clk: qcom: Add rcg ops to return floor value closest to the requested rate

The default behaviour with clk_rcg2_ops is for the
clk_round_rate()/clk_set_rate() to return/set a ceil clock
rate closest to the requested rate by looking up the corresponding
frequency table.
However, we do have some instances (mainly sdcc on various platforms)
of clients expecting a clk_set_rate() to set a floor value instead.
Add a new clk_rcg2_floor_ops to handle this for such specific
rcg instances

Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 16 insertions, 0 deletions

diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index 94569f461ba7..cfab7b400381 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -46,6 +46,22 @@ struct freq_tbl *qcom_find_freq(const struct freq_tbl *f, unsigned long rate)
 }
 EXPORT_SYMBOL_GPL(qcom_find_freq);
 
+const struct freq_tbl *qcom_find_freq_floor(const struct freq_tbl *f,
+					    unsigned long rate)
+{
+	const struct freq_tbl *best = NULL;
+
+	for ( ; f->freq; f++) {
+		if (rate >= f->freq)
+			best = f;
+		else
+			break;
+	}
+
+	return best;
+}
+EXPORT_SYMBOL_GPL(qcom_find_freq_floor);
+
 int qcom_find_src_index(struct clk_hw *hw, const struct parent_map *map, u8 src)
 {
 	int i, num_parents = clk_hw_get_num_parents(hw);