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#include <linux/device.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#define RESET_REG_0 0x0
struct cds9k_reset_priv {
struct reset_controller_dev rcdev;
struct regmap *regmap;
u32 base;
};
static int cds9k_reset_reset(struct reset_controller_dev *rcdev, unsigned long id)
{
struct cds9k_reset_priv *priv = container_of(rcdev, struct cds9k_reset_priv, rcdev);
/* reset sequence: put 0xDEAD into reg 0 for 250 ms */
struct reg_sequence reset_sequence[] = {
{ priv->base + RESET_REG_0, 0xDEAD, 1500 },
{ priv->base + RESET_REG_0, 0x0000 },
};
if (id != 0)
return -EINVAL;
return regmap_multi_reg_write(priv->regmap, reset_sequence, ARRAY_SIZE(reset_sequence));
}
static int cds9k_reset_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *spec)
{
/* single reset */
return 0;
}
const struct reset_control_ops cds9k_reset_ops = {
.reset = cds9k_reset_reset,
};
static int cds9k_reset_probe(struct platform_device *pdev)
{
struct cds9k_reset_priv *priv;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
ret = device_property_read_u32(&pdev->dev, "reg", &priv->base);
if (ret)
return -EINVAL;
if (!pdev->dev.parent)
return -ENODEV;
priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
if (!priv->regmap)
return -ENODEV;
priv->rcdev.ops = &cds9k_reset_ops;
priv->rcdev.owner = pdev->dev.driver->owner;
priv->rcdev.of_node = pdev->dev.of_node;
priv->rcdev.nr_resets = 1;
priv->rcdev.of_reset_n_cells = 0;
priv->rcdev.of_xlate = cds9k_reset_xlate;
return devm_reset_controller_register(&pdev->dev, &priv->rcdev);
}
static struct of_device_id cds9k_reset_of_match[] = {
{ .compatible = "david,cds9k-reset" },
{}
};
MODULE_DEVICE_TABLE(of, cds9k_reset_of_match);
static struct platform_driver cds9k_reset = {
.driver = {
.name = "cds9k-reset",
.of_match_table = cds9k_reset_of_match,
},
.probe = cds9k_reset_probe
};
module_platform_driver(cds9k_reset);
MODULE_AUTHOR("David Phillips <david@yeah.nah.nz>");
MODULE_DESCRIPTION("Reset driver for the CDS9K board controller");
MODULE_LICENSE("GPL v2");
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