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/*
* OMAP4-specific DPLL control functions
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Rajendra Nayak
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include "clock.h"
/*
* Maximum DPLL input frequency (FINT) and output frequency (FOUT) that
* can supported when using the DPLL low-power mode. Frequencies are
* defined in OMAP4430/60 Public TRM section 3.6.3.3.2 "Enable Control,
* Status, and Low-Power Operation Mode".
*/
#define OMAP4_DPLL_LP_FINT_MAX 1000000
#define OMAP4_DPLL_LP_FOUT_MAX 100000000
/*
* Bitfield declarations
*/
#define OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK (1 << 8)
#define OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK (1 << 10)
#define OMAP4430_DPLL_REGM4XEN_MASK (1 << 11)
/* Static rate multiplier for OMAP4 REGM4XEN clocks */
#define OMAP4430_REGM4XEN_MULT 4
/* Supported only on OMAP4 */
int omap4_dpllmx_gatectrl_read(struct clk_hw_omap *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg)
return -EINVAL;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = omap2_clk_readl(clk, clk->clksel_reg);
v &= mask;
v >>= __ffs(mask);
return v;
}
void omap4_dpllmx_allow_gatectrl(struct clk_hw_omap *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg)
return;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = omap2_clk_readl(clk, clk->clksel_reg);
/* Clear the bit to allow gatectrl */
v &= ~mask;
omap2_clk_writel(v, clk, clk->clksel_reg);
}
void omap4_dpllmx_deny_gatectrl(struct clk_hw_omap *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg)
return;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = omap2_clk_readl(clk, clk->clksel_reg);
/* Set the bit to deny gatectrl */
v |= mask;
omap2_clk_writel(v, clk, clk->clksel_reg);
}
const struct clk_hw_omap_ops clkhwops_omap4_dpllmx = {
.allow_idle = omap4_dpllmx_allow_gatectrl,
.deny_idle = omap4_dpllmx_deny_gatectrl,
};
/**
* omap4_dpll_lpmode_recalc - compute DPLL low-power setting
* @dd: pointer to the dpll data structure
*
* Calculates if low-power mode can be enabled based upon the last
* multiplier and divider values calculated. If low-power mode can be
* enabled, then the bit to enable low-power mode is stored in the
* last_rounded_lpmode variable. This implementation is based upon the
* criteria for enabling low-power mode as described in the OMAP4430/60
* Public TRM section 3.6.3.3.2 "Enable Control, Status, and Low-Power
* Operation Mode".
*/
static void omap4_dpll_lpmode_recalc(struct dpll_data *dd)
{
long fint, fout;
fint = __clk_get_rate(dd->clk_ref) / (dd->last_rounded_n + 1);
fout = fint * dd->last_rounded_m;
if ((fint < OMAP4_DPLL_LP_FINT_MAX) && (fout < OMAP4_DPLL_LP_FOUT_MAX))
dd->last_rounded_lpmode = 1;
else
dd->last_rounded_lpmode = 0;
}
/**
* omap4_dpll_regm4xen_recalc - compute DPLL rate, considering REGM4XEN bit
* @clk: struct clk * of the DPLL to compute the rate for
*
* Compute the output rate for the OMAP4 DPLL represented by @clk.
* Takes the REGM4XEN bit into consideration, which is needed for the
* OMAP4 ABE DPLL. Returns the DPLL's output rate (before M-dividers)
* upon success, or 0 upon error.
*/
unsigned long omap4_dpll_regm4xen_recalc(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_hw_omap *clk = to_clk_hw_omap(hw);
u32 v;
unsigned long rate;
struct dpll_data *dd;
if (!clk || !clk->dpll_data)
return 0;
dd = clk->dpll_data;
rate = omap2_get_dpll_rate(clk);
/* regm4xen adds a multiplier of 4 to DPLL calculations */
v = omap2_clk_readl(clk, dd->control_reg);
if (v & OMAP4430_DPLL_REGM4XEN_MASK)
rate *= OMAP4430_REGM4XEN_MULT;
return rate;
}
/**
* omap4_dpll_regm4xen_round_rate - round DPLL rate, considering REGM4XEN bit
* @clk: struct clk * of the DPLL to round a rate for
* @target_rate: the desired rate of the DPLL
*
* Compute the rate that would be programmed into the DPLL hardware
* for @clk if set_rate() were to be provided with the rate
* @target_rate. Takes the REGM4XEN bit into consideration, which is
* needed for the OMAP4 ABE DPLL. Returns the rounded rate (before
* M-dividers) upon success, -EINVAL if @clk is null or not a DPLL, or
* ~0 if an error occurred in omap2_dpll_round_rate().
*/
long omap4_dpll_regm4xen_round_rate(struct clk_hw *hw,
unsigned long target_rate,
unsigned long *parent_rate)
{
struct clk_hw_omap *clk = to_clk_hw_omap(hw);
struct dpll_data *dd;
long r;
if (!clk || !clk->dpll_data)
return -EINVAL;
dd = clk->dpll_data;
dd->last_rounded_m4xen = 0;
/*
* First try to compute the DPLL configuration for
* target rate without using the 4X multiplier.
*/
r = omap2_dpll_round_rate(hw, target_rate, NULL);
if (r != ~0)
goto out;
/*
* If we did not find a valid DPLL configuration, try again, but
* this time see if using the 4X multiplier can help. Enabling the
* 4X multiplier is equivalent to dividing the target rate by 4.
*/
r = omap2_dpll_round_rate(hw, target_rate / OMAP4430_REGM4XEN_MULT,
NULL);
if (r == ~0)
return r;
dd->last_rounded_rate *= OMAP4430_REGM4XEN_MULT;
dd->last_rounded_m4xen = 1;
out:
omap4_dpll_lpmode_recalc(dd);
return dd->last_rounded_rate;
}
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