[PATCH v9 02/12] reset: Add Realtek basic reset support

[Philipp Zabel]

On Mi, 2026-06-24 at 19:29 +0800, Yu-Chun Lin wrote:
> From: Cheng-Yu Lee <cylee12 at realtek.com>
> 
> Define the reset operations backed by a regmap-based register interface
> and prepare the reset controller to be registered through the reset
> framework.
> 
> Since the reset controllers on Realtek SoCs often share the same register
> space with the clock controllers, this common framework is designed to
> extract the regmap and device tree node from the parent device
> (e.g., an auxiliary device parent).
> 
> Signed-off-by: Cheng-Yu Lee <cylee12 at realtek.com>
> Co-developed-by: Yu-Chun Lin <eleanor.lin at realtek.com>
> Signed-off-by: Yu-Chun Lin <eleanor.lin at realtek.com>
> ---
> Changes in v8:
> - Rename common.[ch] to reset-rtk-common.[ch].
> ---
>  MAINTAINERS                              |  1 +
>  drivers/reset/Kconfig                    |  1 +
>  drivers/reset/Makefile                   |  1 +
>  drivers/reset/realtek/Kconfig            |  8 +++
>  drivers/reset/realtek/Makefile           |  2 +
>  drivers/reset/realtek/reset-rtk-common.c | 90 ++++++++++++++++++++++++
>  drivers/reset/realtek/reset-rtk-common.h | 29 ++++++++
>  7 files changed, 132 insertions(+)
>  create mode 100644 drivers/reset/realtek/Kconfig
>  create mode 100644 drivers/reset/realtek/Makefile
>  create mode 100644 drivers/reset/realtek/reset-rtk-common.c
>  create mode 100644 drivers/reset/realtek/reset-rtk-common.h
> 
[...]
> diff --git a/drivers/reset/realtek/reset-rtk-common.c b/drivers/reset/realtek/reset-rtk-common.c
> new file mode 100644
> index 000000000000..75b27cb2a208
> --- /dev/null
> +++ b/drivers/reset/realtek/reset-rtk-common.c
> @@ -0,0 +1,90 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2019-2026 Realtek Semiconductor Corporation
> + */
> +
> +#include <linux/device.h>
> +#include <linux/export.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +#include "reset-rtk-common.h"
> +
> +static inline struct rtk_reset_data *to_rtk_reset_controller(struct reset_controller_dev *r)
> +{
> +	return container_of(r, struct rtk_reset_data, rcdev);
> +}
> +
> +static inline const struct rtk_reset_desc *rtk_reset_get_desc(struct rtk_reset_data *data,
> +							      unsigned long idx)
> +{
> +	return &data->descs[idx];
> +}
> +
> +static int rtk_reset_assert(struct reset_controller_dev *rcdev,
> +			    unsigned long idx)
> +{
> +	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
> +	const struct rtk_reset_desc *desc;
> +	u32 mask, val;
> +
> +	desc = rtk_reset_get_desc(data, idx);
> +	mask = desc->write_en ? (0x3U << desc->bit) : BIT(desc->bit);
> +	val  = desc->write_en ? (0x2U << desc->bit) : 0;
> +
> +	return regmap_update_bits(data->regmap, desc->ofs, mask, val);
> +}
> +
> +static int rtk_reset_deassert(struct reset_controller_dev *rcdev,
> +			      unsigned long idx)
> +{
> +	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
> +	const struct rtk_reset_desc *desc;
> +	u32 mask, val;
> +
> +	desc = rtk_reset_get_desc(data, idx);
> +	mask = desc->write_en ? (0x3U << desc->bit) : BIT(desc->bit);
> +	val = mask;
> +
> +	return regmap_update_bits(data->regmap, desc->ofs, mask, val);

You can use regmap_set_bits() here.

> +}
> +
> +static int rtk_reset_status(struct reset_controller_dev *rcdev,
> +			    unsigned long idx)
> +{
> +	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
> +	const struct rtk_reset_desc *desc;
> +	u32 val;

	unsigned int val;

> +	int ret;
> +
> +	desc = rtk_reset_get_desc(data, idx);
> +	ret = regmap_read(data->regmap, desc->ofs, &val);
> +	if (ret)
> +		return ret;
> +
> +	return !((val >> desc->bit) & 1);
> +}
> +
> +static const struct reset_control_ops rtk_reset_ops = {
> +	.assert   = rtk_reset_assert,
> +	.deassert = rtk_reset_deassert,
> +	.status   = rtk_reset_status,
> +};
> +
> +/* The caller must initialize data->descs, data->rcdev.nr_resets and
> + * data->rcdev.owner before calling rtk_reset_controller_add().
> + */
> +int rtk_reset_controller_add(struct device *dev,
> +			     struct rtk_reset_data *data)
> +{
> +	data->regmap          = dev_get_platdata(dev);
> +	data->rcdev.ops       = &rtk_reset_ops;
> +	data->rcdev.dev       = dev;
> +	data->rcdev.of_node   = dev->parent->of_node;

This split rcdev initialization is more hassle than it is worth.
Please just export rtk_reset_ops and duplicate the
regmap/ops/dev/of_node assignment in the probe functions.

Alternatively, consolidate the probe function and export it from here.

regards
Philipp