arch/arm/include/asm/arch-tegra20/pwm.h

   1 /*
   2  * Tegra pulse width frequency modulator definitions
   3  *
   4  * Copyright (c) 2011 The Chromium OS Authors.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #ifndef __ASM_ARCH_TEGRA_PWM_H
  10 #define __ASM_ARCH_TEGRA_PWM_H
  11
  12 /* This is a single PWM channel */
  13 struct pwm_ctlr {
  14         uint control;           /* Control register */
  15         uint reserved[3];       /* Space space */
  16 };
  17
  18 #define PWM_NUM_CHANNELS        4
  19
  20 /* PWM_CONTROLLER_PWM_CSR_0/1/2/3_0 */
  21 #define PWM_ENABLE_SHIFT        31
  22 #define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT)
  23
  24 #define PWM_WIDTH_SHIFT 16
  25 #define PWM_WIDTH_MASK          (0x7FFF << PWM_WIDTH_SHIFT)
  26
  27 #define PWM_DIVIDER_SHIFT       0
  28 #define PWM_DIVIDER_MASK        (0x1FFF << PWM_DIVIDER_SHIFT)
  29
  30 /**
  31  * Program the PWM with the given parameters.
  32  *
  33  * @param channel       PWM channel to update
  34  * @param rate          Clock rate to use for PWM
  35  * @param pulse_width   high pulse width: 0=always low, 1=1/256 pulse high,
  36  *                      n = n/256 pulse high
  37  * @param freq_divider  frequency divider value (1 to use rate as is)
  38  */
  39 void pwm_enable(unsigned channel, int rate, int pulse_width, int freq_divider);
  40
  41 /**
  42  * Request a pwm channel as referenced by a device tree node.
  43  *
  44  * This channel can then be passed to pwm_enable().
  45  *
  46  * @param blob          Device tree blob
  47  * @param node          Node containing reference to pwm
  48  * @param prop_name     Property name of pwm reference
  49  * @return channel number, if ok, else -1
  50  */
  51 int pwm_request(const void *blob, int node, const char *prop_name);
  52
  53 /**
  54  * Set up the pwm controller, by looking it up in the fdt.
  55  *
  56  * @return 0 if ok, -1 if the device tree node was not found or invalid.
  57  */
  58 int pwm_init(const void *blob);
  59
  60 #endif  /* __ASM_ARCH_TEGRA_PWM_H */