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/*
* TI SYSCON regmap reset driver
*
* Copyright (C) 2015-2016 Texas Instruments Incorporated - https://www.ti.com/
* Andrew F. Davis <afd@ti.com>
* Suman Anna <afd@ti.com>
*
* 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.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset-controller.h>
#include <dt-bindings/reset/ti-syscon.h>
/**
* struct ti_syscon_reset_control - reset control structure
* @assert_offset: reset assert control register offset from syscon base
* @assert_bit: reset assert bit in the reset assert control register
* @deassert_offset: reset deassert control register offset from syscon base
* @deassert_bit: reset deassert bit in the reset deassert control register
* @status_offset: reset status register offset from syscon base
* @status_bit: reset status bit in the reset status register
* @flags: reset flag indicating how the (de)assert and status are handled
*/
struct ti_syscon_reset_control {
unsigned int assert_offset;
unsigned int assert_bit;
unsigned int deassert_offset;
unsigned int deassert_bit;
unsigned int status_offset;
unsigned int status_bit;
u32 flags;
};
/**
* struct ti_syscon_reset_data - reset controller information structure
* @rcdev: reset controller entity
* @regmap: regmap handle containing the memory-mapped reset registers
* @controls: array of reset controls
* @nr_controls: number of controls in control array
*/
struct ti_syscon_reset_data {
struct reset_controller_dev rcdev;
struct regmap *regmap;
struct ti_syscon_reset_control *controls;
unsigned int nr_controls;
};
#define to_ti_syscon_reset_data(rcdev) \
container_of(rcdev, struct ti_syscon_reset_data, rcdev)
/**
* ti_syscon_reset_assert() - assert device reset
* @rcdev: reset controller entity
* @id: ID of the reset to be asserted
*
* This function implements the reset driver op to assert a device's reset.
* This asserts the reset in a manner prescribed by the reset flags.
*
* Return: 0 for successful request, else a corresponding error value
*/
static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
struct ti_syscon_reset_control *control;
unsigned int mask, value;
if (id >= data->nr_controls)
return -EINVAL;
control = &data->controls[id];
if (control->flags & ASSERT_NONE)
return -ENOTSUPP; /* assert not supported for this reset */
mask = BIT(control->assert_bit);
value = (control->flags & ASSERT_SET) ? mask : 0x0;
return regmap_write_bits(data->regmap, control->assert_offset, mask, value);
}
/**
* ti_syscon_reset_deassert() - deassert device reset
* @rcdev: reset controller entity
* @id: ID of reset to be deasserted
*
* This function implements the reset driver op to deassert a device's reset.
* This deasserts the reset in a manner prescribed by the reset flags.
*
* Return: 0 for successful request, else a corresponding error value
*/
static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
struct ti_syscon_reset_control *control;
unsigned int mask, value;
if (id >= data->nr_controls)
return -EINVAL;
control = &data->controls[id];
if (control->flags & DEASSERT_NONE)
return -ENOTSUPP; /* deassert not supported for this reset */
mask = BIT(control->deassert_bit);
value = (control->flags & DEASSERT_SET) ? mask : 0x0;
return regmap_write_bits(data->regmap, control->deassert_offset, mask, value);
}
/**
* ti_syscon_reset_status() - check device reset status
* @rcdev: reset controller entity
* @id: ID of the reset for which the status is being requested
*
* This function implements the reset driver op to return the status of a
* device's reset.
*
* Return: 0 if reset is deasserted, true if reset is asserted, else a
* corresponding error value
*/
static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
struct ti_syscon_reset_control *control;
unsigned int reset_state;
int ret;
if (id >= data->nr_controls)
return -EINVAL;
control = &data->controls[id];
if (control->flags & STATUS_NONE)
return -ENOTSUPP; /* status not supported for this reset */
ret = regmap_read(data->regmap, control->status_offset, &reset_state);
if (ret)
return ret;
return !(reset_state & BIT(control->status_bit)) ==
!(control->flags & STATUS_SET);
}
static const struct reset_control_ops ti_syscon_reset_ops = {
.assert = ti_syscon_reset_assert,
.deassert = ti_syscon_reset_deassert,
.status = ti_syscon_reset_status,
};
static int ti_syscon_reset_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct ti_syscon_reset_data *data;
struct regmap *regmap;
const __be32 *list;
struct ti_syscon_reset_control *controls;
int size, nr_controls, i;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
regmap = syscon_node_to_regmap(np->parent);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
list = of_get_property(np, "ti,reset-bits", &size);
if (!list || (size / sizeof(*list)) % 7 != 0) {
dev_err(dev, "invalid DT reset description\n");
return -EINVAL;
}
nr_controls = (size / sizeof(*list)) / 7;
controls = devm_kcalloc(dev, nr_controls, sizeof(*controls),
GFP_KERNEL);
if (!controls)
return -ENOMEM;
for (i = 0; i < nr_controls; i++) {
controls[i].assert_offset = be32_to_cpup(list++);
controls[i].assert_bit = be32_to_cpup(list++);
controls[i].deassert_offset = be32_to_cpup(list++);
controls[i].deassert_bit = be32_to_cpup(list++);
controls[i].status_offset = be32_to_cpup(list++);
controls[i].status_bit = be32_to_cpup(list++);
controls[i].flags = be32_to_cpup(list++);
}
data->rcdev.ops = &ti_syscon_reset_ops;
data->rcdev.owner = THIS_MODULE;
data->rcdev.of_node = np;
data->rcdev.nr_resets = nr_controls;
data->regmap = regmap;
data->controls = controls;
data->nr_controls = nr_controls;
platform_set_drvdata(pdev, data);
return devm_reset_controller_register(dev, &data->rcdev);
}
static const struct of_device_id ti_syscon_reset_of_match[] = {
{ .compatible = "ti,syscon-reset", },
{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);
static struct platform_driver ti_syscon_reset_driver = {
.probe = ti_syscon_reset_probe,
.driver = {
.name = "ti-syscon-reset",
.of_match_table = ti_syscon_reset_of_match,
},
};
module_platform_driver(ti_syscon_reset_driver);
MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver");
MODULE_LICENSE("GPL v2");
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