linux/arch/arm/mach-omap2/clkt2xxx_osc.c
Paul Walmsley cc1d230cfb OMAP2+: clock: comment that osc_ck/osc_sys_ck should use clockfw autoidle control
Place some comments in the OMAP oscillator clock control code to note that
its autoidle mode should eventually be controlled via the new OMAP clockfw
autoidle control interface.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Rajendra Nayak <rnayak@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
2011-03-07 20:02:21 -07:00

77 lines
1.9 KiB
C

/*
* OMAP2xxx osc_clk-specific clock code
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <plat/clock.h>
#include "clock.h"
#include "clock2xxx.h"
#include "prm2xxx_3xxx.h"
#include "prm-regbits-24xx.h"
/*
* XXX This does not actually enable the osc_ck, since the osc_ck must
* be running for this function to be called. Instead, this function
* is used to disable an autoidle mode on the osc_ck. The existing
* clk_enable/clk_disable()-based usecounting for osc_ck should be
* replaced with autoidle-based usecounting.
*/
static int omap2_enable_osc_ck(struct clk *clk)
{
u32 pcc;
pcc = __raw_readl(prcm_clksrc_ctrl);
__raw_writel(pcc & ~OMAP_AUTOEXTCLKMODE_MASK, prcm_clksrc_ctrl);
return 0;
}
/*
* XXX This does not actually disable the osc_ck, since doing so would
* immediately halt the system. Instead, this function is used to
* enable an autoidle mode on the osc_ck. The existing
* clk_enable/clk_disable()-based usecounting for osc_ck should be
* replaced with autoidle-based usecounting.
*/
static void omap2_disable_osc_ck(struct clk *clk)
{
u32 pcc;
pcc = __raw_readl(prcm_clksrc_ctrl);
__raw_writel(pcc | OMAP_AUTOEXTCLKMODE_MASK, prcm_clksrc_ctrl);
}
const struct clkops clkops_oscck = {
.enable = omap2_enable_osc_ck,
.disable = omap2_disable_osc_ck,
};
unsigned long omap2_osc_clk_recalc(struct clk *clk)
{
return omap2xxx_get_apll_clkin() * omap2xxx_get_sysclkdiv();
}