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Subject: Re: [PATCH v8 1/5] media: i2c: Add driver for RDACM21 camera module
To:     Jacopo Mondi <jacopo+renesas@jmondi.org>,
        kieran.bingham+renesas@ideasonboard.com,
        laurent.pinchart+renesas@ideasonboard.com,
        niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org
Cc:     linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Hyun Kwon <hyunk@xilinx.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
        sergei.shtylyov@gmail.com,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>
References: <20210114170429.139762-1-jacopo+renesas@jmondi.org>
 <20210114170429.139762-2-jacopo+renesas@jmondi.org>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <c5fc0815-7754-1fac-af0a-ccbca922e479@xs4all.nl>
Date:   Mon, 8 Feb 2021 12:28:52 +0100
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Hi Jacopo,

On 14/01/2021 18:04, Jacopo Mondi wrote:
> The RDACM21 is a GMSL camera supporting 1280x1080 resolution images
> developed by IMI based on an Omnivision OV10640 sensor, an Omnivision
> OV490 ISP and a Maxim MAX9271 GMSL serializer.
> 
> The driver uses the max9271 library module, to maximize code reuse with
> other camera module drivers using the same serializer, such as rdacm20.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
>  MAINTAINERS                 |  12 +
>  drivers/media/i2c/Kconfig   |  13 +
>  drivers/media/i2c/Makefile  |   2 +
>  drivers/media/i2c/rdacm21.c | 623 ++++++++++++++++++++++++++++++++++++
>  4 files changed, 650 insertions(+)
>  create mode 100644 drivers/media/i2c/rdacm21.c
> 

<snip>

> diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c
> new file mode 100644
> index 000000000000..dcc21515e5a4
> --- /dev/null
> +++ b/drivers/media/i2c/rdacm21.c

<snip>

> +static int ov10640_initialize(struct rdacm21_device *dev)
> +{
> +	u8 val;
> +
> +	/* Power-up OV10640 by setting RESETB and PWDNB pins high. */
> +	ov490_write_reg(dev, OV490_GPIO_SEL0, OV490_GPIO0);
> +	ov490_write_reg(dev, OV490_GPIO_SEL1, OV490_SPWDN0);
> +	ov490_write_reg(dev, OV490_GPIO_DIRECTION0, OV490_GPIO0);
> +	ov490_write_reg(dev, OV490_GPIO_DIRECTION1, OV490_SPWDN0);
> +	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_GPIO0);
> +	ov490_write_reg(dev, OV490_GPIO_OUTPUT_VALUE0, OV490_SPWDN0);
> +	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, (u8)OV10640_CHIP_ID);

This line results in a sparse warning:

drivers/media/i2c/rdacm21.c:348:62: warning: cast truncates bits from constant value (300a becomes a)

Just replace with OV10640_CHIP_ID & 0xff.

Regards,

	Hans