238 lines
7.1 KiB
C
238 lines
7.1 KiB
C
/*
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* TI SYSCON regmap reset driver
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*
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* Copyright (C) 2015-2016 Texas Instruments Incorporated - http://www.ti.com/
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* Andrew F. Davis <afd@ti.com>
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* Suman Anna <afd@ti.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/mfd/syscon.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/regmap.h>
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#include <linux/reset-controller.h>
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#include <dt-bindings/reset/ti-syscon.h>
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/**
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* struct ti_syscon_reset_control - reset control structure
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* @assert_offset: reset assert control register offset from syscon base
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* @assert_bit: reset assert bit in the reset assert control register
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* @deassert_offset: reset deassert control register offset from syscon base
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* @deassert_bit: reset deassert bit in the reset deassert control register
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* @status_offset: reset status register offset from syscon base
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* @status_bit: reset status bit in the reset status register
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* @flags: reset flag indicating how the (de)assert and status are handled
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*/
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struct ti_syscon_reset_control {
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unsigned int assert_offset;
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unsigned int assert_bit;
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unsigned int deassert_offset;
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unsigned int deassert_bit;
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unsigned int status_offset;
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unsigned int status_bit;
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u32 flags;
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};
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/**
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* struct ti_syscon_reset_data - reset controller information structure
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* @rcdev: reset controller entity
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* @regmap: regmap handle containing the memory-mapped reset registers
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* @controls: array of reset controls
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* @nr_controls: number of controls in control array
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*/
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struct ti_syscon_reset_data {
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struct reset_controller_dev rcdev;
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struct regmap *regmap;
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struct ti_syscon_reset_control *controls;
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unsigned int nr_controls;
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};
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#define to_ti_syscon_reset_data(rcdev) \
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container_of(rcdev, struct ti_syscon_reset_data, rcdev)
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/**
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* ti_syscon_reset_assert() - assert device reset
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* @rcdev: reset controller entity
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* @id: ID of the reset to be asserted
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*
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* This function implements the reset driver op to assert a device's reset.
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* This asserts the reset in a manner prescribed by the reset flags.
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*
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* Return: 0 for successful request, else a corresponding error value
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*/
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static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
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struct ti_syscon_reset_control *control;
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unsigned int mask, value;
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if (id >= data->nr_controls)
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return -EINVAL;
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control = &data->controls[id];
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if (control->flags & ASSERT_NONE)
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return -ENOTSUPP; /* assert not supported for this reset */
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mask = BIT(control->assert_bit);
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value = (control->flags & ASSERT_SET) ? mask : 0x0;
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return regmap_update_bits(data->regmap, control->assert_offset, mask, value);
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}
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/**
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* ti_syscon_reset_deassert() - deassert device reset
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* @rcdev: reset controller entity
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* @id: ID of reset to be deasserted
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*
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* This function implements the reset driver op to deassert a device's reset.
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* This deasserts the reset in a manner prescribed by the reset flags.
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*
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* Return: 0 for successful request, else a corresponding error value
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*/
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static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
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struct ti_syscon_reset_control *control;
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unsigned int mask, value;
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if (id >= data->nr_controls)
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return -EINVAL;
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control = &data->controls[id];
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if (control->flags & DEASSERT_NONE)
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return -ENOTSUPP; /* deassert not supported for this reset */
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mask = BIT(control->deassert_bit);
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value = (control->flags & DEASSERT_SET) ? mask : 0x0;
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return regmap_update_bits(data->regmap, control->deassert_offset, mask, value);
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}
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/**
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* ti_syscon_reset_status() - check device reset status
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* @rcdev: reset controller entity
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* @id: ID of the reset for which the status is being requested
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*
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* This function implements the reset driver op to return the status of a
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* device's reset.
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*
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* Return: 0 if reset is deasserted, true if reset is asserted, else a
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* corresponding error value
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*/
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static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
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struct ti_syscon_reset_control *control;
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unsigned int reset_state;
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int ret;
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if (id >= data->nr_controls)
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return -EINVAL;
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control = &data->controls[id];
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if (control->flags & STATUS_NONE)
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return -ENOTSUPP; /* status not supported for this reset */
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ret = regmap_read(data->regmap, control->status_offset, &reset_state);
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if (ret)
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return ret;
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return !(reset_state & BIT(control->status_bit)) ==
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!(control->flags & STATUS_SET);
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}
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static struct reset_control_ops ti_syscon_reset_ops = {
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.assert = ti_syscon_reset_assert,
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.deassert = ti_syscon_reset_deassert,
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.status = ti_syscon_reset_status,
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};
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static int ti_syscon_reset_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct ti_syscon_reset_data *data;
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struct regmap *regmap;
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const __be32 *list;
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struct ti_syscon_reset_control *controls;
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int size, nr_controls, i;
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data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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regmap = syscon_node_to_regmap(np->parent);
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if (IS_ERR(regmap))
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return PTR_ERR(regmap);
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list = of_get_property(np, "ti,reset-bits", &size);
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if (!list || (size / sizeof(*list)) % 7 != 0) {
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dev_err(dev, "invalid DT reset description\n");
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return -EINVAL;
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}
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nr_controls = (size / sizeof(*list)) / 7;
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controls = devm_kzalloc(dev, nr_controls * sizeof(*controls), GFP_KERNEL);
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if (!controls)
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return -ENOMEM;
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for (i = 0; i < nr_controls; i++) {
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controls[i].assert_offset = be32_to_cpup(list++);
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controls[i].assert_bit = be32_to_cpup(list++);
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controls[i].deassert_offset = be32_to_cpup(list++);
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controls[i].deassert_bit = be32_to_cpup(list++);
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controls[i].status_offset = be32_to_cpup(list++);
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controls[i].status_bit = be32_to_cpup(list++);
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controls[i].flags = be32_to_cpup(list++);
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}
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data->rcdev.ops = &ti_syscon_reset_ops;
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data->rcdev.owner = THIS_MODULE;
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data->rcdev.of_node = np;
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data->rcdev.nr_resets = nr_controls;
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data->regmap = regmap;
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data->controls = controls;
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data->nr_controls = nr_controls;
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platform_set_drvdata(pdev, data);
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return devm_reset_controller_register(dev, &data->rcdev);
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}
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static const struct of_device_id ti_syscon_reset_of_match[] = {
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{ .compatible = "ti,syscon-reset", },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);
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static struct platform_driver ti_syscon_reset_driver = {
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.probe = ti_syscon_reset_probe,
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.driver = {
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.name = "ti-syscon-reset",
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.of_match_table = ti_syscon_reset_of_match,
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},
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};
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module_platform_driver(ti_syscon_reset_driver);
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MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
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MODULE_AUTHOR("Suman Anna <s-anna@ti.com>");
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MODULE_DESCRIPTION("TI SYSCON Regmap Reset Driver");
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MODULE_LICENSE("GPL v2");
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