linux/drivers/clk/qcom/clk-rcg2.c
Stephen Boyd bcd61c0f53 clk: qcom: Add support for root clock generators (RCGs)
Add support for the root clock generators on Qualcomm devices.
RCGs are highly customizable mux/divider/counter clocks that can
be used to generate almost any rate desired given some input
source that is faster than the desired rate.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-01-16 12:01:00 -08:00

292 lines
6.5 KiB
C

/*
* Copyright (c) 2013, The Linux Foundation. All rights reserved.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that 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.
*/
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/bug.h>
#include <linux/export.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <asm/div64.h>
#include "clk-rcg.h"
#define CMD_REG 0x0
#define CMD_UPDATE BIT(0)
#define CMD_ROOT_EN BIT(1)
#define CMD_DIRTY_CFG BIT(4)
#define CMD_DIRTY_N BIT(5)
#define CMD_DIRTY_M BIT(6)
#define CMD_DIRTY_D BIT(7)
#define CMD_ROOT_OFF BIT(31)
#define CFG_REG 0x4
#define CFG_SRC_DIV_SHIFT 0
#define CFG_SRC_SEL_SHIFT 8
#define CFG_SRC_SEL_MASK (0x7 << CFG_SRC_SEL_SHIFT)
#define CFG_MODE_SHIFT 12
#define CFG_MODE_MASK (0x3 << CFG_MODE_SHIFT)
#define CFG_MODE_DUAL_EDGE (0x2 << CFG_MODE_SHIFT)
#define M_REG 0x8
#define N_REG 0xc
#define D_REG 0x10
static int clk_rcg2_is_enabled(struct clk_hw *hw)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
u32 cmd;
int ret;
ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG, &cmd);
if (ret)
return ret;
return (cmd & CMD_ROOT_OFF) != 0;
}
static u8 clk_rcg2_get_parent(struct clk_hw *hw)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
int num_parents = __clk_get_num_parents(hw->clk);
u32 cfg;
int i, ret;
ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, &cfg);
if (ret)
return ret;
cfg &= CFG_SRC_SEL_MASK;
cfg >>= CFG_SRC_SEL_SHIFT;
for (i = 0; i < num_parents; i++)
if (cfg == rcg->parent_map[i])
return i;
return -EINVAL;
}
static int update_config(struct clk_rcg2 *rcg)
{
int count, ret;
u32 cmd;
struct clk_hw *hw = &rcg->clkr.hw;
const char *name = __clk_get_name(hw->clk);
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG,
CMD_UPDATE, CMD_UPDATE);
if (ret)
return ret;
/* Wait for update to take effect */
for (count = 500; count > 0; count--) {
ret = regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CMD_REG, &cmd);
if (ret)
return ret;
if (!(cmd & CMD_UPDATE))
return 0;
udelay(1);
}
WARN(1, "%s: rcg didn't update its configuration.", name);
return 0;
}
static int clk_rcg2_set_parent(struct clk_hw *hw, u8 index)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
int ret;
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG,
CFG_SRC_SEL_MASK,
rcg->parent_map[index] << CFG_SRC_SEL_SHIFT);
if (ret)
return ret;
return update_config(rcg);
}
/*
* Calculate m/n:d rate
*
* parent_rate m
* rate = ----------- x ---
* hid_div n
*/
static unsigned long
calc_rate(unsigned long rate, u32 m, u32 n, u32 mode, u32 hid_div)
{
if (hid_div) {
rate *= 2;
rate /= hid_div + 1;
}
if (mode) {
u64 tmp = rate;
tmp *= m;
do_div(tmp, n);
rate = tmp;
}
return rate;
}
static unsigned long
clk_rcg2_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
u32 cfg, hid_div, m = 0, n = 0, mode = 0, mask;
regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, &cfg);
if (rcg->mnd_width) {
mask = BIT(rcg->mnd_width) - 1;
regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + M_REG, &m);
m &= mask;
regmap_read(rcg->clkr.regmap, rcg->cmd_rcgr + N_REG, &n);
n = ~n;
n &= mask;
n += m;
mode = cfg & CFG_MODE_MASK;
mode >>= CFG_MODE_SHIFT;
}
mask = BIT(rcg->hid_width) - 1;
hid_div = cfg >> CFG_SRC_DIV_SHIFT;
hid_div &= mask;
return calc_rate(parent_rate, m, n, mode, hid_div);
}
static const
struct freq_tbl *find_freq(const struct freq_tbl *f, unsigned long rate)
{
if (!f)
return NULL;
for (; f->freq; f++)
if (rate <= f->freq)
return f;
return NULL;
}
static long _freq_tbl_determine_rate(struct clk_hw *hw,
const struct freq_tbl *f, unsigned long rate,
unsigned long *p_rate, struct clk **p)
{
unsigned long clk_flags;
f = find_freq(f, rate);
if (!f)
return -EINVAL;
clk_flags = __clk_get_flags(hw->clk);
*p = clk_get_parent_by_index(hw->clk, f->src);
if (clk_flags & CLK_SET_RATE_PARENT) {
if (f->pre_div) {
rate /= 2;
rate *= f->pre_div + 1;
}
if (f->n) {
u64 tmp = rate;
tmp = tmp * f->n;
do_div(tmp, f->m);
rate = tmp;
}
} else {
rate = __clk_get_rate(*p);
}
*p_rate = rate;
return f->freq;
}
static long clk_rcg2_determine_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *p_rate, struct clk **p)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
return _freq_tbl_determine_rate(hw, rcg->freq_tbl, rate, p_rate, p);
}
static int __clk_rcg2_set_rate(struct clk_hw *hw, unsigned long rate)
{
struct clk_rcg2 *rcg = to_clk_rcg2(hw);
const struct freq_tbl *f;
u32 cfg, mask;
int ret;
f = find_freq(rcg->freq_tbl, rate);
if (!f)
return -EINVAL;
if (rcg->mnd_width && f->n) {
mask = BIT(rcg->mnd_width) - 1;
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + M_REG,
mask, f->m);
if (ret)
return ret;
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + N_REG,
mask, ~(f->n - f->m));
if (ret)
return ret;
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + D_REG,
mask, ~f->n);
if (ret)
return ret;
}
mask = BIT(rcg->hid_width) - 1;
mask |= CFG_SRC_SEL_MASK | CFG_MODE_MASK;
cfg = f->pre_div << CFG_SRC_DIV_SHIFT;
cfg |= rcg->parent_map[f->src] << CFG_SRC_SEL_SHIFT;
if (rcg->mnd_width && f->n)
cfg |= CFG_MODE_DUAL_EDGE;
ret = regmap_update_bits(rcg->clkr.regmap, rcg->cmd_rcgr + CFG_REG, mask,
cfg);
if (ret)
return ret;
return update_config(rcg);
}
static int clk_rcg2_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
return __clk_rcg2_set_rate(hw, rate);
}
static int clk_rcg2_set_rate_and_parent(struct clk_hw *hw,
unsigned long rate, unsigned long parent_rate, u8 index)
{
return __clk_rcg2_set_rate(hw, rate);
}
const struct clk_ops clk_rcg2_ops = {
.is_enabled = clk_rcg2_is_enabled,
.get_parent = clk_rcg2_get_parent,
.set_parent = clk_rcg2_set_parent,
.recalc_rate = clk_rcg2_recalc_rate,
.determine_rate = clk_rcg2_determine_rate,
.set_rate = clk_rcg2_set_rate,
.set_rate_and_parent = clk_rcg2_set_rate_and_parent,
};
EXPORT_SYMBOL_GPL(clk_rcg2_ops);