// SPDX-License-Identifier: GPL-2.0
/*
* r8a7790 Common Clock Framework support
*
* Copyright (C) 2013 Renesas Solutions Corp.
*
* Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
*/
#include <linux/clk-provider.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include "clk-div6.h"
#define CPG_DIV6_CKSTP BIT(8)
#define CPG_DIV6_DIV(d) ((d) & 0x3f)
#define CPG_DIV6_DIV_MASK 0x3f
/**
* struct div6_clock - CPG 6 bit divider clock
* @hw: handle between common and hardware-specific interfaces
* @reg: IO-remapped register
* @div: divisor value (1-64)
* @src_shift: Shift to access the register bits to select the parent clock
* @src_width: Number of register bits to select the parent clock (may be 0)
* @nb: Notifier block to save/restore clock state for system resume
* @parents: Array to map from valid parent clocks indices to hardware indices
*/
struct div6_clock {
struct clk_hw hw;
void __iomem *reg;
unsigned int div;
u32 src_shift;
u32 src_width;
struct notifier_block nb;
u8 parents[];
};
#define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw)
static int cpg_div6_clock_enable(struct clk_hw *hw)
{
struct div6_clock *clock = to_div6_clock(hw);
u32 val;
val = (readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP))
| CPG_DIV6_DIV(clock->div - 1);
writel(val, clock->reg);
return 0;
}
static void cpg_div6_clock_disable(struct clk_hw *hw)
{
struct div6_clock *clock = to_div6_clock(hw);
u32 val;
val = readl(clock->reg);
val |= CPG_DIV6_CKSTP;
/*
* DIV6 clocks require the divisor field to be non-zero when stopping
* the clock. However, some clocks (e.g. ZB on sh73a0) fail to be
* re-enabled later if the divisor field is changed when stopping the
* clock
*/
if (!(val & CPG_DIV6_DIV_MASK))
val |= CPG_DIV6_DIV_MASK;
writel(val, clock->reg);
}
static int cpg_div6_clock_is_enabled(struct clk_hw *hw)
{
struct div6_clock *clock = to_div6_clock(hw);
return !(readl(clock->reg) & CPG_DIV6_CKSTP);
}
static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct div6_clock *clock = to_div6_clock(hw);
return parent_rate / clock->div;
}
static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
unsigned long parent_rate)
{
unsigned int div;
if (!rate)
rate = 1;
div = DIV_ROUND_CLOSEST(parent_rate, rate);
return clamp_t(unsigned int, div, 1, 64);
}
static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate);
return *parent_rate / div;
}
static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct div6_clock *clock = to_div6_clock(hw);
unsigned int div = cpg_div6_clock_calc_div(rate, parent_rate);
u32 val;
clock->div = div;
val = readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
/* Only program the new divisor if the clock isn't stopped. */
if (!(val & CPG_DIV6_CKSTP))
writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg);
return 0;
}
static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
{
struct div6_clock *clock = to_div6_clock(hw);
unsigned int i;
u8 hw_index;
if (clock->src_width == 0)
return 0;
hw_index = (readl(clock->reg) >> clock->src_shift) &
(BIT(clock->src_width) - 1);
for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
if (clock->parents[i] == hw_index)
return i;
}
pr_err("%s: %s DIV6 clock set to invalid parent %u\n",
__func__, clk_hw_get_name(hw), hw_index);
return 0;
}
static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index)
{
struct div6_clock *clock = to_div6_clock(hw);
u8 hw_index;
u32 mask;
if (index >= clk_hw_get_num_parents(hw))
return -EINVAL;
mask = ~((BIT(clock->src_width) - 1) << clock->src_shift);
hw_index = clock->parents[index];
writel((readl(clock->reg) & mask) | (hw_index << clock->src_shift),
clock->reg);
return 0;
}
static const struct clk_ops cpg_div6_clock_ops = {
.enable = cpg_div6_clock_enable,
.disable = cpg_div6_clock_disable,
.is_enabled = cpg_div6_clock_is_enabled,
.get_parent = cpg_div6_clock_get_parent,
.set_parent = cpg_div6_clock_set_parent,
.recalc_rate = cpg_div6_clock_recalc_rate,
.round_rate = cpg_div6_clock_round_rate,
.set_rate = cpg_div6_clock_set_rate,
};
static int cpg_div6_clock_notifier_call(struct notifier_block *nb,
unsigned long action, void *data)
{
struct div6_clock *clock = container_of(nb, struct div6_clock, nb);
switch (action) {
case PM_EVENT_RESUME:
/*
* TODO: This does not yet support DIV6 clocks with multiple
* parents, as the parent selection bits are not restored.
* Fortunately so far such DIV6 clocks are found only on
* R/SH-Mobile SoCs, while the resume functionality is only
* needed on R-Car Gen3.
*/
if (__clk_get_enable_count(clock->hw.clk))
cpg_div6_clock_enable(&clock->hw);
else
cpg_div6_clock_disable(&clock->hw);
return NOTIFY_OK;
}
return NOTIFY_DONE;
}
/**
* cpg_div6_register - Register a DIV6 clock
* @name: Name of the DIV6 clock
* @num_parents: Number of parent clocks of the DIV6 clock (1, 4, or 8)
* @parent_names: Array containing the names of the parent clocks
* @reg: Mapped register used to control the DIV6 clock
* @notifiers: Optional notifier chain to save/restore state for system resume
*/
struct clk * __init cpg_div6_register(const char *name,
unsigned int num_parents,
const char **parent_names,
void __iomem *reg,
struct raw_notifier_head *notifiers)
{
unsigned int valid_parents;
struct clk_init_data init;
struct div6_clock *clock;
struct clk *clk;
unsigned int i;
clock = kzalloc(struct_size(clock, parents, num_parents), GFP_KERNEL);
if (!clock)
return ERR_PTR(-ENOMEM);
clock->reg = reg;
/*
* Read the divisor. Disabling the clock overwrites the divisor, so we
* need to cache its value for the enable operation.
*/
clock->div = (readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
switch (num_parents) {
case 1:
/* fixed parent clock */
clock->src_shift = clock->src_width = 0;
break;
case 4:
/* clock with EXSRC bits 6-7 */
clock->src_shift = 6;
clock->src_width = 2;
break;
case 8:
/* VCLK with EXSRC bits 12-14 */
clock->src_shift = 12;
clock->src_width = 3;
break;
default:
pr_err("%s: invalid number of parents for DIV6 clock %s\n",
__func__, name);
clk = ERR_PTR(-EINVAL);
goto free_clock;
}
/* Filter out invalid parents */
for (i = 0, valid_parents = 0; i < num_parents; i++) {
if (parent_names[i]) {
parent_names[valid_parents] = parent_names[i];
clock->parents[valid_parents] = i;
valid_parents++;
}
}
/* Register the clock. */
init.name = name;
init.ops = &cpg_div6_clock_ops;
init.flags = 0;
init.parent_names = parent_names;
init.num_parents = valid_parents;
clock->hw.init = &init;
clk = clk_register(NULL, &clock->hw);
if (IS_ERR(clk))
goto free_clock;
if (notifiers) {
clock->nb.notifier_call = cpg_div6_clock_notifier_call;
raw_notifier_chain_register(notifiers, &clock->nb);
}
return clk;
free_clock:
kfree(clock);
return clk;
}
static void __init cpg_div6_clock_init(struct device_node *np)
{
unsigned int num_parents;
const char **parent_names;
const char *clk_name = np->name;
void __iomem *reg;
struct clk *clk;
unsigned int i;
num_parents = of_clk_get_parent_count(np);
if (num_parents < 1) {
pr_err("%s: no parent found for %pOFn DIV6 clock\n",
__func__, np);
return;
}
parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
GFP_KERNEL);
if (!parent_names)
return;
reg = of_iomap(np, 0);
if (reg == NULL) {
pr_err("%s: failed to map %pOFn DIV6 clock register\n",
__func__, np);
goto error;
}
/* Parse the DT properties. */
of_property_read_string(np, "clock-output-names", &clk_name);
for (i = 0; i < num_parents; i++)
parent_names[i] = of_clk_get_parent_name(np, i);
clk = cpg_div6_register(clk_name, num_parents, parent_names, reg, NULL);
if (IS_ERR(clk)) {
pr_err("%s: failed to register %pOFn DIV6 clock (%ld)\n",
__func__, np, PTR_ERR(clk));
goto error;
}
of_clk_add_provider(np, of_clk_src_simple_get, clk);
kfree(parent_names);
return;
error:
if (reg)
iounmap(reg);
kfree(parent_names);
}
CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);
