163 lines
3.5 KiB
C
163 lines
3.5 KiB
C
/*
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* Copyright (c) 2022 Andrei-Edward Popa
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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 raspberrypi_pico_reset
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#include <limits.h>
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#include <zephyr/arch/cpu.h>
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#include <zephyr/device.h>
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#include <zephyr/drivers/reset.h>
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struct reset_rpi_config {
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DEVICE_MMIO_ROM;
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uint8_t reg_width;
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uint8_t active_low;
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uintptr_t base_address;
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};
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static int reset_rpi_read_register(const struct device *dev, uint16_t offset, uint32_t *value)
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{
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const struct reset_rpi_config *config = dev->config;
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uint32_t base_address = config->base_address;
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switch (config->reg_width) {
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case 1:
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*value = sys_read8(base_address + offset);
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break;
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case 2:
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*value = sys_read16(base_address + offset);
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break;
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case 4:
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*value = sys_read32(base_address + offset);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static int reset_rpi_write_register(const struct device *dev, uint16_t offset, uint32_t value)
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{
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const struct reset_rpi_config *config = dev->config;
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uint32_t base_address = config->base_address;
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switch (config->reg_width) {
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case 1:
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sys_write8(value, base_address + offset);
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break;
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case 2:
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sys_write16(value, base_address + offset);
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break;
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case 4:
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sys_write32(value, base_address + offset);
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static int reset_rpi_status(const struct device *dev, uint32_t id, uint8_t *status)
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{
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const struct reset_rpi_config *config = dev->config;
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uint16_t offset;
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uint32_t value;
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uint8_t regbit;
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int ret;
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offset = id / (config->reg_width * CHAR_BIT);
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regbit = id % (config->reg_width * CHAR_BIT);
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ret = reset_rpi_read_register(dev, offset, &value);
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if (ret) {
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return ret;
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}
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*status = !(value & BIT(regbit)) ^ !config->active_low;
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return ret;
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}
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static int reset_rpi_update(const struct device *dev, uint32_t id, uint8_t assert)
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{
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const struct reset_rpi_config *config = dev->config;
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uint16_t offset;
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uint32_t value;
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uint8_t regbit;
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int ret;
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offset = id / (config->reg_width * CHAR_BIT);
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regbit = id % (config->reg_width * CHAR_BIT);
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ret = reset_rpi_read_register(dev, offset, &value);
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if (ret) {
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return ret;
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}
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if (assert ^ config->active_low) {
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value |= BIT(regbit);
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} else {
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value &= ~BIT(regbit);
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}
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return reset_rpi_write_register(dev, offset, value);
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}
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static int reset_rpi_line_assert(const struct device *dev, uint32_t id)
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{
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return reset_rpi_update(dev, id, 1);
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}
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static int reset_rpi_line_deassert(const struct device *dev, uint32_t id)
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{
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return reset_rpi_update(dev, id, 0);
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}
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static int reset_rpi_line_toggle(const struct device *dev, uint32_t id)
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{
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int ret;
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ret = reset_rpi_line_assert(dev, id);
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if (ret) {
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return ret;
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}
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return reset_rpi_line_deassert(dev, id);
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}
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static int reset_rpi_init(const struct device *dev)
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{
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DEVICE_MMIO_MAP(dev, K_MEM_CACHE_NONE);
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return 0;
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}
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static const struct reset_driver_api reset_rpi_driver_api = {
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.status = reset_rpi_status,
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.line_assert = reset_rpi_line_assert,
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.line_deassert = reset_rpi_line_deassert,
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.line_toggle = reset_rpi_line_toggle,
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};
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#define RPI_RESET_INIT(idx) \
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static const struct reset_rpi_config reset_rpi_config_##idx = { \
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DEVICE_MMIO_ROM_INIT(DT_DRV_INST(idx)), \
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.reg_width = DT_INST_PROP_OR(idx, reg_width, 4), \
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.active_low = DT_INST_PROP_OR(idx, active_low, 0), \
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.base_address = DT_INST_REG_ADDR(idx), \
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}; \
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\
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DEVICE_DT_INST_DEFINE(idx, reset_rpi_init, \
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NULL, NULL, \
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&reset_rpi_config_##idx, PRE_KERNEL_1, \
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CONFIG_RESET_INIT_PRIORITY, \
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&reset_rpi_driver_api);
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DT_INST_FOREACH_STATUS_OKAY(RPI_RESET_INIT);
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