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From d46285327ba5961c992643d468b2862c70f4c7e5 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Thu, 2 May 2019 15:24:04 -0700
Subject: [PATCH] clk: bcm2835: Allow reparenting leaf clocks while
they're running.
This falls under the same "we can reprogram glitch-free as long as we
pause generation" rule as updating the div/frac fields. This can be
used for runtime reclocking of V3D to manage power leakage.
Signed-off-by: Eric Anholt <eric@anholt.net>
---
drivers/clk/bcm/clk-bcm2835.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1086,8 +1086,10 @@ static int bcm2835_clock_on(struct clk_h
return 0;
}
-static int bcm2835_clock_set_rate(struct clk_hw *hw,
- unsigned long rate, unsigned long parent_rate)
+static int bcm2835_clock_set_rate_and_parent(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate,
+ u8 parent)
{
struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
struct bcm2835_cprman *cprman = clock->cprman;
@@ -1109,6 +1111,11 @@ static int bcm2835_clock_set_rate(struct
bcm2835_clock_wait_busy(clock);
}
+ if (parent != 0xff) {
+ ctl &= ~(CM_SRC_MASK << CM_SRC_SHIFT);
+ ctl |= parent << CM_SRC_SHIFT;
+ }
+
ctl &= ~CM_FRAC;
ctl |= (div & CM_DIV_FRAC_MASK) ? CM_FRAC : 0;
cprman_write(cprman, data->ctl_reg, ctl);
@@ -1120,6 +1127,12 @@ static int bcm2835_clock_set_rate(struct
return 0;
}
+static int bcm2835_clock_set_rate(struct clk_hw *hw,
+ unsigned long rate, unsigned long parent_rate)
+{
+ return bcm2835_clock_set_rate_and_parent(hw, rate, parent_rate, 0xff);
+}
+
static bool
bcm2835_clk_is_pllc(struct clk_hw *hw)
{
@@ -1303,6 +1316,7 @@ static const struct clk_ops bcm2835_cloc
.unprepare = bcm2835_clock_off,
.recalc_rate = bcm2835_clock_get_rate,
.set_rate = bcm2835_clock_set_rate,
+ .set_rate_and_parent = bcm2835_clock_set_rate_and_parent,
.determine_rate = bcm2835_clock_determine_rate,
.set_parent = bcm2835_clock_set_parent,
.get_parent = bcm2835_clock_get_parent,
@@ -1479,7 +1493,6 @@ static struct clk_hw *bcm2835_register_c
init.ops = &bcm2835_vpu_clock_clk_ops;
} else {
init.ops = &bcm2835_clock_clk_ops;
- init.flags |= CLK_SET_PARENT_GATE;
/* If the clock wasn't actually enabled at boot, it's not
* critical.
|
