[PATCH v3 1/5] reset: add reset-simple to unify socfpga, stm32, sunxi, and zx2967
From: Philipp Zabel
Date: Wed Aug 16 2017 - 05:48:22 EST
Split reusable parts out of the sunxi driver, to add a driver for simple
reset controllers with reset lines that can be controlled by toggling
bits in exclusive, contiguous register ranges using read-modify-write
cycles under a spinlock. The separate sunxi driver still remains to
register the early reset controllers, but it reuses the reset-simple
ops.
The following patches will replace compatible reset drivers with
reset-simple, extending it where necessary.
Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
---
Changes since v2:
- Add kerneldoc comment for struct reset_simple_devdata and struct
reset_simple_data.
- Rename "inverted" properties to "active_low".
- Use of_device_get_match_data instead of of_match_device.
---
drivers/reset/Kconfig | 11 ++++
drivers/reset/Makefile | 1 +
drivers/reset/reset-simple.c | 134 +++++++++++++++++++++++++++++++++++++++++++
drivers/reset/reset-simple.h | 41 +++++++++++++
drivers/reset/reset-sunxi.c | 104 ++-------------------------------
5 files changed, 193 insertions(+), 98 deletions(-)
create mode 100644 drivers/reset/reset-simple.c
create mode 100644 drivers/reset/reset-simple.h
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 52d5251660b9b..f7ba01a71daee 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -68,6 +68,16 @@ config RESET_PISTACHIO
help
This enables the reset driver for ImgTec Pistachio SoCs.
+config RESET_SIMPLE
+ bool "Simple Reset Controller Driver" if COMPILE_TEST
+ default ARCH_SUNXI
+ 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 Allwinner SoCs.
+
config RESET_SOCFPGA
bool "SoCFPGA Reset Driver" if COMPILE_TEST
default ARCH_SOCFPGA
@@ -83,6 +93,7 @@ config RESET_STM32
config RESET_SUNXI
bool "Allwinner SoCs Reset Driver" if COMPILE_TEST && !ARCH_SUNXI
default ARCH_SUNXI
+ select RESET_SIMPLE
help
This enables the reset driver for Allwinner SoCs.
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index b62783f50fe5b..ab4af99c3dfdc 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
obj-$(CONFIG_RESET_MESON) += reset-meson.o
obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
obj-$(CONFIG_RESET_PISTACHIO) += reset-pistachio.o
+obj-$(CONFIG_RESET_SIMPLE) += reset-simple.o
obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
obj-$(CONFIG_RESET_STM32) += reset-stm32.o
obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
diff --git a/drivers/reset/reset-simple.c b/drivers/reset/reset-simple.c
new file mode 100644
index 0000000000000..70c57c0758c39
--- /dev/null
+++ b/drivers/reset/reset-simple.c
@@ -0,0 +1,134 @@
+/*
+ * Simple Reset Controller Driver
+ *
+ * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@xxxxxxxxxxxxxx>
+ *
+ * Based on Allwinner SoCs Reset Controller driver
+ *
+ * Copyright 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+#include "reset-simple.h"
+
+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_set(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);
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ 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));
+
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ return 0;
+}
+
+static int reset_simple_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return reset_simple_set(rcdev, id, true);
+}
+
+static int reset_simple_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return reset_simple_set(rcdev, id, false);
+}
+
+const struct reset_control_ops reset_simple_ops = {
+ .assert = reset_simple_assert,
+ .deassert = reset_simple_deassert,
+};
+
+/**
+ * struct reset_simple_devdata - simple reset controller properties
+ * @active_low: if true, bits are cleared to assert the reset. Otherwise, bits
+ * are set to assert the reset.
+ */
+struct reset_simple_devdata {
+ bool active_low;
+};
+
+static const struct reset_simple_devdata reset_simple_active_low = {
+ .active_low = true,
+};
+
+static const struct of_device_id reset_simple_dt_ids[] = {
+ { .compatible = "allwinner,sun6i-a31-clock-reset",
+ .data = &reset_simple_active_low },
+ { /* sentinel */ },
+};
+
+static int reset_simple_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ const struct reset_simple_devdata *devdata;
+ struct reset_simple_data *data;
+ void __iomem *membase;
+ struct resource *res;
+
+ devdata = of_device_get_match_data(dev);
+
+ 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);
+
+ spin_lock_init(&data->lock);
+ data->membase = membase;
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
+ data->rcdev.ops = &reset_simple_ops;
+ data->rcdev.of_node = dev->of_node;
+
+ if (devdata)
+ data->active_low = devdata->active_low;
+
+ return devm_reset_controller_register(dev, &data->rcdev);
+}
+
+static struct platform_driver reset_simple_driver = {
+ .probe = reset_simple_probe,
+ .driver = {
+ .name = "simple-reset",
+ .of_match_table = reset_simple_dt_ids,
+ },
+};
+builtin_platform_driver(reset_simple_driver);
diff --git a/drivers/reset/reset-simple.h b/drivers/reset/reset-simple.h
new file mode 100644
index 0000000000000..39af2014b5f12
--- /dev/null
+++ b/drivers/reset/reset-simple.h
@@ -0,0 +1,41 @@
+/*
+ * Simple Reset Controller ops
+ *
+ * Based on Allwinner SoCs Reset Controller driver
+ *
+ * Copyright 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __RESET_SIMPLE_H__
+#define __RESET_SIMPLE_H__
+
+#include <linux/io.h>
+#include <linux/reset-controller.h>
+#include <linux/spinlock.h>
+
+/**
+ * struct reset_simple_data - driver data for simple reset controllers
+ * @lock: spinlock to protect registers during read-modify-write cycles
+ * @membase: memory mapped I/O register range
+ * @rcdev: reset controller device base structure
+ * @active_low: if true, bits are cleared to assert the reset. Otherwise, bits
+ * are set to assert the reset. Note that this says nothing about
+ * the voltage level of the actual reset line.
+ */
+struct reset_simple_data {
+ spinlock_t lock;
+ void __iomem *membase;
+ struct reset_controller_dev rcdev;
+ bool active_low;
+};
+
+extern const struct reset_control_ops reset_simple_ops;
+
+#endif /* __RESET_SIMPLE_H__ */
diff --git a/drivers/reset/reset-sunxi.c b/drivers/reset/reset-sunxi.c
index 2c7dd1fd08df6..db9a1a75523f4 100644
--- a/drivers/reset/reset-sunxi.c
+++ b/drivers/reset/reset-sunxi.c
@@ -22,64 +22,11 @@
#include <linux/spinlock.h>
#include <linux/types.h>
-struct sunxi_reset_data {
- spinlock_t lock;
- void __iomem *membase;
- struct reset_controller_dev rcdev;
-};
-
-static int sunxi_reset_assert(struct reset_controller_dev *rcdev,
- unsigned long id)
-{
- struct sunxi_reset_data *data = container_of(rcdev,
- struct sunxi_reset_data,
- rcdev);
- int reg_width = sizeof(u32);
- int bank = id / (reg_width * BITS_PER_BYTE);
- int offset = id % (reg_width * BITS_PER_BYTE);
- unsigned long flags;
- u32 reg;
-
- spin_lock_irqsave(&data->lock, flags);
-
- reg = readl(data->membase + (bank * reg_width));
- writel(reg & ~BIT(offset), data->membase + (bank * reg_width));
-
- spin_unlock_irqrestore(&data->lock, flags);
-
- return 0;
-}
-
-static int sunxi_reset_deassert(struct reset_controller_dev *rcdev,
- unsigned long id)
-{
- struct sunxi_reset_data *data = container_of(rcdev,
- struct sunxi_reset_data,
- rcdev);
- int reg_width = sizeof(u32);
- int bank = id / (reg_width * BITS_PER_BYTE);
- int offset = id % (reg_width * BITS_PER_BYTE);
- unsigned long flags;
- u32 reg;
-
- spin_lock_irqsave(&data->lock, flags);
-
- reg = readl(data->membase + (bank * reg_width));
- writel(reg | BIT(offset), data->membase + (bank * reg_width));
-
- spin_unlock_irqrestore(&data->lock, flags);
-
- return 0;
-}
-
-static const struct reset_control_ops sunxi_reset_ops = {
- .assert = sunxi_reset_assert,
- .deassert = sunxi_reset_deassert,
-};
+#include "reset-simple.h"
static int sunxi_reset_init(struct device_node *np)
{
- struct sunxi_reset_data *data;
+ struct reset_simple_data *data;
struct resource res;
resource_size_t size;
int ret;
@@ -108,8 +55,9 @@ static int sunxi_reset_init(struct device_node *np)
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = size * 8;
- data->rcdev.ops = &sunxi_reset_ops;
+ data->rcdev.ops = &reset_simple_ops;
data->rcdev.of_node = np;
+ data->active_low = true;
return reset_controller_register(&data->rcdev);
@@ -122,6 +70,8 @@ static int sunxi_reset_init(struct device_node *np)
* These are the reset controller we need to initialize early on in
* our system, before we can even think of using a regular device
* driver for it.
+ * The controllers that we can register through the regular device
+ * model are handled by the simple reset driver directly.
*/
static const struct of_device_id sunxi_early_reset_dt_ids[] __initconst = {
{ .compatible = "allwinner,sun6i-a31-ahb1-reset", },
@@ -135,45 +85,3 @@ void __init sun6i_reset_init(void)
for_each_matching_node(np, sunxi_early_reset_dt_ids)
sunxi_reset_init(np);
}
-
-/*
- * And these are the controllers we can register through the regular
- * device model.
- */
-static const struct of_device_id sunxi_reset_dt_ids[] = {
- { .compatible = "allwinner,sun6i-a31-clock-reset", },
- { /* sentinel */ },
-};
-
-static int sunxi_reset_probe(struct platform_device *pdev)
-{
- struct sunxi_reset_data *data;
- struct resource *res;
-
- data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
- if (!data)
- return -ENOMEM;
-
- res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- data->membase = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(data->membase))
- return PTR_ERR(data->membase);
-
- spin_lock_init(&data->lock);
-
- data->rcdev.owner = THIS_MODULE;
- data->rcdev.nr_resets = resource_size(res) * 8;
- data->rcdev.ops = &sunxi_reset_ops;
- data->rcdev.of_node = pdev->dev.of_node;
-
- return devm_reset_controller_register(&pdev->dev, &data->rcdev);
-}
-
-static struct platform_driver sunxi_reset_driver = {
- .probe = sunxi_reset_probe,
- .driver = {
- .name = "sunxi-reset",
- .of_match_table = sunxi_reset_dt_ids,
- },
-};
-builtin_platform_driver(sunxi_reset_driver);
--
2.11.0