arch/arm/mach-omap2/clkt2xxx_osc.c

   1 /*
   2  * OMAP2xxx osc_clk-specific clock code
   3  *
   4  * Copyright (C) 2005-2008 Texas Instruments, Inc.
   5  * Copyright (C) 2004-2010 Nokia Corporation
   6  *
   7  * Contacts:
   8  * Richard Woodruff <r-woodruff2@ti.com>
   9  * Paul Walmsley
  10  *
  11  * Based on earlier work by Tuukka Tikkanen, Tony Lindgren,
  12  * Gordon McNutt and RidgeRun, Inc.
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License version 2 as
  16  * published by the Free Software Foundation.
  17  */
  18 #undef DEBUG
  19
  20 #include <linux/module.h>
  21 #include <linux/kernel.h>
  22 #include <linux/errno.h>
  23 #include <linux/clk.h>
  24 #include <linux/io.h>
  25
  26 #include <plat/clock.h>
  27
  28 #include "clock.h"
  29 #include "clock2xxx.h"
  30 #include "prm2xxx_3xxx.h"
  31 #include "prm-regbits-24xx.h"
  32
  33 /*
  34  * XXX This does not actually enable the osc_ck, since the osc_ck must
  35  * be running for this function to be called.  Instead, this function
  36  * is used to disable an autoidle mode on the osc_ck.  The existing
  37  * clk_enable/clk_disable()-based usecounting for osc_ck should be
  38  * replaced with autoidle-based usecounting.
  39  */
  40 static int omap2_enable_osc_ck(struct clk *clk)
  41 {
  42         u32 pcc;
  43
  44         pcc = __raw_readl(prcm_clksrc_ctrl);
  45
  46         __raw_writel(pcc & ~OMAP_AUTOEXTCLKMODE_MASK, prcm_clksrc_ctrl);
  47
  48         return 0;
  49 }
  50
  51 /*
  52  * XXX This does not actually disable the osc_ck, since doing so would
  53  * immediately halt the system.  Instead, this function is used to
  54  * enable an autoidle mode on the osc_ck.  The existing
  55  * clk_enable/clk_disable()-based usecounting for osc_ck should be
  56  * replaced with autoidle-based usecounting.
  57  */
  58 static void omap2_disable_osc_ck(struct clk *clk)
  59 {
  60         u32 pcc;
  61
  62         pcc = __raw_readl(prcm_clksrc_ctrl);
  63
  64         __raw_writel(pcc | OMAP_AUTOEXTCLKMODE_MASK, prcm_clksrc_ctrl);
  65 }
  66
  67 const struct clkops clkops_oscck = {
  68         .enable         = omap2_enable_osc_ck,
  69         .disable        = omap2_disable_osc_ck,
  70 };
  71
  72 unsigned long omap2_osc_clk_recalc(struct clk *clk)
  73 {
  74         return omap2xxx_get_apll_clkin() * omap2xxx_get_sysclkdiv();
  75 }
  76