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/*
* Copyright (c) 2015 Endless Mobile, Inc.
* Author: Carlo Caione <carlo@endlessm.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/>.
*/
/*
* CPU clock path:
*
* +-[/N]-----|3|
* MUX2 +--[/3]-+----------|2| MUX1
* [sys_pll]---|1| |--[/2]------------|1|-|1|
* | |---+------------------|0| | |----- [a5_clk]
* +--|0| | |
* [xtal]---+-------------------------------|0|
*
*
*
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#define MESON_CPU_CLK_CNTL1 0x00
#define MESON_CPU_CLK_CNTL 0x40
#define MESON_CPU_CLK_MUX1 BIT(7)
#define MESON_CPU_CLK_MUX2 BIT(0)
#define MESON_N_WIDTH 9
#define MESON_N_SHIFT 20
#define MESON_SEL_WIDTH 2
#define MESON_SEL_SHIFT 2
#include "clkc.h"
#define to_meson_clk_cpu_hw(_hw) container_of(_hw, struct meson_clk_cpu, hw)
#define to_meson_clk_cpu_nb(_nb) container_of(_nb, struct meson_clk_cpu, clk_nb)
static long meson_clk_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw);
return divider_round_rate(hw, rate, prate, clk_cpu->div_table,
MESON_N_WIDTH, CLK_DIVIDER_ROUND_CLOSEST);
}
static int meson_clk_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw);
unsigned int div, sel, N = 0;
u32 reg;
div = DIV_ROUND_UP(parent_rate, rate);
if (div <= 3) {
sel = div - 1;
} else {
sel = 3;
N = div / 2;
}
reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1);
reg = PARM_SET(MESON_N_WIDTH, MESON_N_SHIFT, reg, N);
writel(reg, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1);
reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL);
reg = PARM_SET(MESON_SEL_WIDTH, MESON_SEL_SHIFT, reg, sel);
writel(reg, clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL);
return 0;
}
static unsigned long meson_clk_cpu_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_hw(hw);
unsigned int N, sel;
unsigned int div = 1;
u32 reg;
reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL1);
N = PARM_GET(MESON_N_WIDTH, MESON_N_SHIFT, reg);
reg = readl(clk_cpu->base + clk_cpu->reg_off + MESON_CPU_CLK_CNTL);
sel = PARM_GET(MESON_SEL_WIDTH, MESON_SEL_SHIFT, reg);
if (sel < 3)
div = sel + 1;
else
div = 2 * N;
return parent_rate / div;
}
/* FIXME MUX1 & MUX2 should be struct clk_hw objects */
static int meson_clk_cpu_pre_rate_change(struct meson_clk_cpu *clk_cpu,
struct clk_notifier_data *ndata)
{
u32 cpu_clk_cntl;
/* switch MUX1 to xtal */
cpu_clk_cntl = readl(clk_cpu->base + clk_cpu->reg_off
+ MESON_CPU_CLK_CNTL);
cpu_clk_cntl &= ~MESON_CPU_CLK_MUX1;
writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off
+ MESON_CPU_CLK_CNTL);
udelay(100);
/* switch MUX2 to sys-pll */
cpu_clk_cntl |= MESON_CPU_CLK_MUX2;
writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off
+ MESON_CPU_CLK_CNTL);
return 0;
}
/* FIXME MUX1 & MUX2 should be struct clk_hw objects */
static int meson_clk_cpu_post_rate_change(struct meson_clk_cpu *clk_cpu,
struct clk_notifier_data *ndata)
{
u32 cpu_clk_cntl;
/* switch MUX1 to divisors' output */
cpu_clk_cntl = readl(clk_cpu->base + clk_cpu->reg_off
+ MESON_CPU_CLK_CNTL);
cpu_clk_cntl |= MESON_CPU_CLK_MUX1;
writel(cpu_clk_cntl, clk_cpu->base + clk_cpu->reg_off
+ MESON_CPU_CLK_CNTL);
udelay(100);
return 0;
}
/*
* This clock notifier is called when the frequency of the of the parent
* PLL clock is to be changed. We use the xtal input as temporary parent
* while the PLL frequency is stabilized.
*/
int meson_clk_cpu_notifier_cb(struct notifier_block *nb,
unsigned long event, void *data)
{
struct clk_notifier_data *ndata = data;
struct meson_clk_cpu *clk_cpu = to_meson_clk_cpu_nb(nb);
int ret = 0;
if (event == PRE_RATE_CHANGE)
ret = meson_clk_cpu_pre_rate_change(clk_cpu, ndata);
else if (event == POST_RATE_CHANGE)
ret = meson_clk_cpu_post_rate_change(clk_cpu, ndata);
return notifier_from_errno(ret);
}
const struct clk_ops meson_clk_cpu_ops = {
.recalc_rate = meson_clk_cpu_recalc_rate,
.round_rate = meson_clk_cpu_round_rate,
.set_rate = meson_clk_cpu_set_rate,
};
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