Patch "clk: qcom: Allow constant ratio freq tables for rcg" has been added to the 4.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    clk: qcom: Allow constant ratio freq tables for rcg

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-qcom-allow-constant-ratio-freq-tables-for-rcg.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c16326e33ae66f495ac365f93ece800bf7abf93b
Author: Jeffrey Hugo <jeffrey.l.hugo@xxxxxxxxx>
Date:   Thu Oct 31 11:57:15 2019 -0700

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

diff --git a/drivers/clk/qcom/clk-rcg2.c b/drivers/clk/qcom/clk-rcg2.c
index a071bba8018c..0ae1b0a66eb5 100644
--- a/drivers/clk/qcom/clk-rcg2.c
+++ b/drivers/clk/qcom/clk-rcg2.c
@@ -196,6 +196,8 @@ static int _freq_tbl_determine_rate(struct clk_hw *hw,
 	p = clk_hw_get_parent_by_index(hw, index);
 	if (clk_flags & CLK_SET_RATE_PARENT) {
 		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 fffcbaf0fba7..f89a9f0aa606 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -37,6 +37,9 @@ 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;