On 25/01/2019 03:23, Joseph Lo wrote:

Hi Jon,

Thanks for reviewing.

On 1/24/19 6:30 PM, Jon Hunter wrote:

quoted

On 07/01/2019 03:28, Joseph Lo wrote:

quoted

The Tegra210 timer provides fourteen 29-bit timer counters and one
32-bit
timestamp counter. The TMRs run at either a fixed 1 MHz clock rate
derived
from the oscillator clock (TMR0-TMR9) or directly at the oscillator
clock
(TMR10-TMR13). Each TMR can be programmed to generate one-shot periodic,
or watchdog interrupts.

Cc: Daniel Lezcano <redacted>
Cc: Thomas Gleixner <redacted>
Cc: linux-kernel@vger.kernel.org
Cc: devicetree@vger.kernel.org
Signed-off-by: Joseph Lo <redacted>
---
  .../bindings/timer/nvidia,tegra210-timer.txt  | 25 +++++++++++++++++++
  1 file changed, 25 insertions(+)
  create mode 100644
Documentation/devicetree/bindings/timer/nvidia,tegra210-timer.txt

diff --git
a/Documentation/devicetree/bindings/timer/nvidia,tegra210-timer.txt
b/Documentation/devicetree/bindings/timer/nvidia,tegra210-timer.txt
new file mode 100644
index 000000000000..ba511220a669

--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/nvidia,tegra210-timer.txt

@@ -0,0 +1,25 @@
+NVIDIA Tegra210 timer
+
+The Tegra210 timer provides fourteen 29-bit timer counters and one

32-bit
+timestamp counter. The TMRs run at either a fixed 1 MHz clock rate
derived
+from the oscillator clock (TMR0-TMR9) or directly at the oscillator
clock
+(TMR10-TMR13). Each TMR can be programmed to generate one-shot,
periodic,
+or watchdog interrupts.
+
+Required properties:
+- compatible : "nvidia,tegra210-timer".
+- reg : Specifies base physical address and size of the registers.
+- interrupts : A list of 4 interrupts; one per each of TMR10 through
TMR13.

Why do we only add the interrupts for TMR10 - TMR13? What about the
others?

The others (TMR0-TMR9) are occupied for other usages. TMR5 is occupied
for the watchdog timer in the upstream kernel. And others (still in
TMR0-TMR9) are occupied for different usages in our downstream kernel.

Where is TMR5 reserved for the watchdog? I don't see this?

And notice that only TMR10-TMR13 are running at the oscillator clock
(clk_m). With the Tegra210 timer driver, we introduce in this series,
which only replace the clock event device function that was originally
owned by the arch timer (armv8 timer) and it also running at the
oscillator clock. The sched_timer still owns by the arch timer. So the
timer resolution will be the same. That's why we choose TMR10-TMR13 as
the timer for Tegra210.

That maybe fine, but DT should describe the hardware and so I don't see
why we would not list all the interrupts. We can still only use TMR10-13
in the driver.

Cheers
Jon

-- 
nvpublic

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