ARC: reset: introduce AXS10x reset driver

Binding for the AXS10x reset controller

This binding describes the ARC AXS10x boards custom IP-block which allows

to control reset signals of selected peripherals. For example DW GMAC, etc...

This block is controlled via memory-mapped register (AKA CREG) which

represents up-to 32 reset lines.

As of today only the following lines are used:

 - DW GMAC - line 5

This binding uses the common reset binding[1].

[1] Documentation/devicetree/bindings/reset/reset.txt

Required properties:

- compatible: should be "snps,axs10x-reset".

- reg: should always contain pair address - length: for creg reset

  bits register.

- #reset-cells: from common reset binding; Should always be set to 1.

Example:

	reset: reset-controller@11220 {

		compatible = "snps,axs10x-reset";

		#reset-cells = <1>;

		reg = <0x11220 0x4>;

	};

Specifying reset lines connected to IP modules:

	ethernet@.... {

		....

		resets = <&reset 5>;

		....

	};

F:	arch/arc/boot/dts/ax*

F:	Documentation/devicetree/bindings/arc/axs10*

SYNOPSYS AXS10x RESET CONTROLLER DRIVER

M:	Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>

S:	Supported

F:	drivers/reset/reset-axs10x.c

F:	Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt

SYNOPSYS DESIGNWARE DMAC DRIVER

M:	Viresh Kumar <vireshk@kernel.org>

M:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>

	  This enables the ATH79 reset controller driver that supports the

	  AR71xx SoC reset controller.

config RESET_AXS10X

	bool "AXS10x Reset Driver" if COMPILE_TEST

	default ARC_PLAT_AXS10X

	help

	  This enables the reset controller driver for AXS10x.

config RESET_BERLIN

	bool "Berlin Reset Driver" if COMPILE_TEST

	default ARCH_BERLIN

obj-$(CONFIG_ARCH_TEGRA) += tegra/

obj-$(CONFIG_RESET_A10SR) += reset-a10sr.o

obj-$(CONFIG_RESET_ATH79) += reset-ath79.o

obj-$(CONFIG_RESET_AXS10X) += reset-axs10x.o

obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o

obj-$(CONFIG_RESET_HSDK_V1) += reset-hsdk-v1.o

obj-$(CONFIG_RESET_IMX7) += reset-imx7.o

/*

 * Copyright (C) 2017 Synopsys.

 *

 * Synopsys AXS10x reset driver.

 *

 * This file is licensed under the terms of the GNU General Public

 * License version 2. This program is licensed "as is" without any

 * warranty of any kind, whether express or implied.

 */

#include <linux/io.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/reset-controller.h>

#define to_axs10x_rst(p)	container_of((p), struct axs10x_rst, rcdev)

#define AXS10X_MAX_RESETS	32

struct axs10x_rst {

	void __iomem			*regs_rst;

	spinlock_t			lock;

	struct reset_controller_dev	rcdev;

};

static int axs10x_reset_reset(struct reset_controller_dev *rcdev,

			      unsigned long id)

{

	struct axs10x_rst *rst = to_axs10x_rst(rcdev);

	unsigned long flags;

	spin_lock_irqsave(&rst->lock, flags);

	writel(BIT(id), rst->regs_rst);

	spin_unlock_irqrestore(&rst->lock, flags);

	return 0;

}

static const struct reset_control_ops axs10x_reset_ops = {

	.reset	= axs10x_reset_reset,

};

static int axs10x_reset_probe(struct platform_device *pdev)

{

	struct axs10x_rst *rst;

	struct resource *mem;

	rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);

	if (!rst)

		return -ENOMEM;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);

	if (IS_ERR(rst->regs_rst))

		return PTR_ERR(rst->regs_rst);

	spin_lock_init(&rst->lock);

	rst->rcdev.owner = THIS_MODULE;

	rst->rcdev.ops = &axs10x_reset_ops;

	rst->rcdev.of_node = pdev->dev.of_node;

	rst->rcdev.nr_resets = AXS10X_MAX_RESETS;

	return devm_reset_controller_register(&pdev->dev, &rst->rcdev);

}

static const struct of_device_id axs10x_reset_dt_match[] = {

	{ .compatible = "snps,axs10x-reset" },

	{ },

};

static struct platform_driver axs10x_reset_driver = {

	.probe	= axs10x_reset_probe,

	.driver	= {

		.name = "axs10x-reset",

		.of_match_table = axs10x_reset_dt_match,

	},

};

builtin_platform_driver(axs10x_reset_driver);

MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>");

MODULE_DESCRIPTION("Synopsys AXS10x reset driver");

MODULE_LICENSE("GPL v2");