From: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
The VBATTB controllers controls the clock for the RTC on the Renesas
RZ/G3S. The HW block diagram for the clock logic is as follows:
+----------+ XC `\
RTXIN --->| |----->| \ +----+ VBATTCLK
| 32K clock| | |----->|gate|----------->
| osc | XBYP | | +----+
RTXOUT --->| |----->| /
+----------+ ,/
One could connect as input to this HW block either a crystal oscillator or
an external clock device.
After discussions w/ Stephen Boyd the clock tree associated with this
hardware block was exported in Linux as:
input-xtal
xbyp
xc
mux
vbattclk
where:
- input-xtal is the input clock (connected to RTXIN, RTXOUT pins)
- xc, xbyp are mux inputs
- mux is the internal mux
- vbattclk is the gate clock that feeds in the end the RTC
to allow selecting the input of the MUX though assigned-clock DT
properties, using the already existing clock drivers and avoid adding
other DT properties.
This allows select the input of the mux based on the type of the
connected input clock:
- if the 32768 crystal oscillator is connected as input for the VBATTB,
the input of the mux should be xc
- if an external clock device is connected as input for the VBATTB the
input of the mux should be xbyp
Add clock IDs for the VBATTB controller.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
---
Changes in v3:
- none; this patch is new
include/dt-bindings/clock/r9a08g045-vbattb.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
create mode 100644 include/dt-bindings/clock/r9a08g045-vbattb.h
diff --git a/include/dt-bindings/clock/r9a08g045-vbattb.h b/include/dt-bindings/clock/r9a08g045-vbattb.h
new file mode 100644
index 000000000000..67774eafad06
--- /dev/null
+++ b/include/dt-bindings/clock/r9a08g045-vbattb.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+ *
+ * Copyright (C) 2024 Renesas Electronics Corp.
+ */
+#ifndef __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__
+#define __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__
+
+#define VBATTB_XC 0
+#define VBATTB_XBYP 1
+#define VBATTB_MUX 2
+#define VBATTB_VBATTCLK 3
+
+#endif /* __DT_BINDINGS_CLOCK_R9A08G045_VBATTB_H__ */
--
2.39.2
