/****************************************************************************
* arch/arm/src/lpc43/lpc43_cgu.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <errno.h>
#include "up_arch.h"
#include "lpc43_cgu.h"
#include <arch/board/board.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Maximum/Threashold Frequencies *******************************************/
#define LOW_XTAL_FREQUENCY 15000000
#define MAX_XTAL_FREQUENCY 25000000
#define MAX_FCLKOUT_FREQUENCY 156000000
#define MAX_FCCO_FRQUENCY 320000000
/* Configuration ************************************************************/
/* This supports configuration of CGU clocking from board-specific parameters
* that must be provided in the board.h header file.
*
* That header file must provided the following values:
*
* BOARD_XTAL_FREQUENCY - The LPC43xx XTAL oscillator input frequency
*/
#ifndef BOARD_XTAL_FREQUENCY
# error "board.h must provide the LPC43xx cystal input frequency (BOARD_XTAL_FREQUENCY)"
#endif
#if BOARD_XTAL_FREQUENCY >= MAX_XTAL_FREQUENCY
# error "BOARD_XTAL_FREQUENCY exceeds the maximum value"
#endif
#if !defined(BOARD_PLL1_DIRECT) && (BOARD_FCLKOUT_FREQUENCY > MAX_FCLKOUT_FREQUENCY)
# error "BOARD_FCLKOUT_FREQUENCY exceed the maximum"
#endif
#if BOARD_FCCO_FREQUENCY > MAX_FCCO_FRQUENCY
# error "BOARD_FCCO_FREQUENCY exceed the maximum"
#endif
/* Convert the user-friendly definitions in board.h to register bit settings */
#if BOARD_PLL_PSEL == 1
# define CTRL_PSEL_VALUE PLL1_CTRL_PSEL_DIV1
#elif BOARD_PLL_PSEL == 2
# define CTRL_PSEL_VALUE PLL1_CTRL_PSEL_DIV2
#elif BOARD_PLL_PSEL == 4
# define CTRL_PSEL_VALUE PLL1_CTRL_PSEL_DIV4
#elif BOARD_PLL_PSEL == 8
# define CTRL_PSEL_VALUE PLL1_CTRL_PSEL_DIV8
#else
# error "Unsupported value of BOARD_PLL_PSEL"
#endif
#if BOARD_PLL_NSEL == 1
# define CTRL_NSEL_VALUE PLL1_CTRL_NSEL_DIV1
#elif BOARD_PLL_NSEL == 2
# define CTRL_NSEL_VALUE PLL1_CTRL_NSEL_DIV2
#elif BOARD_PLL_NSEL == 3
# define CTRL_NSEL_VALUE PLL1_CTRL_NSEL_DIV3
#elif BOARD_PLL_NSEL == 4
# define CTRL_NSEL_VALUE PLL1_CTRL_NSEL_DIV4
#else
# error "Unsupported value of BOARD_PLL_NSEL"
#endif
#if (BOARD_PLL_MSEL > 0) && (BOARD_PLL_MSEL < 256)
# define CTRL_MSEL_VALUE PLL1_CTRL_MSEL(BOARD_PLL_MSEL)
#else
# error "Unsupported value of BOARD_PLL_NSEL"
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: lpc43_xtalconfig
*
* Description:
* Configure the cystal input to PLL1 using the settings provided in
* the board.h file.
*
****************************************************************************/
static inline void lpc43_xtalconfig(void)
{
/* Configure the crystal input to PLL1 */
uint32_t regval;
/* Set/clear the HF bit in the crystal oscillator control register.
* - The bit must be cleared if low-frequency oscillators (<=15MHz)
* - The HF bit must be set for high-frequency osciallators (>20MHz)
* - For oscillators in the range 15-20 MHz, the HF setting does not matter.
*/
regval = getreg32(LPC43_XTAL_OSC_CTRL);
#if BOARD_XTAL_FREQUENCY <= LOW_XTAL_FREQUENCY
regval &= ~XTAL_OSC_CTRL_HF;
#else
regval |= XTAL_OSC_CTRL_HF;
#endif
putreg32(regval, LPC43_XTAL_OSC_CTRL);
/* Enable the crystal oscillator */
regval |= XTAL_OSC_CTRL_ENABLE;
putreg32(regval, LPC43_XTAL_OSC_CTRL);
/* Delay for stable clock input */
up_mdelay(20);
/* Select the crystal oscillator as the input to PLL1 */
regval = getreg32(LPC43_PLL1_CTRL);
regval &= PLL1_CTRL_CLKSEL_MASK;
regval |= PLL1_CLKSEL_XTAL | PLL1_CTRL_AUTOBLOCK;
putreg32(regval, LPC43_PLL1_CTRL);
}
/****************************************************************************
* Name: lpc43_clockconfig
*
* Description:
* Configure PLL1 dividers and multipliers per the settings in the board.h
* file to generate the desired Fclkcout and Fcco frequencies.
*
****************************************************************************/
static inline void lpc43_pll1config(void)
{
uint32_t regval;
/* Clear PLL1 controls:
*
* - PLL1_CTRL_BYPASS: Input clock bypass control
* - PLL1_CTRL_FBSEL: PLL1 feedback select
* - PLL1_CTRL_DIRECT: PLL1 direct CCO output
* - PLL1_CTRL_PSEL_MASK: Post-divider division ratio P (psel)
* - PLL1_CTRL_NSEL_MASK: Pre-divider division ratio N (nsel)
* - PLL1_CTRL_MSEL_MASK: Feedback-divider division ratio M (msel)
*/
regval = getreg32(LPC43_PLL1_CTRL);
regval &= ~(PLL1_CTRL_BYPASS | PLL1_CTRL_FBSEL | PLL1_CTRL_DIRECT |
PLL1_CTRL_PSEL_MASK | PLL1_CTRL_NSEL_MASK |
PLL1_CTRL_MSEL_MASK);
putreg32(regval, LPC43_PLL1_CTRL);
/* Clear PLL1 controls:
*
* - PLL1_CTRL_FBSEL: Set in both integer and direct modes
* - PLL1_CTRL_DIRECT: Set in direct mode
* - PLL1_CTRL_PSEL: Set to the value from board.h
* - PLL1_CTRL_NSEL: Set to the value from board.h
* - PLL1_CTRL_MSEL: Set to the value from board.h
*/
#ifdef BOARD_PLL1_DIRECT
regval |= (PLL1_CTRL_FBSEL | PLL1_CTRL_DIRECT | CTRL_PSEL_VALUE |
CTRL_NSEL_VALUE | CTRL_MSEL_VALUE);
#else
regval |= (PLL1_CTRL_FBSEL | CTRL_PSEL_VALUE | CTRL_NSEL_VALUE |
CTRL_MSEL_VALUE);
#endif
putreg32(regval, LPC43_PLL1_CTRL);
}
/****************************************************************************
* Name: lpc43_pll1enable
*
* Description:
* Take PLL1 out of power-down mode and wait until it is locked onto the
* input clock.
*
****************************************************************************/
static inline void lpc43_pll1enable(void)
{
uint32_t regval;
/* Take PLL1 out of power down mode. The reset state of the PD bit
* is one, i.e., powered down.
*/
regval = getreg32(LPC43_PLL1_CTRL);
regval &= ~PLL1_CTRL_PD;
putreg32(regval, LPC43_PLL1_CTRL);
/* When the power-down mode is terminated, PPL1 will resume its normal
* operation and will make the lock signal high once it has regained
* lock on the input clock
*
* Wait for PLL1 to report that it is locked.
*/
while ((getreg32(LPC43_PLL1_STAT) & PLL1_STAT_LOCK) == 0);
}
/****************************************************************************
* Name: lpc32_m4clkselect
*
* Description:
* Select PLL1 output as the Cortex-M4 source clock.
*
****************************************************************************/
static inline void lpc32_m4clkselect(void)
{
uint32_t regval;
regval = getreg32(LPC43_BASE_M4_CLK);
regval &= ~BASE_M4_CLK_CLKSEL_MASK;
regval |= BASE_M4_CLKSEL_PLL1;
putreg32(regval, LPC43_BASE_M4_CLK);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lpc43_clockconfig
*
* Description:
* Called to initialize the LPC43XX. This does whatever setup is needed
* to put the MCU in a usable state. This includes the initialization of
* clocking using the settings in board.h.
*
****************************************************************************/
void lpc43_clockconfig(void)
{
/* Configure the crystal input to PLL1 */
lpc43_xtalconfig();
/* Configure PLL1 */
lpc43_pll1config();
/* Enable PLL1 */
lpc43_pll1enable();
/* Set up PLL1 output as the M4 clock */
lpc32_m4clkselect();
}
