Re: [PATCH v5 2/2] media: i2c: hm1092: add Himax HM1092 mono NIR sensor driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Unnecessary device power-on sequence in probe() introduces a ~22ms boot delay per camera with no functional benefit.
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--- Patch [2]: [PATCH v5 2/2] media: i2c: hm1092: add Himax HM1092 mono NIR sensor driver ---
commit 4abd5da551efe32eec434d2e88b53c45de5fc3dc
Author: Ramshouriesh R <rshouriesh@gmail.com>

media: i2c: hm1092: add Himax HM1092 mono NIR sensor driver

Add a V4L2 subdev driver for the Himax HM1092 monochrome near-infrared
image sensor. The driver supports the sensor's native 560x360 10-bit mono
mode, test patterns, and standard fwnode properties.

> diff --git a/drivers/media/i2c/hm1092.c b/drivers/media/i2c/hm1092.c
> new file mode 100644
> index 0000000000000..c7cde6928bb91
> --- /dev/null
> +++ b/drivers/media/i2c/hm1092.c

[ ... ]

> +static int hm1092_probe(struct i2c_client *client)
> +{
> +	struct hm1092 *hm1092;
> +	unsigned long freq;
> +	int ret;

[ ... ]

> +	hm1092->regmap = devm_cci_regmap_init_i2c(client, 16);
> +	if (IS_ERR(hm1092->regmap))
> +		return PTR_ERR(hm1092->regmap);
> +
> +	ret = hm1092_power_on(hm1092->dev);
> +	if (ret)
> +		return dev_err_probe(hm1092->dev, ret, "failed to power on\n");

[Severity: Medium]
Does this driver need to power on the sensor during probe?

Looking at hm1092_power_on(), the sequence introduces ~22ms of sleep delays
to bring up regulators and clocks. However, there doesn't appear to be any
I2C communication (such as reading a hardware ID register to verify the chip
is present) that follows in the hm1092_probe() function.

Since the device is just powered on and then immediately idled and suspended
shortly after via pm_runtime_idle(), could this power-on step be deferred
entirely to runtime PM or streaming initialization to avoid the boot delay?

> +
> +	ret = hm1092_init_controls(hm1092);
> +	if (ret)
> +		goto err_power_off;

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Sashiko AI review · https://sashiko.dev/#/patchset/20260709-hm1092-driver-v5-0-a1f5baa6fe08@gmail.com?part=2