155 lines
3.5 KiB
C
155 lines
3.5 KiB
C
/*
|
|
* Copyright (C) 2012 ST Microelectronics
|
|
* Viresh Kumar <vireshk@kernel.org>
|
|
*
|
|
* This file is licensed under the terms of the GNU General Public
|
|
* License version 2. This program is licensed "as is" without any
|
|
* warranty of any kind, whether express or implied.
|
|
*
|
|
* General Purpose Timer Synthesizer clock implementation
|
|
*/
|
|
|
|
#define pr_fmt(fmt) "clk-gpt-synth: " fmt
|
|
|
|
#include <linux/clk-provider.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/io.h>
|
|
#include <linux/err.h>
|
|
#include "clk.h"
|
|
|
|
#define GPT_MSCALE_MASK 0xFFF
|
|
#define GPT_NSCALE_SHIFT 12
|
|
#define GPT_NSCALE_MASK 0xF
|
|
|
|
/*
|
|
* DOC: General Purpose Timer Synthesizer clock
|
|
*
|
|
* Calculates gpt synth clk rate for different values of mscale and nscale
|
|
*
|
|
* Fout= Fin/((2 ^ (N+1)) * (M+1))
|
|
*/
|
|
|
|
#define to_clk_gpt(_hw) container_of(_hw, struct clk_gpt, hw)
|
|
|
|
static unsigned long gpt_calc_rate(struct clk_hw *hw, unsigned long prate,
|
|
int index)
|
|
{
|
|
struct clk_gpt *gpt = to_clk_gpt(hw);
|
|
struct gpt_rate_tbl *rtbl = gpt->rtbl;
|
|
|
|
prate /= ((1 << (rtbl[index].nscale + 1)) * (rtbl[index].mscale + 1));
|
|
|
|
return prate;
|
|
}
|
|
|
|
static long clk_gpt_round_rate(struct clk_hw *hw, unsigned long drate,
|
|
unsigned long *prate)
|
|
{
|
|
struct clk_gpt *gpt = to_clk_gpt(hw);
|
|
int unused;
|
|
|
|
return clk_round_rate_index(hw, drate, *prate, gpt_calc_rate,
|
|
gpt->rtbl_cnt, &unused);
|
|
}
|
|
|
|
static unsigned long clk_gpt_recalc_rate(struct clk_hw *hw,
|
|
unsigned long parent_rate)
|
|
{
|
|
struct clk_gpt *gpt = to_clk_gpt(hw);
|
|
unsigned long flags = 0;
|
|
unsigned int div = 1, val;
|
|
|
|
if (gpt->lock)
|
|
spin_lock_irqsave(gpt->lock, flags);
|
|
|
|
val = readl_relaxed(gpt->reg);
|
|
|
|
if (gpt->lock)
|
|
spin_unlock_irqrestore(gpt->lock, flags);
|
|
|
|
div += val & GPT_MSCALE_MASK;
|
|
div *= 1 << (((val >> GPT_NSCALE_SHIFT) & GPT_NSCALE_MASK) + 1);
|
|
|
|
if (!div)
|
|
return 0;
|
|
|
|
return parent_rate / div;
|
|
}
|
|
|
|
/* Configures new clock rate of gpt */
|
|
static int clk_gpt_set_rate(struct clk_hw *hw, unsigned long drate,
|
|
unsigned long prate)
|
|
{
|
|
struct clk_gpt *gpt = to_clk_gpt(hw);
|
|
struct gpt_rate_tbl *rtbl = gpt->rtbl;
|
|
unsigned long flags = 0, val;
|
|
int i;
|
|
|
|
clk_round_rate_index(hw, drate, prate, gpt_calc_rate, gpt->rtbl_cnt,
|
|
&i);
|
|
|
|
if (gpt->lock)
|
|
spin_lock_irqsave(gpt->lock, flags);
|
|
|
|
val = readl(gpt->reg) & ~GPT_MSCALE_MASK;
|
|
val &= ~(GPT_NSCALE_MASK << GPT_NSCALE_SHIFT);
|
|
|
|
val |= rtbl[i].mscale & GPT_MSCALE_MASK;
|
|
val |= (rtbl[i].nscale & GPT_NSCALE_MASK) << GPT_NSCALE_SHIFT;
|
|
|
|
writel_relaxed(val, gpt->reg);
|
|
|
|
if (gpt->lock)
|
|
spin_unlock_irqrestore(gpt->lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct clk_ops clk_gpt_ops = {
|
|
.recalc_rate = clk_gpt_recalc_rate,
|
|
.round_rate = clk_gpt_round_rate,
|
|
.set_rate = clk_gpt_set_rate,
|
|
};
|
|
|
|
struct clk *clk_register_gpt(const char *name, const char *parent_name, unsigned
|
|
long flags, void __iomem *reg, struct gpt_rate_tbl *rtbl, u8
|
|
rtbl_cnt, spinlock_t *lock)
|
|
{
|
|
struct clk_init_data init;
|
|
struct clk_gpt *gpt;
|
|
struct clk *clk;
|
|
|
|
if (!name || !parent_name || !reg || !rtbl || !rtbl_cnt) {
|
|
pr_err("Invalid arguments passed");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
gpt = kzalloc(sizeof(*gpt), GFP_KERNEL);
|
|
if (!gpt) {
|
|
pr_err("could not allocate gpt clk\n");
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* struct clk_gpt assignments */
|
|
gpt->reg = reg;
|
|
gpt->rtbl = rtbl;
|
|
gpt->rtbl_cnt = rtbl_cnt;
|
|
gpt->lock = lock;
|
|
gpt->hw.init = &init;
|
|
|
|
init.name = name;
|
|
init.ops = &clk_gpt_ops;
|
|
init.flags = flags;
|
|
init.parent_names = &parent_name;
|
|
init.num_parents = 1;
|
|
|
|
clk = clk_register(NULL, &gpt->hw);
|
|
if (!IS_ERR_OR_NULL(clk))
|
|
return clk;
|
|
|
|
pr_err("clk register failed\n");
|
|
kfree(gpt);
|
|
|
|
return NULL;
|
|
}
|