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zephyr/drivers/led_strip/ws2812_rpi_pico_pio.c

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/*
* Copyright (c) 2023 TOKITA Hiroshi
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/drivers/pinctrl.h>
#include <zephyr/drivers/led_strip.h>
#include <zephyr/drivers/misc/pio_rpi_pico/pio_rpi_pico.h>
#include <zephyr/dt-bindings/led/led.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(ws2812_rpi_pico_pio, CONFIG_LED_STRIP_LOG_LEVEL);
#define DT_DRV_COMPAT worldsemi_ws2812_rpi_pico_pio
struct ws2812_led_strip_data {
uint32_t sm;
};
struct ws2812_led_strip_config {
const struct device *piodev;
uint32_t output_pin;
uint8_t num_colors;
uint32_t frequency;
const uint8_t *const color_mapping;
uint16_t reset_delay;
uint32_t cycles_per_bit;
};
struct ws2812_rpi_pico_pio_config {
const struct device *piodev;
const struct pinctrl_dev_config *const pcfg;
struct pio_program program;
};
static int ws2812_led_strip_sm_init(const struct device *dev)
{
const struct ws2812_led_strip_config *config = dev->config;
const float clkdiv =
sys_clock_hw_cycles_per_sec() / (config->cycles_per_bit * config->frequency);
pio_sm_config sm_config = pio_get_default_sm_config();
PIO pio;
int sm;
pio = pio_rpi_pico_get_pio(config->piodev);
sm = pio_claim_unused_sm(pio, false);
if (sm < 0) {
return -EINVAL;
}
sm_config_set_sideset(&sm_config, 1, false, false);
sm_config_set_sideset_pins(&sm_config, config->output_pin);
sm_config_set_out_shift(&sm_config, false, true, (config->num_colors == 4 ? 32 : 24));
sm_config_set_fifo_join(&sm_config, PIO_FIFO_JOIN_TX);
sm_config_set_clkdiv(&sm_config, clkdiv);
pio_sm_set_consecutive_pindirs(pio, sm, config->output_pin, 1, true);
pio_sm_init(pio, sm, -1, &sm_config);
pio_sm_set_enabled(pio, sm, true);
return sm;
}
/*
* Latch current color values on strip and reset its state machines.
*/
static inline void ws2812_led_strip_reset_delay(uint16_t delay)
{
k_usleep(delay);
}
static int ws2812_led_strip_update_rgb(const struct device *dev, struct led_rgb *pixels,
size_t num_pixels)
{
const struct ws2812_led_strip_config *config = dev->config;
struct ws2812_led_strip_data *data = dev->data;
PIO pio = pio_rpi_pico_get_pio(config->piodev);
for (size_t i = 0; i < num_pixels; i++) {
uint32_t color = 0;
for (size_t j = 0; j < config->num_colors; j++) {
switch (config->color_mapping[j]) {
/* White channel is not supported by LED strip API. */
case LED_COLOR_ID_WHITE:
color |= 0;
break;
case LED_COLOR_ID_RED:
color |= pixels[i].r << (8 * (2 - j));
break;
case LED_COLOR_ID_GREEN:
color |= pixels[i].g << (8 * (2 - j));
break;
case LED_COLOR_ID_BLUE:
color |= pixels[i].b << (8 * (2 - j));
break;
}
}
pio_sm_put_blocking(pio, data->sm, color << (config->num_colors == 4 ? 0 : 8));
}
ws2812_led_strip_reset_delay(config->reset_delay);
return 0;
}
static int ws2812_led_strip_update_channels(const struct device *dev, uint8_t *channels,
size_t num_channels)
{
LOG_DBG("update_channels not implemented");
return -ENOTSUP;
}
static const struct led_strip_driver_api ws2812_led_strip_api = {
.update_rgb = ws2812_led_strip_update_rgb,
.update_channels = ws2812_led_strip_update_channels,
};
/*
* Retrieve the channel to color mapping (e.g. RGB, BGR, GRB, ...) from the
* "color-mapping" DT property.
*/
static int ws2812_led_strip_init(const struct device *dev)
{
const struct ws2812_led_strip_config *config = dev->config;
struct ws2812_led_strip_data *data = dev->data;
int sm;
if (!device_is_ready(config->piodev)) {
LOG_ERR("%s: PIO device not ready", dev->name);
return -ENODEV;
}
for (uint32_t i = 0; i < config->num_colors; i++) {
switch (config->color_mapping[i]) {
case LED_COLOR_ID_WHITE:
case LED_COLOR_ID_RED:
case LED_COLOR_ID_GREEN:
case LED_COLOR_ID_BLUE:
break;
default:
LOG_ERR("%s: invalid channel to color mapping."
" Check the color-mapping DT property",
dev->name);
return -EINVAL;
}
}
sm = ws2812_led_strip_sm_init(dev);
if (sm < 0) {
return sm;
}
data->sm = sm;
return 0;
}
static int ws2812_rpi_pico_pio_init(const struct device *dev)
{
const struct ws2812_rpi_pico_pio_config *config = dev->config;
PIO pio;
if (!device_is_ready(config->piodev)) {
LOG_ERR("%s: PIO device not ready", dev->name);
return -ENODEV;
}
pio = pio_rpi_pico_get_pio(config->piodev);
pio_add_program(pio, &config->program);
return pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
}
#define CYCLES_PER_BIT(node) \
(DT_PROP_BY_IDX(node, bit_waveform, 0) + DT_PROP_BY_IDX(node, bit_waveform, 1) + \
DT_PROP_BY_IDX(node, bit_waveform, 2))
#define WS2812_CHILD_INIT(node) \
static const uint8_t ws2812_led_strip_##node##_color_mapping[] = \
DT_PROP(node, color_mapping); \
struct ws2812_led_strip_data ws2812_led_strip_##node##_data; \
\
static const struct ws2812_led_strip_config ws2812_led_strip_##node##_config = { \
.piodev = DEVICE_DT_GET(DT_PARENT(DT_PARENT(node))), \
.output_pin = DT_PROP(node, output_pin), \
.num_colors = DT_PROP_LEN(node, color_mapping), \
.color_mapping = ws2812_led_strip_##node##_color_mapping, \
.reset_delay = DT_PROP(node, reset_delay), \
.frequency = DT_PROP(node, frequency), \
.cycles_per_bit = CYCLES_PER_BIT(DT_PARENT(node)), \
}; \
\
DEVICE_DT_DEFINE(node, &ws2812_led_strip_init, NULL, &ws2812_led_strip_##node##_data, \
&ws2812_led_strip_##node##_config, POST_KERNEL, \
CONFIG_LED_STRIP_INIT_PRIORITY, &ws2812_led_strip_api);
#define SET_DELAY(op, inst, i) \
(op | (((DT_INST_PROP_BY_IDX(inst, bit_waveform, i) - 1) & 0xF) << 8))
/*
* This pio program runs [T0+T1+T2] cycles per 1 loop.
* The first `out` instruction outputs 0 by [T2] times to the sideset pin.
* These zeros are padding. Here is the start of actual data transmission.
* The second `jmp` instruction output 1 by [T0] times to the sideset pin.
* This `jmp` instruction jumps to line 3 if the value of register x is true.
* Otherwise, jump to line 4.
* The third `jmp` instruction outputs 1 by [T1] times to the sideset pin.
* After output, return to the first line.
* The fourth `jmp` instruction outputs 0 by [T1] times.
* After output, return to the first line and output 0 by [T2] times.
*
* In the case of configuration, T0=3, T1=3, T2 =4,
* the final output is 1110000000 in case register x is false.
* It represents code 0, defined in the datasheet.
* And outputs 1111110000 in case of x is true. It represents code 1.
*/
#define WS2812_RPI_PICO_PIO_INIT(inst) \
PINCTRL_DT_INST_DEFINE(inst); \
\
DT_INST_FOREACH_CHILD_STATUS_OKAY(inst, WS2812_CHILD_INIT); \
\
static const uint16_t rpi_pico_pio_ws2812_instructions_##inst[] = { \
SET_DELAY(0x6021, inst, 2), /* 0: out x, 1 side 0 [T2 - 1] */ \
SET_DELAY(0x1023, inst, 0), /* 1: jmp !x, 3 side 1 [T0 - 1] */ \
SET_DELAY(0x1000, inst, 1), /* 2: jmp 0 side 1 [T1 - 1] */ \
SET_DELAY(0x0000, inst, 1), /* 3: jmp 0 side 0 [T1 - 1] */ \
}; \
\
static const struct ws2812_rpi_pico_pio_config rpi_pico_pio_ws2812_##inst##_config = { \
.piodev = DEVICE_DT_GET(DT_INST_PARENT(inst)), \
.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(inst), \
.program = \
{ \
.instructions = rpi_pico_pio_ws2812_instructions_##inst, \
.length = ARRAY_SIZE(rpi_pico_pio_ws2812_instructions_##inst), \
.origin = -1, \
}, \
}; \
\
DEVICE_DT_INST_DEFINE(inst, &ws2812_rpi_pico_pio_init, NULL, NULL, \
&rpi_pico_pio_ws2812_##inst##_config, POST_KERNEL, \
CONFIG_LED_STRIP_INIT_PRIORITY, NULL);
DT_INST_FOREACH_STATUS_OKAY(WS2812_RPI_PICO_PIO_INIT)
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