linux/arch/arm/mach-omap2/dpll44xx.c
Mike Turquette a1900f2efe ARM: OMAP4: clock: round_rate and recalc functions for DPLL_ABE
OMAP4 DPLL_ABE can enable a 4X multipler on top of the normal MN multipler
and divider. This is achieved by setting CM_CLKMODE_DPLL_ABE.DPLL_REGM4XEN
bit in CKGEN module of CM1. From the OMAP4 TRM:

Fdpll = Fref x 2 x (4 x M/(N+1)) in case REGM4XEN bit field is set (only
applicable to DPLL_ABE).

Add new round_rate() and recalc() functions for OMAP4, that check the
setting of REGM4XEN bit and handle this appropriately. The new functions
are a simple wrapper on top of the existing omap2_dpll_round_rate() and
omap2_dpll_get_rate() functions to handle the REGM4XEN bit.

The REGM4XEN bit is only implemented for the ABE DPLL on OMAP4 and so
only dpll_abe_ck uses omap4_dpll_regm4xen_round_rate() and
omap4_dpll_regm4xen_recalc() functions.

Signed-off-by: Mike Turquette <mturquette@ti.com>
Tested-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
[paul@pwsan.com: fixed attempt to return a negative from a fn returning
		 unsigned; pass along errors from omap2_dpll_round_rate();
		 added documentation; added Jon's S-o-b]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
2011-10-07 00:52:58 -06:00

153 lines
3.7 KiB
C

/*
* 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 <plat/cpu.h>
#include <plat/clock.h>
#include "clock.h"
#include "clock44xx.h"
#include "cm-regbits-44xx.h"
/* Supported only on OMAP4 */
int omap4_dpllmx_gatectrl_read(struct clk *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
return -EINVAL;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = __raw_readl(clk->clksel_reg);
v &= mask;
v >>= __ffs(mask);
return v;
}
void omap4_dpllmx_allow_gatectrl(struct clk *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
return;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = __raw_readl(clk->clksel_reg);
/* Clear the bit to allow gatectrl */
v &= ~mask;
__raw_writel(v, clk->clksel_reg);
}
void omap4_dpllmx_deny_gatectrl(struct clk *clk)
{
u32 v;
u32 mask;
if (!clk || !clk->clksel_reg || !cpu_is_omap44xx())
return;
mask = clk->flags & CLOCK_CLKOUTX2 ?
OMAP4430_DPLL_CLKOUTX2_GATE_CTRL_MASK :
OMAP4430_DPLL_CLKOUT_GATE_CTRL_MASK;
v = __raw_readl(clk->clksel_reg);
/* Set the bit to deny gatectrl */
v |= mask;
__raw_writel(v, clk->clksel_reg);
}
const struct clkops clkops_omap4_dpllmx_ops = {
.allow_idle = omap4_dpllmx_allow_gatectrl,
.deny_idle = omap4_dpllmx_deny_gatectrl,
};
/**
* 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 *clk)
{
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 = __raw_readl(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 *clk, unsigned long target_rate)
{
u32 v;
struct dpll_data *dd;
long r;
if (!clk || !clk->dpll_data)
return -EINVAL;
dd = clk->dpll_data;
/* regm4xen adds a multiplier of 4 to DPLL calculations */
v = __raw_readl(dd->control_reg) & OMAP4430_DPLL_REGM4XEN_MASK;
if (v)
target_rate = target_rate / OMAP4430_REGM4XEN_MULT;
r = omap2_dpll_round_rate(clk, target_rate);
if (r == ~0)
return r;
if (v)
clk->dpll_data->last_rounded_rate *= OMAP4430_REGM4XEN_MULT;
return clk->dpll_data->last_rounded_rate;
}