[PATCH v24 11/15] media: qcom: camss: tpg: Add support for v2.4.0 TPG

[sashiko-bot at kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] media: qcom: camss: uninitialized hw_version check in tpg_reset()
--

commit ea18d39e5144ca1e8d628aa5ab708e84983e10a3
Author: Hangxiang Ma <hangxiang.ma at oss.qualcomm.com>

media: qcom: camss: tpg: Add support for v2.4.0 TPG

This commit adds support for TPG hardware version 2.4.0 on Kaanapali,
controlling test-enable and hardware reset via the TPG_CTRL_CMD register and
routing the TPG output into CSID 1080 RX through the CSI2 TPG mux.

> diff --git a/drivers/media/platform/qcom/camss/camss-tpg-gen1.c b/drivers/media/platform/qcom/camss/camss-tpg-gen1.c
> index d29de5f93c18e..cabbb2638cf38 100644
> --- a/drivers/media/platform/qcom/camss/camss-tpg-gen1.c
> +++ b/drivers/media/platform/qcom/camss/camss-tpg-gen1.c

[ ... ]

> @@ -164,18 +167,26 @@ static int tpg_stream_on(struct tpg_device *tpg)

[ ... ]

>  static int tpg_reset(struct tpg_device *tpg)
>  {
> -	writel(0, tpg->base + TPG_CTRL);
> -	writel(1, tpg->base + TPG_CLEAR);
> +	if (tpg->hw_version < TPG_HW_VER_2_4_0)
> +		writel(0, tpg->base + TPG_CTRL);

[Severity: Medium]
As reported by Sashiko on v17 [1], is tpg->hw_version initialized when
tpg_reset() is called for the first time from tpg_set_power()?

In drivers/media/platform/qcom/camss/camss-tpg.c, tpg_set_power() calls
reset() before hw_version() populates tpg->hw_version from the
TPG_HW_VERSION register:

drivers/media/platform/qcom/camss/camss-tpg.c:tpg_set_power() {
	...
		tpg->res->hw_ops->reset(tpg);

		tpg->res->hw_ops->hw_version(tpg);
	...
}

On the first power-on after probe, tpg->hw_version is still 0, so
tpg->hw_version < TPG_HW_VER_2_4_0 evaluates to true and tpg_reset() writes
0 to TPG_CTRL even on v2.4.0 hardware. Should tpg_set_power() call
hw_version(tpg) before reset(tpg), or should tpg_reset() read the version if
needed?

[1] https://lore.kernel.org/r/20260929061248.E035C1F000FF@smtp.kernel.org

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261102-kaanapali-camss-v24-0-d6b8f3f6f66f@oss.qualcomm.com?part=11