arch/mips/au1000/common/clocks.c

   1 /*
   2  * BRIEF MODULE DESCRIPTION
   3  *      Simple Au1000 clocks routines.
   4  *
   5  * Copyright 2001 MontaVista Software Inc.
   6  * Author: MontaVista Software, Inc.
   7  *              ppopov@mvista.com or source@mvista.com
   8  *
   9  *  This program is free software; you can redistribute  it and/or modify it
  10  *  under  the terms of  the GNU General  Public License as published by the
  11  *  Free Software Foundation;  either version 2 of the  License, or (at your
  12  *  option) any later version.
  13  *
  14  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
  15  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
  16  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  17  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
  18  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
  20  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  21  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
  22  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  *  You should have received a copy of the  GNU General Public License along
  26  *  with this program; if not, write  to the Free Software Foundation, Inc.,
  27  *  675 Mass Ave, Cambridge, MA 02139, USA.
  28  */
  29
  30 #include <linux/module.h>
  31 #include <asm/mach-au1x00/au1000.h>
  32
  33 static unsigned int au1x00_clock; // Hz
  34 static unsigned int lcd_clock;    // KHz
  35 static unsigned long uart_baud_base;
  36
  37 /*
  38  * Set the au1000_clock
  39  */
  40 void set_au1x00_speed(unsigned int new_freq)
  41 {
  42         au1x00_clock = new_freq;
  43 }
  44
  45 unsigned int get_au1x00_speed(void)
  46 {
  47         return au1x00_clock;
  48 }
  49
  50
  51
  52 /*
  53  * The UART baud base is not known at compile time ... if
  54  * we want to be able to use the same code on different
  55  * speed CPUs.
  56  */
  57 unsigned long get_au1x00_uart_baud_base(void)
  58 {
  59         return uart_baud_base;
  60 }
  61
  62 void set_au1x00_uart_baud_base(unsigned long new_baud_base)
  63 {
  64         uart_baud_base = new_baud_base;
  65 }
  66
  67 /*
  68  * Calculate the Au1x00's LCD clock based on the current
  69  * cpu clock and the system bus clock, and try to keep it
  70  * below 40 MHz (the Pb1000 board can lock-up if the LCD
  71  * clock is over 40 MHz).
  72  */
  73 void set_au1x00_lcd_clock(void)
  74 {
  75         unsigned int static_cfg0;
  76         unsigned int sys_busclk =
  77                 (get_au1x00_speed()/1000) /
  78                 ((int)(au_readl(SYS_POWERCTRL)&0x03) + 2);
  79
  80         static_cfg0 = au_readl(MEM_STCFG0);
  81
  82         if (static_cfg0 & (1<<11))
  83                 lcd_clock = sys_busclk / 5; /* note: BCLK switching fails with D5 */
  84         else
  85                 lcd_clock = sys_busclk / 4;
  86
  87         if (lcd_clock > 50000) /* Epson MAX */
  88                 printk("warning: LCD clock too high (%d KHz)\n", lcd_clock);
  89 }
  90
  91 unsigned int get_au1x00_lcd_clock(void)
  92 {
  93         return lcd_clock;
  94 }
  95
  96 EXPORT_SYMBOL(get_au1x00_lcd_clock);