Thread (35 messages) 35 messages, 8 authors, 2018-01-09

[PATCH 01/11] clk: sunxi-ng: Don't set k if width is 0 for nkmp plls

From: maxime.ripard at free-electrons.com <hidden>
Date: 2018-01-04 14:25:34
Also in: dri-devel, linux-clk, linux-devicetree, lkml

Hi,

On Sat, Dec 30, 2017 at 10:01:53PM +0100, Jernej Skrabec wrote:
For example, A83T have nmp plls which are modelled as nkmp plls. Since k
is not specified, it has offset 0, shift 0 and lowest value 1. This
means that LSB bit is always set to 1, which may change clock rate.

Fix that by applying k factor only if k width is greater than 0.

Signed-off-by: Jernej Skrabec <redacted>
This looks fine...
quoted hunk ↗ jump to hunk
---
 drivers/clk/sunxi-ng/ccu_nkmp.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.c b/drivers/clk/sunxi-ng/ccu_nkmp.c
index e58c95787f94..709f528af2b3 100644
--- a/drivers/clk/sunxi-ng/ccu_nkmp.c
+++ b/drivers/clk/sunxi-ng/ccu_nkmp.c
@@ -81,7 +81,7 @@ static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,
 					unsigned long parent_rate)
 {
 	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
-	unsigned long n, m, k, p;
+	unsigned long n, m, k = 1, p;
 	u32 reg;
 
 	reg = readl(nkmp->common.base + nkmp->common.reg);
@@ -92,11 +92,13 @@ static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,
 	if (!n)
 		n++;
 
-	k = reg >> nkmp->k.shift;
-	k &= (1 << nkmp->k.width) - 1;
-	k += nkmp->k.offset;
-	if (!k)
-		k++;
+	if (nkmp->k.width) {
+		k = reg >> nkmp->k.shift;
+		k &= (1 << nkmp->k.width) - 1;
+		k += nkmp->k.offset;
+		if (!k)
+			k++;
+	}
... but could you add a comment there to explain why you're using a
different construct than the one used for the other factors?

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20180104/d66be374/attachment.sig>
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help