From: Rudraksha Gupta <guptarud@gmail.com>
Some flash ICs use the same one-wire pulse-count protocol as the RT8515
but have only a single GPIO line for both flash and torch modes, plus an
optional unlock gate (e.g. a PMIC MPP) that must be driven high before
the chip responds to the enable GPIO.
Make ent-gpios optional and add an unlock-gpios property to support
these variants. Add a oneOf constraint requiring exactly one of
ent-gpios or unlock-gpios. Add a binding example showing the
single-GPIO configuration.
Signed-off-by: Rudraksha Gupta <guptarud@gmail.com>
---
.../devicetree/bindings/leds/richtek,rt8515.yaml | 36 +++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
index 0356371a6b01..820cf8c55090 100644
--- a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
+++ b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml
@@ -15,6 +15,10 @@ description: |
current for each mode is defined in hardware using two resistors
RFS and RTS.
+ This driver also supports single-GPIO flash ICs that use the same
+ one-wire pulse-count protocol on one line for both flash and torch.
+ For these, only enf-gpios is required.
+
properties:
compatible:
const: richtek,rt8515
@@ -26,6 +30,14 @@ properties:
ent-gpios:
maxItems: 1
description: A connection to the 'ENT' (enable torch) pin.
+ Optional for single-GPIO flash ICs where enf-gpios is used for
+ both flash and torch modes.
+
+ unlock-gpios:
+ maxItems: 1
+ description: Optional GPIO to unlock the flash LED circuit. Some
+ boards use a PMIC MPP pin that must be driven high before the
+ flash IC will respond to the enable GPIOs.
richtek,rfs-ohms:
minimum: 7680
@@ -81,10 +93,15 @@ properties:
required:
- compatible
- - ent-gpios
- enf-gpios
- led
+oneOf:
+ - required:
+ - ent-gpios
+ - required:
+ - unlock-gpios
+
additionalProperties: false
examples:
@@ -108,4 +125,21 @@ examples:
};
};
+ - |
+ /* Single-GPIO flash IC with unlock gate */
+ #include <dt-bindings/gpio/gpio.h>
+ #include <dt-bindings/leds/common.h>
+
+ led-controller {
+ compatible = "richtek,rt8515";
+ enf-gpios = <&tlmm 3 GPIO_ACTIVE_HIGH>;
+ unlock-gpios = <&pm8921_mpps 4 GPIO_ACTIVE_HIGH>;
+
+ led {
+ function = LED_FUNCTION_FLASH;
+ color = <LED_COLOR_ID_WHITE>;
+ flash-max-timeout-us = <250000>;
+ };
+ };
+
...
--
2.53.0Hi Rudraksha, thanks for your patch! On Sat, Mar 7, 2026 at 1:58 AM Rudraksha Gupta via B4 Relay <devnull+guptarud.gmail.com@kernel.org> wrote: > ent-gpios: > maxItems: 1 > description: A connection to the 'ENT' (enable torch) pin. > + Optional for single-GPIO flash ICs where enf-gpios is used for > + both flash and torch modes. Fair enough, that can be done. > + unlock-gpios: > + maxItems: 1 > + description: Optional GPIO to unlock the flash LED circuit. Some > + boards use a PMIC MPP pin that must be driven high before the > + flash IC will respond to the enable GPIOs. But this IC has no pin named "unlock". This is something else. Given the way it works it looks like a regulator enable signal. If you don't have any better idea about what this is, I would suggest adding vin-supply to the RT8615 bindings instead and then use a GPIO regulator in your device tree to provide the voltage to it from that GPIO. Yours, Linus Walleij
On 3/8/26 16:20, Linus Walleij wrote: > Hi Rudraksha, > > thanks for your patch! > > On Sat, Mar 7, 2026 at 1:58 AM Rudraksha Gupta via B4 Relay > <devnull+guptarud.gmail.com@kernel.org> wrote: > >> ent-gpios: >> maxItems: 1 >> description: A connection to the 'ENT' (enable torch) pin. >> + Optional for single-GPIO flash ICs where enf-gpios is used for >> + both flash and torch modes. > Fair enough, that can be done. > >> + unlock-gpios: >> + maxItems: 1 >> + description: Optional GPIO to unlock the flash LED circuit. Some >> + boards use a PMIC MPP pin that must be driven high before the >> + flash IC will respond to the enable GPIOs. > But this IC has no pin named "unlock". This is something else. > > Given the way it works it looks like a regulator enable signal. > > If you don't have any better idea about what this is, I would > suggest adding > > vin-supply > > to the RT8615 bindings instead and then use a GPIO regulator > in your device tree to provide the voltage to it from that GPIO. Hello Linus, Thanks for your comments (both in this email and others)! I have addressed these in v2. Rudraksha > > Yours, > Linus Walleij
On Fri, Mar 06, 2026 at 04:58:02PM -0800, Rudraksha Gupta wrote: > Some flash ICs use the same one-wire pulse-count protocol as the RT8515 > but have only a single GPIO line for both flash and torch modes, plus an > optional unlock gate (e.g. a PMIC MPP) that must be driven high before > the chip responds to the enable GPIO. > > Make ent-gpios optional and add an unlock-gpios property to support > these variants. Add a oneOf constraint requiring exactly one of > ent-gpios or unlock-gpios. Add a binding example showing the > single-GPIO configuration. > > Signed-off-by: Rudraksha Gupta <guptarud@gmail.com> > --- > .../devicetree/bindings/leds/richtek,rt8515.yaml | 36 +++++++++++++++++++++- > 1 file changed, 35 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml > index 0356371a6b01..820cf8c55090 100644 > --- a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml > +++ b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml > @@ -15,6 +15,10 @@ description: | > current for each mode is defined in hardware using two resistors > RFS and RTS. > > + This driver also supports single-GPIO flash ICs that use the same Drop reference to driver and explain the hardware here. > + one-wire pulse-count protocol on one line for both flash and torch. > + For these, only enf-gpios is required. > + > properties: > compatible: > const: richtek,rt8515 > @@ -26,6 +30,14 @@ properties: > ent-gpios: > maxItems: 1 > description: A connection to the 'ENT' (enable torch) pin. > + Optional for single-GPIO flash ICs where enf-gpios is used for > + both flash and torch modes. So what happens with ENT GPIO on such boards? How is it connected? Best regards, Krzysztof
On 3/7/26 07:46, Krzysztof Kozlowski wrote: > On Fri, Mar 06, 2026 at 04:58:02PM -0800, Rudraksha Gupta wrote: >> Some flash ICs use the same one-wire pulse-count protocol as the RT8515 >> but have only a single GPIO line for both flash and torch modes, plus an >> optional unlock gate (e.g. a PMIC MPP) that must be driven high before >> the chip responds to the enable GPIO. >> >> Make ent-gpios optional and add an unlock-gpios property to support >> these variants. Add a oneOf constraint requiring exactly one of >> ent-gpios or unlock-gpios. Add a binding example showing the >> single-GPIO configuration. >> >> Signed-off-by: Rudraksha Gupta <guptarud@gmail.com> >> --- >> .../devicetree/bindings/leds/richtek,rt8515.yaml | 36 +++++++++++++++++++++- >> 1 file changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml >> index 0356371a6b01..820cf8c55090 100644 >> --- a/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml >> +++ b/Documentation/devicetree/bindings/leds/richtek,rt8515.yaml >> @@ -15,6 +15,10 @@ description: | >> current for each mode is defined in hardware using two resistors >> RFS and RTS. >> >> + This driver also supports single-GPIO flash ICs that use the same > Drop reference to driver and explain the hardware here. > >> + one-wire pulse-count protocol on one line for both flash and torch. >> + For these, only enf-gpios is required. >> + >> properties: >> compatible: >> const: richtek,rt8515 >> @@ -26,6 +30,14 @@ properties: >> ent-gpios: >> maxItems: 1 >> description: A connection to the 'ENT' (enable torch) pin. >> + Optional for single-GPIO flash ICs where enf-gpios is used for >> + both flash and torch modes. > So what happens with ENT GPIO on such boards? How is it connected? Hello Krzysztof, Thanks for these comments. I have addressed these in v2 Rudraksha > > Best regards, > Krzysztof >
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