arch/mips/au1000/common/clocks.c

   1 /*
   2  * BRIEF MODULE DESCRIPTION
   3  *      Simple Au1xx0 clocks routines.
   4  *
   5  * Copyright 2001, 2008 MontaVista Software Inc.
   6  * Author: MontaVista Software, Inc. <source@mvista.com>
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  14  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  15  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  16  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  17  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  19  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  20  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  21  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  *
  24  *  You should have received a copy of the  GNU General Public License along
  25  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  26  *  675 Mass Ave, Cambridge, MA 02139, USA.
  27  */
  28
  29 #include <linux/module.h>
  30 #include <asm/mach-au1x00/au1000.h>
  31
  32 static unsigned int au1x00_clock; /*  Hz */
  33 static unsigned int lcd_clock;    /* KHz */
  34 static unsigned long uart_baud_base;
  35
  36 /*
  37  * Set the au1000_clock
  38  */
  39 void set_au1x00_speed(unsigned int new_freq)
  40 {
  41         au1x00_clock = new_freq;
  42 }
  43
  44 unsigned int get_au1x00_speed(void)
  45 {
  46         return au1x00_clock;
  47 }
  48
  49 /*
  50  * The UART baud base is not known at compile time ... if
  51  * we want to be able to use the same code on different
  52  * speed CPUs.
  53  */
  54 unsigned long get_au1x00_uart_baud_base(void)
  55 {
  56         return uart_baud_base;
  57 }
  58
  59 void set_au1x00_uart_baud_base(unsigned long new_baud_base)
  60 {
  61         uart_baud_base = new_baud_base;
  62 }
  63
  64 /*
  65  * Calculate the Au1x00's LCD clock based on the current
  66  * cpu clock and the system bus clock, and try to keep it
  67  * below 40 MHz (the Pb1000 board can lock-up if the LCD
  68  * clock is over 40 MHz).
  69  */
  70 void set_au1x00_lcd_clock(void)
  71 {
  72         unsigned int static_cfg0;
  73         unsigned int sys_busclk = (get_au1x00_speed() / 1000) /
  74                                   ((int)(au_readl(SYS_POWERCTRL) & 0x03) + 2);
  75
  76         static_cfg0 = au_readl(MEM_STCFG0);
  77
  78         if (static_cfg0 & (1 << 11))
  79                 lcd_clock = sys_busclk / 5; /* note: BCLK switching fails with D5 */
  80         else
  81                 lcd_clock = sys_busclk / 4;
  82
  83         if (lcd_clock > 50000) /* Epson MAX */
  84                 printk(KERN_WARNING "warning: LCD clock too high (%u KHz)\n",
  85                                     lcd_clock);
  86 }
  87
  88 unsigned int get_au1x00_lcd_clock(void)
  89 {
  90         return lcd_clock;
  91 }
  92 EXPORT_SYMBOL(get_au1x00_lcd_clock);