[PATCH v3 02/25] clk: sunxi-ng: Add check for minimal rate to NKM PLLs

[Jagan Teki]

Some NKM PLLs doesn't work well when their output clock rate is set below
certain rate.

So, add support for minimal rate for relevant PLLs.

Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Tested-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
---
Changes for v3:
- collect Stephen Ack
- add tested credit
Changes for v2:
- none

 drivers/clk/sunxi-ng/ccu_nkm.c | 7 +++++++
 drivers/clk/sunxi-ng/ccu_nkm.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index 841840e35e61..d17539dc88dd 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -125,6 +125,13 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate *= nkm->fixed_post_div;
 
+	if (rate < nkm->min_rate) {
+		rate = nkm->min_rate;
+		if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+			rate /= nkm->fixed_post_div;
+		return rate;
+	}
+
 	ccu_nkm_find_best(*parent_rate, rate, &_nkm);
 
 	rate = *parent_rate * _nkm.n * _nkm.k / _nkm.m;
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
index cc6efb70a102..ff5bd00f429f 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.h
+++ b/drivers/clk/sunxi-ng/ccu_nkm.h
@@ -35,6 +35,7 @@ struct ccu_nkm {
 	struct ccu_mux_internal	mux;
 
 	unsigned int		fixed_post_div;
+	unsigned int		min_rate;
 
 	struct ccu_common	common;
 };
-- 
2.18.0.321.gffc6fa0e3