[PATCH v2 3/3] clk: mediatek: mt7988: use MUX_CLR_SET for gate-less muxes

[Chen-Yu Tsai]

On Thu, Mar 26, 2026 at 1:11 PM Daniel Golle <daniel at makrotopia.org> wrote:
>
> All 19 muxes in the infra_muxes[] array are pure mux selectors without
> a clock gate or update register, yet they were defined using
> MUX_GATE_CLR_SET_UPD with gate_shift = -1.
>
> This macro assigns mtk_mux_gate_clr_set_upd_ops, whose
> enable/disable/is_enabled callbacks perform BIT(gate_shift). Since
> gate_shift is stored as u8, the -1 truncates to 255, causing a
> shift-out-of-bounds at runtime:
>
> UBSAN: shift-out-of-bounds in drivers/clk/mediatek/clk-mux.c:76:8
> shift exponent 255 is too large for 64-bit type 'long unsigned int'
>
> UBSAN: shift-out-of-bounds in drivers/clk/mediatek/clk-mux.c:102:4
> shift exponent 255 is too large for 64-bit type 'long unsigned int'
>
> UBSAN: shift-out-of-bounds in drivers/clk/mediatek/clk-mux.c:122:16
> shift exponent 255 is too large for 64-bit type 'long unsigned int'
>
> Switch these definitions to MUX_CLR_SET, which uses
> mtk_mux_clr_set_upd_ops (no gate callbacks) and does not require
> callers to pass sentinel values for unused update register fields.
> The actual clock gating for these peripherals is handled by the
> separate GATE_INFRA* definitions further down.
>
> Fixes: 4b4719437d85f ("clk: mediatek: add drivers for MT7988 SoC")
> Signed-off-by: Daniel Golle <daniel at makrotopia.org>

Reviewed-by: Chen-Yu Tsai <wenst at chromium.org>