ARM: msm: Rework timer binding to be more general

The msm timer binding I wrote is bad. First off, the clock
frequency in the binding for the dgt is wrong. Software divides
down the input rate by 4 to achieve the rate listed in the
binding. We also treat each individual timer as a separate
hardware component, when in reality there is one timer block
(that may be duplicated per cpu) with multiple timers within it.
Depending on the version of the hardware there can be one or two
general purpose timers, status and divider control registers, and
an entirely different register layout.

In the next patch we'll need to know about the different register
layouts so that we can properly check the status register after
clearing the count. The current binding makes this complicated
because the general purpose timer's reg property doesn't indicate
where that status register is, and in fact it is beyond the size
of the reg property.

Clean all this up by just having one node for the timer hardware,
and describe all the interrupts and clock frequencies supported
while having one reg property that covers the entire timer
register region. We'll use the compatible field in the future to
determine different register layouts and if we should read the
status registers, etc.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>

1 files changed, 20 insertions, 21 deletions

diff --git a/Documentation/devicetree/bindings/arm/msm/timer.txt b/Documentation/devicetree/bindings/arm/msm/timer.txt
index 8c5907b9cae8..c6ef8f13dc7e 100644
--- a/Documentation/devicetree/bindings/arm/msm/timer.txt
+++ b/Documentation/devicetree/bindings/arm/msm/timer.txt
@@ -3,36 +3,35 @@
 Properties:
 
 - compatible : Should at least contain "qcom,msm-timer". More specific
-  properties such as "qcom,msm-gpt" and "qcom,msm-dgt" specify a general
-  purpose timer and a debug timer respectively.
+               properties specify which subsystem the timers are paired with.
 
-- interrupts : Interrupt indicating a match event.
+               "qcom,kpss-timer" - krait subsystem
+               "qcom,scss-timer" - scorpion subsystem
 
-- reg : Specifies the base address of the timer registers. The second region
-  specifies an optional register used to configure the clock divider.
+- interrupts : Interrupts for the the debug timer, the first general purpose
+               timer, and optionally a second general purpose timer in that
+               order.
 
-- clock-frequency : The frequency of the timer in Hz.
+- reg : Specifies the base address of the timer registers.
+
+- clock-frequency : The frequency of the debug timer and the general purpose
+                    timer(s) in Hz in that order.
 
 Optional:
 
 - cpu-offset : per-cpu offset used when the timer is accessed without the
-  CPU remapping facilities. The offset is cpu-offset * cpu-nr.
+               CPU remapping facilities. The offset is
+               cpu-offset + (0x10000 * cpu-nr).
 
 Example:
 
-       timer@200a004 {
-               compatible = "qcom,msm-gpt", "qcom,msm-timer";
-               interrupts = <1 2 0x301>;
-               reg = <0x0200a004 0x10>;
-               clock-frequency = <32768>;
-               cpu-offset = <0x40000>;
-       };
-
-       timer@200a024 {
-               compatible = "qcom,msm-dgt", "qcom,msm-timer";
-               interrupts = <1 3 0x301>;
-               reg = <0x0200a024 0x10>,
-                     <0x0200a034 0x4>;
-               clock-frequency = <6750000>;
+       timer@200a000 {
+               compatible = "qcom,scss-timer", "qcom,msm-timer";
+               interrupts = <1 1 0x301>,
+                            <1 2 0x301>,
+                            <1 3 0x301>;
+               reg = <0x0200a000 0x100>;
+               clock-frequency = <19200000>,
+                                 <32768>;
                cpu-offset = <0x40000>;
        };