mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-11 22:03:15 +00:00
e1ae0d1f71
The pulse width/frequency modulation peripheral supports generating a repeating pulse. It is useful for controlling LCD brightness. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Warren <twarren@nvidia.com>
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
|
|
* Tegra pulse width frequency modulator definitions
|
|
*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* See file CREDITS for list of people who contributed to this
|
|
* project.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
* MA 02111-1307 USA
|
|
*/
|
|
|
|
#ifndef __ASM_ARCH_TEGRA_PWM_H
|
|
#define __ASM_ARCH_TEGRA_PWM_H
|
|
|
|
/* This is a single PWM channel */
|
|
struct pwm_ctlr {
|
|
uint control; /* Control register */
|
|
uint reserved[3]; /* Space space */
|
|
};
|
|
|
|
#define PWM_NUM_CHANNELS 4
|
|
|
|
/* PWM_CONTROLLER_PWM_CSR_0/1/2/3_0 */
|
|
#define PWM_ENABLE_SHIFT 31
|
|
#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT)
|
|
|
|
#define PWM_WIDTH_SHIFT 16
|
|
#define PWM_WIDTH_MASK (0x7FFF << PWM_WIDTH_SHIFT)
|
|
|
|
#define PWM_DIVIDER_SHIFT 0
|
|
#define PWM_DIVIDER_MASK (0x1FFF << PWM_DIVIDER_SHIFT)
|
|
|
|
/**
|
|
* Program the PWM with the given parameters.
|
|
*
|
|
* @param channel PWM channel to update
|
|
* @param rate Clock rate to use for PWM
|
|
* @param pulse_width high pulse width: 0=always low, 1=1/256 pulse high,
|
|
* n = n/256 pulse high
|
|
* @param freq_divider frequency divider value (1 to use rate as is)
|
|
*/
|
|
void pwm_enable(unsigned channel, int rate, int pulse_width, int freq_divider);
|
|
|
|
/**
|
|
* Request a pwm channel as referenced by a device tree node.
|
|
*
|
|
* This channel can then be passed to pwm_enable().
|
|
*
|
|
* @param blob Device tree blob
|
|
* @param node Node containing reference to pwm
|
|
* @param prop_name Property name of pwm reference
|
|
* @return channel number, if ok, else -1
|
|
*/
|
|
int pwm_request(const void *blob, int node, const char *prop_name);
|
|
|
|
/**
|
|
* Set up the pwm controller, by looking it up in the fdt.
|
|
*
|
|
* @return 0 if ok, -1 if the device tree node was not found or invalid.
|
|
*/
|
|
int pwm_init(const void *blob);
|
|
|
|
#endif /* __ASM_ARCH_TEGRA_PWM_H */
|