Adds Atlantis Reset Controller and auxiliary device definitions for
reset to share same regmap interface as prcm (clock controller).

This version of the reset controller driver covers resets from the RCPU
prcm.

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com>
---
 MAINTAINERS                                |   2 +
 drivers/reset/Kconfig                      |  11 ++
 drivers/reset/Makefile                     |   1 +
 drivers/reset/reset-tenstorrent-atlantis.c | 163 +++++++++++++++++++++++++++++
 include/soc/tenstorrent/atlantis-prcm.h    |  31 ++++++
 5 files changed, 208 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 0fc7bc6d0458..0cde1774567d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22537,7 +22537,9 @@ T:	git https://github.com/tenstorrent/linux.git
 F:	Documentation/devicetree/bindings/clock/tenstorrent,atlantis-prcm.yaml
 F:	Documentation/devicetree/bindings/riscv/tenstorrent.yaml
 F:	arch/riscv/boot/dts/tenstorrent/
+F:	drivers/reset/reset-tenstorrent-atlantis.c
 F:	include/dt-bindings/clock/tenstorrent,atlantis-prcm.h
+F:	include/soc/tenstorrent/
 
 RISC-V THEAD SoC SUPPORT
 M:	Drew Fustini <fustini@kernel.org>
diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 6e5d6deffa7d..cade77717492 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -324,6 +324,17 @@ config RESET_SUNXI
 	help
 	  This enables the reset driver for Allwinner SoCs.
 
+config RESET_TENSTORRENT_ATLANTIS
+	tristate "Tenstorrent atlantis reset driver"
+	depends on ARCH_TENSTORRENT || COMPILE_TEST
+	select AUXILIARY_BUS
+	default ARCH_TENSTORRENT
+	help
+	  This enables the driver for the reset controller
+	  present in the Tenstorrent Atlantis SoC.
+	  Enable this option to be able to use hardware
+	  resets on Atalantis based systems.
+
 config RESET_TH1520
 	tristate "T-HEAD TH1520 reset controller"
 	depends on ARCH_THEAD || COMPILE_TEST
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 9c3e484dfd81..a31959da0a88 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -41,6 +41,7 @@ obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_SPACEMIT) += reset-spacemit.o
 obj-$(CONFIG_RESET_SUNPLUS) += reset-sunplus.o
 obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o
+obj-$(CONFIG_RESET_TENSTORRENT_ATLANTIS) += reset-tenstorrent-atlantis.o
 obj-$(CONFIG_RESET_TH1520) += reset-th1520.o
 obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
 obj-$(CONFIG_RESET_TI_SYSCON) += reset-ti-syscon.o
diff --git a/drivers/reset/reset-tenstorrent-atlantis.c b/drivers/reset/reset-tenstorrent-atlantis.c
new file mode 100644
index 000000000000..c5068273f9a0
--- /dev/null
+++ b/drivers/reset/reset-tenstorrent-atlantis.c
@@ -0,0 +1,163 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Tenstorrent Atlantis PRCM Reset Driver
+ *
+ * Copyright (c) 2026 Tenstorrent
+ */
+
+#include <dt-bindings/clock/tenstorrent,atlantis-prcm.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/reset-controller.h>
+#include <linux/regmap.h>
+#include <soc/tenstorrent/atlantis-prcm.h>
+
+struct atlantis_reset_data {
+	u8 bit;
+	u16 reg;
+	bool active_low;
+};
+
+struct atlantis_reset_controller_data {
+	const struct atlantis_reset_data *reset_data;
+	size_t count;
+};
+
+struct atlantis_reset_controller {
+	struct reset_controller_dev rcdev;
+	const struct atlantis_reset_controller_data *data;
+	struct regmap *regmap;
+};
+
+static inline struct atlantis_reset_controller *
+to_atlantis_reset_controller(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct atlantis_reset_controller, rcdev);
+}
+
+#define RESET_DATA(_reg, _bit, _active_low)                          \
+	{                                                            \
+		.bit = _bit, .reg = _reg, .active_low = _active_low, \
+	}
+
+static const struct atlantis_reset_data atlantis_rcpu_resets[] = {
+	[RST_SMNDMA0]	= RESET_DATA(RCPU_BLK_RST_REG, 0, true),
+	[RST_SMNDMA1]	= RESET_DATA(RCPU_BLK_RST_REG, 1, true),
+	[RST_WDT0]	= RESET_DATA(RCPU_BLK_RST_REG, 2, true),
+	[RST_WDT1]	= RESET_DATA(RCPU_BLK_RST_REG, 3, true),
+	[RST_TMR]	= RESET_DATA(RCPU_BLK_RST_REG, 4, true),
+	[RST_PVTC]	= RESET_DATA(RCPU_BLK_RST_REG, 12, true),
+	[RST_PMU]	= RESET_DATA(RCPU_BLK_RST_REG, 13, true),
+	[RST_MAILBOX]	= RESET_DATA(RCPU_BLK_RST_REG, 14, true),
+	[RST_SPACC]	= RESET_DATA(RCPU_BLK_RST_REG, 26, true),
+	[RST_OTP]	= RESET_DATA(RCPU_BLK_RST_REG, 28, true),
+	[RST_TRNG]	= RESET_DATA(RCPU_BLK_RST_REG, 29, true),
+	[RST_CRC]	= RESET_DATA(RCPU_BLK_RST_REG, 30, true),
+	[RST_QSPI]	= RESET_DATA(LSIO_BLK_RST_REG, 0, true),
+	[RST_I2C0]	= RESET_DATA(LSIO_BLK_RST_REG, 1, true),
+	[RST_I2C1]	= RESET_DATA(LSIO_BLK_RST_REG, 2, true),
+	[RST_I2C2]	= RESET_DATA(LSIO_BLK_RST_REG, 3, true),
+	[RST_I2C3]	= RESET_DATA(LSIO_BLK_RST_REG, 4, true),
+	[RST_I2C4]	= RESET_DATA(LSIO_BLK_RST_REG, 5, true),
+	[RST_UART0]	= RESET_DATA(LSIO_BLK_RST_REG, 6, true),
+	[RST_UART1]	= RESET_DATA(LSIO_BLK_RST_REG, 7, true),
+	[RST_UART2]	= RESET_DATA(LSIO_BLK_RST_REG, 8, true),
+	[RST_UART3]	= RESET_DATA(LSIO_BLK_RST_REG, 9, true),
+	[RST_UART4]	= RESET_DATA(LSIO_BLK_RST_REG, 10, true),
+	[RST_SPI0]	= RESET_DATA(LSIO_BLK_RST_REG, 11, true),
+	[RST_SPI1]	= RESET_DATA(LSIO_BLK_RST_REG, 12, true),
+	[RST_SPI2]	= RESET_DATA(LSIO_BLK_RST_REG, 13, true),
+	[RST_SPI3]	= RESET_DATA(LSIO_BLK_RST_REG, 14, true),
+	[RST_GPIO]	= RESET_DATA(LSIO_BLK_RST_REG, 15, true),
+	[RST_CAN0]	= RESET_DATA(LSIO_BLK_RST_REG, 17, true),
+	[RST_CAN1]	= RESET_DATA(LSIO_BLK_RST_REG, 18, true),
+	[RST_I2S0]	= RESET_DATA(LSIO_BLK_RST_REG, 19, true),
+	[RST_I2S1]	= RESET_DATA(LSIO_BLK_RST_REG, 20, true),
+
+};
+
+static const struct atlantis_reset_controller_data atlantis_rcpu_reset_data = {
+	.reset_data = atlantis_rcpu_resets,
+	.count = ARRAY_SIZE(atlantis_rcpu_resets),
+};
+
+static int atlantis_reset_update(struct reset_controller_dev *rcdev,
+				 unsigned long id, bool assert)
+{
+	unsigned int val;
+	struct atlantis_reset_controller *rst =
+		to_atlantis_reset_controller(rcdev);
+	const struct atlantis_reset_data *data = &rst->data->reset_data[id];
+	unsigned int mask = BIT(data->bit);
+	struct regmap *regmap = rst->regmap;
+
+	if (data->active_low ^ assert)
+		val = mask;
+	else
+		val = 0;
+
+	return regmap_update_bits(regmap, data->reg, mask, val);
+}
+
+static int atlantis_reset_assert(struct reset_controller_dev *rcdev,
+				 unsigned long id)
+{
+	return atlantis_reset_update(rcdev, id, true);
+}
+
+static int atlantis_reset_deassert(struct reset_controller_dev *rcdev,
+				   unsigned long id)
+{
+	return atlantis_reset_update(rcdev, id, false);
+}
+
+static const struct reset_control_ops atlantis_reset_control_ops = {
+	.assert = atlantis_reset_assert,
+	.deassert = atlantis_reset_deassert,
+};
+
+static int
+atlantis_reset_controller_register(struct device *dev,
+				   struct atlantis_reset_controller *controller)
+{
+	struct reset_controller_dev *rcdev = &controller->rcdev;
+
+	rcdev->ops = &atlantis_reset_control_ops;
+	rcdev->owner = THIS_MODULE;
+	rcdev->of_node = dev->of_node;
+	rcdev->nr_resets = controller->data->count;
+
+	return devm_reset_controller_register(dev, &controller->rcdev);
+}
+static int atlantis_reset_probe(struct auxiliary_device *adev,
+				const struct auxiliary_device_id *id)
+{
+	struct atlantis_prcm_adev *rdev = to_atlantis_prcm_adev(adev);
+	struct atlantis_reset_controller *controller;
+	struct device *dev = &adev->dev;
+
+	controller = devm_kzalloc(dev, sizeof(*controller), GFP_KERNEL);
+	if (!controller)
+		return -ENOMEM;
+	controller->data =
+		(const struct atlantis_reset_controller_data *)id->driver_data;
+	controller->regmap = rdev->regmap;
+
+	return atlantis_reset_controller_register(dev, controller);
+}
+
+static const struct auxiliary_device_id atlantis_reset_ids[] = {
+	{ .name = "atlantis_prcm.rcpu-reset",
+	  .driver_data = (kernel_ulong_t)&atlantis_rcpu_reset_data },
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, atlantis_reset_ids);
+
+static struct auxiliary_driver atlantis_reset_driver = {
+	.probe = atlantis_reset_probe,
+	.id_table = atlantis_reset_ids,
+};
+module_auxiliary_driver(atlantis_reset_driver);
+
+MODULE_AUTHOR("Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com>");
+MODULE_DESCRIPTION("Atlantis PRCM reset controller driver");
+MODULE_LICENSE("GPL");
diff --git a/include/soc/tenstorrent/atlantis-prcm.h b/include/soc/tenstorrent/atlantis-prcm.h
new file mode 100644
index 000000000000..841516cbefd9
--- /dev/null
+++ b/include/soc/tenstorrent/atlantis-prcm.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
+/*
+ * Shared definitions for Atlantis PRCM Clock and Reset Drivers
+ *
+ * Copyright (c) 2026 Tenstorrent
+ */
+#ifndef __SOC_ATLANTIS_PRCM_H__
+#define __SOC_ATLANTIS_PRCM_H__
+
+#include <linux/bits.h>
+#include <linux/types.h>
+
+struct atlantis_prcm_adev {
+	struct auxiliary_device adev;
+	struct regmap *regmap;
+};
+
+static inline struct atlantis_prcm_adev *
+to_atlantis_prcm_adev(struct auxiliary_device *adev)
+{
+	return container_of(adev, struct atlantis_prcm_adev, adev);
+}
+
+/* RCPU Reset Register Offsets */
+#define RCPU_BLK_RST_REG 0x001c
+#define LSIO_BLK_RST_REG 0x0020
+#define HSIO_BLK_RST_REG 0x000c
+#define PCIE_SUBS_RST_REG 0x0000
+#define MM_RSTN_REG 0x0014
+
+#endif

-- 
2.43.0

On Mon, Feb 02, 2026 at 01:46:50PM -0600, Anirudh Srinivasan wrote:
> diff --git a/include/soc/tenstorrent/atlantis-prcm.h b/include/soc/tenstorrent/atlantis-prcm.h
> new file mode 100644
> index 000000000000..841516cbefd9
> --- /dev/null
> +++ b/include/soc/tenstorrent/atlantis-prcm.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> +/*
> + * Shared definitions for Atlantis PRCM Clock and Reset Drivers
> + *
> + * Copyright (c) 2026 Tenstorrent
> + */
> +#ifndef __SOC_ATLANTIS_PRCM_H__
> +#define __SOC_ATLANTIS_PRCM_H__
> +
> +#include <linux/bits.h>
> +#include <linux/types.h>
> +
> +struct atlantis_prcm_adev {
> +	struct auxiliary_device adev;
> +	struct regmap *regmap;
> +};

Drop, there is no driver-wide user of this.

> +
> +static inline struct atlantis_prcm_adev *
> +to_atlantis_prcm_adev(struct auxiliary_device *adev)

Same here.

Do not add symbols to headers which nothing uses. These are private to
the driver so they must stay ONLY in the driver.

Best regards,
Krzysztof

Hello Krzysztof,

On Thu, Feb 5, 2026 at 3:27 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On Mon, Feb 02, 2026 at 01:46:50PM -0600, Anirudh Srinivasan wrote:
> > diff --git a/include/soc/tenstorrent/atlantis-prcm.h b/include/soc/tenstorrent/atlantis-prcm.h
> > new file mode 100644
> > index 000000000000..841516cbefd9
> > --- /dev/null
> > +++ b/include/soc/tenstorrent/atlantis-prcm.h
> > @@ -0,0 +1,31 @@
> > +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> > +/*
> > + * Shared definitions for Atlantis PRCM Clock and Reset Drivers
> > + *
> > + * Copyright (c) 2026 Tenstorrent
> > + */
> > +#ifndef __SOC_ATLANTIS_PRCM_H__
> > +#define __SOC_ATLANTIS_PRCM_H__
> > +
> > +#include <linux/bits.h>
> > +#include <linux/types.h>
> > +
> > +struct atlantis_prcm_adev {
> > +     struct auxiliary_device adev;
> > +     struct regmap *regmap;
> > +};
>
> Drop, there is no driver-wide user of this.

>
> > +
> > +static inline struct atlantis_prcm_adev *
> > +to_atlantis_prcm_adev(struct auxiliary_device *adev)
>
> Same here.
>
> Do not add symbols to headers which nothing uses. These are private to
> the driver so they must stay ONLY in the driver.

The definitions in these files are shared between the clock and reset
driver (which are in drivers/clk/tenstorrent/ and drivers/reset/),
hence they have been put here.

>
> Best regards,
> Krzysztof
>

On 05/02/2026 15:18, Anirudh Srinivasan wrote:
> Hello Krzysztof,
> 
> On Thu, Feb 5, 2026 at 3:27 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>>
>> On Mon, Feb 02, 2026 at 01:46:50PM -0600, Anirudh Srinivasan wrote:
>>> diff --git a/include/soc/tenstorrent/atlantis-prcm.h b/include/soc/tenstorrent/atlantis-prcm.h
>>> new file mode 100644
>>> index 000000000000..841516cbefd9
>>> --- /dev/null
>>> +++ b/include/soc/tenstorrent/atlantis-prcm.h
>>> @@ -0,0 +1,31 @@
>>> +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
>>> +/*
>>> + * Shared definitions for Atlantis PRCM Clock and Reset Drivers
>>> + *
>>> + * Copyright (c) 2026 Tenstorrent
>>> + */
>>> +#ifndef __SOC_ATLANTIS_PRCM_H__
>>> +#define __SOC_ATLANTIS_PRCM_H__
>>> +
>>> +#include <linux/bits.h>
>>> +#include <linux/types.h>
>>> +
>>> +struct atlantis_prcm_adev {
>>> +     struct auxiliary_device adev;
>>> +     struct regmap *regmap;
>>> +};
>>
>> Drop, there is no driver-wide user of this.
> 
>>
>>> +
>>> +static inline struct atlantis_prcm_adev *
>>> +to_atlantis_prcm_adev(struct auxiliary_device *adev)
>>
>> Same here.
>>
>> Do not add symbols to headers which nothing uses. These are private to
>> the driver so they must stay ONLY in the driver.
> 
> The definitions in these files are shared between the clock and reset
> driver (which are in drivers/clk/tenstorrent/ and drivers/reset/),
> hence they have been put here.


Ah, but then I wonder why your clock driver needs to access reset driver
structures. Or vice versa. You are only expected to get regmap from the
parent, no?


Best regards,
Krzysztof

On Thu, Feb 5, 2026 at 12:47 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 05/02/2026 15:18, Anirudh Srinivasan wrote:
> > Hello Krzysztof,
> >
> > On Thu, Feb 5, 2026 at 3:27 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >>
> >> On Mon, Feb 02, 2026 at 01:46:50PM -0600, Anirudh Srinivasan wrote:
> >>> diff --git a/include/soc/tenstorrent/atlantis-prcm.h b/include/soc/tenstorrent/atlantis-prcm.h
> >>> new file mode 100644
> >>> index 000000000000..841516cbefd9
> >>> --- /dev/null
> >>> +++ b/include/soc/tenstorrent/atlantis-prcm.h
> >>> @@ -0,0 +1,31 @@
> >>> +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> >>> +/*
> >>> + * Shared definitions for Atlantis PRCM Clock and Reset Drivers
> >>> + *
> >>> + * Copyright (c) 2026 Tenstorrent
> >>> + */
> >>> +#ifndef __SOC_ATLANTIS_PRCM_H__
> >>> +#define __SOC_ATLANTIS_PRCM_H__
> >>> +
> >>> +#include <linux/bits.h>
> >>> +#include <linux/types.h>
> >>> +
> >>> +struct atlantis_prcm_adev {
> >>> +     struct auxiliary_device adev;
> >>> +     struct regmap *regmap;
> >>> +};
> >>
> >> Drop, there is no driver-wide user of this.
> >
> >>
> >>> +
> >>> +static inline struct atlantis_prcm_adev *
> >>> +to_atlantis_prcm_adev(struct auxiliary_device *adev)
> >>
> >> Same here.
> >>
> >> Do not add symbols to headers which nothing uses. These are private to
> >> the driver so they must stay ONLY in the driver.
> >
> > The definitions in these files are shared between the clock and reset
> > driver (which are in drivers/clk/tenstorrent/ and drivers/reset/),
> > hence they have been put here.
>
>
> Ah, but then I wonder why your clock driver needs to access reset driver
> structures. Or vice versa. You are only expected to get regmap from the
> parent, no?

Yes, it seems to be doable without these structs. I will remove them,
and move the register definitions into the specific drivers.

>
>
> Best regards,
> Krzysztof