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linux-next/arch/arm/mach-omap2/clkt2xxx_apll.c
Paul Walmsley 81b34fbecb OMAP2 clock: split OMAP2420, OMAP2430 clock data into their own files
In preparation for multi-OMAP2 kernels, split
mach-omap2/clock2xxx_data.c into mach-omap2/clock2420_data.c and
mach-omap2/clock2430_data.c.  2430 uses a different device space
physical memory layout than past or future OMAPs, and we use a
different virtual memory layout as well, which causes trouble for
architecture-level code/data that tries to support both.  We tried
using offsets from the virtual base last year, but those patches never
made it upstream; so after some discussion with Tony about the best
all-around approach, we'll just grit our teeth and duplicate the
structures.  The maintenance advantages of a single kernel config that
can compile and boot on OMAP2, 3, and 4 platforms are simply too
compelling.

This approach does have some nice benefits beyond multi-OMAP 2 kernel
support.  The runtime size of OMAP2420-specific and OMAP2430-specific
kernels is smaller, since unused clocks for the other OMAP2 chip will
no longer be compiled in.  (At some point we will mark the clock data
__initdata and allocate it during registration, which will eliminate
the runtime memory advantage.)  It also makes the clock trees slightly
easier to read, since 2420-specific and 2430-specific clocks are no
longer mixed together.

This patch also splits 2430-specific clock code into its own file,
mach-omap2/clock2430.c, which is only compiled in for 2430 builds -
mostly for organizational clarity.

While here, fix a bug in the OMAP2430 clock tree: "emul_ck" was
incorrectly marked as being 2420-only, when actually it is present on
both OMAP2420 and OMAP2430.

Thanks to Tony for some good discussions about how to approach this
problem.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
2010-02-24 12:29:42 -07:00

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2.6 KiB
C

/*
* OMAP2xxx APLL clock control functions
*
* Copyright (C) 2005-2008 Texas Instruments, Inc.
* Copyright (C) 2004-2010 Nokia Corporation
*
* Contacts:
* Richard Woodruff <r-woodruff2@ti.com>
* Paul Walmsley
*
* Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
* Gordon McNutt and RidgeRun, Inc.
*
* 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.
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <plat/clock.h>
#include <plat/prcm.h>
#include "clock.h"
#include "clock2xxx.h"
#include "cm.h"
#include "cm-regbits-24xx.h"
/* CM_CLKEN_PLL.EN_{54,96}M_PLL options (24XX) */
#define EN_APLL_STOPPED 0
#define EN_APLL_LOCKED 3
/* CM_CLKSEL1_PLL.APLLS_CLKIN options (24XX) */
#define APLLS_CLKIN_19_2MHZ 0
#define APLLS_CLKIN_13MHZ 2
#define APLLS_CLKIN_12MHZ 3
void __iomem *cm_idlest_pll;
/* Private functions */
/* Enable an APLL if off */
static int omap2_clk_apll_enable(struct clk *clk, u32 status_mask)
{
u32 cval, apll_mask;
apll_mask = EN_APLL_LOCKED << clk->enable_bit;
cval = cm_read_mod_reg(PLL_MOD, CM_CLKEN);
if ((cval & apll_mask) == apll_mask)
return 0; /* apll already enabled */
cval &= ~apll_mask;
cval |= apll_mask;
cm_write_mod_reg(cval, PLL_MOD, CM_CLKEN);
omap2_cm_wait_idlest(cm_idlest_pll, status_mask,
OMAP24XX_CM_IDLEST_VAL, clk->name);
/*
* REVISIT: Should we return an error code if omap2_wait_clock_ready()
* fails?
*/
return 0;
}
static int omap2_clk_apll96_enable(struct clk *clk)
{
return omap2_clk_apll_enable(clk, OMAP24XX_ST_96M_APLL);
}
static int omap2_clk_apll54_enable(struct clk *clk)
{
return omap2_clk_apll_enable(clk, OMAP24XX_ST_54M_APLL);
}
/* Stop APLL */
static void omap2_clk_apll_disable(struct clk *clk)
{
u32 cval;
cval = cm_read_mod_reg(PLL_MOD, CM_CLKEN);
cval &= ~(EN_APLL_LOCKED << clk->enable_bit);
cm_write_mod_reg(cval, PLL_MOD, CM_CLKEN);
}
/* Public data */
const struct clkops clkops_apll96 = {
.enable = omap2_clk_apll96_enable,
.disable = omap2_clk_apll_disable,
};
const struct clkops clkops_apll54 = {
.enable = omap2_clk_apll54_enable,
.disable = omap2_clk_apll_disable,
};
/* Public functions */
u32 omap2xxx_get_apll_clkin(void)
{
u32 aplls, srate = 0;
aplls = cm_read_mod_reg(PLL_MOD, CM_CLKSEL1);
aplls &= OMAP24XX_APLLS_CLKIN_MASK;
aplls >>= OMAP24XX_APLLS_CLKIN_SHIFT;
if (aplls == APLLS_CLKIN_19_2MHZ)
srate = 19200000;
else if (aplls == APLLS_CLKIN_13MHZ)
srate = 13000000;
else if (aplls == APLLS_CLKIN_12MHZ)
srate = 12000000;
return srate;
}