781375f1d1
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
118 lines
3.4 KiB
C
118 lines
3.4 KiB
C
/*
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* Copyright (C) 2015, Intel Corporation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "i2c.h"
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#include "pwm-pca9685.h"
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#define REG_MODE1 0x00
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#define REG_MODE2 0x01
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#define REG_LED_ON_L(n) ((4 * n) + 0x06)
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#define REG_LED_ON_H(n) ((4 * n) + 0x07)
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#define REG_LED_OFF_L(n) ((4 * n) + 0x08)
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#define REG_LED_OFF_H(n) ((4 * n) + 0x09)
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#define MAX_PWM_OUT 16
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#define PWM_ONE_PERIOD_TICKS 4096
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int
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pwm_pca9685_set_values(struct pwm_pca9685_data *data, uint32_t pwm, uint32_t on, uint32_t off)
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{
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uint8_t buf[5] = { 0 };
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if (!quarkX1000_i2c_is_available())
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return -1;
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if (pwm > MAX_PWM_OUT)
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return -1;
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buf[0] = REG_LED_ON_L(pwm);
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if ((on >= PWM_ONE_PERIOD_TICKS) || (off >= PWM_ONE_PERIOD_TICKS)) {
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/* Treat as 100% */
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buf[1] = 0x0;
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buf[2] = (1 << 4);
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buf[3] = 0x0;
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buf[4] = 0x0;
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} else if (off == 0) {
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/* Treat it as 0% */
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buf[1] = 0x0;
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buf[2] = 0x0;
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buf[3] = 0x0;
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buf[4] = (1 << 4);
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} else {
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/* Populate registers accordingly */
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buf[0] = (on & 0xFF);
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buf[1] = ((on >> 8) & 0x0F);
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buf[2] = (off & 0xFF);
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buf[3] = ((off >> 8) & 0x0F);
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}
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return quarkX1000_i2c_polling_write(buf, sizeof(buf), data->i2c_slave_addr);
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}
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int
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pwm_pca9685_set_duty_cycle(struct pwm_pca9685_data *data, uint32_t pwm, uint8_t duty)
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{
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uint32_t on, off;
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if (duty == 0) {
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on = 0;
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off = 0;
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} else if (duty >= 100) {
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on = PWM_ONE_PERIOD_TICKS + 1;
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off = PWM_ONE_PERIOD_TICKS + 1;
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} else {
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on = PWM_ONE_PERIOD_TICKS * duty / 100;
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off = PWM_ONE_PERIOD_TICKS - 1;
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}
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return pwm_pca9685_set_values(data, pwm, on, off);
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}
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int
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pwm_pca9685_init(struct pwm_pca9685_data *data, uint16_t i2c_slave_addr)
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{
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uint8_t buf[2] = { 0 };
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/* has to init after I2C master */
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if (!quarkX1000_i2c_is_available())
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return -1;
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data->i2c_slave_addr = i2c_slave_addr;
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buf[0] = REG_MODE1;
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buf[1] = (1 << 5);
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if (quarkX1000_i2c_polling_write(buf, 2, i2c_slave_addr) < 0)
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return -1;
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return 0;
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}
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