[PATCH 2/2] reset: uniphier: add USB3 controller reset control

[Kunihiko Hayashi]

Add reset lines for USB3 controller 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 lines is included in the USB3 glue layer, and it's necessary
to enable clocks and deassert resets of the layer before using this
reset lines.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@xxxxxxxxxxxxx>
---
 drivers/reset/Kconfig               |  10 ++
 drivers/reset/Makefile              |   1 +
 drivers/reset/reset-uniphier-usb3.c | 183 ++++++++++++++++++++++++++++++++++++
 3 files changed, 194 insertions(+)
 create mode 100644 drivers/reset/reset-uniphier-usb3.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index c0b292b..851c9c3 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 USB3 reset controllers on UniPhier SoCs.
+	  Say Y if you want to control reset signals provided by
+	  USB3 controller block.
+
 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..397e6c9
--- /dev/null
+++ b/drivers/reset/reset-uniphier-usb3.c
@@ -0,0 +1,183 @@
+// 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 {
+	const char *clock_names[MAX_CLKS];
+	const char *reset_names[MAX_RSTS];
+};
+
+struct uniphier_usb3_reset_priv {
+	int nclks;
+	struct clk *clk[MAX_CLKS];
+	int nrsts;
+	struct reset_control *rst[MAX_RSTS];
+	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 reset_simple_data *rst_data;
+	struct resource *res;
+	resource_size_t size;
+	const char *name;
+	int i, ret, nc, 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))
+		return -EINVAL;
+
+	rst_data = devm_kzalloc(dev, sizeof(*rst_data), GFP_KERNEL);
+	if (!rst_data)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	size = resource_size(res);
+	rst_data->membase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(rst_data->membase))
+		return PTR_ERR(rst_data->membase);
+
+	for (i = 0; i < MAX_CLKS; i++) {
+		name = priv->data->clock_names[i];
+		if (!name)
+			break;
+		priv->clk[i] = devm_clk_get(dev, name);
+		if (IS_ERR(priv->clk[i]))
+			return PTR_ERR(priv->clk[i]);
+		priv->nclks++;
+	}
+
+	for (i = 0; i < MAX_RSTS; i++) {
+		name = priv->data->reset_names[i];
+		if (!name)
+			break;
+		priv->rst[i] = devm_reset_control_get_shared(dev, name);
+		if (IS_ERR(priv->rst[i]))
+			return PTR_ERR(priv->rst[i]);
+		priv->nrsts++;
+	}
+
+	for (nc = 0; nc < priv->nclks; nc++) {
+		ret = clk_prepare_enable(priv->clk[nc]);
+		if (ret)
+			goto out_clk_disable;
+	}
+
+	for (nr = 0; nr < priv->nrsts; nr++) {
+		ret = reset_control_deassert(priv->rst[nr]);
+		if (ret)
+			goto out_rst_assert;
+	}
+
+	spin_lock_init(&rst_data->lock);
+	rst_data->rcdev.owner = THIS_MODULE;
+	rst_data->rcdev.nr_resets = size * BITS_PER_BYTE;
+	rst_data->rcdev.ops = &reset_simple_ops;
+	rst_data->rcdev.of_node = dev->of_node;
+	rst_data->active_low = true;
+
+	platform_set_drvdata(pdev, priv);
+
+	ret = devm_reset_controller_register(dev, &rst_data->rcdev);
+	if (ret)
+		goto out_rst_assert;
+
+	return 0;
+
+out_rst_assert:
+	while (nr--)
+		reset_control_assert(priv->rst[nr]);
+out_clk_disable:
+	while (nc--)
+		clk_disable_unprepare(priv->clk[nc]);
+
+	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->nrsts; i++)
+		reset_control_assert(priv->rst[i]);
+	for (i = 0; i < priv->nclks; i++)
+		clk_disable_unprepare(priv->clk[i]);
+
+	return 0;
+}
+
+static const struct uniphier_usb3_reset_soc_data uniphier_pro4_data = {
+	.clock_names = { "gio", "link", },
+	.reset_names = { "gio", "link", },
+};
+
+static const struct uniphier_usb3_reset_soc_data uniphier_pxs2_data = {
+	.clock_names = { "link", },
+	.reset_names = { "link", },
+};
+
+static const struct uniphier_usb3_reset_soc_data uniphier_ld20_data = {
+	.clock_names = { "link", },
+	.reset_names = { "link", },
+};
+
+static const struct uniphier_usb3_reset_soc_data uniphier_pxs3_data = {
+	.clock_names = { "link", },
+	.reset_names = { "link", },
+};
+
+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_ld20_data,
+	},
+	{
+		.compatible = "socionext,uniphier-pxs3-usb3-reset",
+		.data = &uniphier_pxs3_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