blob: 692f25bd0dcac26434b028253c0edf2badc02933 [file] [log] [blame] [edit]
/*
* Copyright (c) 2018 Intel Corporation
* Copyright (c) 2019 Nordic Semiconductor ASA
* Copyright (c) 2021 Seagate Technology LLC
*
* SPDX-License-Identifier: Apache-2.0
*/
#define DT_DRV_COMPAT worldsemi_ws2812_gpio
#include <zephyr/drivers/led_strip.h>
#include <string.h>
#define LOG_LEVEL CONFIG_LED_STRIP_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(ws2812_gpio);
#include <zephyr/kernel.h>
#include <soc.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/device.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/drivers/clock_control/nrf_clock_control.h>
#include <zephyr/dt-bindings/led/led.h>
struct ws2812_gpio_cfg {
struct gpio_dt_spec in_gpio;
uint8_t num_colors;
const uint8_t *color_mapping;
};
/*
* This is hard-coded to nRF51 in two ways:
*
* 1. The assembly delays T1H, T0H, TxL
* 2. GPIO set/clear
*/
/*
* T1H: 1 bit high pulse delay: 12 cycles == .75 usec
* T0H: 0 bit high pulse delay: 4 cycles == .25 usec
* TxL: inter-bit low pulse delay: 8 cycles == .5 usec
*
* We can't use k_busy_wait() here: its argument is in microseconds,
* and we need roughly .05 microsecond resolution.
*/
#define DELAY_T1H "nop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\n"
#define DELAY_T0H "nop\nnop\nnop\nnop\n"
#define DELAY_TxL "nop\nnop\nnop\nnop\nnop\nnop\nnop\nnop\n"
/*
* GPIO set/clear (these make assumptions about assembly details
* below).
*
* This uses OUTCLR == OUTSET+4.
*
* We should be able to make this portable using the results of
* https://github.com/zephyrproject-rtos/zephyr/issues/11917.
*
* We already have the GPIO device stashed in ws2812_gpio_config, so
* this driver can be used as a test case for the optimized API.
*
* Per Arm docs, both Rd and Rn must be r0-r7, so we use the "l"
* constraint in the below assembly.
*/
#define SET_HIGH "str %[p], [%[r], #0]\n" /* OUTSET = BIT(LED_PIN) */
#define SET_LOW "str %[p], [%[r], #4]\n" /* OUTCLR = BIT(LED_PIN) */
/* Send out a 1 bit's pulse */
#define ONE_BIT(base, pin) do { \
__asm volatile (SET_HIGH \
DELAY_T1H \
SET_LOW \
DELAY_TxL \
:: \
[r] "l" (base), \
[p] "l" (pin)); } while (false)
/* Send out a 0 bit's pulse */
#define ZERO_BIT(base, pin) do { \
__asm volatile (SET_HIGH \
DELAY_T0H \
SET_LOW \
DELAY_TxL \
:: \
[r] "l" (base), \
[p] "l" (pin)); } while (false)
static int send_buf(const struct device *dev, uint8_t *buf, size_t len)
{
const struct ws2812_gpio_cfg *config = dev->config;
volatile uint32_t *base = (uint32_t *)&NRF_GPIO->OUTSET;
const uint32_t val = BIT(config->in_gpio.pin);
struct onoff_manager *mgr =
z_nrf_clock_control_get_onoff(CLOCK_CONTROL_NRF_SUBSYS_HF);
struct onoff_client cli;
unsigned int key;
int rc;
sys_notify_init_spinwait(&cli.notify);
rc = onoff_request(mgr, &cli);
if (rc < 0) {
return rc;
}
while (sys_notify_fetch_result(&cli.notify, &rc)) {
/* pend until clock is up and running */
}
key = irq_lock();
while (len--) {
uint32_t b = *buf++;
int32_t i;
/*
* Generate signal out of the bits, MSbit first.
*
* Accumulator maintenance and branching mean the
* inter-bit time will be longer than TxL, but the
* wp.josh.com blog post says we have at least 5 usec
* of slack time between bits before we risk the
* signal getting latched, so this will be fine as
* long as the compiler does something minimally
* reasonable.
*/
for (i = 7; i >= 0; i--) {
if (b & BIT(i)) {
ONE_BIT(base, val);
} else {
ZERO_BIT(base, val);
}
}
}
irq_unlock(key);
rc = onoff_release(mgr);
/* Returns non-negative value on success. Cap to 0 as API states. */
rc = MIN(rc, 0);
return rc;
}
static int ws2812_gpio_update_rgb(const struct device *dev,
struct led_rgb *pixels,
size_t num_pixels)
{
const struct ws2812_gpio_cfg *config = dev->config;
uint8_t *ptr = (uint8_t *)pixels;
size_t i;
/* Convert from RGB to on-wire format (e.g. GRB, GRBW, RGB, etc) */
for (i = 0; i < num_pixels; i++) {
uint8_t j;
for (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:
*ptr++ = 0;
break;
case LED_COLOR_ID_RED:
*ptr++ = pixels[i].r;
break;
case LED_COLOR_ID_GREEN:
*ptr++ = pixels[i].g;
break;
case LED_COLOR_ID_BLUE:
*ptr++ = pixels[i].b;
break;
default:
return -EINVAL;
}
}
}
return send_buf(dev, (uint8_t *)pixels, num_pixels * config->num_colors);
}
static int ws2812_gpio_update_channels(const struct device *dev,
uint8_t *channels,
size_t num_channels)
{
LOG_ERR("update_channels not implemented");
return -ENOTSUP;
}
static const struct led_strip_driver_api ws2812_gpio_api = {
.update_rgb = ws2812_gpio_update_rgb,
.update_channels = ws2812_gpio_update_channels,
};
/*
* Retrieve the channel to color mapping (e.g. RGB, BGR, GRB, ...) from the
* "color-mapping" DT property.
*/
#define WS2812_COLOR_MAPPING(idx) \
static const uint8_t ws2812_gpio_##idx##_color_mapping[] = \
DT_INST_PROP(idx, color_mapping)
#define WS2812_NUM_COLORS(idx) (DT_INST_PROP_LEN(idx, color_mapping))
/*
* The inline assembly above is designed to work on nRF51 devices with
* the 16 MHz clock enabled.
*
* TODO: try to make this portable, or at least port to more devices.
*/
#define WS2812_GPIO_DEVICE(idx) \
\
static int ws2812_gpio_##idx##_init(const struct device *dev) \
{ \
const struct ws2812_gpio_cfg *cfg = dev->config; \
uint8_t i; \
\
if (!device_is_ready(cfg->in_gpio.port)) { \
LOG_ERR("GPIO device not ready"); \
return -ENODEV; \
} \
\
for (i = 0; i < cfg->num_colors; i++) { \
switch (cfg->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; \
} \
} \
\
return gpio_pin_configure_dt(&cfg->in_gpio, GPIO_OUTPUT); \
} \
\
WS2812_COLOR_MAPPING(idx); \
\
static const struct ws2812_gpio_cfg ws2812_gpio_##idx##_cfg = { \
.in_gpio = GPIO_DT_SPEC_INST_GET(idx, in_gpios), \
.num_colors = WS2812_NUM_COLORS(idx), \
.color_mapping = ws2812_gpio_##idx##_color_mapping, \
}; \
\
DEVICE_DT_INST_DEFINE(idx, \
ws2812_gpio_##idx##_init, \
NULL, \
NULL, \
&ws2812_gpio_##idx##_cfg, POST_KERNEL, \
CONFIG_LED_STRIP_INIT_PRIORITY, \
&ws2812_gpio_api);
DT_INST_FOREACH_STATUS_OKAY(WS2812_GPIO_DEVICE)