clk: qcom: Allow constant ratio freq tables for rcg

[ Upstream commit efd164b5520afd6fb2883b68e0d408a7de29c491 ]

Some RCGs (the gfx_3d_src_clk in msm8998 for example) are basically just
some constant ratio from the input across the entire frequency range.  It
would be great if we could specify the frequency table as a single entry
constant ratio instead of a long list, ie:

	{ .src = P_GPUPLL0_OUT_EVEN, .pre_div = 3 },
        { }

So, lets support that.

We need to fix a corner case in qcom_find_freq() where if the freq table
is non-null, but has no frequencies, we end up returning an "entry" before
the table array, which is bad.  Then, we need ignore the freq from the
table, and instead base everything on the requested freq.

Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Link: https://lkml.kernel.org/r/20191031185715.15504-1-jeffrey.l.hugo@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index b98b81ef43a14aad0759a3661966893fc757e244..5a89ed88cc27a9c2548cf2769ac85153726de820 100644 (file)
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -220,6 +220,8 @@ static int _freq_tbl_determine_rate(struct clk_hw *hw, const struct freq_tbl *f,
        if (clk_flags & CLK_SET_RATE_PARENT) {
                rate = f->freq;
                if (f->pre_div) {
+                       if (!rate)
+                               rate = req->rate;
                        rate /= 2;
                        rate *= f->pre_div + 1;
                }

diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index 28ddc747d703520f28fb8beed57a23aacee97f08..bdeacebbf0e470f1df16c5c25e0f5f365512f800 100644 (file)
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -29,6 +29,9 @@ struct freq_tbl *qcom_find_freq(const struct freq_tbl *f, unsigned long rate)
        if (!f)
                return NULL;
 
+       if (!f->freq)
+               return f;
+
        for (; f->freq; f++)
                if (rate <= f->freq)
                        return f;