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SubjectRe: [PATCH] clk: aspeed: Prevent reset if clock is enabled
On Thu, Mar 8, 2018 at 11:42 AM, Joel Stanley <joel@jms.id.au> wrote:
>> + /* Only reset/enable/unreset if clock is stopped */
>> + regmap_read(gate->map, ASPEED_CLK_STOP_CTRL, &reg);
>> + if (!(reg & clk))
>> + return 0;
>
> This doesn't generalise to all of the clocks, as some clocks use set
> to disable. Perhaps we could do something like this:
>
> /* Only reset/enable/unreset if clock is stopped. The LPC clock
> on ast2500 has issues otherwise */
> enval = (gate->flags & CLK_GATE_SET_TO_DISABLE) ? 0 : clk;
> regmap_read(gate->map, ASPEED_CLK_STOP_CTRL, &reg);
> if ((reg & clk) == enval) {
> spin_unlock_irqrestore(gate->lock, flags);
> return 0;
> }
>
> I think we should also do this operation under the lock.
>
> Please cc Ryan Chen <ryan_chen@aspeedtech.com> so he can confirm that
> this workaround is valid, and credit Lei who spent a lot of time
> investigating this issue. Perhaps "Root-caused-by".
>

The code has aspeed_clk_is_enabled() already, why not just:

if (aspeed_clk_is_enabled(hw))
return 0;

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