Re: [PATCH 3/4] clocksource: armada-370-xp: Use the reference clock on A375 SoC

Ezequiel Garcia
2014-10-22T15:25:07Z

On 10/22/2014 10:54 AM, Thomas Petazzoni wrote:
> Dear Ezequiel Garcia,
>
> On Wed, 22 Oct 2014 10:34:43 -0300, Ezequiel Garcia wrote:
>
>> +static void __init armada_375_timer_init(struct device_node *np)
>> +{
>> + struct clk *clk;
>> +
>> + clk = of_clk_get_by_name(np, "fixed");
>> + if (!IS_ERR(clk)) {
>> + clk_prepare_enable(clk);
>> + timer_clk = clk_get_rate(clk);
>> + } else {
>> +
>> + /*
>> + * This fallback is required in order to retain proper
>> + * devicetree backwards compatibility.
>> + */
>> + clk = of_clk_get(np, 0);
>> +
>> + /* Must have at least a clock */
>> + BUG_ON(IS_ERR(clk));
>> + clk_prepare_enable(clk);
>> + timer_clk = clk_get_rate(clk) / TIMER_DIVIDER;
>> + timer25Mhz = false;
>> + }
>
> Maybe we could re-use a bit more existing code, don't know if it makes
> things clearer though:
>
> clk = of_clk_get_by_name(np, "fixed");
> if (!IS_ERR(clk))
> armada_xp_timer_init(np);
> else
> armada_370_timer_init(np);
>

Yeah, I thought about this option, but chosen to implement it explicitly.

The reason is that I wanted to make sure we had a sane backward
compatibility fallback, which is specifically crafted for A375.

By re-using the 370 and XP, we are exposed to someone changing the
armada_xp_timer_init() thinking it will only affect AXP, which might
break things for A375.
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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