206 строки
4.7 KiB
C
206 строки
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2013 STMicroelectronics Limited
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* Author: Stephen Gallimore <stephen.gallimore@st.com>
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*
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* Inspired by mach-imx/src.c
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*/
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/types.h>
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#include <linux/of_device.h>
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#include <linux/regmap.h>
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#include <linux/mfd/syscon.h>
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#include "reset-syscfg.h"
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/**
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* Reset channel regmap configuration
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*
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* @reset: regmap field for the channel's reset bit.
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* @ack: regmap field for the channel's ack bit (optional).
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*/
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struct syscfg_reset_channel {
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struct regmap_field *reset;
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struct regmap_field *ack;
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};
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/**
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* A reset controller which groups together a set of related reset bits, which
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* may be located in different system configuration registers.
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*
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* @rst: base reset controller structure.
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* @active_low: are the resets in this controller active low, i.e. clearing
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* the reset bit puts the hardware into reset.
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* @channels: An array of reset channels for this controller.
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*/
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struct syscfg_reset_controller {
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struct reset_controller_dev rst;
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bool active_low;
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struct syscfg_reset_channel *channels;
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};
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#define to_syscfg_reset_controller(_rst) \
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container_of(_rst, struct syscfg_reset_controller, rst)
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static int syscfg_reset_program_hw(struct reset_controller_dev *rcdev,
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unsigned long idx, int assert)
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{
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struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev);
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const struct syscfg_reset_channel *ch;
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u32 ctrl_val = rst->active_low ? !assert : !!assert;
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int err;
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if (idx >= rcdev->nr_resets)
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return -EINVAL;
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ch = &rst->channels[idx];
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err = regmap_field_write(ch->reset, ctrl_val);
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if (err)
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return err;
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if (ch->ack) {
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unsigned long timeout = jiffies + msecs_to_jiffies(1000);
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u32 ack_val;
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while (true) {
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err = regmap_field_read(ch->ack, &ack_val);
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if (err)
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return err;
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if (ack_val == ctrl_val)
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break;
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if (time_after(jiffies, timeout))
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return -ETIME;
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cpu_relax();
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}
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}
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return 0;
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}
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static int syscfg_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long idx)
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{
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return syscfg_reset_program_hw(rcdev, idx, true);
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}
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static int syscfg_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long idx)
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{
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return syscfg_reset_program_hw(rcdev, idx, false);
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}
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static int syscfg_reset_dev(struct reset_controller_dev *rcdev,
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unsigned long idx)
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{
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int err;
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err = syscfg_reset_assert(rcdev, idx);
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if (err)
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return err;
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return syscfg_reset_deassert(rcdev, idx);
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}
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static int syscfg_reset_status(struct reset_controller_dev *rcdev,
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unsigned long idx)
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{
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struct syscfg_reset_controller *rst = to_syscfg_reset_controller(rcdev);
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const struct syscfg_reset_channel *ch;
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u32 ret_val = 0;
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int err;
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if (idx >= rcdev->nr_resets)
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return -EINVAL;
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ch = &rst->channels[idx];
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if (ch->ack)
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err = regmap_field_read(ch->ack, &ret_val);
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else
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err = regmap_field_read(ch->reset, &ret_val);
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if (err)
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return err;
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return rst->active_low ? !ret_val : !!ret_val;
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}
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static const struct reset_control_ops syscfg_reset_ops = {
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.reset = syscfg_reset_dev,
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.assert = syscfg_reset_assert,
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.deassert = syscfg_reset_deassert,
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.status = syscfg_reset_status,
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};
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static int syscfg_reset_controller_register(struct device *dev,
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const struct syscfg_reset_controller_data *data)
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{
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struct syscfg_reset_controller *rc;
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int i, err;
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rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
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if (!rc)
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return -ENOMEM;
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rc->channels = devm_kcalloc(dev, data->nr_channels,
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sizeof(*rc->channels), GFP_KERNEL);
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if (!rc->channels)
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return -ENOMEM;
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rc->rst.ops = &syscfg_reset_ops,
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rc->rst.of_node = dev->of_node;
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rc->rst.nr_resets = data->nr_channels;
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rc->active_low = data->active_low;
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for (i = 0; i < data->nr_channels; i++) {
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struct regmap *map;
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struct regmap_field *f;
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const char *compatible = data->channels[i].compatible;
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map = syscon_regmap_lookup_by_compatible(compatible);
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if (IS_ERR(map))
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return PTR_ERR(map);
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f = devm_regmap_field_alloc(dev, map, data->channels[i].reset);
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if (IS_ERR(f))
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return PTR_ERR(f);
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rc->channels[i].reset = f;
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if (!data->wait_for_ack)
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continue;
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f = devm_regmap_field_alloc(dev, map, data->channels[i].ack);
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if (IS_ERR(f))
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return PTR_ERR(f);
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rc->channels[i].ack = f;
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}
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err = reset_controller_register(&rc->rst);
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if (!err)
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dev_info(dev, "registered\n");
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return err;
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}
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int syscfg_reset_probe(struct platform_device *pdev)
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{
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struct device *dev = pdev ? &pdev->dev : NULL;
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const struct of_device_id *match;
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if (!dev || !dev->driver)
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return -ENODEV;
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match = of_match_device(dev->driver->of_match_table, dev);
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if (!match || !match->data)
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return -EINVAL;
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return syscfg_reset_controller_register(dev, match->data);
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}
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