345 lines
9.5 KiB
C
345 lines
9.5 KiB
C
/*
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* Copyright (c) 2022 Jimmy Ou <yanagiis@gmail.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT maxim_max7219
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/**
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* @file
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* @brief MAX7219 LED display driver
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*
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* This driver map the segment as x, digit as y.
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*
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* A MAX7219 has 8x8 pixels.
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* Two MAX7219s (with cascading) have 8x16 pixels.
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* So on and so forth.
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*
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* Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf
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*
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* Limitations:
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* 1. This driver only implements no-decode mode.
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*/
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#include <stddef.h>
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#include <zephyr/drivers/display.h>
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#include <zephyr/drivers/spi.h>
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#include <zephyr/logging/log.h>
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#include <zephyr/sys/byteorder.h>
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#include <zephyr/sys/util.h>
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#include <zephyr/kernel.h>
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LOG_MODULE_REGISTER(max7219, CONFIG_DISPLAY_LOG_LEVEL);
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#define MAX7219_SEGMENTS_PER_DIGIT 8
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#define MAX7219_DIGITS_PER_DEVICE 8
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/* clang-format off */
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/* MAX7219 registers and fields */
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#define MAX7219_REG_NOOP 0x00
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#define MAX7219_NOOP 0x00
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#define MAX7219_REG_DECODE_MODE 0x09
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#define MAX7219_NO_DECODE 0x00
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#define MAX7219_REG_INTENSITY 0x0A
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#define MAX7219_REG_SCAN_LIMIT 0x0B
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#define MAX7219_REG_SHUTDOWN 0x0C
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#define MAX7219_SHUTDOWN_MODE 0x00
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#define MAX7219_LEAVE_SHUTDOWN_MODE 0x01
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#define MAX7219_REG_DISPLAY_TEST 0x0F
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#define MAX7219_LEAVE_DISPLAY_TEST_MODE 0x00
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#define MAX7219_DISPLAY_TEST_MODE 0x01
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/* clang-format on */
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struct max7219_config {
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struct spi_dt_spec spi;
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uint32_t num_cascading;
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uint8_t intensity;
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uint8_t scan_limit;
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};
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struct max7219_data {
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/* Keep all digit_buf for all cascading MAX7219 */
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uint8_t *digit_buf;
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uint8_t *tx_buf;
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};
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static int max7219_transmit_all(const struct device *dev, const uint8_t addr, const uint8_t value)
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{
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const struct max7219_config *dev_config = dev->config;
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struct max7219_data *dev_data = dev->data;
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const struct spi_buf tx_buf = {
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.buf = dev_data->tx_buf,
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.len = dev_config->num_cascading * 2,
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};
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const struct spi_buf_set tx_bufs = {
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.buffers = &tx_buf,
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.count = 1U,
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};
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for (int i = 0; i < dev_config->num_cascading; i++) {
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dev_data->tx_buf[i * 2] = addr;
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dev_data->tx_buf[i * 2 + 1] = value;
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}
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return spi_write_dt(&dev_config->spi, &tx_bufs);
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}
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static int max7219_transmit_one(const struct device *dev, const uint8_t max7219_idx,
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const uint8_t addr, const uint8_t value)
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{
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const struct max7219_config *dev_config = dev->config;
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struct max7219_data *dev_data = dev->data;
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const struct spi_buf tx_buf = {
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.buf = dev_data->tx_buf,
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.len = dev_config->num_cascading * 2,
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};
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const struct spi_buf_set tx_bufs = {
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.buffers = &tx_buf,
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.count = 1U,
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};
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for (int i = 0; i < dev_config->num_cascading; i++) {
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if (i != (dev_config->num_cascading - 1 - max7219_idx)) {
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dev_data->tx_buf[i * 2] = MAX7219_REG_NOOP;
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dev_data->tx_buf[i * 2 + 1] = MAX7219_NOOP;
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continue;
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}
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dev_data->tx_buf[i * 2] = addr;
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dev_data->tx_buf[i * 2 + 1] = value;
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}
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return spi_write_dt(&dev_config->spi, &tx_bufs);
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}
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static inline uint8_t next_pixel(uint8_t *mask, uint8_t *data, const uint8_t **buf)
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{
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*mask <<= 1;
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if (!*mask) {
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*mask = 0x01;
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*data = *(*buf)++;
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}
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return *data & *mask;
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}
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static inline void skip_pixel(uint8_t *mask, uint8_t *data, const uint8_t **buf, uint16_t count)
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{
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while (count--) {
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next_pixel(mask, data, buf);
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}
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}
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static int max7219_write(const struct device *dev, const uint16_t x, const uint16_t y,
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const struct display_buffer_descriptor *desc, const void *buf)
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{
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const struct max7219_config *dev_config = dev->config;
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struct max7219_data *dev_data = dev->data;
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const uint16_t max_width = MAX7219_SEGMENTS_PER_DIGIT;
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const uint16_t max_height = dev_config->num_cascading * MAX7219_DIGITS_PER_DEVICE;
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/*
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* MAX7219 only supports PIXEL_FORMAT_MONO01. 1 bit stands for 1 pixel.
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*/
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__ASSERT((desc->pitch * desc->height) <= (desc->buf_size * 8U), "Input buffer to small");
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__ASSERT(desc->width <= desc->pitch, "Pitch is smaller then width");
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__ASSERT(desc->pitch <= max_width, "Pitch in descriptor is larger than screen size");
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__ASSERT(desc->height <= max_height, "Height in descriptor is larger than screen size");
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__ASSERT(x + desc->pitch <= max_width,
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"Writing outside screen boundaries in horizontal direction");
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__ASSERT(y + desc->height <= max_height,
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"Writing outside screen boundaries in vertical direction");
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if (desc->width > desc->pitch || (desc->pitch * desc->height) > (desc->buf_size * 8U)) {
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return -EINVAL;
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}
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if ((x + desc->pitch) > max_width || (y + desc->height) > max_height) {
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return -EINVAL;
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}
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const uint16_t end_x = x + desc->width;
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const uint16_t end_y = y + desc->height;
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const uint8_t *byte_buf = buf;
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const uint16_t to_skip = desc->pitch - desc->width;
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uint8_t mask = 0;
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uint8_t data = 0;
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for (uint16_t py = y; py < end_y; ++py) {
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const uint8_t max7219_idx = py / MAX7219_DIGITS_PER_DEVICE;
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const uint8_t digit_idx = py % MAX7219_DIGITS_PER_DEVICE;
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uint8_t segment = dev_data->digit_buf[py];
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int ret;
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for (uint16_t px = x; px < end_x; ++px) {
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WRITE_BIT(segment, px, next_pixel(&mask, &data, &byte_buf));
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}
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skip_pixel(&mask, &data, &byte_buf, to_skip);
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/* led register address begins from 1 */
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ret = max7219_transmit_one(dev, max7219_idx, digit_idx + 1, segment);
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if (ret < 0) {
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return ret;
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}
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dev_data->digit_buf[y] = segment;
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}
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return 0;
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}
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static int max7219_set_brightness(const struct device *dev, const uint8_t brightness)
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{
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int ret;
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/*
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* max7219 supports intensity value from 0x0 to 0xF.
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* map the brightness from [0, 255] to [0, 15]
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*/
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ret = max7219_transmit_all(dev, MAX7219_REG_INTENSITY, brightness >> 4);
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if (ret < 0) {
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LOG_ERR("Failed to set brightness");
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return ret;
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}
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return 0;
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}
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static int max7219_set_pixel_format(const struct device *dev,
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const enum display_pixel_format format)
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{
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ARG_UNUSED(dev);
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switch (format) {
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case PIXEL_FORMAT_MONO01:
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return 0;
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default:
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return -ENOTSUP;
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}
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}
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static int max7219_set_orientation(const struct device *dev,
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const enum display_orientation orientation)
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{
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ARG_UNUSED(dev);
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switch (orientation) {
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case DISPLAY_ORIENTATION_NORMAL:
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return 0;
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default:
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return -ENOTSUP;
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}
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}
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static void max7219_get_capabilities(const struct device *dev, struct display_capabilities *caps)
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{
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const struct max7219_config *dev_config = dev->config;
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caps->x_resolution = MAX7219_SEGMENTS_PER_DIGIT;
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caps->y_resolution = MAX7219_DIGITS_PER_DEVICE * dev_config->num_cascading;
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caps->supported_pixel_formats = PIXEL_FORMAT_MONO01;
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caps->screen_info = 0;
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caps->current_pixel_format = PIXEL_FORMAT_MONO01;
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caps->current_orientation = DISPLAY_ORIENTATION_NORMAL;
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}
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static const struct display_driver_api max7219_api = {
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.write = max7219_write,
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.set_brightness = max7219_set_brightness,
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.get_capabilities = max7219_get_capabilities,
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.set_pixel_format = max7219_set_pixel_format,
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.set_orientation = max7219_set_orientation,
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};
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static int max7219_init(const struct device *dev)
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{
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const struct max7219_config *dev_config = dev->config;
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struct max7219_data *dev_data = dev->data;
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int ret;
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if (!spi_is_ready_dt(&dev_config->spi)) {
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LOG_ERR("SPI device not ready");
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return -ENODEV;
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}
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/* turn off all leds */
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memset(dev_data->digit_buf, 0,
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dev_config->num_cascading * MAX7219_DIGITS_PER_DEVICE * sizeof(uint8_t));
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ret = max7219_transmit_all(dev, MAX7219_REG_DISPLAY_TEST, MAX7219_LEAVE_DISPLAY_TEST_MODE);
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if (ret < 0) {
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LOG_ERR("Failed to disable display test");
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return ret;
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}
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ret = max7219_transmit_all(dev, MAX7219_REG_DECODE_MODE, MAX7219_NO_DECODE);
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if (ret < 0) {
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LOG_ERR("Failed to set decode mode");
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return ret;
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}
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ret = max7219_transmit_all(dev, MAX7219_REG_INTENSITY, dev_config->intensity);
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if (ret < 0) {
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LOG_ERR("Failed to set global brightness");
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return ret;
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}
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ret = max7219_transmit_all(dev, MAX7219_REG_SCAN_LIMIT, dev_config->scan_limit);
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if (ret < 0) {
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LOG_ERR("Failed to set scan limit");
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return ret;
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}
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ret = max7219_transmit_all(dev, MAX7219_REG_SHUTDOWN, MAX7219_LEAVE_SHUTDOWN_MODE);
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if (ret < 0) {
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LOG_ERR("Failed to leave shutdown state");
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return ret;
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}
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const struct display_buffer_descriptor desc = {
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.buf_size = dev_config->num_cascading * MAX7219_DIGITS_PER_DEVICE,
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.height = dev_config->num_cascading * MAX7219_DIGITS_PER_DEVICE,
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.width = MAX7219_DIGITS_PER_DEVICE,
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.pitch = MAX7219_DIGITS_PER_DEVICE,
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};
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ret = max7219_write(dev, 0, 0, &desc, dev_data->digit_buf);
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if (ret < 0) {
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return ret;
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}
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return 0;
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}
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#define DISPLAY_MAX7219_INIT(n) \
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static uint8_t max7219_digit_data_##n[DT_INST_PROP(n, num_cascading) * \
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MAX7219_DIGITS_PER_DEVICE]; \
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static uint8_t max7219_tx_buf##n[DT_INST_PROP(n, num_cascading) * 2]; \
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static struct max7219_data max7219_data_##n = { \
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.digit_buf = max7219_digit_data_##n, \
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.tx_buf = max7219_tx_buf##n, \
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}; \
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static const struct max7219_config max7219_config_##n = { \
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.spi = SPI_DT_SPEC_INST_GET( \
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n, SPI_OP_MODE_MASTER | SPI_WORD_SET(8U), 0U), \
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.num_cascading = DT_INST_PROP(n, num_cascading), \
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.intensity = DT_INST_PROP(n, intensity), \
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.scan_limit = DT_INST_PROP(n, scan_limit), \
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}; \
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DEVICE_DT_INST_DEFINE(n, max7219_init, NULL, &max7219_data_##n, \
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&max7219_config_##n, POST_KERNEL, \
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CONFIG_DISPLAY_INIT_PRIORITY, &max7219_api);
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DT_INST_FOREACH_STATUS_OKAY(DISPLAY_MAX7219_INIT)
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