5113f6f70
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/*
* Copyright (c) 2014 Marvell Technology Group Ltd.
*
* Alexandre Belloni <alexandre.belloni@free-electrons.com>
* Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/bitops.h>
#include <linux/clk-provider.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include "berlin2-div.h"
/*
* Clock dividers in Berlin2 SoCs comprise a complex cell to select
* input pll and divider. The virtual structure as it is used in Marvell
* BSP code can be seen as:
*
* +---+
* pll0 --------------->| 0 | +---+
* +---+ |(B)|--+--------------->| 0 | +---+
* pll1.0 -->| 0 | +-->| 1 | | +--------+ |(E)|----->| 0 | +---+
* pll1.1 -->| 1 | | +---+ +-->|(C) 1:M |-->| 1 | |(F)|-->|(G)|->
* ... -->|(A)|--+ | +--------+ +---+ +-->| 1 | +---+
* ... -->| | +-->|(D) 1:3 |----------+ +---+
* pll1.N -->| N | +---------
* +---+
*
* (A) input pll clock mux controlled by <PllSelect[1:n]>
* (B) input pll bypass mux controlled by <PllSwitch>
* (C) programmable clock divider controlled by <Select[1:n]>
* (D) constant div-by-3 clock divider
* (E) programmable clock divider bypass controlled by <Switch>
* (F) constant div-by-3 clock mux controlled by <D3Switch>
* (G) clock gate controlled by <Enable>
*
* For whatever reason, above control signals come in two flavors:
* - single register dividers with all bits in one register
* - shared register dividers with bits spread over multiple registers
* (including signals for the same cell spread over consecutive registers)
*
* Also, clock gate and pll mux is not available on every div cell, so
* we have to deal with those, too. We reuse common clock composite driver
* for it.
*/
#define PLL_SELECT_MASK 0x7
#define DIV_SELECT_MASK 0x7
struct berlin2_div {
struct clk_hw hw;
void __iomem *base;
struct berlin2_div_map map;
spinlock_t *lock;
};
#define to_berlin2_div(hw) container_of(hw, struct berlin2_div, hw)
static u8 clk_div[] = { 1, 2, 4, 6, 8, 12, 1, 1 };
static int berlin2_div_is_enabled(struct clk_hw *hw)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 reg;
if (div->lock)
spin_lock(div->lock);
reg = readl_relaxed(div->base + map->gate_offs);
reg >>= map->gate_shift;
if (div->lock)
spin_unlock(div->lock);
return (reg & 0x1);
}
static int berlin2_div_enable(struct clk_hw *hw)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 reg;
if (div->lock)
spin_lock(div->lock);
reg = readl_relaxed(div->base + map->gate_offs);
reg |= BIT(map->gate_shift);
writel_relaxed(reg, div->base + map->gate_offs);
if (div->lock)
spin_unlock(div->lock);
return 0;
}
static void berlin2_div_disable(struct clk_hw *hw)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 reg;
if (div->lock)
spin_lock(div->lock);
reg = readl_relaxed(div->base + map->gate_offs);
reg &= ~BIT(map->gate_shift);
writel_relaxed(reg, div->base + map->gate_offs);
if (div->lock)
spin_unlock(div->lock);
}
static int berlin2_div_set_parent(struct clk_hw *hw, u8 index)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 reg;
if (div->lock)
spin_lock(div->lock);
/* index == 0 is PLL_SWITCH */
reg = readl_relaxed(div->base + map->pll_switch_offs);
if (index == 0)
reg &= ~BIT(map->pll_switch_shift);
else
reg |= BIT(map->pll_switch_shift);
writel_relaxed(reg, div->base + map->pll_switch_offs);
/* index > 0 is PLL_SELECT */
if (index > 0) {
reg = readl_relaxed(div->base + map->pll_select_offs);
reg &= ~(PLL_SELECT_MASK << map->pll_select_shift);
reg |= (index - 1) << map->pll_select_shift;
writel_relaxed(reg, div->base + map->pll_select_offs);
}
if (div->lock)
spin_unlock(div->lock);
return 0;
}
static u8 berlin2_div_get_parent(struct clk_hw *hw)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 reg;
u8 index = 0;
if (div->lock)
spin_lock(div->lock);
/* PLL_SWITCH == 0 is index 0 */
reg = readl_relaxed(div->base + map->pll_switch_offs);
reg &= BIT(map->pll_switch_shift);
if (reg) {
reg = readl_relaxed(div->base + map->pll_select_offs);
reg >>= map->pll_select_shift;
reg &= PLL_SELECT_MASK;
index = 1 + reg;
}
if (div->lock)
spin_unlock(div->lock);
return index;
}
static unsigned long berlin2_div_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct berlin2_div *div = to_berlin2_div(hw);
struct berlin2_div_map *map = &div->map;
u32 divsw, div3sw, divider = 1;
if (div->lock)
spin_lock(div->lock);
divsw = readl_relaxed(div->base + map->div_switch_offs) &
(1 << map->div_switch_shift);
div3sw = readl_relaxed(div->base + map->div3_switch_offs) &
(1 << map->div3_switch_shift);
/* constant divide-by-3 (dominant) */
if (div3sw != 0) {
divider = 3;
/* divider can be bypassed with DIV_SWITCH == 0 */
} else if (divsw == 0) {
divider = 1;
/* clock divider determined by DIV_SELECT */
} else {
u32 reg;
reg = readl_relaxed(div->base + map->div_select_offs);
reg >>= map->div_select_shift;
reg &= DIV_SELECT_MASK;
divider = clk_div[reg];
}
if (div->lock)
spin_unlock(div->lock);
return parent_rate / divider;
}
static const struct clk_ops berlin2_div_rate_ops = {
.recalc_rate = berlin2_div_recalc_rate,
};
static const struct clk_ops berlin2_div_gate_ops = {
.is_enabled = berlin2_div_is_enabled,
.enable = berlin2_div_enable,
.disable = berlin2_div_disable,
};
static const struct clk_ops berlin2_div_mux_ops = {
.set_parent = berlin2_div_set_parent,
.get_parent = berlin2_div_get_parent,
};
struct clk * __init
berlin2_div_register(const struct berlin2_div_map *map,
void __iomem *base, const char *name, u8 div_flags,
const char **parent_names, int num_parents,
unsigned long flags, spinlock_t *lock)
{
const struct clk_ops *mux_ops = &berlin2_div_mux_ops;
const struct clk_ops *rate_ops = &berlin2_div_rate_ops;
const struct clk_ops *gate_ops = &berlin2_div_gate_ops;
struct berlin2_div *div;
div = kzalloc(sizeof(*div), GFP_KERNEL);
if (!div)
return ERR_PTR(-ENOMEM);
/* copy div_map to allow __initconst */
memcpy(&div->map, map, sizeof(*map));
div->base = base;
div->lock = lock;
if ((div_flags & BERLIN2_DIV_HAS_GATE) == 0)
gate_ops = NULL;
if ((div_flags & BERLIN2_DIV_HAS_MUX) == 0)
mux_ops = NULL;
return clk_register_composite(NULL, name, parent_names, num_parents,
&div->hw, mux_ops, &div->hw, rate_ops,
&div->hw, gate_ops, flags);
}
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