172 lines
4.0 KiB
C
172 lines
4.0 KiB
C
/*
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* Copyright (c) 2015 Intel Corporation.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file Driver for PCA9685 I2C-based PWM driver.
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*/
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#include <errno.h>
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#include <kernel.h>
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#include <drivers/i2c.h>
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#include <drivers/pwm.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 REG_ALL_LED_ON_L 0xFA
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#define REG_ALL_LED_ON_H 0xFB
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#define REG_ALL_LED_OFF_L 0xFC
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#define REG_ALL_LED_OFF_H 0xFD
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#define REG_PRE_SCALE 0xFE
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/* Maximum PWM outputs */
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#define MAX_PWM_OUT 16
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/* How many ticks per one period */
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#define PWM_ONE_PERIOD_TICKS 4096
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/**
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* @brief Check to see if a I2C master is identified for communication.
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*
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* @param dev Device struct.
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* @return 1 if I2C master is identified, 0 if not.
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*/
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static inline int has_i2c_master(struct device *dev)
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{
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struct pwm_pca9685_drv_data * const drv_data =
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(struct pwm_pca9685_drv_data * const)dev->driver_data;
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struct device * const i2c_master = drv_data->i2c_master;
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if (i2c_master) {
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return 1;
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} else {
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return 0;
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}
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}
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/*
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* period_count is always taken as 4095. To control the on period send
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* value to pulse_count
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*/
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static int pwm_pca9685_pin_set_cycles(struct device *dev, u32_t pwm,
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u32_t period_count, u32_t pulse_count)
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{
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const struct pwm_pca9685_config * const config =
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dev->config->config_info;
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struct pwm_pca9685_drv_data * const drv_data =
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(struct pwm_pca9685_drv_data * const)dev->driver_data;
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struct device * const i2c_master = drv_data->i2c_master;
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u16_t i2c_addr = config->i2c_slave_addr;
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u8_t buf[] = { 0, 0, 0, 0, 0};
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ARG_UNUSED(period_count);
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if (!has_i2c_master(dev)) {
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return -EINVAL;
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}
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if (pwm > MAX_PWM_OUT) {
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return -EINVAL;
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}
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buf[0] = REG_LED_ON_L(pwm);
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/* If either pulse_count > max ticks, treat PWM as 100%.
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* If pulse_count value == 0, treat it as 0%.
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* Otherwise, populate registers accordingly.
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*/
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if (pulse_count >= PWM_ONE_PERIOD_TICKS) {
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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 (pulse_count == 0U) {
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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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/* No start delay given. When the count is 0 the
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* pwm will be high .
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*/
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buf[0] = 0x0;
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buf[1] = 0x0;
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buf[2] = (pulse_count & 0xFF);
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buf[3] = ((pulse_count >> 8) & 0x0F);
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}
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return i2c_write(i2c_master, buf, sizeof(buf), i2c_addr);
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}
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static const struct pwm_driver_api pwm_pca9685_drv_api_funcs = {
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.pin_set = pwm_pca9685_pin_set_cycles
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};
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/**
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* @brief Initialization function of PCA9685
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*
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* @param dev Device struct
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* @return 0 if successful, failed otherwise.
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*/
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int pwm_pca9685_init(struct device *dev)
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{
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const struct pwm_pca9685_config * const config =
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dev->config->config_info;
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struct pwm_pca9685_drv_data * const drv_data =
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(struct pwm_pca9685_drv_data * const)dev->driver_data;
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struct device *i2c_master;
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u8_t buf[] = {0, 0};
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int ret;
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/* Find out the device struct of the I2C master */
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i2c_master = device_get_binding((char *)config->i2c_master_dev_name);
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if (!i2c_master) {
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return -EINVAL;
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}
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drv_data->i2c_master = i2c_master;
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/* MODE1 register */
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buf[0] = REG_MODE1;
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buf[1] = (1 << 5); /* register addr auto increment */
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ret = i2c_write(i2c_master, buf, 2, config->i2c_slave_addr);
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if (ret != 0) {
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return -EPERM;
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}
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return 0;
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}
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/* Initialization for PWM_PCA9685_0 */
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#ifdef CONFIG_PWM_PCA9685_0
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#include <device.h>
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#include <init.h>
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static const struct pwm_pca9685_config pwm_pca9685_0_cfg = {
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.i2c_master_dev_name = CONFIG_PWM_PCA9685_0_I2C_MASTER_DEV_NAME,
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.i2c_slave_addr = CONFIG_PWM_PCA9685_0_I2C_ADDR,
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};
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static struct pwm_pca9685_drv_data pwm_pca9685_0_drvdata;
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/* This has to init after I2C master */
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DEVICE_AND_API_INIT(pwm_pca9685_0, CONFIG_PWM_PCA9685_0_DEV_NAME,
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pwm_pca9685_init,
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&pwm_pca9685_0_drvdata, &pwm_pca9685_0_cfg,
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POST_KERNEL, CONFIG_PWM_PCA9685_INIT_PRIORITY,
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&pwm_pca9685_drv_api_funcs);
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#endif /* CONFIG_PWM_PCA9685_0 */
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