[RFCv3 3/4] reset: reset-zynq: Adding support for Xilinx Zynq reset controller.

Moritz Fischer
2015-07-31T01:13:56Z

This adds a reset controller driver to control the Xilinx Zynq
AP-SoC's various resets.

Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
---
drivers/reset/Makefile | 1 +
drivers/reset/reset-zynq.c | 155 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 156 insertions(+)
create mode 100644 drivers/reset/reset-zynq.c

diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 157d421..3fe50e7 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o
obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o
obj-$(CONFIG_ARCH_STI) += sti/
+obj-$(CONFIG_ARCH_ZYNQ) += reset-zynq.o
diff --git a/drivers/reset/reset-zynq.c b/drivers/reset/reset-zynq.c
new file mode 100644
index 0000000..89318a5
--- /dev/null
+++ b/drivers/reset/reset-zynq.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (c) 2015, National Instruments Corp.
+ *
+ * Xilinx Zynq Reset controller driver
+ *
+ * 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; version 2 of the License.
+ *
+ * This program 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.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset-controller.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct zynq_reset_data {
+ struct regmap *slcr;
+ struct reset_controller_dev rcdev;
+ u32 offset;
+};
+
+#define to_zynq_reset_data(p) \
+ container_of((p), struct zynq_reset_data, rcdev)
+
+static int zynq_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
+
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+
+ pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
+ bank, offset);
+
+ return regmap_update_bits(priv->slcr,
+ priv->offset + (bank * 4),
+ BIT(offset),
+ BIT(offset));
+}
+
+static int zynq_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
+
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+
+ pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
+ bank, offset);
+
+ return regmap_update_bits(priv->slcr,
+ priv->offset + (bank * 4),
+ BIT(offset),
+ ~BIT(offset));
+}
+
+static int zynq_reset_status(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
+
+ int bank = id / BITS_PER_LONG;
+ int offset = id % BITS_PER_LONG;
+ int ret;
+ u32 reg;
+
+ pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
+ bank, offset);
+
+ ret = regmap_read(priv->slcr, priv->offset + (bank * 4), &reg);
+ if (ret)
+ return ret;
+
+ return !!(reg & BIT(offset));
+}
+
+static struct reset_control_ops zynq_reset_ops = {
+ .assert = zynq_reset_assert,
+ .deassert = zynq_reset_deassert,
+ .status = zynq_reset_status,
+};
+
+static int zynq_reset_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct zynq_reset_data *priv;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, priv);
+
+ priv->slcr = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+ "syscon");
+ if (IS_ERR(priv->slcr)) {
+ dev_err(&pdev->dev, "unable to get zynq-slcr regmap");
+ return PTR_ERR(priv->slcr);
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "missing IO resource\n");
+ return -ENODEV;
+ }
+
+ priv->offset = res->start;
+
+ priv->rcdev.owner = THIS_MODULE;
+ priv->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_LONG;
+ priv->rcdev.ops = &zynq_reset_ops;
+ priv->rcdev.of_node = pdev->dev.of_node;
+ reset_controller_register(&priv->rcdev);
+
+ return 0;
+}
+
+static int zynq_reset_remove(struct platform_device *pdev)
+{
+ struct zynq_reset_data *priv = platform_get_drvdata(pdev);
+
+ reset_controller_unregister(&priv->rcdev);
+
+ return 0;
+}
+
+static const struct of_device_id zynq_reset_dt_ids[] = {
+ { .compatible = "xlnx,zynq-reset", },
+ { /* sentinel */ },
+};
+
+static struct platform_driver zynq_reset_driver = {
+ .probe = zynq_reset_probe,
+ .remove = zynq_reset_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = zynq_reset_dt_ids,
+ },
+};
+module_platform_driver(zynq_reset_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
+MODULE_DESCRIPTION("Zynq Reset Controller Driver");
--
2.4.3