linux/drivers/reset/reset-gemini.c

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/*
* Cortina Gemini Reset controller driver
* Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/init.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <dt-bindings/reset/cortina,gemini-reset.h>
/**
* struct gemini_reset - gemini reset controller
* @map: regmap to access the containing system controller
* @rcdev: reset controller device
*/
struct gemini_reset {
struct regmap *map;
struct reset_controller_dev rcdev;
};
#define GEMINI_GLOBAL_SOFT_RESET 0x0c
#define to_gemini_reset(p) \
container_of((p), struct gemini_reset, rcdev)
/*
* This is a self-deasserting reset controller.
*/
static int gemini_reset(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct gemini_reset *gr = to_gemini_reset(rcdev);
/* Manual says to always set BIT 30 (CPU1) to 1 */
return regmap_write(gr->map,
GEMINI_GLOBAL_SOFT_RESET,
BIT(GEMINI_RESET_CPU1) | BIT(id));
}
static int gemini_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct gemini_reset *gr = to_gemini_reset(rcdev);
u32 val;
int ret;
ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val);
if (ret)
return ret;
return !!(val & BIT(id));
}
static const struct reset_control_ops gemini_reset_ops = {
.reset = gemini_reset,
.status = gemini_reset_status,
};
static int gemini_reset_probe(struct platform_device *pdev)
{
struct gemini_reset *gr;
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
int ret;
gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL);
if (!gr)
return -ENOMEM;
gr->map = syscon_node_to_regmap(np);
if (IS_ERR(gr->map)) {
ret = PTR_ERR(gr->map);
dev_err(dev, "unable to get regmap (%d)", ret);
return ret;
}
gr->rcdev.owner = THIS_MODULE;
gr->rcdev.nr_resets = 32;
gr->rcdev.ops = &gemini_reset_ops;
gr->rcdev.of_node = pdev->dev.of_node;
ret = devm_reset_controller_register(&pdev->dev, &gr->rcdev);
if (ret)
return ret;
dev_info(dev, "registered Gemini reset controller\n");
return 0;
}
static const struct of_device_id gemini_reset_dt_ids[] = {
{ .compatible = "cortina,gemini-syscon", },
{ /* sentinel */ },
};
static struct platform_driver gemini_reset_driver = {
.probe = gemini_reset_probe,
.driver = {
.name = "gemini-reset",
.of_match_table = gemini_reset_dt_ids,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(gemini_reset_driver);