[PATCH v3 2/3] reset: mchp: sparx5: add switch reset driver

[Steen Hegelund]

Signed-off-by: Steen Hegelund <steen.hegelund at microchip.com>
---
 drivers/reset/Kconfig                  |   8 ++
 drivers/reset/Makefile                 |   1 +
 drivers/reset/reset-microchip-sparx5.c | 120 +++++++++++++++++++++++++
 3 files changed, 129 insertions(+)
 create mode 100644 drivers/reset/reset-microchip-sparx5.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 71ab75a46491..05c240c47a8a 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -101,6 +101,14 @@ config RESET_LPC18XX
 	help
 	  This enables the reset controller driver for NXP LPC18xx/43xx SoCs.
 
+config RESET_MCHP_SPARX5
+	bool "Microchip Sparx5 reset driver"
+	depends on HAS_IOMEM || COMPILE_TEST
+	default y if SPARX5_SWITCH
+	select MFD_SYSCON
+	help
+	  This driver supports switch core reset for the Microchip Sparx5 SoC.
+
 config RESET_MESON
 	tristate "Meson Reset Driver"
 	depends on ARCH_MESON || COMPILE_TEST
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 1054123fd187..341fd9ab4bf6 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
 obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
 obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o
+obj-$(CONFIG_RESET_MCHP_SPARX5) += reset-microchip-sparx5.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_MESON_AUDIO_ARB) += reset-meson-audio-arb.o
 obj-$(CONFIG_RESET_NPCM) += reset-npcm.o
diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
new file mode 100644
index 000000000000..0dbd2b6161ef
--- /dev/null
+++ b/drivers/reset/reset-microchip-sparx5.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Microchip Sparx5 Switch Reset driver
+ *
+ * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries.
+ *
+ * The Sparx5 Chip Register Model can be browsed at this location:
+ * https://github.com/microchip-ung/sparx-5_reginfo
+ */
+#include <linux/mfd/syscon.h>
+#include <linux/of_device.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+#define PROTECT_REG    0x84
+#define PROTECT_BIT    BIT(10)
+#define SOFT_RESET_REG 0x08
+#define SOFT_RESET_BIT BIT(1)
+
+struct mchp_reset_context {
+	struct regmap *cpu_ctrl;
+	struct regmap *gcb_ctrl;
+	struct reset_controller_dev rcdev;
+};
+
+static int sparx5_switch_reset(struct reset_controller_dev *rcdev,
+			       unsigned long id)
+{
+	struct mchp_reset_context *ctx =
+		container_of(rcdev, struct mchp_reset_context, rcdev);
+	u32 val;
+
+	/* Make sure the core is PROTECTED from reset */
+	regmap_update_bits(ctx->cpu_ctrl, PROTECT_REG, PROTECT_BIT, PROTECT_BIT);
+
+	/* Start soft reset */
+	regmap_write(ctx->gcb_ctrl, SOFT_RESET_REG, SOFT_RESET_BIT);
+
+	/* Wait for soft reset done */
+	return regmap_read_poll_timeout(ctx->gcb_ctrl, SOFT_RESET_REG, val,
+					(val & SOFT_RESET_BIT) == 0,
+					1, 100);
+}
+
+static const struct reset_control_ops sparx5_reset_ops = {
+	.reset = sparx5_switch_reset,
+};
+
+static int mchp_sparx5_reset_probe(struct platform_device *pdev)
+{
+	struct device_node *dn = pdev->dev.of_node;
+	struct regmap *cpu_ctrl, *gcb_ctrl;
+	struct device *dev = &pdev->dev;
+	struct mchp_reset_context *ctx;
+	struct device_node *syscon_np;
+	int err;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	syscon_np = of_parse_phandle(dn, "cpu-syscon", 0);
+	if (!syscon_np)
+		return -ENODEV;
+	cpu_ctrl = syscon_node_to_regmap(syscon_np);
+	of_node_put(syscon_np);
+	if (IS_ERR(cpu_ctrl)) {
+		err = PTR_ERR(cpu_ctrl);
+		dev_err(dev, "No cpu-syscon map: %d\n", err);
+		return err;
+	}
+
+	syscon_np = of_parse_phandle(dn, "gcb-syscon", 0);
+	if (!syscon_np)
+		return -ENODEV;
+	gcb_ctrl = syscon_node_to_regmap(syscon_np);
+	of_node_put(syscon_np);
+	if (IS_ERR(gcb_ctrl)) {
+		err = PTR_ERR(gcb_ctrl);
+		dev_err(dev, "No gcb-syscon map: %d\n", err);
+		return err;
+	}
+
+	ctx->cpu_ctrl = cpu_ctrl;
+	ctx->gcb_ctrl = gcb_ctrl;
+
+	ctx->rcdev.owner = THIS_MODULE;
+	ctx->rcdev.nr_resets = 1;
+	ctx->rcdev.ops = &sparx5_reset_ops;
+	ctx->rcdev.of_node = dn;
+
+	return devm_reset_controller_register(dev, &ctx->rcdev);
+}
+
+static const struct of_device_id mchp_sparx5_reset_of_match[] = {
+	{
+		.compatible = "microchip,sparx5-switch-reset",
+	},
+	{ /*sentinel*/ }
+};
+
+static struct platform_driver mchp_sparx5_reset_driver = {
+	.probe = mchp_sparx5_reset_probe,
+	.driver = {
+		.name = "sparx5-switch-reset",
+		.of_match_table = mchp_sparx5_reset_of_match,
+	},
+};
+
+static int __init mchp_sparx5_reset_init(void)
+{
+	return platform_driver_register(&mchp_sparx5_reset_driver);
+}
+
+postcore_initcall(mchp_sparx5_reset_init);
+
+MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
+MODULE_AUTHOR("Steen Hegelund <steen.hegelund at microchip.com>");
+MODULE_LICENSE("Dual MIT/GPL");
-- 
2.29.2