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clk: divider: read-only divider can propagate rate change

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When a divider clock has CLK_DIVIDER_READ_ONLY set, it means that the
register shall be left un-touched, but it does not mean the clock
should stop rate propagation if CLK_SET_RATE_PARENT is set

This is properly handled in qcom clk-regmap-divider but it was not in
the generic divider

To fix this situation, introduce a new helper function
divider_ro_round_rate, on the same model as divider_round_rate.

Fixes: e6d5e7d90b ("clk-divider: Fix READ_ONLY when divider > 1")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Tested-By: David Lechner <david@lechnology.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Jerome Brunet 2018-02-14 14:43:39 +01:00 committed by Stephen Boyd
parent fe3f338f0c
commit b15ee490e1
2 changed files with 45 additions and 6 deletions
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36
drivers/clk/clk-divider.c
View file

@ -342,19 +342,43 @@ long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
}
EXPORT_SYMBOL_GPL(divider_round_rate_parent);
long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate, unsigned long *prate,
const struct clk_div_table *table, u8 width,
unsigned long flags, unsigned int val)
{
int div;
div = _get_div(table, val, flags, width);
/* Even a read-only clock can propagate a rate change */
if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
if (!parent)
return -EINVAL;
*prate = clk_hw_round_rate(parent, rate * div);
}
return DIV_ROUND_UP_ULL((u64)*prate, div);
}
EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_divider *divider = to_clk_divider(hw);
int bestdiv;
/* if read only, just return current value */
if (divider->flags & CLK_DIVIDER_READ_ONLY) {
bestdiv = clk_readl(divider->reg) >> divider->shift;
bestdiv &= clk_div_mask(divider->width);
bestdiv = _get_div(divider->table, bestdiv, divider->flags,
divider->width);
return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
u32 val;
val = clk_readl(divider->reg) >> divider->shift;
val &= clk_div_mask(divider->width);
return divider_ro_round_rate(hw, rate, prate, divider->table,
divider->width, divider->flags,
val);
}
return divider_round_rate(hw, rate, prate, divider->table,

15
include/linux/clk-provider.h
View file

@ -420,6 +420,10 @@ long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate, unsigned long *prate,
const struct clk_div_table *table,
u8 width, unsigned long flags);
long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
unsigned long rate, unsigned long *prate,
const struct clk_div_table *table, u8 width,
unsigned long flags, unsigned int val);
int divider_get_val(unsigned long rate, unsigned long parent_rate,
const struct clk_div_table *table, u8 width,
unsigned long flags);
@ -780,6 +784,17 @@ static inline long divider_round_rate(struct clk_hw *hw, unsigned long rate,
rate, prate, table, width, flags);
}
static inline long divider_ro_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate,
const struct clk_div_table *table,
u8 width, unsigned long flags,
unsigned int val)
{
return divider_ro_round_rate_parent(hw, clk_hw_get_parent(hw),
rate, prate, table, width, flags,
val);
}
/*
* FIXME clock api without lock protection
*/