Before XO refclk is distributed to PCIe/USB/eDP PHYs, it passes through
a QREF block. QREF is powered by dedicated LDO rails, and the clkref_en
register controls whether refclk is gated through to the PHY side.
These clkref controls are different from typical GCC branch clocks:
- only a single enable bit is present, without branch-style config bits
- regulators must be voted before enable and unvoted after disable
Model this as a dedicated clk_ref clock type with custom clk_ops instead
of reusing struct clk_branch semantics.
Also provide a common registration/probe API so the same clkref model
can be reused regardless of where clkref_en registers are placed, e.g.
TCSR on glymur and TLMM on SM8750.
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Qiang Yu <qiang.yu@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260721-tcsr_qre_0721-v10-3-d2fa68c63b78@oss.qualcomm.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
