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/*
* Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
*
* 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/kernel.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/clk-provider.h>
#include <linux/clk.h>
#include "clk.h"
#define pll_out_override(p) (BIT((p->shift - 6)))
#define div_mask(d) ((1 << (d->width)) - 1)
#define get_mul(d) (1 << d->frac_width)
#define get_max_div(d) div_mask(d)
#define PERIPH_CLK_UART_DIV_ENB BIT(24)
static int get_div(struct tegra_clk_frac_div *divider, unsigned long rate,
unsigned long parent_rate)
{
s64 divider_ux1 = parent_rate;
u8 flags = divider->flags;
int mul;
if (!rate)
return 0;
mul = get_mul(divider);
if (!(flags & TEGRA_DIVIDER_INT))
divider_ux1 *= mul;
if (flags & TEGRA_DIVIDER_ROUND_UP)
divider_ux1 += rate - 1;
do_div(divider_ux1, rate);
if (flags & TEGRA_DIVIDER_INT)
divider_ux1 *= mul;
divider_ux1 -= mul;
if (divider_ux1 < 0)
return 0;
if (divider_ux1 > get_max_div(divider))
return -EINVAL;
return divider_ux1;
}
static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
u32 reg;
int div, mul;
u64 rate = parent_rate;
reg = readl_relaxed(divider->reg) >> divider->shift;
div = reg & div_mask(divider);
mul = get_mul(divider);
div += mul;
rate *= mul;
rate += div - 1;
do_div(rate, div);
return rate;
}
static long clk_frac_div_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
int div, mul;
unsigned long output_rate = *prate;
if (!rate)
return output_rate;
div = get_div(divider, rate, output_rate);
if (div < 0)
return *prate;
mul = get_mul(divider);
return DIV_ROUND_UP(output_rate * mul, div + mul);
}
static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct tegra_clk_frac_div *divider = to_clk_frac_div(hw);
int div;
unsigned long flags = 0;
u32 val;
div = get_div(divider, rate, parent_rate);
if (div < 0)
return div;
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
val = readl_relaxed(divider->reg);
val &= ~(div_mask(divider) << divider->shift);
val |= div << divider->shift;
if (divider->flags & TEGRA_DIVIDER_UART) {
if (div)
val |= PERIPH_CLK_UART_DIV_ENB;
else
val &= ~PERIPH_CLK_UART_DIV_ENB;
}
if (divider->flags & TEGRA_DIVIDER_FIXED)
val |= pll_out_override(divider);
writel_relaxed(val, divider->reg);
if (divider->lock)
spin_unlock_irqrestore(divider->lock, flags);
return 0;
}
const struct clk_ops tegra_clk_frac_div_ops = {
.recalc_rate = clk_frac_div_recalc_rate,
.set_rate = clk_frac_div_set_rate,
.round_rate = clk_frac_div_round_rate,
};
struct clk *tegra_clk_register_divider(const char *name,
const char *parent_name, void __iomem *reg,
unsigned long flags, u8 clk_divider_flags, u8 shift, u8 width,
u8 frac_width, spinlock_t *lock)
{
struct tegra_clk_frac_div *divider;
struct clk *clk;
struct clk_init_data init;
divider = kzalloc(sizeof(*divider), GFP_KERNEL);
if (!divider) {
pr_err("%s: could not allocate fractional divider clk\n",
__func__);
return ERR_PTR(-ENOMEM);
}
init.name = name;
init.ops = &tegra_clk_frac_div_ops;
init.flags = flags;
init.parent_names = parent_name ? &parent_name : NULL;
init.num_parents = parent_name ? 1 : 0;
divider->reg = reg;
divider->shift = shift;
divider->width = width;
divider->frac_width = frac_width;
divider->lock = lock;
divider->flags = clk_divider_flags;
/* Data in .init is copied by clk_register(), so stack variable OK */
divider->hw.init = &init;
clk = clk_register(NULL, ÷r->hw);
if (IS_ERR(clk))
kfree(divider);
return clk;
}
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