On Thu, Jan 09, 2014 at 02:57:42PM +0800, Shawn Guo wrote:
> On Thu, Jan 09, 2014 at 11:49:41AM +0800, Nicolin Chen wrote:
> > On Thu, Jan 09, 2014 at 11:58:12AM +0800, Shawn Guo wrote:
> > > > static struct clk *clk[clk_max];
> > > > @@ -355,6 +355,7 @@ static void __init imx6q_clocks_init(struct
> > > > device_node *ccm_node)
> > > > clk[ecspi5] = imx_clk_gate2("ecspi5",
> > > > "ecspi_root", base + 0x6c, 8);
> > > > clk[enet] = imx_clk_gate2("enet", "ipg",
> > > > base + 0x6c, 10);
> > > > clk[esai] = imx_clk_gate2("esai", "esai_podf",
> > > > base + 0x6c, 16);
> > > > + clk[esai_ahb] = imx_clk_gate2("esai_ahb", "ahb",
> > > > base + 0x6c, 16);
> > >
> > > Hmm, having two clocks operating on the same gate bit will get us
> > > problem in clock disabling. Clock enabling is fine, since either
> > > one who calls clk_enable() first will just set the gate bit. But in
> > > case that clk_enable() is called on both clocks, and then when either
> > > clock calls clk_disable(), the gate bit will be cleared and thus breaks
> > > the other one that might still be in use.
> >
> > Understood. But how could we handle this situation? The only way I can
> > figure
> > out is to make sure the driver open/close them at the same time, it's not a
> > perfect way though.
>
> Hmm, we generally leave the gate bit to the clock used to access
> register, because usually it's the first one to be on and the last one
> to be off.
Then we should attach CLK_IGNORE_UNUSED to clk[esai] since clk[esai_ahb] is
the clock used to access memory, shouldn't we?
Thank you.
Nicolin
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
