alistair23-linux/drivers/clk/meson/clk-regmap.c
Martin Blumenstingl 3cf94c94e8 clk: meson: clk-regmap: add read-only gate ops
Some of the gate clocks are described as "just in case" bits in the
datasheet. Examples are the ABP, PERIPH, AXI and L2 DRAM clocks on
Meson8b.
The datasheet suggests that these bits are not touched. The full
explanation is:
"Set to 1 to manually disable the [...] clock when changing the mux
selection. Typically this bit is set to 0 since the clock muxes can
switch without glitches.".

This adds new read-only ops for gate clocks so we can describe these
clocks in our clock controller drivers while ensuring that we can't
accidentally modify the registers.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lkml.kernel.org/r/20181122214017.25643-3-martin.blumenstingl@googlemail.com
2018-11-23 15:11:58 +01:00

183 lines
4.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2018 BayLibre, SAS.
* Author: Jerome Brunet <jbrunet@baylibre.com>
*/
#include "clk-regmap.h"
static int clk_regmap_gate_endisable(struct clk_hw *hw, int enable)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_gate_data *gate = clk_get_regmap_gate_data(clk);
int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
set ^= enable;
return regmap_update_bits(clk->map, gate->offset, BIT(gate->bit_idx),
set ? BIT(gate->bit_idx) : 0);
}
static int clk_regmap_gate_enable(struct clk_hw *hw)
{
return clk_regmap_gate_endisable(hw, 1);
}
static void clk_regmap_gate_disable(struct clk_hw *hw)
{
clk_regmap_gate_endisable(hw, 0);
}
static int clk_regmap_gate_is_enabled(struct clk_hw *hw)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_gate_data *gate = clk_get_regmap_gate_data(clk);
unsigned int val;
regmap_read(clk->map, gate->offset, &val);
if (gate->flags & CLK_GATE_SET_TO_DISABLE)
val ^= BIT(gate->bit_idx);
val &= BIT(gate->bit_idx);
return val ? 1 : 0;
}
const struct clk_ops clk_regmap_gate_ops = {
.enable = clk_regmap_gate_enable,
.disable = clk_regmap_gate_disable,
.is_enabled = clk_regmap_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(clk_regmap_gate_ops);
const struct clk_ops clk_regmap_gate_ro_ops = {
.is_enabled = clk_regmap_gate_is_enabled,
};
EXPORT_SYMBOL_GPL(clk_regmap_gate_ro_ops);
static unsigned long clk_regmap_div_recalc_rate(struct clk_hw *hw,
unsigned long prate)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
unsigned int val;
int ret;
ret = regmap_read(clk->map, div->offset, &val);
if (ret)
/* Gives a hint that something is wrong */
return 0;
val >>= div->shift;
val &= clk_div_mask(div->width);
return divider_recalc_rate(hw, prate, val, div->table, div->flags,
div->width);
}
static long clk_regmap_div_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
unsigned int val;
int ret;
/* if read only, just return current value */
if (div->flags & CLK_DIVIDER_READ_ONLY) {
ret = regmap_read(clk->map, div->offset, &val);
if (ret)
/* Gives a hint that something is wrong */
return 0;
val >>= div->shift;
val &= clk_div_mask(div->width);
return divider_ro_round_rate(hw, rate, prate, div->table,
div->width, div->flags, val);
}
return divider_round_rate(hw, rate, prate, div->table, div->width,
div->flags);
}
static int clk_regmap_div_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_div_data *div = clk_get_regmap_div_data(clk);
unsigned int val;
int ret;
ret = divider_get_val(rate, parent_rate, div->table, div->width,
div->flags);
if (ret < 0)
return ret;
val = (unsigned int)ret << div->shift;
return regmap_update_bits(clk->map, div->offset,
clk_div_mask(div->width) << div->shift, val);
};
/* Would prefer clk_regmap_div_ro_ops but clashes with qcom */
const struct clk_ops clk_regmap_divider_ops = {
.recalc_rate = clk_regmap_div_recalc_rate,
.round_rate = clk_regmap_div_round_rate,
.set_rate = clk_regmap_div_set_rate,
};
EXPORT_SYMBOL_GPL(clk_regmap_divider_ops);
const struct clk_ops clk_regmap_divider_ro_ops = {
.recalc_rate = clk_regmap_div_recalc_rate,
.round_rate = clk_regmap_div_round_rate,
};
EXPORT_SYMBOL_GPL(clk_regmap_divider_ro_ops);
static u8 clk_regmap_mux_get_parent(struct clk_hw *hw)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_mux_data *mux = clk_get_regmap_mux_data(clk);
unsigned int val;
int ret;
ret = regmap_read(clk->map, mux->offset, &val);
if (ret)
return ret;
val >>= mux->shift;
val &= mux->mask;
return clk_mux_val_to_index(hw, mux->table, mux->flags, val);
}
static int clk_regmap_mux_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_mux_data *mux = clk_get_regmap_mux_data(clk);
unsigned int val = clk_mux_index_to_val(mux->table, mux->flags, index);
return regmap_update_bits(clk->map, mux->offset,
mux->mask << mux->shift,
val << mux->shift);
}
static int clk_regmap_mux_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct clk_regmap_mux_data *mux = clk_get_regmap_mux_data(clk);
return clk_mux_determine_rate_flags(hw, req, mux->flags);
}
const struct clk_ops clk_regmap_mux_ops = {
.get_parent = clk_regmap_mux_get_parent,
.set_parent = clk_regmap_mux_set_parent,
.determine_rate = clk_regmap_mux_determine_rate,
};
EXPORT_SYMBOL_GPL(clk_regmap_mux_ops);
const struct clk_ops clk_regmap_mux_ro_ops = {
.get_parent = clk_regmap_mux_get_parent,
};
EXPORT_SYMBOL_GPL(clk_regmap_mux_ro_ops);