osd-contiki/platform/galileo/drivers/pwm-pca9685.c
Ricardo de Almeida Gonzaga 781375f1d1 x86: Add PCA9685 support
This patch adds pwm-pca9685.c and pwm-pca9685.h files,
which support access to I2C-based PCA9685 PWM controller
configuration register through a function interface.

The PCA9685 is an I2C-bus controlled 16-channel LED controller
optimized for Red/Green/Blue/Amber (RGBA) color backlighting
applications. Each LED output has its own 12-bit resolution
(4096 steps) fixed frequency individual PWM controller that
operates at a programmable frequency from a typical of 24 Hz to
1526 Hz with a duty cycle that is adjustable from 0 % to 100 %
to allow the LED to be set to a specific brightness value.
More about PCA9685 can be found in its datasheet[1].

This driver is needed in order to configure Galileo pinmux.

[1] - http://www.nxp.com/documents/data_sheet/PCA9685.pdf
2015-12-21 08:06:14 -02:00

119 lines
3.4 KiB
C

/*
* Copyright (C) 2015, Intel Corporation. All rights reserved.
*
* 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 of the copyright holder 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 HOLDER 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.
*/
#include "i2c.h"
#include "pwm-pca9685.h"
#define REG_MODE1 0x00
#define REG_MODE2 0x01
#define REG_LED_ON_L(n) ((4 * n) + 0x06)
#define REG_LED_ON_H(n) ((4 * n) + 0x07)
#define REG_LED_OFF_L(n) ((4 * n) + 0x08)
#define REG_LED_OFF_H(n) ((4 * n) + 0x09)
#define MAX_PWM_OUT 16
#define PWM_ONE_PERIOD_TICKS 4096
int
pwm_pca9685_set_values(struct pwm_pca9685_data *data, uint32_t pwm, uint32_t on, uint32_t off)
{
uint8_t buf[5] = { 0 };
if (!quarkX1000_i2c_is_available())
return -1;
if (pwm > MAX_PWM_OUT)
return -1;
buf[0] = REG_LED_ON_L(pwm);
if ((on >= PWM_ONE_PERIOD_TICKS) || (off >= PWM_ONE_PERIOD_TICKS)) {
/* Treat as 100% */
buf[1] = 0x0;
buf[2] = (1 << 4);
buf[3] = 0x0;
buf[4] = 0x0;
} else if (off == 0) {
/* Treat it as 0% */
buf[1] = 0x0;
buf[2] = 0x0;
buf[3] = 0x0;
buf[4] = (1 << 4);
} else {
/* Populate registers accordingly */
buf[0] = (on & 0xFF);
buf[1] = ((on >> 8) & 0x0F);
buf[2] = (off & 0xFF);
buf[3] = ((off >> 8) & 0x0F);
}
return quarkX1000_i2c_polling_write(buf, sizeof(buf), data->i2c_slave_addr);
}
int
pwm_pca9685_set_duty_cycle(struct pwm_pca9685_data *data, uint32_t pwm, uint8_t duty)
{
uint32_t on, off;
if (duty == 0) {
on = 0;
off = 0;
} else if (duty >= 100) {
on = PWM_ONE_PERIOD_TICKS + 1;
off = PWM_ONE_PERIOD_TICKS + 1;
} else {
on = PWM_ONE_PERIOD_TICKS * duty / 100;
off = PWM_ONE_PERIOD_TICKS - 1;
}
return pwm_pca9685_set_values(data, pwm, on, off);
}
int
pwm_pca9685_init(struct pwm_pca9685_data *data, uint16_t i2c_slave_addr)
{
uint8_t buf[2] = { 0 };
/* has to init after I2C master */
if (!quarkX1000_i2c_is_available())
return -1;
data->i2c_slave_addr = i2c_slave_addr;
buf[0] = REG_MODE1;
buf[1] = (1 << 5);
if (quarkX1000_i2c_polling_write(buf, 2, i2c_slave_addr) < 0)
return -1;
return 0;
}