149 lines
3.2 KiB
C
149 lines
3.2 KiB
C
/*
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* Copyright (c) 2018 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <led_strip.h>
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#include <string.h>
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#define SYS_LOG_LEVEL CONFIG_SYS_LOG_LED_STRIP_LEVEL
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#include <logging/sys_log.h>
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#include <zephyr.h>
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#include <board.h>
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#include <gpio.h>
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#include <device.h>
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#include <clock_control.h>
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#define BLOCKING ((void *)1)
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static int send_buf(u8_t *buf, size_t len)
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{
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/* Address of OUTSET. OUTCLR is OUTSET + 4 */
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volatile u32_t *base = (u32_t *)(NRF_GPIO_BASE + 0x508);
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u32_t pin = BIT(CONFIG_WS2812B_SW_GPIO_PIN);
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struct device *clock;
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unsigned int key;
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/* Initilization of i is strictly not needed, but it avoids an
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* uninitialized warning with the inline assembly.
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*/
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u32_t i = 0;
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clock = device_get_binding(CONFIG_CLOCK_CONTROL_NRF5_M16SRC_DRV_NAME);
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if (!clock) {
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SYS_LOG_ERR("Unable to get HF clock");
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return -EIO;
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}
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/* The inline assembly further below is designed to work only with
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* the 16 MHz clock enabled.
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*/
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clock_control_on(clock, BLOCKING);
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key = irq_lock();
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while (len--) {
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u32_t b = *buf++;
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/* Generate signal out of the bits, MSB. 1-bit should be
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* roughly 0.85us high, 0.4us low, whereas a 0-bit should be
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* roughly 0.4us high, 0.85us low.
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*/
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__asm volatile ("movs %[i], #8\n" /* i = 8 */
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".start_bit:\n"
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/* OUTSET = BIT(LED_PIN) */
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"strb %[p], [%[r], #0]\n"
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/* if (b & 0x80) goto .long */
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"tst %[b], %[m]\n"
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"bne .long\n"
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/* 0-bit */
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"nop\nnop\n"
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/* OUTCLR = BIT(LED_PIN) */
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"strb %[p], [%[r], #4]\n"
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"nop\nnop\nnop\n"
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"b .next_bit\n"
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/* 1-bit */
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".long:\n"
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"nop\nnop\nnop\nnop\nnop\nnop\nnop\n"
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/* OUTCLR = BIT(LED_PIN) */
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"strb %[p], [%[r], #4]\n"
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".next_bit:\n"
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/* b <<= 1 */
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"lsl %[b], #1\n"
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/* i-- */
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"sub %[i], #1\n"
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/* if (i > 0) goto .start_bit */
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"bne .start_bit\n"
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:
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[i] "+r" (i)
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:
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[b] "l" (b),
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[m] "l" (0x80),
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[r] "l" (base),
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[p] "r" (pin)
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:);
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}
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irq_unlock(key);
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clock_control_off(clock, NULL);
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return 0;
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}
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static int ws2812b_sw_update_rgb(struct device *dev, struct led_rgb *pixels,
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size_t num_pixels)
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{
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u8_t *ptr = (u8_t *)pixels;
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size_t i;
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/* Convert from RGB to GRB format */
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for (i = 0; i < num_pixels; i++) {
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u8_t r = pixels[i].r;
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u8_t b = pixels[i].b;
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u8_t g = pixels[i].g;
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*ptr++ = g;
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*ptr++ = r;
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*ptr++ = b;
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}
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return send_buf((u8_t *)pixels, num_pixels * 3);
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}
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static int ws2812b_sw_update_channels(struct device *dev, u8_t *channels,
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size_t num_channels)
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{
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SYS_LOG_ERR("update_channels not implemented");
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return -ENOSYS;
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}
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static int ws2812b_sw_init(struct device *dev)
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{
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struct device *gpio;
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gpio = device_get_binding(CONFIG_WS2812B_SW_GPIO_NAME);
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if (!gpio) {
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SYS_LOG_ERR("Unable to find %s", CONFIG_WS2812B_SW_GPIO_NAME);
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return -ENODEV;
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}
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gpio_pin_configure(gpio, CONFIG_WS2812B_SW_GPIO_PIN, GPIO_DIR_OUT);
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return 0;
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}
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static const struct led_strip_driver_api ws2812b_sw_api = {
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.update_rgb = ws2812b_sw_update_rgb,
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.update_channels = ws2812b_sw_update_channels,
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};
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DEVICE_AND_API_INIT(ws2812b_sw, CONFIG_WS2812B_SW_NAME, ws2812b_sw_init, NULL,
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NULL, POST_KERNEL, CONFIG_LED_STRIP_INIT_PRIORITY,
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&ws2812b_sw_api);
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