Re: [PATCH v5 03/10] reset: Add Realtek basic reset support

[Philipp Zabel]

On Di, 2026-03-24 at 10:53 +0800, Yu-Chun Lin wrote:
> From: Cheng-Yu Lee <cylee12@xxxxxxxxxxx>
> 
> Define the reset operations backed by a regmap-based register
> interface and prepare the reset controller to be registered
> through the reset framework.
> 
> Signed-off-by: Cheng-Yu Lee <cylee12@xxxxxxxxxxx>
> Co-developed-by: Yu-Chun Lin <eleanor.lin@xxxxxxxxxxx>
> Signed-off-by: Yu-Chun Lin <eleanor.lin@xxxxxxxxxxx>
> ---
> Changes in v5:
> - Created drivers/reset/realtek/ directory and include/linux/reset/realtek.h.
> - Extracted the common reset helpers:
>  - Moved the source code to drivers/reset/realtek/common.c and
>  - the header to include/linux/reset/realtek.h
> - Renamed rtk_reset_bank to rtk_reset_desc.
> - Added 'bits' member to rtk_reset_desc structure.
> - Removed rtk_reset_get_id() and rtk_reset_get_bank() helper.
> - Introduced rtk_reset_get_desc().
> ---
>  MAINTAINERS                    |  1 +
>  drivers/reset/Kconfig          |  1 +
>  drivers/reset/Makefile         |  1 +
>  drivers/reset/realtek/Kconfig  |  3 ++
>  drivers/reset/realtek/Makefile |  2 +
>  drivers/reset/realtek/common.c | 91 ++++++++++++++++++++++++++++++++++
>  include/linux/reset/realtek.h  | 25 ++++++++++
>  7 files changed, 124 insertions(+)
>  create mode 100644 drivers/reset/realtek/Kconfig
>  create mode 100644 drivers/reset/realtek/Makefile
>  create mode 100644 drivers/reset/realtek/common.c
>  create mode 100644 include/linux/reset/realtek.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 721356d4c02c..9419b0497e0b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -22229,6 +22229,7 @@ L:	devicetree@xxxxxxxxxxxxxxx
>  L:	linux-clk@xxxxxxxxxxxxxxx
>  S:	Supported
>  F:	Documentation/devicetree/bindings/clock/realtek*
> +F:	drivers/reset/realtek/*
>  F:	include/dt-bindings/clock/realtek*
>  
>  REALTEK SPI-NAND
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 7ce151f6a7e4..03be1931f264 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -398,6 +398,7 @@ config RESET_ZYNQMP
>  
>  source "drivers/reset/amlogic/Kconfig"
>  source "drivers/reset/hisilicon/Kconfig"
> +source "drivers/reset/realtek/Kconfig"
>  source "drivers/reset/spacemit/Kconfig"
>  source "drivers/reset/starfive/Kconfig"
>  source "drivers/reset/sti/Kconfig"
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index fc0cc99f8514..4407d1630070 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -2,6 +2,7 @@
>  obj-y += core.o
>  obj-y += amlogic/
>  obj-y += hisilicon/
> +obj-y += realtek/
>  obj-y += spacemit/
>  obj-y += starfive/
>  obj-y += sti/
> diff --git a/drivers/reset/realtek/Kconfig b/drivers/reset/realtek/Kconfig
> new file mode 100644
> index 000000000000..99a14d355803
> --- /dev/null
> +++ b/drivers/reset/realtek/Kconfig
> @@ -0,0 +1,3 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +config RESET_RTK_COMMON
> +	bool
> diff --git a/drivers/reset/realtek/Makefile b/drivers/reset/realtek/Makefile
> new file mode 100644
> index 000000000000..b59a3f7f2453
> --- /dev/null
> +++ b/drivers/reset/realtek/Makefile
> @@ -0,0 +1,2 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +obj-$(CONFIG_RESET_RTK_COMMON) += common.o
> diff --git a/drivers/reset/realtek/common.c b/drivers/reset/realtek/common.c
> new file mode 100644
> index 000000000000..b9e3219dc8f7
> --- /dev/null
> +++ b/drivers/reset/realtek/common.c
> @@ -0,0 +1,91 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2019 Realtek Semiconductor Corporation
> + */
> +
> +#include <linux/device.h>
> +#include <linux/of.h>
> +#include <linux/regmap.h>
> +#include <linux/reset-controller.h>
> +#include <linux/reset/realtek.h>
> +
> +struct rtk_reset_data {
> +	struct reset_controller_dev rcdev;
> +	struct rtk_reset_desc *descs;
> +	struct regmap *regmap;
> +};
> +
> +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 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);
> +	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
> +	u32 mask = desc->write_en ? (0x3 << desc->bit) : BIT(desc->bit);
> +	u32 val  = desc->write_en ? (0x2 << 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);
> +	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
> +	u32 mask = desc->write_en ? (0x3 << desc->bit) : BIT(desc->bit);
> +	u32 val  = mask;
> +
> +	return regmap_update_bits(data->regmap, desc->ofs, mask, val);
> +}
> +
> +static int rtk_reset_status(struct reset_controller_dev *rcdev,
> +			    unsigned long idx)
> +{
> +	struct rtk_reset_data *data = to_rtk_reset_controller(rcdev);
> +	struct rtk_reset_desc *desc = rtk_reset_get_desc(data, idx);
> +	u32 val;
> +	int ret;
> +
> +	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,
> +};
> +
> +int rtk_reset_controller_add(struct device *dev,
> +			     struct rtk_reset_initdata *initdata)
> +{
> +	struct rtk_reset_data *data;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->regmap          = initdata->regmap;
> +	data->descs           = initdata->descs;
> +	data->rcdev.owner     = THIS_MODULE;
> +	data->rcdev.ops       = &rtk_reset_ops;
> +	data->rcdev.dev       = dev;
> +	data->rcdev.of_node   = dev->of_node;
> +	data->rcdev.nr_resets = initdata->num_descs;
> +
> +	return devm_reset_controller_register(dev, &data->rcdev);
> +}
> +EXPORT_SYMBOL_GPL(rtk_reset_controller_add);

Please implement this as an auxiliary device driver. Move the
rtk_reset_initdata definitions in here and select them based on either
auxiliary_device_id (see imx8mp-audiomix or spacemit) or of_device_id
(see eyeq).
The regmap can be retrieved from the parent (clk device) via
dev_get_regmap (see imx8mp-audiomix).

> diff --git a/include/linux/reset/realtek.h b/include/linux/reset/realtek.h
> new file mode 100644
> index 000000000000..3c2226e3ed26
> --- /dev/null
> +++ b/include/linux/reset/realtek.h
> @@ -0,0 +1,25 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __LINUX_RESET_REALTEK_H__
> +#define __LINUX_RESET_REALTEK_H__
> +
> +#include <linux/types.h>
> +
> +struct device;
> +struct regmap;
> +
> +struct rtk_reset_desc {
> +	u32 ofs;
> +	u32 bit;
> +	u32 write_en;
> +};
> +
> +struct rtk_reset_initdata {
> +	struct rtk_reset_desc *descs;
> +	u32 num_descs;
> +	struct regmap *regmap;
> +};
> +
> +int rtk_reset_controller_add(struct device *dev,
> +			     struct rtk_reset_initdata *initdata);
> +
> +#endif /* __LINUX_RESET_REALTEK_H__ */

With the above suggested changes, this header is not necessary.

regards
Philipp