[RFC PATCH 1/3] reset: Add support for the Amlogic Meson GXBB Reset Controller
From: Neil Armstrong
Date: Fri May 13 2016 - 10:01:00 EST
This patch adds the platform driver for the Amlogic Meson GXBB Reset
Controller.
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
drivers/reset/Kconfig | 6 ++
drivers/reset/Makefile | 1 +
drivers/reset/reset-meson-gxbb.c | 160 +++++++++++++++++++++++++++++++++++++++
3 files changed, 167 insertions(+)
create mode 100644 drivers/reset/reset-meson-gxbb.c
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index df37212..4ac5c4d 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -12,5 +12,11 @@ menuconfig RESET_CONTROLLER
If unsure, say no.
+config MESON_GXBB_RESET
+ tristate "Amlogic Meson GXBB Reset Driver"
+ depends on (ARCH_MESON && RESET_CONTROLLER)
+ help
+ Build the Amlogic Meson GxBB reset driver.
+
source "drivers/reset/sti/Kconfig"
source "drivers/reset/hisilicon/Kconfig"
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index a1fc8ed..5ff83a1 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_ARCH_LPC18XX) += reset-lpc18xx.o
obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
obj-$(CONFIG_MACH_PISTACHIO) += reset-pistachio.o
+obj-$(CONFIG_MESON_GXBB_RESET) += reset-meson-gxbb.o
obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
obj-$(CONFIG_ARCH_STI) += sti/
obj-$(CONFIG_ARCH_HISI) += hisilicon/
diff --git a/drivers/reset/reset-meson-gxbb.c b/drivers/reset/reset-meson-gxbb.c
new file mode 100644
index 0000000..798fdf9
--- /dev/null
+++ b/drivers/reset/reset-meson-gxbb.c
@@ -0,0 +1,160 @@
+/*
+ * Copyright (c) 2016 BayLibre, Inc.
+ * Author: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
+ *
+ * This file is dual-licensed: you can use it either under the terms
+ * of the GPL or the X11 license, at your option. Note that this dual
+ * licensing only applies to this file, and not this project as a
+ * whole.
+ *
+ * a) This library 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.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Or, alternatively,
+ *
+ * b) Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define REG_COUNT 7
+#define BITS_PER_REG 16
+
+struct meson_gxbb_reset {
+ void *reg_base;
+ struct reset_controller_dev rcdev;
+};
+
+static int meson_gxbb_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct meson_gxbb_reset *data =
+ container_of(rcdev, struct meson_gxbb_reset, rcdev);
+ unsigned int bank = id / BITS_PER_REG;
+ unsigned int offset = id % BITS_PER_REG;
+ void *reg_addr = data->reg_base + (bank << 2);
+
+ if (bank >= REG_COUNT)
+ return -EINVAL;
+
+ writel(readl(reg_addr) | BIT(offset), reg_addr);
+
+ return 0;
+}
+
+static int meson_gxbb_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct meson_gxbb_reset *data =
+ container_of(rcdev, struct meson_gxbb_reset, rcdev);
+ unsigned int bank = id / BITS_PER_REG;
+ unsigned int offset = id % BITS_PER_REG;
+ void *reg_addr = data->reg_base + (bank << 2);
+
+ if (bank >= REG_COUNT)
+ return -EINVAL;
+
+ writel(readl(reg_addr) & ~BIT(offset), reg_addr);
+
+ return 0;
+}
+
+static int meson_gxbb_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ int err;
+
+ err = meson_gxbb_reset_assert(rcdev, id);
+ if (err)
+ return err;
+
+ return meson_gxbb_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops meson_gxbb_reset_ops = {
+ .reset = meson_gxbb_reset_reset,
+ .assert = meson_gxbb_reset_assert,
+ .deassert = meson_gxbb_reset_deassert,
+};
+
+static const struct of_device_id meson_gxbb_reset_dt_ids[] = {
+ { .compatible = "amlogic,meson-gxbb-reset", },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, meson_gxbb_reset_dt_ids);
+
+static int meson_gxbb_reset_probe(struct platform_device *pdev)
+{
+ struct meson_gxbb_reset *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->reg_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(data->reg_base))
+ return PTR_ERR(data->reg_base);
+
+ platform_set_drvdata(pdev, data);
+
+ data->rcdev.owner = THIS_MODULE;
+ data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
+ data->rcdev.ops = &meson_gxbb_reset_ops;
+ data->rcdev.of_node = pdev->dev.of_node;
+
+ return reset_controller_register(&data->rcdev);
+}
+
+static int meson_gxbb_reset_remove(struct platform_device *pdev)
+{
+ struct meson_gxbb_reset *data = platform_get_drvdata(pdev);
+
+ reset_controller_unregister(&data->rcdev);
+
+ return 0;
+}
+
+static struct platform_driver meson_gxbb_reset_driver = {
+ .probe = meson_gxbb_reset_probe,
+ .remove = meson_gxbb_reset_remove,
+ .driver = {
+ .name = "meson_gxbb_reset",
+ .of_match_table = meson_gxbb_reset_dt_ids,
+ },
+};
+
+module_platform_driver(meson_gxbb_reset_driver);
--
2.7.0