linux/drivers/reset/reset-axs10x.c
Eugeniy Paltsev 376349232a ARC: reset: introduce AXS10x reset driver
ARC AXS10x boards support 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. This regiter is self-clearing so we
don't need to deassert line after reset.

As of today only the following lines are used:
 - DW GMAC - line 5

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2017-09-18 18:41:27 +02:00

84 lines
2.0 KiB
C

/*
* 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");