[PATCH 0/4] power: sys-off: fix Pixel C shutdown via MAX77620

[PATCH 0/4] power: sys-off: fix Pixel C shutdown via MAX77620

[Diogo Ivo]

This series migrates PSCI and MAX77620 poweroff handling to the
sys-off framework and fixes shutdown on the Pixel C (Smaug).

The first two patches replace legacy pm_power_off usage in the PSCI
and MAX77620 drivers with sys-off handlers. Besides aligning both
drivers with the modern poweroff infrastructure, this removes the
global callback dependency and allows multiple handlers to coexist
with explicit priorities.

The remaining patches address shutdown on the Pixel C. Although the
platform exposes PSCI firmware, its SYSTEM_OFF implementation is not
functional:

    __dead2 void tegra_system_off(void)
    {
            ERROR("Tegra System Off: operation not handled.\n");
            panic();
    }

Downstream kernels instead rely on the MAX77620 PMIC to perform the
shutdown sequence. To mirror that behavior upstream, register the
MAX77620 handler with higher priority than PSCI on Smaug systems and
mark the PMIC as the system power controller in device tree.

Patch overview:
  1. firmware: psci: switch SYSTEM_OFF to sys-off handler API
  2. mfd: max77620: convert poweroff support to sys-off API
  3. mfd: max77620: override PSCI poweroff handler on Smaug
  4. arm64: dts: tegra: smaug: mark MAX77620 as system power controller

Tested on a Pixel C, where poweroff now completes successfully
instead of hanging in PSCI firmware.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
Diogo Ivo (4):
      firmware: psci: switch SYSTEM_OFF to sys-off handler API
      mfd: max77620: convert poweroff support to sys-off API
      mfd: max77620: override PSCI poweroff handler on Pixel C
      arm64: tegra: smaug: mark MAX77620 as system power controller

 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts |  2 ++
 drivers/firmware/psci/psci.c                  |  8 +++---
 drivers/mfd/max77620.c                        | 36 ++++++++++++++++++++-------
 3 files changed, 34 insertions(+), 12 deletions(-)
---
base-commit: f327c8ef8a6905ee97b62e42d808603c5b759418
change-id: 20260514-smaug-poweroff-9626c5501bbc

Best regards,
--  
Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>

[PATCH 1/4] firmware: psci: switch SYSTEM_OFF to sys-off handler API

[Diogo Ivo]

Replace the legacy pm_power_off hook with the generic sys-off
handler infrastructure.

Convert psci_sys_poweroff() to the sys-off callback prototype and
register it through register_sys_off_handler() with firmware
priority. This removes the direct dependency on pm_power_off and
drops the now-unused <linux/pm.h> include.

This aligns the PSCI poweroff path with the modern system-off
framework used by other firmware and platform drivers.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
 drivers/firmware/psci/psci.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 38ca190d4a22..d6e9721d11e5 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -13,7 +13,6 @@
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/of.h>
-#include <linux/pm.h>
 #include <linux/printk.h>
 #include <linux/psci.h>
 #include <linux/reboot.h>
@@ -329,9 +328,11 @@ static struct notifier_block psci_sys_reset_nb = {
 	.priority = 129,
 };
 
-static void psci_sys_poweroff(void)
+static int psci_sys_poweroff(struct sys_off_data *data)
 {
 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
+
+	return NOTIFY_DONE;
 }
 
 #ifdef CONFIG_HIBERNATION
@@ -671,7 +672,8 @@ static void __init psci_0_2_set_functions(void)
 
 	register_restart_handler(&psci_sys_reset_nb);
 
-	pm_power_off = psci_sys_poweroff;
+	register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_FIRMWARE,
+				 psci_sys_poweroff, NULL);
 }
 
 /*

-- 
2.54.0

[PATCH 2/4] mfd: max77620: convert poweroff support to sys-off API

[Diogo Ivo]

Convert max77620_pm_power_off() to the sys-off callback prototype and
register it with the sys-off API when the device tree marks the PMIC as
a system power controller. This also removes the global max77620_scratch
pointer by passing the chip instance through the callback data.

This modernizes the driver's poweroff handling and aligns it with
the kernel sys-off infrastructure.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
 drivers/mfd/max77620.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/mfd/max77620.c b/drivers/mfd/max77620.c
index 3af2974b3023..c4f89a9681f3 100644
--- a/drivers/mfd/max77620.c
+++ b/drivers/mfd/max77620.c
@@ -31,11 +31,10 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
-static struct max77620_chip *max77620_scratch;
-
 static const struct resource gpio_resources[] = {
 	DEFINE_RES_IRQ(MAX77620_IRQ_TOP_GPIO),
 };
@@ -484,13 +483,15 @@ static int max77620_read_es_version(struct max77620_chip *chip)
 	return ret;
 }
 
-static void max77620_pm_power_off(void)
+static int max77620_pm_power_off(struct sys_off_data *data)
 {
-	struct max77620_chip *chip = max77620_scratch;
+	struct max77620_chip *chip = data->cb_data;
 
 	regmap_update_bits(chip->rmap, MAX77620_REG_ONOFFCNFG1,
 			   MAX77620_ONOFFCNFG1_SFT_RST,
 			   MAX77620_ONOFFCNFG1_SFT_RST);
+
+	return NOTIFY_DONE;
 }
 
 static int max77620_probe(struct i2c_client *client)
@@ -501,7 +502,6 @@ static int max77620_probe(struct i2c_client *client)
 	struct regmap_irq_chip *chip_desc;
 	const struct mfd_cell *mfd_cells;
 	int n_mfd_cells;
-	bool pm_off;
 	int ret;
 
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
@@ -573,10 +573,14 @@ static int max77620_probe(struct i2c_client *client)
 		return ret;
 	}
 
-	pm_off = of_device_is_system_power_controller(client->dev.of_node);
-	if (pm_off && !pm_power_off) {
-		max77620_scratch = chip;
-		pm_power_off = max77620_pm_power_off;
+	if (of_device_is_system_power_controller(client->dev.of_node)) {
+		ret = devm_register_sys_off_handler(&client->dev,
+						    SYS_OFF_MODE_POWER_OFF,
+						    SYS_OFF_PRIO_DEFAULT,
+						    max77620_pm_power_off, chip);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+					"failed to register power-off handler\n");
 	}
 
 	return 0;

-- 
2.54.0

[PATCH 3/4] mfd: max77620: override PSCI poweroff handler on Pixel C

[Diogo Ivo]

On Pixel C, shutdown must be handled by the MAX77620 PMIC rather
than the PSCI SYSTEM_OFF call, whose firmware implementation is:

__dead2 void tegra_system_off(void)
{
        ERROR("Tegra System Off: operation not handled.\n");
        panic();
}

Raise the MAX77620 sys-off handler priority above SYS_OFF_PRIO_FIRMWARE
on Pixel C systems so it takes precedence over the PSCI poweroff handler.

Other systems continue to use the default sys-off priority.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
 drivers/mfd/max77620.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/mfd/max77620.c b/drivers/mfd/max77620.c
index c4f89a9681f3..3b1f3a2f3566 100644
--- a/drivers/mfd/max77620.c
+++ b/drivers/mfd/max77620.c
@@ -494,6 +494,18 @@ static int max77620_pm_power_off(struct sys_off_data *data)
 	return NOTIFY_DONE;
 }
 
+static int max77620_power_off_priority(void)
+{
+	/*
+	 * For Smaug  we need to override the PSCI poweroff handler
+	 * which is registered at priority SYS_OFF_PRIO_FIRMWARE.
+	 */
+	if (of_machine_is_compatible("google,smaug"))
+		return SYS_OFF_PRIO_FIRMWARE + 1;
+
+	return SYS_OFF_PRIO_DEFAULT;
+}
+
 static int max77620_probe(struct i2c_client *client)
 {
 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
@@ -502,6 +514,7 @@ static int max77620_probe(struct i2c_client *client)
 	struct regmap_irq_chip *chip_desc;
 	const struct mfd_cell *mfd_cells;
 	int n_mfd_cells;
+	int priority;
 	int ret;
 
 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
@@ -574,10 +587,11 @@ static int max77620_probe(struct i2c_client *client)
 	}
 
 	if (of_device_is_system_power_controller(client->dev.of_node)) {
+		priority = max77620_power_off_priority();
 		ret = devm_register_sys_off_handler(&client->dev,
 						    SYS_OFF_MODE_POWER_OFF,
-						    SYS_OFF_PRIO_DEFAULT,
-						    max77620_pm_power_off, chip);
+						    priority, max77620_pm_power_off,
+						    chip);
 		if (ret)
 			return dev_err_probe(&client->dev, ret,
 					"failed to register power-off handler\n");

-- 
2.54.0

Re: [PATCH 3/4] mfd: max77620: override PSCI poweroff handler on Pixel C

[Thierry Reding]

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On Thu, May 14, 2026 at 04:47:21PM +0200, Diogo Ivo wrote:
> On Pixel C, shutdown must be handled by the MAX77620 PMIC rather
> than the PSCI SYSTEM_OFF call, whose firmware implementation is:
> 
> __dead2 void tegra_system_off(void)
> {
>         ERROR("Tegra System Off: operation not handled.\n");
>         panic();
> }

Ugh... sounds very familiar. We have similar stub implementations on
Jetson TX1 and/or Nano, if I remember correctly. Luckily newer platforms
seem to have proper implementations for these.

Thanks for doing this. I might want to take inspiration from this for
these older Jetson platforms.

Thierry

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Re: [PATCH 3/4] mfd: max77620: override PSCI poweroff handler on Pixel C

[Diogo Ivo]

On 5/21/26 09:52, Thierry Reding wrote:
> On Thu, May 14, 2026 at 04:47:21PM +0200, Diogo Ivo wrote:
>> On Pixel C, shutdown must be handled by the MAX77620 PMIC rather
>> than the PSCI SYSTEM_OFF call, whose firmware implementation is:
>>
>> __dead2 void tegra_system_off(void)
>> {
>>          ERROR("Tegra System Off: operation not handled.\n");
>>          panic();
>> }
> 
> Ugh... sounds very familiar. We have similar stub implementations on
> Jetson TX1 and/or Nano, if I remember correctly. Luckily newer platforms
> seem to have proper implementations for these.

Yes, on my TX1 I was encountering the same problem. However in that case
is it possible to update the firmware with a proper implementation?

> Thanks for doing this. I might want to take inspiration from this for
> these older Jetson platforms.

My pleasure!

Diogo

> Thierry

Re: [PATCH 3/4] mfd: max77620: override PSCI poweroff handler on Pixel C

[Thierry Reding]

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On Thu, May 21, 2026 at 11:23:11AM +0200, Diogo Ivo wrote:
> 
> 
> On 5/21/26 09:52, Thierry Reding wrote:
> > On Thu, May 14, 2026 at 04:47:21PM +0200, Diogo Ivo wrote:
> > > On Pixel C, shutdown must be handled by the MAX77620 PMIC rather
> > > than the PSCI SYSTEM_OFF call, whose firmware implementation is:
> > > 
> > > __dead2 void tegra_system_off(void)
> > > {
> > >          ERROR("Tegra System Off: operation not handled.\n");
> > >          panic();
> > > }
> > 
> > Ugh... sounds very familiar. We have similar stub implementations on
> > Jetson TX1 and/or Nano, if I remember correctly. Luckily newer platforms
> > seem to have proper implementations for these.
> 
> Yes, on my TX1 I was encountering the same problem. However in that case
> is it possible to update the firmware with a proper implementation?

I tried, but there were complications, both technical and logistical
because of the point in the product lifecycle. At this point I don't
think it will happen, unfortunately.

Thierry

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Re: [PATCH 3/4] mfd: max77620: override PSCI poweroff handler on Pixel C

[Diogo Ivo]

On 5/21/26 11:43, Thierry Reding wrote:
> On Thu, May 21, 2026 at 11:23:11AM +0200, Diogo Ivo wrote:
>>
>>
>> On 5/21/26 09:52, Thierry Reding wrote:
>>> On Thu, May 14, 2026 at 04:47:21PM +0200, Diogo Ivo wrote:
>>>> On Pixel C, shutdown must be handled by the MAX77620 PMIC rather
>>>> than the PSCI SYSTEM_OFF call, whose firmware implementation is:
>>>>
>>>> __dead2 void tegra_system_off(void)
>>>> {
>>>>           ERROR("Tegra System Off: operation not handled.\n");
>>>>           panic();
>>>> }
>>>
>>> Ugh... sounds very familiar. We have similar stub implementations on
>>> Jetson TX1 and/or Nano, if I remember correctly. Luckily newer platforms
>>> seem to have proper implementations for these.
>>
>> Yes, on my TX1 I was encountering the same problem. However in that case
>> is it possible to update the firmware with a proper implementation?
> 
> I tried, but there were complications, both technical and logistical
> because of the point in the product lifecycle. At this point I don't
> think it will happen, unfortunately.

Ah, I see. Then in that case this approach seems like a viable option
for those platforms :)

Best regards,
Diogo

> Thierry

[PATCH 4/4] arm64: tegra: smaug: mark MAX77620 as system power controller

[Diogo Ivo]

Register the MAX77620 PMIC as the system power controller on
Pixel C so the driver can install its sys-off handler.

This allows the PMIC poweroff sequence to override the non-working
PSCI SYSTEM_OFF implementation on this platform.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
---
 arch/arm64/boot/dts/nvidia/tegra210-smaug.dts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
index f0b8c2c80aa5..1791b47f0a73 100644
--- a/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
+++ b/arch/arm64/boot/dts/nvidia/tegra210-smaug.dts
@@ -1467,6 +1467,8 @@ pmic: pmic@3c {
 			gpio-controller;
 			#gpio-cells = <2>;
 
+			system-power-controller;
+
 			pinctrl-names = "default";
 			pinctrl-0 = <&max77620_default>;
 

-- 
2.54.0

Re: (subset) [PATCH 0/4] power: sys-off: fix Pixel C shutdown via MAX77620

[Lee Jones]

On Thu, 14 May 2026 16:47:18 +0200, Diogo Ivo wrote:
> This series migrates PSCI and MAX77620 poweroff handling to the
> sys-off framework and fixes shutdown on the Pixel C (Smaug).
> 
> The first two patches replace legacy pm_power_off usage in the PSCI
> and MAX77620 drivers with sys-off handlers. Besides aligning both
> drivers with the modern poweroff infrastructure, this removes the
> global callback dependency and allows multiple handlers to coexist
> with explicit priorities.
> 
> [...]

Applied, thanks!

[2/4] mfd: max77620: convert poweroff support to sys-off API
      commit: 1ada6d7f88063dd6fd92d74d0b803875b695fe01
[3/4] mfd: max77620: override PSCI poweroff handler on Pixel C
      commit: ea3f90bcc8524c6d514f6b8183cc202b79b082be

--
Lee Jones [李琼斯]

Re: (subset) [PATCH 0/4] power: sys-off: fix Pixel C shutdown via MAX77620

[Diogo Ivo]

Hi Lee,

On 5/20/26 18:25, Lee Jones wrote:
> On Thu, 14 May 2026 16:47:18 +0200, Diogo Ivo wrote:
>> This series migrates PSCI and MAX77620 poweroff handling to the
>> sys-off framework and fixes shutdown on the Pixel C (Smaug).
>>
>> The first two patches replace legacy pm_power_off usage in the PSCI
>> and MAX77620 drivers with sys-off handlers. Besides aligning both
>> drivers with the modern poweroff infrastructure, this removes the
>> global callback dependency and allows multiple handlers to coexist
>> with explicit priorities.
>>
>> [...]
> 
> Applied, thanks!

Thanks for applying the patches! Just a question and an observation:

  - I'm assuming you were ok with merging [2/4] despite the possible
    deadlock since this risk is already present in mainline in the same
    form so we're not actually making things worse, is that so?

  - The observation is that the comment about overriding PSCI is only
    true after (and if) a reworked [1/4] is actually merged.
    If it isn't then patch [3/4] is actually working around another handler
    in soc/tegra/pmc.c where a handler that only does work for the Nexus
    7 is actually registered at FIRMWARE level for all platforms that
    probe that driver (I will send out a patch shortly to only register
    the handler on the Nexus 7).

Best regards,
Diogo

> [2/4] mfd: max77620: convert poweroff support to sys-off API
>        commit: 1ada6d7f88063dd6fd92d74d0b803875b695fe01
> [3/4] mfd: max77620: override PSCI poweroff handler on Pixel C
>        commit: ea3f90bcc8524c6d514f6b8183cc202b79b082be
> 
> --
> Lee Jones [李琼斯]
> 

Re: (subset) [PATCH 0/4] power: sys-off: fix Pixel C shutdown via MAX77620

[Lee Jones]

On Thu, 21 May 2026, Diogo Ivo wrote:

> Hi Lee,
> 
> On 5/20/26 18:25, Lee Jones wrote:
> > On Thu, 14 May 2026 16:47:18 +0200, Diogo Ivo wrote:
> > > This series migrates PSCI and MAX77620 poweroff handling to the
> > > sys-off framework and fixes shutdown on the Pixel C (Smaug).
> > > 
> > > The first two patches replace legacy pm_power_off usage in the PSCI
> > > and MAX77620 drivers with sys-off handlers. Besides aligning both
> > > drivers with the modern poweroff infrastructure, this removes the
> > > global callback dependency and allows multiple handlers to coexist
> > > with explicit priorities.
> > > 
> > > [...]
> > 
> > Applied, thanks!
> 
> Thanks for applying the patches! Just a question and an observation:
> 
>  - I'm assuming you were ok with merging [2/4] despite the possible
>    deadlock since this risk is already present in mainline in the same
>    form so we're not actually making things worse, is that so?

Did you see the text below?

Both patches 2 and 3 are applied.

>  - The observation is that the comment about overriding PSCI is only
>    true after (and if) a reworked [1/4] is actually merged.
>    If it isn't then patch [3/4] is actually working around another handler
>    in soc/tegra/pmc.c where a handler that only does work for the Nexus
>    7 is actually registered at FIRMWARE level for all platforms that
>    probe that driver (I will send out a patch shortly to only register
>    the handler on the Nexus 7).

I assume the other patches will be applied soon.

If this causes some kind of issue - let me know later on in the cycle
and I'll remove whatever patches you ask me to.

-- 
Lee Jones