Re: [PATCH] ARM: imx6q: Add missing esai_ahb clock to current clock tree

On Thu, Jan 09, 2014 at 11:58:12AM +0800, Shawn Guo wrote:

quoted

 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.

Nicolin



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