[PATCH v2 5/6] dt-bindings: iio: adc: ti,ads1298: add ADS1299

[Stephan Costa Barros <stephanbrrs8@gmail.com>]

The ADS1299 is an 8-channel, 24-bit biopotential ADC for EEG with the
register map of the ADS129x. It differs in its gains, data rates and
ID layout, and has a fixed 4.5 V internal reference. The ADS1299-4 and
ADS1299-6 are the same part with four and six channels.

TI sells the 8-channel part as plain ADS1299, so ti,ads1299 names it,
and it is the fallback for ti,ads1299-4 and ti,ads1299-6: the channel
count can be read from the ID register. The ADS1299 is not compatible
with the ADS1298, so ti,ads1298 is not a fallback for it.

In the same way, give each ADS129x part a compatible, with ti,ads1298 as
the fallback: the ID register tells the parts apart, by family and
channel count. ti,ads1298 alone remains valid, so existing device trees
are not affected.

Both families have a digital supply, DVDD, and an active-low power-down
pin, PWDN, which the binding did not describe. Add them, both optional.

Add myself as a maintainer of the binding, next to Mike.

Signed-off-by: Stephan Costa Barros <stephanbrrs8@gmail.com>
---
 .../bindings/iio/adc/ti,ads1298.yaml          | 41 +++++++++++++++----
 1 file changed, 34 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
index afcc683db..c88f0dd95 100644
--- a/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/ti,ads1298.yaml
@@ -4,19 +4,36 @@
 $id: http://devicetree.org/schemas/iio/adc/ti,ads1298.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Texas Instruments' ads1298 medical ADC chips
+title: Texas Instruments' ads1298 and ads1299 medical ADC chips
 
 description: |
-  Datasheet at: https://www.ti.com/product/ADS1298
-  Bindings for this chip aren't complete.
+  Datasheets at: https://www.ti.com/product/ADS1298
+  and https://www.ti.com/product/ADS1299
+  Bindings for these chips aren't complete.
 
 maintainers:
   - Mike Looijmans <mike.looijmans@topic.nl>
+  - Stephan Costa Barros <stephanbrrs8@gmail.com>
 
 properties:
   compatible:
-    enum:
-      - ti,ads1298
+    oneOf:
+      - enum:
+          - ti,ads1298
+          - ti,ads1299
+      - items:
+          - enum:
+              - ti,ads1294
+              - ti,ads1294r
+              - ti,ads1296
+              - ti,ads1296r
+              - ti,ads1298r
+          - const: ti,ads1298
+      - items:
+          - enum:
+              - ti,ads1299-4
+              - ti,ads1299-6
+          - const: ti,ads1299
 
   reg:
     maxItems: 1
@@ -26,15 +43,25 @@ properties:
   reset-gpios:
     maxItems: 1
 
+  powerdown-gpios:
+    description:
+      Active low GPIO connected to the PWDN pin. While it is asserted, the
+      device is powered down.
+    maxItems: 1
+
   avdd-supply:
     description:
       Analog power supply, voltage between AVDD and AVSS. When providing a
       symmetric +/- 2.5V, the regulator should report 5V.
 
+  dvdd-supply:
+    description: Digital power supply, voltage between DVDD and DGND.
+
   vref-supply:
     description:
-      Optional reference voltage. If omitted, internal reference is used,
-      which is 2.4V when analog supply is below 4.4V, 4V otherwise.
+      Optional reference voltage. If omitted, internal reference is used.
+      On the ads129x, it is 2.4V when analog supply is below 4.4V, 4V
+      otherwise. On the ads1299, it is 4.5V.
 
   clocks:
     description: Optional 2.048 MHz external source clock on CLK pin
-- 
2.43.0