1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/reset/reset-stm32mp1.c b/drivers/reset/reset-stm32mp1.c
new file mode 100644
index 000000000000..b221a28041fa
--- /dev/null
+++ b/drivers/reset/reset-stm32mp1.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
+ * Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+
+#define CLR_OFFSET 0x4
+
+struct stm32_reset_data {
+	struct reset_controller_dev	rcdev;
+	void __iomem			*membase;
+};
+
+static inline struct stm32_reset_data *
+to_stm32_reset_data(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct stm32_reset_data, rcdev);
+}
+
+static int stm32_reset_update(struct reset_controller_dev *rcdev,
+			      unsigned long id, bool assert)
+{
+	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
+	int reg_width = sizeof(u32);
+	int bank = id / (reg_width * BITS_PER_BYTE);
+	int offset = id % (reg_width * BITS_PER_BYTE);
+	void __iomem *addr;
+
+	addr = data->membase + (bank * reg_width);
+	if (!assert)
+		addr += CLR_OFFSET;
+
+	writel(BIT(offset), addr);
+
+	return 0;
+}
+
+static int stm32_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	return stm32_reset_update(rcdev, id, true);
+}
+
+static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return stm32_reset_update(rcdev, id, false);
+}
+
+static int stm32_reset_status(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
+	int reg_width = sizeof(u32);
+	int bank = id / (reg_width * BITS_PER_BYTE);
+	int offset = id % (reg_width * BITS_PER_BYTE);
+	u32 reg;
+
+	reg = readl(data->membase + (bank * reg_width));
+
+	return !!(reg & BIT(offset));
+}
+
+static const struct reset_control_ops stm32_reset_ops = {
+	.assert		= stm32_reset_assert,
+	.deassert	= stm32_reset_deassert,
+	.status		= stm32_reset_status,
+};
+
+static const struct of_device_id stm32_reset_dt_ids[] = {
+	{ .compatible = "st,stm32mp1-rcc"},
+	{ /* sentinel */ },
+};
+
+static int stm32_reset_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct stm32_reset_data *data;
+	void __iomem *membase;
+	struct resource *res;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	membase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(membase))
+		return PTR_ERR(membase);
+
+	data->membase = membase;
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
+	data->rcdev.ops = &stm32_reset_ops;
+	data->rcdev.of_node = dev->of_node;
+
+	return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static struct platform_driver stm32_reset_driver = {
+	.probe	= stm32_reset_probe,
+	.driver = {
+		.name		= "stm32mp1-reset",
+		.of_match_table	= stm32_reset_dt_ids,
+	},
+};
+
+builtin_platform_driver(stm32_reset_driver);