linux-stable/drivers/clk/actions/owl-composite.c
Maxime Ripard 939b61f67e clk: actions: composite: fact: Switch to determine_rate
The Actions composite factor clocks implements a mux with a set_parent
hook, but doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidate to
trigger that parent change is a call to clk_set_rate(), with
determine_rate() figuring out which parent is the best suited for a
given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The driver does implement round_rate() though, which means that we can
change the rate of the clock, but we will never get to change the
parent.

However, It's hard to tell whether it's been done on purpose or not.

Since we'll start mandating a determine_rate() implementation, let's
convert the round_rate() implementation to a determine_rate(), which
will also make the current behavior explicit. And if it was an
oversight, the clock behaviour can be adjusted later on.

Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: linux-actions@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-48-971d5077e7d2@cerno.tech
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2023-06-08 18:39:32 -07:00

212 lines
5.2 KiB
C

// SPDX-License-Identifier: GPL-2.0+
//
// OWL composite clock driver
//
// Copyright (c) 2014 Actions Semi Inc.
// Author: David Liu <liuwei@actions-semi.com>
//
// Copyright (c) 2018 Linaro Ltd.
// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include "owl-composite.h"
static u8 owl_comp_get_parent(struct clk_hw *hw)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_mux_helper_get_parent(&comp->common, &comp->mux_hw);
}
static int owl_comp_set_parent(struct clk_hw *hw, u8 index)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_mux_helper_set_parent(&comp->common, &comp->mux_hw, index);
}
static void owl_comp_disable(struct clk_hw *hw)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
struct owl_clk_common *common = &comp->common;
owl_gate_set(common, &comp->gate_hw, false);
}
static int owl_comp_enable(struct clk_hw *hw)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
struct owl_clk_common *common = &comp->common;
owl_gate_set(common, &comp->gate_hw, true);
return 0;
}
static int owl_comp_is_enabled(struct clk_hw *hw)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
struct owl_clk_common *common = &comp->common;
return owl_gate_clk_is_enabled(common, &comp->gate_hw);
}
static int owl_comp_div_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
long rate;
rate = owl_divider_helper_round_rate(&comp->common, &comp->rate.div_hw,
req->rate, &req->best_parent_rate);
if (rate < 0)
return rate;
req->rate = rate;
return 0;
}
static unsigned long owl_comp_div_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_divider_helper_recalc_rate(&comp->common, &comp->rate.div_hw,
parent_rate);
}
static int owl_comp_div_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_divider_helper_set_rate(&comp->common, &comp->rate.div_hw,
rate, parent_rate);
}
static int owl_comp_fact_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
long rate;
rate = owl_factor_helper_round_rate(&comp->common,
&comp->rate.factor_hw,
req->rate, &req->best_parent_rate);
if (rate < 0)
return rate;
req->rate = rate;
return 0;
}
static unsigned long owl_comp_fact_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_factor_helper_recalc_rate(&comp->common,
&comp->rate.factor_hw,
parent_rate);
}
static int owl_comp_fact_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
return owl_factor_helper_set_rate(&comp->common,
&comp->rate.factor_hw,
rate, parent_rate);
}
static long owl_comp_fix_fact_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
struct clk_fixed_factor *fix_fact_hw = &comp->rate.fix_fact_hw;
return comp->fix_fact_ops->round_rate(&fix_fact_hw->hw, rate, parent_rate);
}
static unsigned long owl_comp_fix_fact_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct owl_composite *comp = hw_to_owl_comp(hw);
struct clk_fixed_factor *fix_fact_hw = &comp->rate.fix_fact_hw;
return comp->fix_fact_ops->recalc_rate(&fix_fact_hw->hw, parent_rate);
}
static int owl_comp_fix_fact_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
/*
* We must report success but we can do so unconditionally because
* owl_comp_fix_fact_round_rate returns values that ensure this call is
* a nop.
*/
return 0;
}
const struct clk_ops owl_comp_div_ops = {
/* mux_ops */
.get_parent = owl_comp_get_parent,
.set_parent = owl_comp_set_parent,
/* gate_ops */
.disable = owl_comp_disable,
.enable = owl_comp_enable,
.is_enabled = owl_comp_is_enabled,
/* div_ops */
.determine_rate = owl_comp_div_determine_rate,
.recalc_rate = owl_comp_div_recalc_rate,
.set_rate = owl_comp_div_set_rate,
};
const struct clk_ops owl_comp_fact_ops = {
/* mux_ops */
.get_parent = owl_comp_get_parent,
.set_parent = owl_comp_set_parent,
/* gate_ops */
.disable = owl_comp_disable,
.enable = owl_comp_enable,
.is_enabled = owl_comp_is_enabled,
/* fact_ops */
.determine_rate = owl_comp_fact_determine_rate,
.recalc_rate = owl_comp_fact_recalc_rate,
.set_rate = owl_comp_fact_set_rate,
};
const struct clk_ops owl_comp_fix_fact_ops = {
/* gate_ops */
.disable = owl_comp_disable,
.enable = owl_comp_enable,
.is_enabled = owl_comp_is_enabled,
/* fix_fact_ops */
.round_rate = owl_comp_fix_fact_round_rate,
.recalc_rate = owl_comp_fix_fact_recalc_rate,
.set_rate = owl_comp_fix_fact_set_rate,
};
const struct clk_ops owl_comp_pass_ops = {
/* mux_ops */
.determine_rate = clk_hw_determine_rate_no_reparent,
.get_parent = owl_comp_get_parent,
.set_parent = owl_comp_set_parent,
/* gate_ops */
.disable = owl_comp_disable,
.enable = owl_comp_enable,
.is_enabled = owl_comp_is_enabled,
};