Incoming STM32 MCU support will leverage this driver, so port it over
from Linux v5.16.
Signed-off-by: Ahmad Fatoum
---
drivers/reset/Kconfig | 17 +++
drivers/reset/Makefile | 1 +
drivers/reset/reset-simple.c | 189 +
include/linux/reset/reset-simple.h | 45 +++
4 files changed, 252 insertions(+)
create mode 100644 drivers/reset/reset-simple.c
create mode 100644 include/linux/reset/reset-simple.h
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 6c70c1026998..82c85162533d 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -15,6 +15,23 @@ menuconfig RESET_CONTROLLER
if RESET_CONTROLLER
+config RESET_SIMPLE
+ bool "Simple Reset Controller Driver" if COMPILE_TEST
+ help
+ This enables a simple reset controller driver for reset lines that
+ that can be asserted and deasserted by toggling bits in a contiguous,
+ exclusive register space.
+
+ Currently this driver supports:
+ - Altera 64-Bit SoCFPGAs
+ - ASPEED BMC SoCs
+ - Bitmain BM1880 SoC
+ - Realtek SoCs
+ - RCC reset controller in STM32 MCUs
+ - Allwinner SoCs
+ - SiFive FU740 SoCs
+
+
config RESET_IMX7
bool "i.MX7 Reset Driver"
default ARCH_IMX7
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index d884a83aa3f7..b4270411fdaf 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-$(CONFIG_RESET_CONTROLLER) += core.o
+obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
obj-$(CONFIG_RESET_STM32) += reset-stm32.o
diff --git a/drivers/reset/reset-simple.c b/drivers/reset/reset-simple.c
new file mode 100644
index ..082956d94dae
--- /dev/null
+++ b/drivers/reset/reset-simple.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Simple Reset Controller Driver
+ *
+ * Copyright (C) 2017 Pengutronix, Philipp Zabel
+ *
+ * Based on Allwinner SoCs Reset Controller driver
+ *
+ * Copyright 2013 Maxime Ripard
+ *
+ * Maxime Ripard
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+static inline struct reset_simple_data *
+to_reset_simple_data(struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct reset_simple_data, rcdev);
+}
+
+static int reset_simple_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct reset_simple_data *data = to_reset_simple_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));
+ if (assert ^ data->active_low)
+ reg |= BIT(offset);
+ else
+ reg &= ~BIT(offset);
+ writel(reg, data->membase + (bank * reg_width));
+
+ return 0;
+}
+
+static int reset_simple_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return reset_simple_update(rcdev, id, true);
+}
+
+static int reset_simple_deassert(struct reset_controller_dev *rcdev,
+unsigned long id)
+{
+ return reset_simple_update(rcdev, id, false);
+}
+
+static int reset_simple_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct reset_simple_data *data = to_reset_simple_data(rcdev);
+ int ret;
+
+ if (!data->reset_us)
+ return -ENOTSUPP;
+
+ ret = reset_simple_assert(rcdev, id);
+ if (ret)
+ return ret;
+
+ udelay(data->reset_us);
+
+ return reset_simple_deassert(rcdev, id);
+}
+
+static int __maybe_unused reset_simple_status(struct reset_controller_dev
*rcdev,
+ unsigned long id)
+{
+ struct reset_simple_data *data = to_reset_simple_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)) ^ !data->status_active_low;
+}
+
+const struct reset_control_ops reset_simple_ops = {
+ .assert = reset_simple_assert,
+ .deassert = reset_simple_deassert,
+ .reset = reset_simple_reset,
+};
+EXPORT_SYMBOL_GPL(reset_simple_ops);
+
+/**
+ * struct reset_simple_devdata - simple reset controller properties
+ * @reg_offset: offset between base address and first reset register.
+ * @nr_resets: number of resets. If not set, default to resource size in bits.
+ * @active_low: if true, bits are cleared to assert the reset.
