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206 lines
4.8 KiB
206 lines
4.8 KiB
// 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 <[email protected]> |
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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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* struct syscfg_reset_channel - 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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* struct syscfg_reset_controller - A reset controller which groups together |
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* a set of related reset bits, which may be located in different system |
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* 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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