nuttx/arch/arm/src/kl/kl_pwm.c

/****************************************************************************
 * arch/arm/src/kl/kl_pwm.c
 *
 *   Copyright (C) 2013, 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *           Alan Carvalho de Assis <acassis@gmail.com>
 *
 * 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 <stdint.h>
#include <stdio.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/timers/pwm.h>
#include <arch/board/board.h>

#include "up_internal.h"
#include "up_arch.h"

#include "chip.h"
#include "kl_pwm.h"
#include "kl_gpio.h"
#include "hardware/kl_tpm.h"
#include "hardware/kl_sim.h"

/* This module then only compiles if there is at least one enabled timer
 * intended for use with the PWM upper half driver.
 */

#if defined(CONFIG_KL_TPM0_PWM)  || defined(CONFIG_KL_TPM1_PWM)  || \
    defined(CONFIG_KL_TPM2_PWM)

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/
/* PWM/Timer Definitions ****************************************************/

/* Debug ********************************************************************/

#ifdef CONFIG_DEBUG_PWM_INFO
#  define pwm_dumpgpio(p,m) kl_dumpgpio(p,m)
#else
#  define pwm_dumpgpio(p,m)
#endif

/****************************************************************************
 * Private Types
 ****************************************************************************/
/* This structure represents the state of one PWM timer */

struct kl_pwmtimer_s
{
  FAR const struct pwm_ops_s *ops;     /* PWM operations */
  uint8_t                     tpmid;   /* Timer/PWM Module ID {0,..,2} */
  uint8_t                     channel; /* Timer/PWM Module channel: {0,..5} */
  uint32_t                    base;    /* The base address of the timer */
  uint32_t                    pincfg;  /* Output pin configuration */
  uint32_t                    pclk;    /* The frequency of the peripheral clock */
};

/****************************************************************************
 * Static Function Prototypes
 ****************************************************************************/
/* Register access */

static uint32_t pwm_getreg(struct kl_pwmtimer_s *priv, int offset);
static void pwm_putreg(struct kl_pwmtimer_s *priv, int offset, uint32_t value);

#ifdef CONFIG_DEBUG_PWM_INFO
static void pwm_dumpregs(struct kl_pwmtimer_s *priv, FAR const char *msg);
#else
#  define pwm_dumpregs(priv,msg)
#endif

/* Timer management */

static int pwm_timer(FAR struct kl_pwmtimer_s *priv,
                     FAR const struct pwm_info_s *info);

/* PWM driver methods */

static int pwm_setup(FAR struct pwm_lowerhalf_s *dev);
static int pwm_shutdown(FAR struct pwm_lowerhalf_s *dev);

static int pwm_start(FAR struct pwm_lowerhalf_s *dev,
                     FAR const struct pwm_info_s *info);

static int pwm_stop(FAR struct pwm_lowerhalf_s *dev);
static int pwm_ioctl(FAR struct pwm_lowerhalf_s *dev,
                     int cmd, unsigned long arg);

/****************************************************************************
 * Private Data
 ****************************************************************************/
/* This is the list of lower half PWM driver methods used by the upper half driver */

static const struct pwm_ops_s g_pwmops =
{
  .setup      = pwm_setup,
  .shutdown   = pwm_shutdown,
  .start      = pwm_start,
  .stop       = pwm_stop,
  .ioctl      = pwm_ioctl,
};

#ifdef CONFIG_KL_TPM0_PWM
static struct kl_pwmtimer_s g_pwm0dev =
{
  .ops        = &g_pwmops,
  .tpmid      = 0,
  .channel    = CONFIG_KL_TPM0_CHANNEL,
  .base       = KL_TPM0_BASE,
  .pincfg     = PWM_TPM0_PINCFG,
  .pclk       = BOARD_CORECLK_FREQ,
};
#endif

#ifdef CONFIG_KL_TPM1_PWM
static struct kl_pwmtimer_s g_pwm1dev =
{
  .ops        = &g_pwmops,
  .tpmid      = 1,
  .channel    = CONFIG_KL_TPM1_CHANNEL,
  .base       = KL_TPM1_BASE,
  .pincfg     = PWM_TPM1_PINCFG,
  .pclk       = BOARD_CORECLK_FREQ,
};
#endif

#ifdef CONFIG_KL_TPM2_PWM
static struct kl_pwmtimer_s g_pwm2dev =
{
  .ops        = &g_pwmops,
  .tpmid      = 2,
  .channel    = CONFIG_KL_TPM2_CHANNEL,
  .base       = KL_TPM2_BASE,
  .pincfg     = PWM_TPM2_PINCFG,
  .pclk       = BOARD_CORECLK_FREQ,
};
#endif

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: pwm_getreg
 *
 * Description:
 *   Read the value of an PWM timer register.
 *
 * Input Parameters:
 *   priv - A reference to the PWM block status
 *   offset - The offset to the register to read
 *
 * Returned Value:
 *   The current contents of the specified register
 *
 ****************************************************************************/

static uint32_t pwm_getreg(struct kl_pwmtimer_s *priv, int offset)
{
  return getreg32(priv->base + offset);
}

/****************************************************************************
 * Name: pwm_putreg
 *
 * Description:
 *   Read the value of an PWM timer register.
 *
 * Input Parameters:
 *   priv - A reference to the PWM block status
 *   offset - The offset to the register to read
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

static void pwm_putreg(struct kl_pwmtimer_s *priv, int offset, uint32_t value)
{
  putreg32(value, priv->base + offset);
}

/****************************************************************************
 * Name: pwm_dumpregs
 *
 * Description:
 *   Dump all timer registers.
 *
 * Input Parameters:
 *   priv - A reference to the PWM block status
 *
 * Returned Value:
 *   None
 *
 ****************************************************************************/

#ifdef CONFIG_DEBUG_PWM_INFO
static void pwm_dumpregs(struct kl_pwmtimer_s *priv, FAR const char *msg)
{
  int nchannels = (priv->tpmid == 0) ? 6 : 2;

  pwminfo("%s:\n", msg);
  pwminfo("  TPM%d_SC:     %04x   TPM%d_CNT:  %04x     TPM%d_MOD:  %04x\n",
          priv->tpmid,
          pwm_getreg(priv, TPM_SC_OFFSET),
          priv->tpmid,
          pwm_getreg(priv, TPM_CNT_OFFSET),
          priv->tpmid,
          pwm_getreg(priv, TPM_MOD_OFFSET));
  pwminfo("  TPM%d_STATUS: %04x   TPM%d_CONF: %04x\n",
          priv->tpmid,
          pwm_getreg(priv, TPM_STATUS_OFFSET),
          priv->tpmid,
          pwm_getreg(priv, TPM_CONF_OFFSET));
  pwminfo("   TPM%d_C0SC:  %04x   TPM%d_C0V:  %04x\n",
          priv->tpmid,
          pwm_getreg(priv, TPM_C0SC_OFFSET),
          priv->tpmid,
          pwm_getreg(priv, TPM_C0V_OFFSET));
  pwminfo("   TPM%d_C1SC:  %04x   TPM%d_C1V:  %04x\n",
          priv->tpmid,
          pwm_getreg(priv, TPM_C1SC_OFFSET),
          priv->tpmid,
          pwm_getreg(priv, TPM_C1V_OFFSET));

  if (nchannels >= 3)
    {
      pwminfo("   TPM%d_C2SC:  %04x   TPM%d_C2V:  %04x\n",
              priv->tpmid,
              pwm_getreg(priv, TPM_C2SC_OFFSET),
              priv->tpmid,
              pwm_getreg(priv, TPM_C2V_OFFSET));
    }

  if (nchannels >= 4)
    {
      pwminfo("   TPM%d_C3SC:  %04x   TPM%d_C3V:  %04x\n",
              priv->tpmid,
              pwm_getreg(priv, TPM_C3SC_OFFSET),
              priv->tpmid,
              pwm_getreg(priv, TPM_C3V_OFFSET));
    }

  if (nchannels >= 5)
    {
      pwminfo("   TPM%d_C4SC:  %04x   TPM%d_C4V:  %04x\n",
              priv->tpmid,
              pwm_getreg(priv, TPM_C4SC_OFFSET),
              priv->tpmid,
              pwm_getreg(priv, TPM_C4V_OFFSET));
    }

  if (nchannels >= 6)
    {
      pwminfo("   TPM%d_C5SC:  %04x   TPM%d_C5V:  %04x\n",
              priv->tpmid,
              pwm_getreg(priv, TPM_C5SC_OFFSET),
              priv->tpmid,
              pwm_getreg(priv, TPM_C5V_OFFSET));
    }
}
#endif

/****************************************************************************
 * Name: pwm_timer
 *
 * Description:
 *   (Re-)initialize the timer resources and start the pulsed output
 *
 * Input Parameters:
 *   priv - A reference to the lower half PWM driver state structure
 *   info - A reference to the characteristics of the pulsed output
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 ****************************************************************************/

static int pwm_timer(FAR struct kl_pwmtimer_s *priv,
                     FAR const struct pwm_info_s *info)
{
  /* Calculated values */

  uint32_t prescaler;
  uint32_t tpmclk;
  uint32_t modulo;
  uint32_t regval;
  uint32_t cv;
  uint8_t i;

  static const uint8_t presc_values[8] = {1, 2, 4, 8, 16, 32, 64, 128};

  /* Register contents */

  DEBUGASSERT(priv != NULL && info != NULL);

  pwminfo("TPM%d channel: %d frequency: %d duty: %08x\n",
          priv->tpmid, priv->channel, info->frequency, info->duty);

  DEBUGASSERT(info->frequency > 0 && info->duty > 0 &&
              info->duty < uitoub16(100));

  /* Calculate optimal values for the timer prescaler and for the timer modulo
   * register.  If' frequency' is the desired frequency, then
   *
   *   modulo = tpmclk / frequency
   *   tpmclk = pclk / presc
   *
   * Or,
   *
   *   modulo = pclk / presc / frequency
   *
   * There are many solutions to do this, but the best solution will be the
   * one that has the largest modulo value and the smallest prescaler value.
   * That is the solution that should give us the most accuracy in the timer
   * control.  Subject to:
   *
   *   1 <= presc  <= 128 (need to be 1, 2, 4, 8, 16, 32, 64, 128)
   *   1 <= modulo <= 65535
   *
   * So presc = pclk / 65535 / frequency would be optimal.
   *
   * Example:
   *
   *  pclk      = 24 MHz
   *  frequency = 100 Hz
   *
   *  prescaler = 24,000,000 / 65,535 / 100
   *            = 3.6 (or 4 -- taking the ceiling always)
   *  timclk    = 24,000,000 / 4
   *            = 6,000,000
   *  modulo    = 6,000,000 / 100
   *            = 60,000
   */

  prescaler = (priv->pclk / info->frequency + 65534) / 65535;

  for (i = 0; i < 7; i++)
    {
      if (prescaler <= presc_values[i])
        {
           break;
        }
    }

  prescaler = i;

  tpmclk = priv->pclk / presc_values[prescaler];

  modulo = tpmclk / info->frequency;
  if (modulo < 1)
    {
      modulo = 1;
    }
  else if (modulo > 65535)
    {
      modulo = 65535;
    }

  /* Duty cycle:
   *
   * duty cycle = cv / modulo (fractional value)
   */

  cv = b16toi(info->duty * modulo + b16HALF);

  pwminfo("TPM%d PCLK: %d frequency: %d TPMCLK: %d prescaler: %d modulo: %d c0v: %d\n",
          priv->tpmid, priv->pclk, info->frequency, tpmclk,
          presc_values[prescaler], modulo, cv);

  /* Disable TPM and reset CNT before writing MOD and PS */

  pwm_putreg(priv, TPM_SC_OFFSET, TPM_SC_CMOD_DIS);
  pwm_putreg(priv, TPM_CNT_OFFSET, 0);

  /* Set the modulo value */

  pwm_putreg(priv, TPM_MOD_OFFSET, (uint16_t)modulo);

  /* Set the duty cycle for channel specific */

  switch (priv->channel)
    {
      case 0:  /* PWM Mode configuration: Channel 0 */
        {
          pwm_putreg(priv, TPM_C0SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C0V_OFFSET, (uint16_t) cv);
        }
        break;

      case 1:  /* PWM Mode configuration: Channel 1 */
        {
          pwm_putreg(priv, TPM_C1SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C1V_OFFSET, (uint16_t) cv);
        }
        break;

      case 2:  /* PWM Mode configuration: Channel 2 */
        {
          pwm_putreg(priv, TPM_C2SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C2V_OFFSET, (uint16_t) cv);
        }
        break;

      case 3:  /* PWM Mode configuration: Channel 3 */
        {
          pwm_putreg(priv, TPM_C3SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C3V_OFFSET, (uint16_t) cv);
        }
        break;

      case 4:  /* PWM Mode configuration: Channel 4 */
        {
          pwm_putreg(priv, TPM_C4SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C4V_OFFSET, (uint16_t) cv);
        }
        break;

      case 5:  /* PWM Mode configuration: Channel 5 */
        {
          pwm_putreg(priv, TPM_C5SC_OFFSET, TPM_CnSC_MSB | TPM_CnSC_ELSB);
          pwm_putreg(priv, TPM_C5V_OFFSET, (uint16_t) cv);
        }
        break;

      default:
        pwmerr("ERROR: No such channel: %d\n", priv->channel);
        return -EINVAL;
    }

  /* Set prescaler and enable clock */

  regval = pwm_getreg(priv, TPM_SC_OFFSET);
  regval &= ~(TPM_SC_PS_MASK);
  regval &= ~(TPM_SC_CMOD_MASK);
  regval |= prescaler | TPM_SC_CMOD_LPTPM_CLK;
  pwm_putreg(priv, TPM_SC_OFFSET, (uint16_t)regval);

  pwm_dumpregs(priv, "After starting");
  return OK;
}

/****************************************************************************
 * Name: pwm_setup
 *
 * Description:
 *   This method is called when the driver is opened.  The lower half driver
 *   should configure and initialize the device so that it is ready for use.
 *   It should not, however, output pulses until the start method is called.
 *
 * Input Parameters:
 *   dev - A reference to the lower half PWM driver state structure
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 * Assumptions:
 *   AHB1 or 2 clocking for the GPIOs and timer has already been configured
 *   by the RCC logic at power up.
 *
 ****************************************************************************/

static int pwm_setup(FAR struct pwm_lowerhalf_s *dev)
{
  uint32_t regval;
  FAR struct kl_pwmtimer_s *priv = (FAR struct kl_pwmtimer_s *)dev;

  /* Enable access to TPM modules */

  regval = getreg32(KL_SIM_SCGC6);
  regval |= SIM_SCGC6_TPM0 | SIM_SCGC6_TPM1 | SIM_SCGC6_TPM2;
  putreg32(regval, KL_SIM_SCGC6);

  pwminfo("TPM%d pincfg: %08x\n", priv->tpmid, priv->pincfg);
  pwm_dumpregs(priv, "Initially");

  /* Configure the PWM output pin, but do not start the timer yet */

  kl_configgpio(priv->pincfg);
  pwm_dumpgpio(priv->pincfg, "PWM setup");
  return OK;
}

/****************************************************************************
 * Name: pwm_shutdown
 *
 * Description:
 *   This method is called when the driver is closed.  The lower half driver
 *   stop pulsed output, free any resources, disable the timer hardware, and
 *   put the system into the lowest possible power usage state
 *
 * Input Parameters:
 *   dev - A reference to the lower half PWM driver state structure
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 ****************************************************************************/

static int pwm_shutdown(FAR struct pwm_lowerhalf_s *dev)
{
  FAR struct kl_pwmtimer_s *priv = (FAR struct kl_pwmtimer_s *)dev;
  uint32_t pincfg;

  pwminfo("TPM%d pincfg: %08x\n", priv->tpmid, priv->pincfg);

  /* Make sure that the output has been stopped */

  pwm_stop(dev);

  /* Then put the GPIO pin back to the default state */

  pincfg  = (priv->pincfg & ~(_PIN_MODE_MASK));
  pincfg |= GPIO_INPUT;
  kl_configgpio(pincfg);
  return OK;
}

/****************************************************************************
 * Name: pwm_start
 *
 * Description:
 *   (Re-)initialize the timer resources and start the pulsed output
 *
 * Input Parameters:
 *   dev - A reference to the lower half PWM driver state structure
 *   info - A reference to the characteristics of the pulsed output
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 ****************************************************************************/

static int pwm_start(FAR struct pwm_lowerhalf_s *dev,
                     FAR const struct pwm_info_s *info)
{
  FAR struct kl_pwmtimer_s *priv = (FAR struct kl_pwmtimer_s *)dev;
  return pwm_timer(priv, info);
}

/****************************************************************************
 * Name: pwm_stop
 *
 * Description:
 *   Stop the pulsed output and reset the timer resources
 *
 * Input Parameters:
 *   dev - A reference to the lower half PWM driver state structure
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 * Assumptions:
 *   This function is called to stop the pulsed output at anytime.  This
 *   method is also called from the timer interrupt handler when a repetition
 *   count expires... automatically stopping the timer.
 *
 ****************************************************************************/

static int pwm_stop(FAR struct pwm_lowerhalf_s *dev)
{
  FAR struct kl_pwmtimer_s *priv = (FAR struct kl_pwmtimer_s *)dev;
  irqstate_t flags;

  pwminfo("TPM%d\n", priv->tpmid);

  /* Disable interrupts momentary to stop any ongoing timer processing and
   * to prevent any concurrent access to the reset register.
  */

  flags = enter_critical_section();

  /* Disable further interrupts and stop the timer */

  pwm_putreg(priv, TPM_SC_OFFSET, TPM_SC_CMOD_DIS);
  pwm_putreg(priv, TPM_CNT_OFFSET, 0);

  /* Determine which timer channel to clear */

  switch (priv->channel)
    {
      case 0:
        pwm_putreg(priv, TPM_C0V_OFFSET, 0);
        break;

      case 1:
        pwm_putreg(priv, TPM_C1V_OFFSET, 0);
        break;

      case 2:
        pwm_putreg(priv, TPM_C2V_OFFSET, 0);
        break;

      case 3:
        pwm_putreg(priv, TPM_C3V_OFFSET, 0);
        break;

      case 4:
        pwm_putreg(priv, TPM_C4V_OFFSET, 0);
        break;

      case 5:
        pwm_putreg(priv, TPM_C5V_OFFSET, 0);
        break;

      default:
        pwmerr("ERROR: No such channel: %d\n", priv->channel);
        return -EINVAL;
    }

  leave_critical_section(flags);

  pwm_dumpregs(priv, "After stop");
  return OK;
}

/****************************************************************************
 * Name: pwm_ioctl
 *
 * Description:
 *   Lower-half logic may support platform-specific ioctl commands
 *
 * Input Parameters:
 *   dev - A reference to the lower half PWM driver state structure
 *   cmd - The ioctl command
 *   arg - The argument accompanying the ioctl command
 *
 * Returned Value:
 *   Zero on success; a negated errno value on failure
 *
 ****************************************************************************/

static int pwm_ioctl(FAR struct pwm_lowerhalf_s *dev, int cmd, unsigned long arg)
{
#ifdef CONFIG_DEBUG_PWM_INFO
  FAR struct kl_pwmtimer_s *priv = (FAR struct kl_pwmtimer_s *)dev;

  /* There are no platform-specific ioctl commands */

  pwminfo("TPM%d\n", priv->tpmid);
#endif
  return -ENOTTY;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: kl_pwminitialize
 *
 * Description:
 *   Initialize one timer for use with the upper_level PWM driver.
 *
 * Input Parameters:
 *   timer - A number identifying the timer use.
 *
 * Returned Value:
 *   On success, a pointer to the KL lower half PWM driver is returned.
 *   NULL is returned on any failure.
 *
 ****************************************************************************/

FAR struct pwm_lowerhalf_s *kl_pwminitialize(int timer)
{
  FAR struct kl_pwmtimer_s *lower;

  pwminfo("TPM%d\n", timer);

  switch (timer)
    {
#ifdef CONFIG_KL_TPM0_PWM
      case 0:
        lower = &g_pwm0dev;

        break;
#endif

#ifdef CONFIG_KL_TPM1_PWM
      case 1:
        lower = &g_pwm1dev;

        break;
#endif

#ifdef CONFIG_KL_TPM2_PWM
      case 2:
        lower = &g_pwm2dev;

        break;
#endif

      default:
        pwmerr("ERROR: No such timer configured\n");
        return NULL;
    }

  return (FAR struct pwm_lowerhalf_s *)lower;
}

#endif /* CONFIG_KL_TPMn_PWM, n = 0,...,2 */