drivers: reset: added Reset Controller for Raspberry Pi Pico

added Reset Controller driver for Raspberry Pi Pico board

Signed-off-by: Andrei-Edward Popa <andrei.popa105@yahoo.com>

drivers/reset/CMakeLists.txt

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_library()
+zephyr_library_sources_ifdef(CONFIG_RESET_RPI_PICO reset_rpi_pico.c)

drivers/reset/Kconfig

@@ -27,4 +27,6 @@ config RESET_INIT_PRIORITY
 
 comment "Reset Controller Drivers"
 
+rsource "Kconfig.rpi_pico"
+
 endif # RESET

drivers/reset/Kconfig.rpi_pico

@@ -0,0 +1,9 @@
+# Copyright (c) 2022 Andrei-Edward Popa
+# SPDX-License-Identifier: Apache-2.0
+
+# Workaround for not being able to have commas in macro arguments
+DT_COMPAT_RPI_PICO_RESET := raspberrypi,pico-reset
+
+config RESET_RPI_PICO
+	bool "Raspberry Pi Reset Controller driver"
+	default $(dt_compat_enabled,$(DT_COMPAT_RPI_PICO_RESET))

drivers/reset/reset_rpi_pico.c

@@ -0,0 +1,159 @@
+/*
+ * Copyright (c) 2022 Andrei-Edward Popa
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT raspberrypi_pico_reset
+
+#include <device.h>
+#include <drivers/reset.h>
+
+struct reset_rpi_config {
+	DEVICE_MMIO_ROM;
+	uint8_t reg_width;
+	uint8_t active_low;
+	uintptr_t base_address;
+};
+
+static int reset_rpi_read_register(const struct device *dev, uint16_t offset, uint32_t *value)
+{
+	const struct reset_rpi_config *config = dev->config;
+	uint32_t base_address = config->base_address;
+
+	switch (config->reg_width) {
+	case 1:
+		*value = sys_read8(base_address + offset);
+		break;
+	case 2:
+		*value = sys_read16(base_address + offset);
+		break;
+	case 4:
+		*value = sys_read32(base_address + offset);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int reset_rpi_write_register(const struct device *dev, uint16_t offset, uint32_t value)
+{
+	const struct reset_rpi_config *config = dev->config;
+	uint32_t base_address = config->base_address;
+
+	switch (config->reg_width) {
+	case 1:
+		sys_write8(value, base_address + offset);
+		break;
+	case 2:
+		sys_write16(value, base_address + offset);
+		break;
+	case 4:
+		sys_write32(value, base_address + offset);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int reset_rpi_status(const struct device *dev, uint32_t id, uint8_t *status)
+{
+	const struct reset_rpi_config *config = dev->config;
+	uint16_t offset;
+	uint32_t value;
+	uint8_t regbit;
+	int ret;
+
+	offset = id / (config->reg_width * CHAR_BIT);
+	regbit = id % (config->reg_width * CHAR_BIT);
+
+	ret = reset_rpi_read_register(dev, offset, &value);
+	if (ret) {
+		return ret;
+	}
+
+	*status = !(value & BIT(regbit)) ^ !config->active_low;
+
+	return ret;
+}
+
+static int reset_rpi_update(const struct device *dev, uint32_t id, uint8_t assert)
+{
+	const struct reset_rpi_config *config = dev->config;
+	uint16_t offset;
+	uint32_t value;
+	uint8_t regbit;
+	int ret;
+
+	offset = id / (config->reg_width * CHAR_BIT);
+	regbit = id % (config->reg_width * CHAR_BIT);
+
+	ret = reset_rpi_read_register(dev, offset, &value);
+	if (ret) {
+		return ret;
+	}
+
+	if (assert ^ config->active_low) {
+		value |= BIT(regbit);
+	} else {
+		value &= ~BIT(regbit);
+	}
+
+	return reset_rpi_write_register(dev, offset, value);
+}
+
+static int reset_rpi_assert(const struct device *dev, uint32_t id)
+{
+	return reset_rpi_update(dev, id, 1);
+}
+
+static int reset_rpi_deassert(const struct device *dev, uint32_t id)
+{
+	return reset_rpi_update(dev, id, 0);
+}
+
+static int reset_rpi_toggle(const struct device *dev, uint32_t id)
+{
+	int ret;
+
+	ret = reset_rpi_assert(dev, id);
+	if (ret) {
+		return ret;
+	}
+
+	return reset_rpi_deassert(dev, id);
+}
+
+static int reset_rpi_init(const struct device *dev)
+{
+	DEVICE_MMIO_MAP(dev, K_MEM_CACHE_NONE);
+
+	return 0;
+}
+
+static const struct reset_driver_api reset_rpi_driver_api = {
+	.status = reset_rpi_status,
+	.assert = reset_rpi_assert,
+	.deassert = reset_rpi_deassert,
+	.toggle = reset_rpi_toggle,
+};
+
+#define RPI_RESET_INIT(idx)							\
+	static const struct reset_rpi_config reset_rpi_config_##idx = {		\
+		DEVICE_MMIO_ROM_INIT(DT_DRV_INST(idx)),				\
+		.reg_width = DT_INST_PROP_OR(idx, reg_width, 4),		\
+		.active_low = DT_INST_PROP_OR(idx, active_low, 0),		\
+		.base_address = DT_INST_REG_ADDR(idx),				\
+	};									\
+										\
+	DEVICE_DT_INST_DEFINE(idx, reset_rpi_init,				\
+			      NULL, NULL,					\
+			      &reset_rpi_config_##idx, PRE_KERNEL_1,		\
+			      CONFIG_RESET_INIT_PRIORITY,			\
+			      &reset_rpi_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(RPI_RESET_INIT);