[PATCH v2 2/2] reset: uniphier: add USB3 core reset control

[Kunihiko Hayashi]

Add a reset line to enable USB3 core implemented in UniPhier SoCs.

This reuses only the reset operations in reset-simple, because
the reset-simple doesn't handle any SoC-dependent clocks and resets.
This reset line is included in the USB3 glue layer, and it's necessary
to enable clocks and deassert resets of the layer before using this
reset line.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
---
 drivers/reset/Kconfig               |  10 +++
 drivers/reset/Makefile              |   1 +
 drivers/reset/reset-uniphier-usb3.c | 171 ++++++++++++++++++++++++++++++++++++
 3 files changed, 182 insertions(+)
 create mode 100644 drivers/reset/reset-uniphier-usb3.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index c0b292b..6b45067 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -138,6 +138,16 @@ config RESET_UNIPHIER
 	  Say Y if you want to control reset signals provided by System Control
 	  block, Media I/O block, Peripheral Block.
 
+config RESET_UNIPHIER_USB3
+	tristate "USB3 reset driver for UniPhier SoCs"
+	depends on (ARCH_UNIPHIER || COMPILE_TEST) && OF
+	default ARCH_UNIPHIER
+	select RESET_SIMPLE
+	help
+	  Support for the USB3 core reset on UniPhier SoCs.
+	  Say Y if you want to control reset signals provided by
+	  USB3 glue layer.
+
 config RESET_ZYNQ
 	bool "ZYNQ Reset Driver" if COMPILE_TEST
 	default ARCH_ZYNQ
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index c1261dc..2638ac4 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -20,5 +20,6 @@ obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
 obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
 obj-$(CONFIG_RESET_TI_SYSCON) += reset-ti-syscon.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
+obj-$(CONFIG_RESET_UNIPHIER_USB3) += reset-uniphier-usb3.o
 obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o
 
diff --git a/drivers/reset/reset-uniphier-usb3.c b/drivers/reset/reset-uniphier-usb3.c
new file mode 100644
index 0000000..ffa1b19
--- /dev/null
+++ b/drivers/reset/reset-uniphier-usb3.c
@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// reset-uniphier-usb3.c - USB3 reset driver for UniPhier
+// Copyright 2018 Socionext Inc.
+// Author: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include "reset-simple.h"
+
+#define MAX_CLKS	2
+#define MAX_RSTS	2
+
+struct uniphier_usb3_reset_soc_data {
+	int nclks;
+	const char * const *clock_names;
+	int nrsts;
+	const char * const *reset_names;
+};
+
+struct uniphier_usb3_reset_priv {
+	struct clk_bulk_data clk[MAX_CLKS];
+	struct reset_control *rst[MAX_RSTS];
+	struct reset_simple_data rdata;
+	const struct uniphier_usb3_reset_soc_data *data;
+};
+
+static int uniphier_usb3_reset_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_usb3_reset_priv *priv;
+	struct resource *res;
+	resource_size_t size;
+	const char *name;
+	int i, ret, nr;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->data = of_device_get_match_data(dev);
+	if (WARN_ON(!priv->data || priv->data->nclks > MAX_CLKS ||
+		    priv->data->nrsts > MAX_RSTS))
+		return -EINVAL;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	size = resource_size(res);
+	priv->rdata.membase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->rdata.membase))
+		return PTR_ERR(priv->rdata.membase);
+
+	for (i = 0; i < priv->data->nclks; i++)
+		priv->clk[i].id = priv->data->clock_names[i];
+	ret = devm_clk_bulk_get(dev, priv->data->nclks, priv->clk);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < priv->data->nrsts; i++) {
+		name = priv->data->reset_names[i];
+		priv->rst[i] = devm_reset_control_get_shared(dev, name);
+		if (IS_ERR(priv->rst[i]))
+			return PTR_ERR(priv->rst[i]);
+	}
+
+	ret = clk_bulk_prepare_enable(priv->data->nclks, priv->clk);
+	if (ret)
+		return ret;
+
+	for (nr = 0; nr < priv->data->nrsts; nr++) {
+		ret = reset_control_deassert(priv->rst[nr]);
+		if (ret)
+			goto out_rst_assert;
+	}
+
+	spin_lock_init(&priv->rdata.lock);
+	priv->rdata.rcdev.owner = THIS_MODULE;
+	priv->rdata.rcdev.nr_resets = size * BITS_PER_BYTE;
+	priv->rdata.rcdev.ops = &reset_simple_ops;
+	priv->rdata.rcdev.of_node = dev->of_node;
+	priv->rdata.active_low = true;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = devm_reset_controller_register(dev, &priv->rdata.rcdev);
+	if (ret)
+		goto out_rst_assert;
+
+	return 0;
+
+out_rst_assert:
+	while (nr--)
+		reset_control_assert(priv->rst[nr]);
+
+	clk_bulk_disable_unprepare(priv->data->nclks, priv->clk);
+
+	return ret;
+}
+
+static int uniphier_usb3_reset_remove(struct platform_device *pdev)
+{
+	struct uniphier_usb3_reset_priv *priv = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < priv->data->nrsts; i++)
+		reset_control_assert(priv->rst[i]);
+
+	clk_bulk_disable_unprepare(priv->data->nclks, priv->clk);
+
+	return 0;
+}
+
+static const char * const uniphier_pro4_clock_reset_names[] = {
+	"gio", "link",
+};
+
+static const struct uniphier_usb3_reset_soc_data uniphier_pro4_data = {
+	.nclks = ARRAY_SIZE(uniphier_pro4_clock_reset_names),
+	.clock_names = uniphier_pro4_clock_reset_names,
+	.nrsts = ARRAY_SIZE(uniphier_pro4_clock_reset_names),
+	.reset_names = uniphier_pro4_clock_reset_names,
+};
+
+static const char * const uniphier_pxs2_clock_reset_names[] = {
+	"link",
+};
+
+static const struct uniphier_usb3_reset_soc_data uniphier_pxs2_data = {
+	.nclks = ARRAY_SIZE(uniphier_pxs2_clock_reset_names),
+	.clock_names = uniphier_pxs2_clock_reset_names,
+	.nrsts = ARRAY_SIZE(uniphier_pxs2_clock_reset_names),
+	.reset_names = uniphier_pxs2_clock_reset_names,
+};
+
+static const struct of_device_id uniphier_usb3_reset_match[] = {
+	{
+		.compatible = "socionext,uniphier-pro4-usb3-reset",
+		.data = &uniphier_pro4_data,
+	},
+	{
+		.compatible = "socionext,uniphier-pxs2-usb3-reset",
+		.data = &uniphier_pxs2_data,
+	},
+	{
+		.compatible = "socionext,uniphier-ld20-usb3-reset",
+		.data = &uniphier_pxs2_data,
+	},
+	{
+		.compatible = "socionext,uniphier-pxs3-usb3-reset",
+		.data = &uniphier_pxs2_data,
+	},
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_usb3_reset_match);
+
+static struct platform_driver uniphier_usb3_reset_driver = {
+	.probe = uniphier_usb3_reset_probe,
+	.remove = uniphier_usb3_reset_remove,
+	.driver = {
+		.name = "uniphier-usb3-reset",
+		.of_match_table = uniphier_usb3_reset_match,
+	},
+};
+module_platform_driver(uniphier_usb3_reset_driver);
+
+MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("UniPhier USB3 Reset Driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4