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/*
* Copyright (c) 2022 Nick Ward <nix.ward@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT nxp_pca9685_pwm
#include <zephyr/device.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/pwm.h>
#include <zephyr/sys/util_macro.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(pwm_pca9685, CONFIG_PWM_LOG_LEVEL);
#define OSC_CLOCK_MAX 50000000
#define CHANNEL_CNT 16
#define ADDR_MODE1 0x00
#define SLEEP BIT(4)
#define AUTO_INC BIT(5)
#define RESTART BIT(7)
#define ADDR_MODE2 0x01
#define OUTDRV_TOTEM_POLE BIT(2)
#define OCH_ON_ACK BIT(3)
#define ADDR_LED0_ON_L 0x06
#define ADDR_LED_ON_L(n) (ADDR_LED0_ON_L + (4 * n))
#define LED_FULL_ON BIT(4)
#define LED_FULL_OFF BIT(4)
#define BYTE_N(word, n) ((word >> (8 * n)) & 0xFF)
#define ADDR_PRE_SCALE 0xFE
/* See PCA9585 datasheet Rev. 4 - 16 April 2015 section 7.3.5 */
#define OSC_CLOCK_INTERNAL 25000000
#define PWM_STEPS 4096
#define PRE_SCALE_MIN 0x03
#define PRE_SCALE_MAX 0xFF
#define PRE_SCALE_DEFAULT 0x1E
#define PWM_PERIOD_COUNT_PS(pre_scale) (PWM_STEPS * (pre_scale + 1))
/*
* When using the internal oscillator this corresponds to an
* update rate of 1526 Hz
*/
#define PWM_PERIOD_COUNT_MIN PWM_PERIOD_COUNT_PS(PRE_SCALE_MIN)
/*
* When using the internal oscillator this corresponds to an
* update rate of 24 Hz
*/
#define PWM_PERIOD_COUNT_MAX PWM_PERIOD_COUNT_PS(PRE_SCALE_MAX)
/*
* When using the internal oscillator this corresponds to an
* update rate of 200 Hz
*/
#define PWM_PERIOD_COUNT_DEFAULT PWM_PERIOD_COUNT_PS(PRE_SCALE_DEFAULT)
/*
* Time allowed for the oscillator to stabilize after the PCA9685's
* RESTART mode is used to wake the chip from SLEEP.
* See PCA9685 datasheet section 7.3.1.1
*/
#define OSCILLATOR_STABILIZE K_USEC(500)
struct pca9685_config {
struct i2c_dt_spec i2c;
bool outdrv_open_drain;
bool och_on_ack;
bool invrt;
};
struct pca9685_data {
struct k_mutex mutex;
uint8_t pre_scale;
};
static int set_reg(const struct device *dev, uint8_t addr, uint8_t value)
{
const struct pca9685_config *config = dev->config;
uint8_t buf[] = {addr, value};
int ret;
ret = i2c_write_dt(&config->i2c, buf, sizeof(buf));
if (ret != 0) {
LOG_ERR("I2C write [0x%02X]=0x%02X: %d", addr, value, ret);
} else {
LOG_DBG("[0x%02X]=0x%02X", addr, value);
}
return ret;
}
static int get_reg(const struct device *dev, uint8_t addr, uint8_t *value)
{
const struct pca9685_config *config = dev->config;
int ret;
ret = i2c_write_read_dt(&config->i2c, &addr, sizeof(addr), value,
sizeof(*value));
if (ret != 0) {
LOG_ERR("I2C write [0x%02X]=0x%02X: %d", addr, *value, ret);
}
return ret;
}
static int set_pre_scale(const struct device *dev, uint8_t value)
{
struct pca9685_data *data = dev->data;
uint8_t mode1;
int ret;
k_mutex_lock(&data->mutex, K_FOREVER);
/* Unblock write to PRE_SCALE by setting SLEEP bit to logic 1 */
ret = set_reg(dev, ADDR_MODE1, AUTO_INC | SLEEP);
if (ret != 0) {
goto out;
}
ret = get_reg(dev, ADDR_MODE1, &mode1);
if (ret != 0) {
goto out;
}
if ((mode1 & RESTART) == 0x00) {
LOG_ERR("RESTART bit should be set");
ret = -EIO;
goto out;
}
ret = set_reg(dev, ADDR_PRE_SCALE, value);
if (ret != 0) {
goto out;
}
/* Clear SLEEP bit - See datasheet section 7.3.1.1 */
ret = set_reg(dev, ADDR_MODE1, AUTO_INC);
if (ret != 0) {
goto out;
}
k_sleep(OSCILLATOR_STABILIZE);
ret = set_reg(dev, ADDR_MODE1, AUTO_INC | RESTART);
if (ret != 0) {
goto out;
}
out:
k_mutex_unlock(&data->mutex);
return ret;
}
static int pca9685_set_cycles(const struct device *dev,
uint32_t channel, uint32_t period_count,
uint32_t pulse_count, pwm_flags_t flags)
{
const struct pca9685_config *config = dev->config;
struct pca9685_data *data = dev->data;
uint8_t buf[5] = { 0 };
uint32_t led_off_count;
int32_t pre_scale;
int ret;
ARG_UNUSED(flags);
if (channel >= CHANNEL_CNT) {
LOG_WRN("channel out of range: %u", channel);
return -EINVAL;
}
pre_scale = DIV_ROUND_UP((int64_t)period_count, PWM_STEPS) - 1;
if (pre_scale < PRE_SCALE_MIN) {
LOG_ERR("period_count %u < %u (min)", period_count,
PWM_PERIOD_COUNT_MIN);
return -ENOTSUP;
} else if (pre_scale > PRE_SCALE_MAX) {
LOG_ERR("period_count %u > %u (max)", period_count,
PWM_PERIOD_COUNT_MAX);
return -ENOTSUP;
}
/* Only one output frequency - simple conversion to equivalent PWM */
if (pre_scale != data->pre_scale) {
data->pre_scale = pre_scale;
ret = set_pre_scale(dev, pre_scale);
if (ret != 0) {
return ret;
}
}
/* Adjust PWM output for the resolution of the PCA9685 */
led_off_count = DIV_ROUND_UP(pulse_count * PWM_STEPS, period_count);
buf[0] = ADDR_LED_ON_L(channel);
if (led_off_count == 0) {
buf[4] = LED_FULL_OFF;
} else if (led_off_count < PWM_STEPS) {
/* LED turns on at count 0 */
buf[3] = BYTE_N(led_off_count, 0);
buf[4] = BYTE_N(led_off_count, 1);
} else {
buf[2] = LED_FULL_ON;
}
return i2c_write_dt(&config->i2c, buf, sizeof(buf));
}
static int pca9685_get_cycles_per_sec(const struct device *dev,
uint32_t channel, uint64_t *cycles)
{
ARG_UNUSED(dev);
ARG_UNUSED(channel);
*cycles = OSC_CLOCK_INTERNAL;
return 0;
}
static const struct pwm_driver_api pca9685_api = {
.set_cycles = pca9685_set_cycles,
.get_cycles_per_sec = pca9685_get_cycles_per_sec,
};
static int pca9685_init(const struct device *dev)
{
const struct pca9685_config *config = dev->config;
struct pca9685_data *data = dev->data;
uint8_t value;
int ret;
(void)k_mutex_init(&data->mutex);
if (!i2c_is_ready_dt(&config->i2c)) {
LOG_ERR("I2C device not ready");
return -ENODEV;
}
ret = set_reg(dev, ADDR_MODE1, AUTO_INC);
if (ret != 0) {
LOG_ERR("set_reg MODE1: %d", ret);
return ret;
}
value = 0x00;
if (!config->outdrv_open_drain) {
value |= OUTDRV_TOTEM_POLE;
}
if (config->och_on_ack) {
value |= OCH_ON_ACK;
}
ret = set_reg(dev, ADDR_MODE2, value);
if (ret != 0) {
LOG_ERR("set_reg MODE2: %d", ret);
return ret;
}
return 0;
}
#define PCA9685_INIT(inst) \
static const struct pca9685_config pca9685_##inst##_config = { \
.i2c = I2C_DT_SPEC_INST_GET(inst), \
.outdrv_open_drain = DT_INST_PROP(inst, open_drain), \
.och_on_ack = DT_INST_PROP(inst, och_on_ack), \
.invrt = DT_INST_PROP(inst, invert), \
}; \
\
static struct pca9685_data pca9685_##inst##_data; \
\
DEVICE_DT_INST_DEFINE(inst, pca9685_init, NULL, \
&pca9685_##inst##_data, \
&pca9685_##inst##_config, POST_KERNEL, \
CONFIG_PWM_INIT_PRIORITY, \
&pca9685_api);
DT_INST_FOREACH_STATUS_OKAY(PCA9685_INIT);