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path: root/drivers/clk/stm32/reset-stm32.c
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Diffstat (limited to 'drivers/clk/stm32/reset-stm32.c')
-rw-r--r--drivers/clk/stm32/reset-stm32.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/clk/stm32/reset-stm32.c b/drivers/clk/stm32/reset-stm32.c
new file mode 100644
index 000000000..e89381528
--- /dev/null
+++ b/drivers/clk/stm32/reset-stm32.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) STMicroelectronics 2022 - All Rights Reserved
+ * Author: Gabriel Fernandez <gabriel.fernandez@foss.st.com> for STMicroelectronics.
+ */
+
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "clk-stm32-core.h"
+
+#define STM32_RESET_ID_MASK GENMASK(15, 0)
+
+struct stm32_reset_data {
+ /* reset lock */
+ spinlock_t lock;
+ struct reset_controller_dev rcdev;
+ void __iomem *membase;
+ u32 clear_offset;
+};
+
+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);
+
+ if (data->clear_offset) {
+ void __iomem *addr;
+
+ addr = data->membase + (bank * reg_width);
+ if (!assert)
+ addr += data->clear_offset;
+
+ writel(BIT(offset), addr);
+
+ } else {
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ reg = readl(data->membase + (bank * reg_width));
+
+ if (assert)
+ reg |= BIT(offset);
+ else
+ reg &= ~BIT(offset);
+
+ writel(reg, data->membase + (bank * reg_width));
+
+ spin_unlock_irqrestore(&data->lock, flags);
+ }
+
+ 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,
+};
+
+int stm32_rcc_reset_init(struct device *dev, const struct of_device_id *match,
+ void __iomem *base)
+{
+ const struct stm32_rcc_match_data *data = match->data;
+ struct stm32_reset_data *reset_data = NULL;
+
+ data = match->data;
+
+ reset_data = kzalloc(sizeof(*reset_data), GFP_KERNEL);
+ if (!reset_data)
+ return -ENOMEM;
+
+ spin_lock_init(&reset_data->lock);
+ reset_data->membase = base;
+ reset_data->rcdev.owner = THIS_MODULE;
+ reset_data->rcdev.ops = &stm32_reset_ops;
+ reset_data->rcdev.of_node = dev_of_node(dev);
+ reset_data->rcdev.nr_resets = STM32_RESET_ID_MASK;
+ reset_data->clear_offset = data->clear_offset;
+
+ return reset_controller_register(&reset_data->rcdev);
+}