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19f7def264
Add reset_reset() and reset_reset_bulk() functions to the reset controller API. These functions assert and then deassert reset signals in a single call, providing a convenient way to pulse/toggle a reset line. This mimics the Linux kernel's reset_control_reset() and reset_control_bulk_reset() APIs. The new functions are useful for drivers that need to cycle a reset line during initialization or error recovery but with also passing delay parameter. If a driver implements the rst_reset op, it will be called directly with the delay parameter. Otherwise, the reset core performs reset_assert(), optional udelay(), and reset_deassert() as fallback. Reviewed-by: Simon Glass <sjg@chromium.org> Signed-off-by: Michal Simek <michal.simek@amd.com> Link: https://lore.kernel.org/r/55ddd313c9e7b2d4dc79ab36bdd0040f871610f6.1779709539.git.michal.simek@amd.com
109 lines
3.4 KiB
C
109 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (c) 2016, NVIDIA CORPORATION.
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*/
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#ifndef _RESET_UCLASS_H
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#define _RESET_UCLASS_H
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/* See reset.h for background documentation. */
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#include <reset.h>
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struct ofnode_phandle_args;
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struct udevice;
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/**
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* struct reset_ops - The functions that a reset controller driver must
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* implement.
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*/
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struct reset_ops {
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/**
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* of_xlate - Translate a client's device-tree (OF) reset specifier.
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*
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* The reset core calls this function as the first step in implementing
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* a client's reset_get_by_*() call.
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*
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* If this function pointer is set to NULL, the reset core will use a
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* default implementation, which assumes #reset-cells = <1>, and that
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* the DT cell contains a simple integer reset signal ID.
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*
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* At present, the reset API solely supports device-tree. If this
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* changes, other xxx_xlate() functions may be added to support those
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* other mechanisms.
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*
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* @reset_ctl: The reset control struct to hold the translation result.
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* @args: The reset specifier values from device tree.
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* @return 0 if OK, or a negative error code.
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*/
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int (*of_xlate)(struct reset_ctl *reset_ctl,
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struct ofnode_phandle_args *args);
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/**
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* request - Request a translated reset control.
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*
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* The reset core calls this function as the second step in
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* implementing a client's reset_get_by_*() call, following a
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* successful xxx_xlate() call.
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*
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* @reset_ctl: The reset control struct to request; this has been
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* filled in by a previoux xxx_xlate() function call.
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* @return 0 if OK, or a negative error code.
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*/
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int (*request)(struct reset_ctl *reset_ctl);
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/**
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* rfree - Free a previously requested reset control.
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*
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* This is the implementation of the client reset_free() API.
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*
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* @reset_ctl: The reset control to free.
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* @return 0 if OK, or a negative error code.
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*/
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int (*rfree)(struct reset_ctl *reset_ctl);
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/**
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* rst_assert - Assert a reset signal.
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*
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* Note: This function is named rst_assert not assert to avoid
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* conflicting with global macro assert().
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*
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* @reset_ctl: The reset signal to assert.
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* @return 0 if OK, or a negative error code.
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*/
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int (*rst_assert)(struct reset_ctl *reset_ctl);
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/**
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* rst_deassert - Deassert a reset signal.
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*
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* @reset_ctl: The reset signal to deassert.
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* @return 0 if OK, or a negative error code.
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*/
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int (*rst_deassert)(struct reset_ctl *reset_ctl);
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/**
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* rst_reset - Reset a HW module.
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*
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* This optional function triggers a reset pulse on the reset line.
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* If not implemented, reset_reset() falls back to rst_assert(),
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* udelay(@delay_us), then rst_deassert(); that delay is therefore
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* observed only on the fallback path.
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*
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* When rst_reset is provided, @delay_us is controller-specific: the
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* implementation should honour it if the hardware needs a minimum
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* assertion time before release. It may ignore @delay_us when the
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* pulse shape is fixed elsewhere (for example a firmware pulse).
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*
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* @reset_ctl: The reset signal to pulse.
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* @delay_us: Minimum delay in microseconds between assert and
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* deassert where applicable; see above.
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* @return 0 if OK, or a negative error code.
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*/
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int (*rst_reset)(struct reset_ctl *reset_ctl, ulong delay_us);
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/**
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* rst_status - Check reset signal status.
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*
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* @reset_ctl: The reset signal to check.
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* @return 0 if deasserted, positive if asserted, or a negative
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* error code.
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*/
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int (*rst_status)(struct reset_ctl *reset_ctl);
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};
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#endif
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