[PATCH v3 1/3] dt-bindings: watchdog: sunxi: Add compatibles for R329

Samuel Holland
2021-09-02T22:58:09Z

On existing SoCs, the watchdog has a single clock input: HOSC (OSC24M)
divided by 750. However, starting with R329, LOSC (OSC32k) is added as
an alternative clock source, with a bit to switch between them.

Since 24 MHz / 750 == 32 kHz, not 32.768 kHz, the hardware adjusts the
cycle counts to keep the timeouts independent of the clock source. This
keeps the programming interface backward-compatible.

Furthermore, the R329 has two watchdogs: one for use by the ARM CPUs
at 0x20000a0, and a second one for use by the DSPs at 0x7020400. The
first of these adds two more new registers, to allow software to
immediately assert the SoC reset signal. Add an additional "-reset"
suffix to signify the presence of this feature.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---
Changes v2 to v3:
- Add else case
- Add additional allwinner,sun50i-r329-wdt-reset compatible
Changes v1 to v2:
- Switch clock-names from enum to const
- Add descriptions to "clocks" items

.../watchdog/allwinner,sun4i-a10-wdt.yaml | 42 ++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml b/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
index 9aa3c313c49f..877f47759814 100644
--- a/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/allwinner,sun4i-a10-wdt.yaml
@@ -24,6 +24,8 @@ properties:
- allwinner,sun50i-a100-wdt
- allwinner,sun50i-h6-wdt
- allwinner,sun50i-h616-wdt
+ - allwinner,sun50i-r329-wdt
+ - allwinner,sun50i-r329-wdt-reset
- const: allwinner,sun6i-a31-wdt
- items:
- const: allwinner,suniv-f1c100s-wdt
@@ -33,7 +35,18 @@ properties:
maxItems: 1

clocks:
- maxItems: 1
+ minItems: 1
+ maxItems: 2
+ items:
+ - description: High-frequency oscillator input, divided internally
+ - description: Low-frequency oscillator input, only found on some variants
+
+ clock-names:
+ minItems: 1
+ maxItems: 2
+ items:
+ - const: hosc
+ - const: losc

interrupts:
maxItems: 1
@@ -44,6 +57,33 @@ required:
- clocks
- interrupts

+if:
+ properties:
+ compatible:
+ contains:
+ enum:
+ - allwinner,sun50i-r329-wdt
+ - allwinner,sun50i-r329-wdt-reset
+
+then:
+ properties:
+ clocks:
+ minItems: 2
+
+ clock-names:
+ minItems: 2
+
+ required:
+ - clock-names
+
+else:
+ properties:
+ clocks:
+ maxItems: 1
+
+ clock-names:
+ maxItems: 1
+
unevaluatedProperties: false

examples:
--
2.31.1