arch/arm/mach-omap2/clock3xxx.c

   1 /*
   2  * OMAP3-specific clock framework functions
   3  *
   4  * Copyright (C) 2007-2008 Texas Instruments, Inc.
   5  * Copyright (C) 2007-2010 Nokia Corporation
   6  *
   7  * Paul Walmsley
   8  * Jouni Högander
   9  *
  10  * Parts of this code are based on code written by
  11  * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  */
  17 #undef DEBUG
  18
  19 #include <linux/kernel.h>
  20 #include <linux/errno.h>
  21 #include <linux/clk.h>
  22 #include <linux/io.h>
  23
  24 #include "soc.h"
  25 #include "clock.h"
  26 #include "clock3xxx.h"
  27 #include "prm2xxx_3xxx.h"
  28 #include "prm-regbits-34xx.h"
  29 #include "cm2xxx_3xxx.h"
  30 #include "cm-regbits-34xx.h"
  31
  32 /*
  33  * DPLL5_FREQ_FOR_USBHOST: USBHOST and USBTLL are the only clocks
  34  * that are sourced by DPLL5, and both of these require this clock
  35  * to be at 120 MHz for proper operation.
  36  */
  37 #define DPLL5_FREQ_FOR_USBHOST          120000000
  38
  39 /* needed by omap3_core_dpll_m2_set_rate() */
  40 struct clk *sdrc_ick_p, *arm_fck_p;
  41 int omap3_dpll4_set_rate(struct clk_hw *hw, unsigned long rate,
  42                                 unsigned long parent_rate)
  43 {
  44         /*
  45          * According to the 12-5 CDP code from TI, "Limitation 2.5"
  46          * on 3430ES1 prevents us from changing DPLL multipliers or dividers
  47          * on DPLL4.
  48          */
  49         if (omap_rev() == OMAP3430_REV_ES1_0) {
  50                 pr_err("clock: DPLL4 cannot change rate due to silicon 'Limitation 2.5' on 3430ES1.\n");
  51                 return -EINVAL;
  52         }
  53
  54         return omap3_noncore_dpll_set_rate(hw, rate, parent_rate);
  55 }
  56
  57 void __init omap3_clk_lock_dpll5(void)
  58 {
  59         struct clk *dpll5_clk;
  60         struct clk *dpll5_m2_clk;
  61
  62         dpll5_clk = clk_get(NULL, "dpll5_ck");
  63         clk_set_rate(dpll5_clk, DPLL5_FREQ_FOR_USBHOST);
  64         clk_prepare_enable(dpll5_clk);
  65
  66         /* Program dpll5_m2_clk divider for no division */
  67         dpll5_m2_clk = clk_get(NULL, "dpll5_m2_ck");
  68         clk_prepare_enable(dpll5_m2_clk);
  69         clk_set_rate(dpll5_m2_clk, DPLL5_FREQ_FOR_USBHOST);
  70
  71         clk_disable_unprepare(dpll5_m2_clk);
  72         clk_disable_unprepare(dpll5_clk);
  73         return;
  74 }
  75
  76 /* Common clock code */
  77
  78 /*
  79  * Switch the MPU rate if specified on cmdline.  We cannot do this
  80  * early until cmdline is parsed.  XXX This should be removed from the
  81  * clock code and handled by the OPP layer code in the near future.
  82  */
  83 static int __init omap3xxx_clk_arch_init(void)
  84 {
  85         int ret;
  86
  87         if (!cpu_is_omap34xx())
  88                 return 0;
  89
  90         ret = omap2_clk_switch_mpurate_at_boot("dpll1_ck");
  91         if (!ret)
  92                 omap2_clk_print_new_rates("osc_sys_ck", "core_ck", "arm_fck");
  93
  94         return ret;
  95 }
  96
  97 omap_arch_initcall(omap3xxx_clk_arch_init);
  98
  99