[PATCH 0/2] Add support for SA8255P in the phy-qcom-snps-femto-v2 phy driver

[PATCH 0/2] Add support for SA8255P in the phy-qcom-snps-femto-v2 phy driver

[Mattijs Korpershoek]

The Qualcomm automotive SA8255p SoC relies on firmware to configure
platform resources, including clocks, interconnects and TLMM.
The driver requests resources operations over SCMI using power protocols.

The SCMI power protocol enables or disables resources like clocks,
interconnect paths, and TLMM (GPIOs) using runtime PM framework APIs,
such as resume/suspend, to control power on/off.

Power domain "core" controls the GDSC, resets, and TLMM (GPIOs)
whereas power domain "transfer" controls clocks and interconnects.

Patch 1 adds the binding for sa8255p. Similarly to what has been done
for I2C [1], this is a separate binding.

Patch 2 adds the driver change, which is based on a public vendor
patch from qualcomm [2].
I did the following changes on top of that:
* Use devm_add_action_or_reset() for dev_pm_domain_detach_list() instead
  of implementing a driver .remove()
* Changed power domain names to drop 'usb_' prefix
* Fixed various error handling paths
* Added suspend/resume support

This has been tested on next-20260728 with a Ride4 SA8775P board that
has SCMI firmware (which is compatible).

[1] https://lore.kernel.org/all/20260617-enable-i2c-on-sa8255p-v7-1-ad736dbeab57@oss.qualcomm.com/
[2] https://git.codelinaro.org/clo/le/meta-qti-auto-kernel/-/blob/LY.AU.0.1.0.r1-16800-gen4meta.0/recipes-kernel/linux/files/usb/0014-PENDING-phy-qcom-snps-femto-v2-Add-support-for-SA825.patch

Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
---
Mattijs Korpershoek (1):
      dt-bindings: phy: Add sa8255p high-speed USB PHY

Sriram Dash (1):
      phy: qcom-snps-femto-v2: Add support for SA8255P

 .../bindings/phy/qcom,sa8255p-usb-hs-phy.yaml      |  52 +++++++++
 drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c      | 126 +++++++++++++++++++--
 2 files changed, 169 insertions(+), 9 deletions(-)
---
base-commit: 3652b49adac266a3d27cb41cdfdb7d8790fc3633
change-id: 20260729-phy-qcom-snps-femto-v2-8255-90ffe7674001

Best regards,
--  
Mattijs Korpershoek <mkorpershoek@kernel.org>

[PATCH 1/2] dt-bindings: phy: Add sa8255p high-speed USB PHY

[Mattijs Korpershoek]

SA8255p platform abstracts resources such as clocks, interconnect and
GPIO pins configuration in Firmware. SCMI power protocol is used to
request resource configurations.

Two power domains can be requested: transfer and core.
transfer controls clocks and interconnects and core controls
the GDSC, resets and TLMM (GPIOs).

Add a new binding for the Qualcomm SA8255p Synopsys Femto High-Speed
USB PHY V2 found in SA8255P.

Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
---
 .../bindings/phy/qcom,sa8255p-usb-hs-phy.yaml      | 52 ++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
new file mode 100644
index 000000000000..09f7ca6e7f72
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
@@ -0,0 +1,52 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/qcom,sa8255p-usb-hs-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm SA8255p Synopsys Femto High-Speed USB PHY V2
+
+maintainers:
+  - Mattijs Korpershoek <mkorpershoek@kernel.org>
+
+properties:
+  compatible:
+    const: qcom,sa8255p-usb-hs-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  power-domains:
+    maxItems: 2
+
+  power-domain-names:
+    items:
+      - const: transfer
+      - const: core
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+  - power-domains
+  - power-domain-names
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        phy@88e4000 {
+            compatible = "qcom,sa8255p-usb-hs-phy";
+            reg = <0x0 0x088e4000 0x0 0x120>;
+            #phy-cells = <0>;
+            power-domains = <&scmi12_pd 0>, <&scmi12_pd 1>;
+            power-domain-names = "transfer", "core";
+        };
+    };

-- 
2.55.0

[PATCH 2/2] phy: qcom-snps-femto-v2: Add support for SA8255P

[Mattijs Korpershoek]

From: Sriram Dash <quic_sriramd@quicinc.com>

The Qualcomm automotive SA8255p SoC relies on firmware to configure
platform resources, including clocks, interconnects and TLMM.
The driver requests resources operations over SCMI using power protocols.

The SCMI power protocol enables or disables resources like clocks,
interconnect paths, and TLMM (GPIOs) using runtime PM framework APIs,
such as resume/suspend, to control power on/off.

Power domain "core" controls the GDSC, resets, and TLMM (GPIOs)
whereas power domain "transfer" controls clocks and interconnects.

In this variant, two disjoint sets of resources are modeled against
the power domain suppliers which can be turned on/off to achieve modeled
device states. Two modeled low power states d1 and d3 are supported.

transition: d0 <--> d3  :: both core and transfer suppliers
transition: d0 <--> d1  :: only transfer supplier

Signed-off-by: Sriram Dash <quic_sriramd@quicinc.com>
Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
---
 drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 126 ++++++++++++++++++++++++--
 1 file changed, 117 insertions(+), 9 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
index eb0b0f61d98e..4a9bd3ae0e53 100644
--- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
+++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
@@ -12,6 +12,7 @@
 #include <linux/of.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/pm_domain.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/reset.h>
@@ -95,6 +96,7 @@ struct override_param_map {
 	u8 table_size;
 	u8 reg_offset;
 	u8 param_mask;
+	bool fw_managed;
 };
 
 struct phy_override_seq {
@@ -121,6 +123,7 @@ struct phy_override_seq {
  * @phy_initialized: if PHY has been initialized correctly
  * @mode: contains the current mode the PHY is in
  * @update_seq_cfg: tuning parameters for phy init
+ * @pd_list: list of power domains associated with the device
  */
 struct qcom_snps_hsphy {
 	struct device *dev;
@@ -136,8 +139,81 @@ struct qcom_snps_hsphy {
 	bool phy_initialized;
 	enum phy_mode mode;
 	struct phy_override_seq update_seq_cfg[NUM_HSPHY_TUNING_PARAMS];
+
+	struct dev_pm_domain_list *pd_list;
 };
 
+static void qcom_snps_domain_detach(void *data)
+{
+	struct qcom_snps_hsphy *hsphy = data;
+
+	dev_pm_domain_detach_list(hsphy->pd_list);
+}
+
+static int qcom_snps_domain_attach(struct qcom_snps_hsphy *hsphy)
+{
+	struct dev_pm_domain_attach_data pd_data = {
+		.pd_flags       = PD_FLAG_NO_DEV_LINK,
+		.pd_names       = (const char*[]) { "transfer", "core" },
+		.num_pd_names   = 2,
+	};
+	struct device *dev = hsphy->dev;
+	int ret;
+
+	ret = dev_pm_domain_attach_list(dev, &pd_data, &hsphy->pd_list);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "domain attach failed\n");
+
+	return 0;
+}
+
+/* d3_to_d0 transition by turning on all the suppliers */
+static int qcom_snps_d3_to_d0(struct qcom_snps_hsphy *hsphy)
+{
+	int ret;
+
+	if (!hsphy->pd_list)
+		return 0;
+
+	ret = pm_runtime_resume_and_get(hsphy->pd_list->pd_devs[0]);
+	if (ret)
+		return ret;
+
+	ret = pm_runtime_resume_and_get(hsphy->pd_list->pd_devs[1]);
+	if (ret)
+		pm_runtime_put_sync(hsphy->pd_list->pd_devs[0]);
+
+	return ret;
+}
+
+/* d0_to_d3 transition by turning off all the suppliers */
+static void qcom_snps_d0_to_d3(struct qcom_snps_hsphy *hsphy)
+{
+	if (!hsphy->pd_list)
+		return;
+
+	pm_runtime_put_sync(hsphy->pd_list->pd_devs[1]);
+	pm_runtime_put_sync(hsphy->pd_list->pd_devs[0]);
+}
+
+/* d1_to_d0 transition by turning on the 'transfer' supplier */
+static int qcom_snps_d1_to_d0(struct qcom_snps_hsphy *hsphy)
+{
+	if (!hsphy->pd_list)
+		return 0;
+
+	return pm_runtime_resume_and_get(hsphy->pd_list->pd_devs[0]);
+}
+
+/* d0_to_d1 transition by turning off the 'transfer' supplier */
+static void qcom_snps_d0_to_d1(struct qcom_snps_hsphy *hsphy)
+{
+	if (!hsphy->pd_list)
+		return;
+
+	pm_runtime_put_sync(hsphy->pd_list->pd_devs[0]);
+}
+
 static int qcom_snps_hsphy_clk_init(struct qcom_snps_hsphy *hsphy)
 {
 	struct device *dev = hsphy->dev;
@@ -196,6 +272,8 @@ static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy)
 					   0, USB2_AUTO_RESUME);
 	}
 
+	qcom_snps_d0_to_d1(hsphy);
+
 	return 0;
 }
 
@@ -203,7 +281,7 @@ static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy)
 {
 	dev_dbg(&hsphy->phy->dev, "Resume QCOM SNPS PHY, mode\n");
 
-	return 0;
+	return qcom_snps_d1_to_d0(hsphy);
 }
 
 static int __maybe_unused qcom_snps_hsphy_runtime_suspend(struct device *dev)
@@ -316,6 +394,10 @@ static const struct override_param ls_fs_output_impedance_sc7280[] = {
 	{ 1310, 0 },
 };
 
+static const struct override_param_map sa8255p_snps_hs_phy = {
+	.fw_managed = true,
+};
+
 static const struct override_param_map sc7280_snps_7nm_phy[] = {
 	{
 		"qcom,hs-disconnect-bp",
@@ -390,9 +472,15 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 
 	dev_vdbg(&phy->dev, "%s(): Initializing SNPS HS phy\n", __func__);
 
+	ret = qcom_snps_d3_to_d0(hsphy);
+	if (ret < 0) {
+		dev_err(hsphy->dev, "Failed to transition to d0 state\n");
+		return ret;
+	}
+
 	ret = regulator_bulk_enable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
 	if (ret)
-		return ret;
+		goto transition_to_d3;
 
 	ret = clk_bulk_prepare_enable(hsphy->num_clks, hsphy->clks);
 	if (ret) {
@@ -472,6 +560,8 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 	clk_bulk_disable_unprepare(hsphy->num_clks, hsphy->clks);
 poweroff_phy:
 	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
+transition_to_d3:
+	qcom_snps_d0_to_d3(hsphy);
 
 	return ret;
 }
@@ -485,6 +575,8 @@ static int qcom_snps_hsphy_exit(struct phy *phy)
 	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
 	hsphy->phy_initialized = false;
 
+	qcom_snps_d0_to_d3(hsphy);
+
 	return 0;
 }
 
@@ -496,6 +588,10 @@ static const struct phy_ops qcom_snps_hsphy_gen_ops = {
 };
 
 static const struct of_device_id qcom_snps_hsphy_of_match_table[] = {
+	{
+		.compatible	= "qcom,sa8255p-usb-hs-phy",
+		.data		= &sa8255p_snps_hs_phy,
+	},
 	{ .compatible	= "qcom,sm8150-usb-hs-phy", },
 	{ .compatible	= "qcom,usb-snps-hs-5nm-phy", },
 	{
@@ -565,6 +661,7 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct qcom_snps_hsphy *hsphy;
+	const struct override_param_map *cfg;
 	struct phy_provider *phy_provider;
 	struct phy *generic_phy;
 	int ret, i;
@@ -580,14 +677,25 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 	if (IS_ERR(hsphy->base))
 		return PTR_ERR(hsphy->base);
 
-	ret = qcom_snps_hsphy_clk_init(hsphy);
-	if (ret)
-		return dev_err_probe(dev, ret, "failed to initialize clocks\n");
+	cfg = of_device_get_match_data(dev);
+	if (cfg && cfg->fw_managed) {
+		ret = qcom_snps_domain_attach(hsphy);
+		if (ret)
+			return ret;
+
+		ret = devm_add_action_or_reset(dev, qcom_snps_domain_detach, hsphy);
+		if (ret)
+			return ret;
+	} else {
+		ret = qcom_snps_hsphy_clk_init(hsphy);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to initialize clocks\n");
 
-	hsphy->phy_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
-	if (IS_ERR(hsphy->phy_reset)) {
-		dev_err(dev, "failed to get phy core reset\n");
-		return PTR_ERR(hsphy->phy_reset);
+		hsphy->phy_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+		if (IS_ERR(hsphy->phy_reset)) {
+			dev_err(dev, "failed to get phy core reset\n");
+			return PTR_ERR(hsphy->phy_reset);
+		}
 	}
 
 	num = ARRAY_SIZE(hsphy->vregs);

-- 
2.55.0

Re: [PATCH 1/2] dt-bindings: phy: Add sa8255p high-speed USB PHY

[Krzysztof Kozlowski]

On Thu, Jul 30, 2026 at 03:58:14PM +0200, Mattijs Korpershoek wrote:
> SA8255p platform abstracts resources such as clocks, interconnect and
> GPIO pins configuration in Firmware. SCMI power protocol is used to
> request resource configurations.
> 
> Two power domains can be requested: transfer and core.
> transfer controls clocks and interconnects and core controls
> the GDSC, resets and TLMM (GPIOs).
> 
> Add a new binding for the Qualcomm SA8255p Synopsys Femto High-Speed
> USB PHY V2 found in SA8255P.
> 
> Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
> ---
>  .../bindings/phy/qcom,sa8255p-usb-hs-phy.yaml      | 52 ++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
> new file mode 100644
> index 000000000000..09f7ca6e7f72
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/phy/qcom,sa8255p-usb-hs-phy.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm SA8255p Synopsys Femto High-Speed USB PHY V2
> +
> +maintainers:
> +  - Mattijs Korpershoek <mkorpershoek@kernel.org>
> +
> +properties:
> +  compatible:
> +    const: qcom,sa8255p-usb-hs-phy
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#phy-cells":
> +    const: 0
> +
> +  power-domains:
> +    maxItems: 2
> +
> +  power-domain-names:
> +    items:
> +      - const: transfer
> +      - const: core

Here and in your other binding you call these 'transfer' and 'core' but
all other bindings call them 'power' and 'perf'. Why this difference?
What are these domains responsible for?

Commit msg is pretty useless here - repeats the diff. I can read the
diff but I still do not understand why such naming.

And why core is not the first one? It clearly feels like the power
domain thus the main one.

Best regards,
Krzysztof

Re: [PATCH 1/2] dt-bindings: phy: Add sa8255p high-speed USB PHY

[Mattijs Korpershoek]

On Tue, Aug 04, 2026 at 10:07, Krzysztof Kozlowski <krzk@kernel.org> wrote:

> On Thu, Jul 30, 2026 at 03:58:14PM +0200, Mattijs Korpershoek wrote:
>> SA8255p platform abstracts resources such as clocks, interconnect and
>> GPIO pins configuration in Firmware. SCMI power protocol is used to
>> request resource configurations.
>> 
>> Two power domains can be requested: transfer and core.
>> transfer controls clocks and interconnects and core controls
>> the GDSC, resets and TLMM (GPIOs).
>> 
>> Add a new binding for the Qualcomm SA8255p Synopsys Femto High-Speed
>> USB PHY V2 found in SA8255P.
>> 
>> Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
>> ---
>>  .../bindings/phy/qcom,sa8255p-usb-hs-phy.yaml      | 52 ++++++++++++++++++++++
>>  1 file changed, 52 insertions(+)
>> 
>> diff --git a/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
>> new file mode 100644
>> index 000000000000..09f7ca6e7f72
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/phy/qcom,sa8255p-usb-hs-phy.yaml
>> @@ -0,0 +1,52 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/phy/qcom,sa8255p-usb-hs-phy.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm SA8255p Synopsys Femto High-Speed USB PHY V2
>> +
>> +maintainers:
>> +  - Mattijs Korpershoek <mkorpershoek@kernel.org>
>> +
>> +properties:
>> +  compatible:
>> +    const: qcom,sa8255p-usb-hs-phy
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  "#phy-cells":
>> +    const: 0
>> +
>> +  power-domains:
>> +    maxItems: 2
>> +
>> +  power-domain-names:
>> +    items:
>> +      - const: transfer
>> +      - const: core
>
> Here and in your other binding you call these 'transfer' and 'core' but
> all other bindings call them 'power' and 'perf'. Why this difference?

Thanks for the question. I had to do some digging because I did not know
the answer to this.

Per my understanding, the SCMI firmware (in my case, gearvm) exposes
multiple protocols identified by a protocol_id.

For example, power domains have protocol_id=0x11 and and performance
domain have protocol_id=0x13. This is defined in ARM's den0056 spec:
https://support.arm.com/documentation/den0056/f/

Each USB phy has 2 distinct power domains.
This can be observed at runtime from linux via:

/sys/kernel/debug/pm_genpd # grep 'scmi-power-usb0.*phy.*' pm_genpd_summary
scmi-power-usb0-ss-phy-pm       off-0                           0
scmi-power-usb0-ss-phy-rpm      off-0                           0
scmi-power-usb0-hs-phy-pm       off-0                           0
scmi-power-usb0-hs-phy-rpm      off-0                           0

In the case of the other bindings - for example i2c - there is only one
power domain (0x11) and one perf domain (protocol_id 0x13):

/sys/kernel/debug/pm_genpd # grep i2c0 pm_genpd_summary
scmi-perf-i2c0_7                on                              0
scmi-power-i2c0                 off-0                           0

I hope that explains the naming difference. Please let me know if this
is still unclear.

> What are these domains responsible for?

If we take the example of the high-speed (hs) phy, we can see that on
the firmware side, the only difference is the -pm or -rpm suffix.
When Linux requests scmi-power-usb0-hs-phy-pm (mapped to 'core' in the
bindings), the SCMI firmware (gearvm) will interact with the reset line,
the clks and the regulator.
When requesting scmi-power-usb0-hs-phy-rpms (mapped to 'transfer' in the
bindings), the SCMI firmware will only interact with the USB clocks
(reset and regulators remain unchanged).

>
> Commit msg is pretty useless here - repeats the diff. I can read the
> diff but I still do not understand why such naming.

'core' controls reset, clocks and regulators.
'transfer' only controls clocks. Putting 'transfer' to 'off' is
interesting in case of runtime suspend/resume as it cuts the data
transfer (by disabling usb clock)

Is it more clear that way?

>
> And why core is not the first one? It clearly feels like the power
> domain thus the main one.

The order is based on how it's defined in the SCMI firmware. It's not a
problem to put 'core' first as power-domain-names property is only used
by the linux driver. Only the SCMI channel (in my case 12) and domain
indices (0,1) matter here.

>
> Best regards,
> Krzysztof