Thread (2 messages) flat view 2 messages, 2 authors, 2017-08-25

Re: [PATCH 1/2] rtc: v3020: Add documentation for DT bindings

From: Rob Herring <hidden>
Date: 2017-08-25 21:54:57

On Tue, Aug 22, 2017 at 05:05:47PM -0400, Brandon Martin wrote:
quoted hunk
Document the DT bindings for the rtc-v3020 driver.  MMIO and GPIO
attachment modes are both supported via DT.

Signed-off-by: Brandon Martin <martinbv-cvVvTOR6QHAqDJ6do+/SaQ@public.gmane.org>
---
 .../devicetree/bindings/rtc/rtc-v3020.txt          | 38 ++++++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rtc/rtc-v3020.txt
diff --git a/Documentation/devicetree/bindings/rtc/rtc-v3020.txt b/Documentation/devicetree/bindings/rtc/rtc-v3020.txt
new file mode 100644
index 000000000000..8b32e6a79960
--- /dev/null
+++ b/Documentation/devicetree/bindings/rtc/rtc-v3020.txt
@@ -0,0 +1,38 @@
+ EM Micro v3020 RTC
+~~~~~~~~~~~~~~~~~~~~
+
+Required properties:
+  - compatible : "emmicro,v3020"
+
+Required for MMIO connection:
+  - reg : should contain registers location and length.
Looking at the datasheet, there's really no such thing. You'd have to 
have some specialized h/w to generate the serial waveform.
+
+Required for GPIO connection:
+- emmicro,use-gpio
+- cs-gpios, wr-gpios, rd-gpios, io-gpios : specify gpios connected to
+  corresponding pins of the RTC
+
+Optional properties:
+- emmicro,mmio-left-shift : data bit to which IO line is connected for MMIO
+  connection (defaults to 0)
This has come up several times on RTCs (LP8841, DS1302). This really 
looks like SPI and could probably use the spi-gpio bitbang driver. 

Rob
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