On 7/25/23 07:17, Naresh Solanki wrote:
Hi Rob,
On Tue, 25 Jul 2023 at 18:40, Rob Herring <robh@xxxxxxxxxx> wrote:
On Tue, Jul 25, 2023 at 01:40:26PM +0200, Naresh Solanki wrote:
From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
The TDA38640 has a bug in SVID mode and to enable a workaround
remove the TDA38640 from trivial-devices and add a complete schema.
The schema adds the custom property 'infineon,en-pin-fixed-level' to
signal a fixed level on the ENABLE pin and to enable the workaround.
When the ENABLE pin is left floating it's internally pulled low.
If not specified the driver will continue to use the PMBUS_OPERATION
register to enable the regulator. When specified the driver will use
the PMBUS_ON_OFF_CONFIG register to enable the regulator.
Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
---
.../hwmon/pmbus/infineon,tda38640.yaml | 50 +++++++++++++++++++
.../devicetree/bindings/trivial-devices.yaml | 2 -
2 files changed, 50 insertions(+), 2 deletions(-)
create mode 100644 Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
diff --git a/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
new file mode 100644
index 000000000000..520112e4e271
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/pmbus/infineon,tda38640.yaml
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/hwmon/pmbus/infineon,tda38640.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Infineon TDA38640 Synchronous Buck Regulator with SVID and I2C
+
+description: |
+ The Infineon TDA38640 is a 40A Single-voltage Synchronous Buck
+ Regulator with SVID and I2C designed for Industrial use.
+
+ Datasheet: https://www.infineon.com/dgdl/Infineon-TDA38640-0000-DataSheet-v02_04-EN.pdf?fileId=8ac78c8c80027ecd018042f2337f00c9
+
+properties:
+ compatible:
+ enum:
+ - infineon,tda38640
+
+ reg:
+ maxItems: 1
+
+ infineon,en-pin-fixed-level:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ Fixed level of the ENABLE pin. When specified the PMBUS_ON_OFF_CONFIG
+ register is used to enable the regulator instead of the PMBUS_OPERATION
+ register to workaround a bug of the tda38640 when operating in SVID-mode.
+ If the ENABLE pin is left floating the internal pull-down causes a low
+ level on the pin.
Neither this nor the commit message answers how do I decide if I set
this property or not? How you work-around it is not that relevant to the
binding.
Sure will update this as:
The property becomes relevant when dealing with the tda38640 in
SVID-mode, providing an alternative method to enable the regulator by
using the PMBUS_ON_OFF_CONFIG register instead of the PMBUS_OPERATION
register
As mentioned in the other e-mail, I'll want to see an explanation why
this property is even needed. The series claims that the chip has a bug
in SVID mode. It is kind of unusual that we would enable a workaround
for a bug with a devicetree property if the circumstance (SVID mode)
can be determined automatically.
Guenter
Regards,
Naresh
+
+required:
+ - compatible
+ - reg
+
+additionalProperties: false
+
+examples:
+ - |
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ tda38640@40 {
+ compatible = "infineon,tda38640";
+ reg = <0x40>;
+ };
+ };
+
diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index 6e24c4d25ec3..2b1fbb2a672b 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -151,8 +151,6 @@ properties:
- infineon,slb9645tt
# Infineon SLB9673 I2C TPM 2.0
- infineon,slb9673
- # Infineon TDA38640 Voltage Regulator
- - infineon,tda38640
# Infineon TLV493D-A1B6 I2C 3D Magnetic Sensor
- infineon,tlv493d-a1b6
# Infineon Multi-phase Digital VR Controller xdpe11280
base-commit: 55612007f16b5d7b1fb83a7b0f5bb686829db7c7
--
2.41.0
