Re: [PATCH 1/3] clk: qcom: smd-rpm: Add rate hooks for clk_smd_rpm_branch_ops

On Tue, Sep 14, 2021 at 07:55:21PM -0700, Bjorn Andersson wrote:

On Mon 13 Sep 19:55 PDT 2021, Shawn Guo wrote:

quoted

On QCM2290 platform, the clock xo_board runs at 38400000, while the
child clock bi_tcxo needs to run at 19200000.  That said,
clk_smd_rpm_branch_ops needs the capability of setting rate. Add rate
hooks into clk_smd_rpm_branch_ops to make it possible.

Most platforms has a crystal oscillator ticking at 38.4MHz feeding the
PMIC (represented by the rpmcc and its "xo" parent) and out comes the
bi_tcxo with a fixed 19.2MHz rate.

Yeah, but all those platforms are running clk-rpmh driver, I think.

Is there a problem with the way sdm660_bi_tcxo is defined in this
regard?

There is no problem if xo clock is 19.2MHz, but for platforms with
38.4MHz xo, bi_tcxo will be seen as 38.4MHz in clock tree, while we
expect it to be 19.2MHz.

Shawn