clk: composite: allow fixed rates & fixed dividers

The composite clock assumes that any clock implementing the .recalc_rate
callback will also implement .round_rate and .set_rate.  This is not
always true; the basic fixed-rate clock will only implement .recalc_rate
and a fixed-divider clock may choose to implement .recalc_rate and
.round_rate but not .set_rate.

Fix this by conditionally registering .round_rate and .set_rate
callbacks based on the rate_ops passed in to clk_composite_register.

Signed-off-by: Mike Turquette <mturquette@linaro.org>
Cc: Prashant Gaikwad <pgaikwad@nvidia.com>
Tested-by: Emilio López <emilio@elopez.com.ar>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/clk/clk-composite.c b/drivers/clk/clk-composite.c
index 6f4728c6dbd1..a33f46f20a41 100644
--- a/drivers/clk/clk-composite.c
+++ b/drivers/clk/clk-composite.c
@@ -150,17 +150,26 @@ struct clk *clk_register_composite(struct device *dev, const char *name,
         }
 
         if (rate_hw && rate_ops) {
-                if (!rate_ops->recalc_rate || !rate_ops->round_rate ||
-                    !rate_ops->set_rate) {
+                if (!rate_ops->recalc_rate) {
                         clk = ERR_PTR(-EINVAL);
                         goto err;
                 }
 
+                /* .round_rate is a prerequisite for .set_rate */
+                if (rate_ops->round_rate) {
+                        clk_composite_ops->round_rate = clk_composite_round_rate;
+                        if (rate_ops->set_rate) {
+                                clk_composite_ops->set_rate = clk_composite_set_rate;
+                        }
+                } else {
+                        WARN(rate_ops->set_rate,
+                                "%s: missing round_rate op is required\n",
+                                __func__);
+                }
+
                 composite->rate_hw = rate_hw;
                 composite->rate_ops = rate_ops;
                 clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
-                clk_composite_ops->round_rate = clk_composite_round_rate;
-                clk_composite_ops->set_rate = clk_composite_set_rate;
         }
 
         if (gate_hw && gate_ops) {