openwrt/target/linux/ipq806x/patches-3.18/130-clk_mux-Fix-set_parent-doing-the-wrong-thing-when-IN.patch
John Crispin 8e49b4b902 ipq806x: add & enable cpufreq support
This change set enables frequency scaling on ipq806x, which speeds-up
the CPU and allows it to achieve its max frequency.

These patches are cherry-picked & backported from the following location:
*130-132: linux-next
*133-143: LKML - https://lkml.org/lkml/2015/3/21/15
*144: derived from other qcom similar dts
*145: derived from https://chromium.googlesource.com/chromiumos/third_party/kernel/+/chromeos-3.14/drivers/cpufreq/cpufreq-krait.c

Signed-off-by: Mathieu Olivari <mathieu@codeaurora.org>

SVN-Revision: 45730
2015-05-23 15:28:02 +00:00

61 lines
1.7 KiB
Diff

From 6793b3cd5da817c4be218bd8632f07cf4d2b0d26 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Wed, 19 Nov 2014 14:48:59 +0100
Subject: [PATCH] clk_mux: Fix set_parent doing the wrong thing when INDEX_BIT
&& index >= 3
If CLK_MUX_INDEX_BIT is set, then each bit turns on / off a single parent,
so theoretically multiple parents could be enabled at the same time, but in
practice only one bit should ever be 1. So to select parent 0, set
the register (*) to 0x01, to select parent 1 set it 0x02, parent 2, 0x04,
parent 3, 0x08, etc.
But the current code does:
if (mux->flags & CLK_MUX_INDEX_BIT)
index = (1 << ffs(index));
Which means that:
For an input index of 0, ffs returns 0, so we set the register
to 0x01, ok.
For an input index of 1, ffs returns 1, so we set the register
to 0x02, ok.
For an input index of 2, ffs returns 2, so we set the register
to 0x04, ok.
For an input index of 3, ffs returns 1, so we set the register
to 0x02, not good!
The code should simply be:
if (mux->flags & CLK_MUX_INDEX_BIT)
index = 1 << index;
Which always does the right thing, this commit fixes this.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
---
drivers/clk/clk-mux.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/clk/clk-mux.c b/drivers/clk/clk-mux.c
index 4f96ff3..6e1ecf9 100644
--- a/drivers/clk/clk-mux.c
+++ b/drivers/clk/clk-mux.c
@@ -77,7 +77,7 @@ static int clk_mux_set_parent(struct clk_hw *hw, u8 index)
else {
if (mux->flags & CLK_MUX_INDEX_BIT)
- index = (1 << ffs(index));
+ index = 1 << index;
if (mux->flags & CLK_MUX_INDEX_ONE)
index++;
--
2.1.4