From b15ee490e16324c35b51f04bad54ae45a2cefd29 Mon Sep 17 00:00:00 2001 From: Jerome Brunet Date: Wed, 14 Feb 2018 14:43:39 +0100 Subject: [PATCH] clk: divider: read-only divider can propagate rate change 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: e6d5e7d90be9 ("clk-divider: Fix READ_ONLY when divider > 1") Signed-off-by: Jerome Brunet Tested-By: David Lechner Signed-off-by: Michael Turquette Signed-off-by: Stephen Boyd --- drivers/clk/clk-divider.c | 36 ++++++++++++++++++++++++++++++------ include/linux/clk-provider.h | 15 +++++++++++++++ 2 files changed, 45 insertions(+), 6 deletions(-) diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index 3c98d2650fa3..b6234a5da12d 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -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, diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index cb18526d69cb..210a890008f9 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -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 */ -- 2.20.1