[BUG] drm/rockchip: vop2: uninitialized variables passed to ilog2 and writel

[BUG] drm/rockchip: vop2: uninitialized variables passed to ilog2 and writel

[Ahmad Fatoum]

Hi,

Running clang-analyzer[1] on the VOP2 driver in barebox[2], which was ported
from Linux reports that following variables:

  dclk_out_div, if_pixclk_div, if_dclk_div

defined in rk3588_set_intf_mux() and passed to rk3588_calc_cru_cfg()
are given as uninitialized arguments to ilog2() and in some cases even
used afterwards unconditionally (outside of error cases):

  - dclk_out_div: is not initialized in the HDMI, eDP and DPI cases,
    but is passed to ilog2 unconditionally and the result is written
    into the RK3588_VP_CLK_CTRL register

  - if_pixclk_div: is not initialized in the DP and DPI cases,
    but is passed to ilog2 unconditionally.
    However, the result seems unused.

  - if_clk_div: is not initialized in the DP, MIPI and DPI cases,
    but is passed to ilog2 unconditionally.
    However, the result seems unused.

I checked against Linux v6.14-rc6.

I am not fully sure what a suitable default value would be for the first
case, which is why I report this without a patch.

[1]: https://lore.kernel.org/barebox/20250313080950.3222757-1-a.fatoum@pengutronix.de/T/#m78ca98c01b73ef7fe3316e73ce62cfe4b2c111d0
[2]: https://github.com/barebox/barebox/blob/v2025.02.0/drivers/video/rockchip/rockchip_drm_vop2.c

Thanks,
Ahmad
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