g

> image sensor powerdown signal is kept high by an internal pull up
> resistor and occasionally fails to startup correctly if the powerdown
> line is not asserted explicitely. Failures in the OV10640 startup causes
> the OV490 firmware to fail to boot correctly resulting in the camera
> module initialization to fail consequentially.
> 
> Fix this by powering up the OV10640 image sensor before testing the
> OV490 firmware boot completion, by splitting the ov10640_initialize()
> function in an ov10640_power_up() one and an ov10640_check_id() one.
> 
> Also make sure the OV10640 identification procedure gives enough time to
> the image sensor to resume after the programming phase performed by the
> OV490 firmware by repeating the ID read procedure.
> 
> This commit fixes a sporadic start-up error triggered by a failure to
> detect the OV490 firmware boot completion:
> rdacm21 8-0054: Timeout waiting for firmware boot
> 
> Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module")
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/i2c/rdacm21.c | 46 ++++++++++++++++++++++++++-----------
>  1 file changed, 32 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> index 7c0a4a84340a..43c41cb800a4 100644
> --- a/drivers/media/i2c/rdacm21.c
> +++ b/drivers/media/i2c/rdacm21.c
> @@ -69,6 +69,7 @@
>  #define OV490_ISP_VSIZE_LOW		0x80820062
>  #define OV490_ISP_VSIZE_HIGH		0x80820063
>  
> +#define OV10640_PID_TIMEOUT		20
>  #define OV10640_ID_HIGH			0xa6
>  #define OV10640_CHIP_ID			0x300a
>  #define OV10640_PIXEL_RATE		55000000
> @@ -329,10 +330,8 @@ static const struct v4l2_subdev_ops rdacm21_subdev_ops = {
>  	.pad		= &rdacm21_subdev_pad_ops,
>  };
>  
> -static int ov10640_initialize(struct rdacm21_device *dev)
> +static void ov10640_power_up(struct rdacm21_device *dev)
>  {
> -	u8 val;
> -
>  	/* Enable GPIO0#0 (reset) and GPIO1#0 (pwdn) as output lines. */
>  	ov490_write_reg(dev, OV490_GPIO_SEL0, OV490_GPIO0);
>  	ov490_write_reg(dev, OV490_GPIO_SEL1, OV490_SPWDN0);
> @@ -347,18 +346,35 @@ static int ov10640_initialize(struct rdacm21_device *dev)
>  	usleep_range(1500, 3000);
>  	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
>  	usleep_range(3000, 5000);
> +}
>  
> -	/* Read OV10640 ID to test communications. */
> -	ov490_write_reg(dev, OV490_SCCB_SLAVE0_DIR, OV490_SCCB_SLAVE_READ);
> -	ov490_write_reg(dev, OV490_SCCB_SLAVE0_ADDR_HIGH, OV10640_CHIP_ID >> 8);
> -	ov490_write_reg(dev, OV490_SCCB_SLAVE0_ADDR_LOW, OV10640_CHIP_ID & 0xff);
> -
> -	/* Trigger SCCB slave transaction and give it some time to complete. */
> -	ov490_write_reg(dev, OV490_HOST_CMD, OV490_HOST_CMD_TRIGGER);
> -	usleep_range(1000, 1500);
> +static int ov10640_check_id(struct rdacm21_device *dev)
> +{
> +	unsigned int i;
> +	u8 val;
>  
> -	ov490_read_reg(dev, OV490_SCCB_SLAVE0_DIR, &val);
> -	if (val != OV10640_ID_HIGH) {
> +	/* Read OV10640 ID to test communications. */
> +	for (i = 0; i < OV10640_PID_TIMEOUT; ++i) {
> +		ov490_write_reg(dev, OV490_SCCB_SLAVE0_DIR,
> +				OV490_SCCB_SLAVE_READ);
> +		ov490_write_reg(dev, OV490_SCCB_SLAVE0_ADDR_HIGH,
> +				OV10640_CHIP_ID >> 8);
> +		ov490_write_reg(dev, OV490_SCCB_SLAVE0_ADDR_LOW,
> +				OV10640_CHIP_ID & 0xff);
> +
> +		/*
> +		 * Trigger SCCB slave transaction and give it some time
> +		 * to complete.
> +		 */
> +		ov490_write_reg(dev, OV490_HOST_CMD, OV490_HOST_CMD_TRIGGER);
> +		usleep_range(1000, 1500);
> +
> +		ov490_read_reg(dev, OV490_SCCB_SLAVE0_DIR, &val);
> +		if (val == OV10640_ID_HIGH)
> +			break;
> +		usleep_range(1000, 1500);
> +	}
> +	if (i == OV10640_PID_TIMEOUT) {
>  		dev_err(dev->dev, "OV10640 ID mismatch: (0x%02x)\n", val);
>  		return -ENODEV;
>  	}
> @@ -374,6 +390,8 @@ static int ov490_initialize(struct rdacm21_device *dev)
>  	unsigned int i;
>  	int ret;
>  
> +	ov10640_power_up(dev);
> +
>  	/*
>  	 * Read OV490 Id to test communications. Give it up to 40msec to
>  	 * exit from reset.
> @@ -411,7 +429,7 @@ static int ov490_initialize(struct rdacm21_device *dev)
>  		return -ENODEV;
>  	}
>  
> -	ret = ov10640_initialize(dev);
> +	ret = ov10640_check_id(dev);
>  	if (ret)
>  		return ret;
>  

-- 
Regards,

Laurent Pinchart