Re: [PATCH v8 40/42] ARM: davinci: add device tree support to timer

[Sekhar Nori]

On Friday 16 March 2018 08:22 AM, David Lechner wrote:
> +static int __init of_davinci_timer_init(struct device_node *np)
> +{
> + struct clk *clk;
> +
> + clk = of_clk_get(np, 0);
> + if (IS_ERR(clk)) {
> + struct of_phandle_args clkspec;
> +
> + /*
> +  * Fall back to using ref_clk if the actual clock is not
> +  * available. This currently always happens because platform
> +  * clocks (i.e PLLs and PSCs) are registered as platform
> +  * devices and therefore are not available at this point in
> +  * the boot process.

It seems to me that this is not going to be a temporary problem (or at
least will be around for quite a while). So, I think we can as well just
look for ref_clk directly.

> +  */
> + clkspec.np = of_find_node_by_name(NULL, "ref_clk");
> + if (IS_ERR(clkspec.np)) {
> + pr_err("%s: No clock available for timer!\n", __func__);
> + return PTR_ERR(clkspec.np);
> + }
> + clk = of_clk_get_from_provider(&clkspec);
> + of_node_put(clkspec.np);
> + }
> +
> + davinci_timer_init(clk);
> +
> + return 0;
> +}
> +TIMER_OF_DECLARE(davinci_timer, "ti,davinci-timer", of_davinci_timer_init);

Here, I think we should use "ti,da850-timer" so we can change the fixed
clock we are looking for based on the SoC. At a minimum, we should have
"ti,da850-timer" in the DT along with "ti,davinci-timer".

BTW, I noticed that "ti,davinci-timer" is not documented. I think we
need to add a binding documentation too.

Thanks,
Sekhar

[PATCH v8 40/42] ARM: davinci: add device tree support to timer

[David Lechner]

This adds device tree support to the davinci timer so that when clocks
are moved to device tree, the timer will still work.

Signed-off-by: David Lechner 
---

v8 changes:
- none

v7 changes:
- add workaround for platform devices not available in early boot

v6 changes:
- none

 arch/arm/mach-davinci/Kconfig |  1 +
 arch/arm/mach-davinci/time.c  | 31 +++
 2 files changed, 32 insertions(+)

diff --git a/arch/arm/mach-davinci/Kconfig b/arch/arm/mach-davinci/Kconfig
index ba9912b..da8a039 100644
--- a/arch/arm/mach-davinci/Kconfig
+++ b/arch/arm/mach-davinci/Kconfig
@@ -59,6 +59,7 @@ config MACH_DA8XX_DT
default y
depends on ARCH_DAVINCI_DA850
select PINCTRL
+   select TIMER_OF
help
  Say y here to include support for TI DaVinci DA850 based using
  Flattened Device Tree. More information at Documentation/devicetree
diff --git a/arch/arm/mach-davinci/time.c b/arch/arm/mach-davinci/time.c
index d6a78f7..590b118 100644
--- a/arch/arm/mach-davinci/time.c
+++ b/arch/arm/mach-davinci/time.c
@@ -17,6 +17,7 @@
 #include 
 #include 
 #include 
+#include 
 #include 
 #include 
 
@@ -405,3 +406,33 @@ void __init davinci_timer_init(struct clk *timer_clk)
for (i=0; i< ARRAY_SIZE(timers); i++)
timer32_config(&timers[i]);
 }
+
+static int __init of_davinci_timer_init(struct device_node *np)
+{
+   struct clk *clk;
+
+   clk = of_clk_get(np, 0);
+   if (IS_ERR(clk)) {
+   struct of_phandle_args clkspec;
+
+   /*
+* Fall back to using ref_clk if the actual clock is not
+* available. This currently always happens because platform
+* clocks (i.e PLLs and PSCs) are registered as platform
+* devices and therefore are not available at this point in
+* the boot process.
+*/
+   clkspec.np = of_find_node_by_name(NULL, "ref_clk");
+   if (IS_ERR(clkspec.np)) {
+   pr_err("%s: No clock available for timer!\n", __func__);
+   return PTR_ERR(clkspec.np);
+   }
+   clk = of_clk_get_from_provider(&clkspec);
+   of_node_put(clkspec.np);
+   }
+
+   davinci_timer_init(clk);
+
+   return 0;
+}
+TIMER_OF_DECLARE(davinci_timer, "ti,davinci-timer", of_davinci_timer_init);
-- 
2.7.4