2cb8a39b67
The amount of time required between asserting and deasserting the reset signal can vary depending on the involved hardware component. Sometimes 1 us might not be enough and a larger delay is necessary to conform to the specifications. Usually this is worked around in the consuming drivers, by replacing reset_control_reset() with a sequence of reset_control_assert(), waiting for a custom delay, followed by reset_control_deassert(). However, in some cases the driver making use of the reset is generic and can be used with different reset controllers. In this case the reset time requirement is better handled directly by the reset controller driver. Make this possible by adding an "udelay" field to the qcom_reset_map that allows setting a different reset delay (in microseconds). Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20220706134132.3623415-4-stephan.gerhold@kernkonzept.com
58 lines
1.4 KiB
C
58 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2013, The Linux Foundation. All rights reserved.
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*/
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#include <linux/bitops.h>
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#include <linux/export.h>
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#include <linux/regmap.h>
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#include <linux/reset-controller.h>
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#include <linux/delay.h>
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#include "reset.h"
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static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct qcom_reset_controller *rst = to_qcom_reset_controller(rcdev);
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rcdev->ops->assert(rcdev, id);
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udelay(rst->reset_map[id].udelay ?: 1); /* use 1 us as default */
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rcdev->ops->deassert(rcdev, id);
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return 0;
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}
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static int
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qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct qcom_reset_controller *rst;
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const struct qcom_reset_map *map;
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u32 mask;
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rst = to_qcom_reset_controller(rcdev);
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map = &rst->reset_map[id];
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mask = BIT(map->bit);
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return regmap_update_bits(rst->regmap, map->reg, mask, mask);
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}
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static int
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qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
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{
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struct qcom_reset_controller *rst;
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const struct qcom_reset_map *map;
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u32 mask;
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rst = to_qcom_reset_controller(rcdev);
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map = &rst->reset_map[id];
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mask = BIT(map->bit);
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return regmap_update_bits(rst->regmap, map->reg, mask, 0);
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}
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const struct reset_control_ops qcom_reset_ops = {
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.reset = qcom_reset,
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.assert = qcom_reset_assert,
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.deassert = qcom_reset_deassert,
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};
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EXPORT_SYMBOL_GPL(qcom_reset_ops);
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