[PATCH v8 10/16] reset: Add a reset controller driver for the Lantiq XWAY based SoCs

Hauke Mehrtens
2017-08-02T23:00:12Z

From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

The reset controllers (on xRX200 and newer SoCs have two of them) are
provided by the RCU module. This was initially implemented as a simple
reset controller. However, the RCU module provides more functionality
(ethernet GPHYs, USB PHY, etc.), which makes it a MFD device.
The old reset controller driver implementation from
arch/mips/lantiq/xway/reset.c did not honor this fact.

For some devices the request and the status bits are different.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
.../devicetree/bindings/reset/lantiq,reset.txt | 30 +++
drivers/reset/Kconfig | 6 +
drivers/reset/Makefile | 1 +
drivers/reset/reset-lantiq.c | 224 +++++++++++++++++++++
4 files changed, 261 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reset/lantiq,reset.txt
create mode 100644 drivers/reset/reset-lantiq.c

diff --git a/Documentation/devicetree/bindings/reset/lantiq,reset.txt b/Documentation/devicetree/bindings/reset/lantiq,reset.txt
new file mode 100644
index 000000000000..c1c48aa099b3
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/lantiq,reset.txt
@@ -0,0 +1,30 @@
+Lantiq XWAY SoC RCU reset controller binding
+============================================
+
+This binding describes a reset-controller found on the RCU module on Lantiq
+XWAY SoCs.
+
+This driver has to be a sub node of the Lantiq RCU block.
+
+-------------------------------------------------------------------------------
+Required properties:
+- compatible : Should be one of
+ "lantiq,danube-reset"
+ "lantiq,xrx200-reset"
+- reg : Defines the following sets of registers in the parent
+ syscon device
+ - Offset of the reset set register
+ - Offset of the reset status register
+- #reset-cells : Specifies the number of cells needed to encode the
+ reset line, should be 2.
+ The first cell takes the reset set bit and the
+ second cell takes the status bit.
+
+-------------------------------------------------------------------------------
+Example for the reset-controllers on the xRX200 SoCs:
+ reset0: reset-controller@0 {
+ compatible = "lantiq,xrx200-reset";
+ reg <0x10 0x04>, <0x14 0x04>;
+
+ #reset-cells = <2>;
+ };
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 608c071e4bbf..4172ea1827f8 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -48,6 +48,12 @@ config RESET_IMX7
help
This enables the reset controller driver for i.MX7 SoCs.

+config RESET_LANTIQ
+ bool "Lantiq XWAY Reset Driver" if COMPILE_TEST
+ default SOC_TYPE_XWAY
+ help
+ This enables the reset controller driver for Lantiq / Intel XWAY SoCs.
+
config RESET_LPC18XX
bool "LPC18xx/43xx Reset Driver" if COMPILE_TEST
default ARCH_LPC18XX
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 7081f9da2599..54d8b3f703f2 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_RESET_ATH79) += reset-ath79.o
obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
obj-$(CONFIG_RESET_GEMINI) += reset-gemini.o
obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
+obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
obj-$(CONFIG_RESET_MESON) += reset-meson.o
obj-$(CONFIG_RESET_OXNAS) += reset-oxnas.o
diff --git a/drivers/reset/reset-lantiq.c b/drivers/reset/reset-lantiq.c
new file mode 100644
index 000000000000..b84c45e7e6b8
--- /dev/null
+++ b/drivers/reset/reset-lantiq.c
@@ -0,0 +1,224 @@
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * Copyright (C) 2010 John Crispin <blogic@phrozen.org>
+ * Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG
+ * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+
+#define LANTIQ_RCU_RESET_TIMEOUT 10000
+
+struct lantiq_rcu_reset_priv {
+ struct reset_controller_dev rcdev;
+ struct device *dev;
+ struct regmap *regmap;
+ u32 reset_offset;
+ u32 status_offset;
+};
+
+static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv(
+ struct reset_controller_dev *rcdev)
+{
+ return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev);
+}
+
+static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
+ unsigned int status = (id >> 8) & 0x1f;
+ u32 val;
+ int ret;
+
+ ret = regmap_read(priv->regmap, priv->status_offset, &val);
+ if (ret)
+ return ret;
+
+ return !!(val & BIT(status));
+}
+
+static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ int ret;
+ int retry = LANTIQ_RCU_RESET_TIMEOUT;
+
+ do {
+ ret = lantiq_rcu_reset_status(rcdev, id);
+ if (ret < 0)
+ return ret;
+ if (ret == assert)
+ return 0;
+ usleep_range(20, 40);
+ } while (--retry);
+
+ return -ETIMEDOUT;
+}
+
+static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev,
+ unsigned long id, bool assert)
+{
+ struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
+ unsigned int set = id & 0x1f;
+ u32 val = assert ? BIT(set) : 0;
+ int ret;
+
+ ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set),
+ val);
+ if (ret) {
+ dev_err(priv->dev, "Failed to set reset bit %u\n", set);
+ return ret;
+ }
+
+
+ ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert);
+ if (ret)
+ dev_err(priv->dev, "Failed to %s bit %u\n",
+ assert ? "assert" : "deassert", set);
+
+ return ret;
+}
+
+static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return lantiq_rcu_reset_update(rcdev, id, true);
+}
+
+static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return lantiq_rcu_reset_update(rcdev, id, false);
+}
+
+static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ int ret;
+
+ ret = lantiq_rcu_reset_assert(rcdev, id);
+ if (ret)
+ return ret;
+
+ return lantiq_rcu_reset_deassert(rcdev, id);
+}
+
+static const struct reset_control_ops lantiq_rcu_reset_ops = {
+ .assert = lantiq_rcu_reset_assert,
+ .deassert = lantiq_rcu_reset_deassert,
+ .status = lantiq_rcu_reset_status,
+ .reset = lantiq_rcu_reset_reset,
+};
+
+static int lantiq_rcu_reset_of_probe(struct platform_device *pdev,
+ struct lantiq_rcu_reset_priv *priv)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct resource res_parent;
+ int ret;
+
+ priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
+ if (IS_ERR(priv->regmap)) {
+ dev_err(&pdev->dev, "Failed to lookup RCU regmap\n");
+ return PTR_ERR(priv->regmap);
+ }
+
+ ret = of_address_to_resource(dev->of_node->parent, 0, &res_parent);
+ if (ret)
+ return ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "Failed to get RCU reset offset\n");
+ return ret;
+ }
+
+ if (res->start < res_parent.start)
+ return -ENOENT;
+ priv->reset_offset = res->start - res_parent.start;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res) {
+ dev_err(&pdev->dev, "Failed to get RCU status offset\n");
+ return ret;
+ }
+
+ if (res->start < res_parent.start)
+ return -ENOENT;
+ priv->status_offset = res->start - res_parent.start;
+
+ return 0;
+}
+
+static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ unsigned int status, set;
+
+ set = reset_spec->args[0];
+ status = reset_spec->args[1];
+
+ if (set >= rcdev->nr_resets || status >= rcdev->nr_resets)
+ return -EINVAL;
+
+ return (status << 8) | set;
+}
+
+static int lantiq_rcu_reset_probe(struct platform_device *pdev)
+{
+ struct lantiq_rcu_reset_priv *priv;
+ int err;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->dev = &pdev->dev;
+ platform_set_drvdata(pdev, priv);
+
+ err = lantiq_rcu_reset_of_probe(pdev, priv);
+ if (err)
+ return err;
+
+ priv->rcdev.ops = &lantiq_rcu_reset_ops;
+ priv->rcdev.owner = THIS_MODULE;
+ priv->rcdev.of_node = pdev->dev.of_node;
+ priv->rcdev.nr_resets = 32;
+ priv->rcdev.of_xlate = lantiq_rcu_reset_xlate;
+ priv->rcdev.of_reset_n_cells = 2;
+
+ return reset_controller_register(&priv->rcdev);
+}
+
+static const struct of_device_id lantiq_rcu_reset_dt_ids[] = {
+ { .compatible = "lantiq,danube-reset", },
+ { .compatible = "lantiq,xrx200-reset", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids);
+
+static struct platform_driver lantiq_rcu_reset_driver = {
+ .probe = lantiq_rcu_reset_probe,
+ .driver = {
+ .name = "lantiq-reset",
+ .of_match_table = lantiq_rcu_reset_dt_ids,
+ },
+};
+module_platform_driver(lantiq_rcu_reset_driver);
+
+MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
+MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver");
+MODULE_LICENSE("GPL");
--
2.11.0