clk: at91: keep slow clk enabled to prevent system hang (dca1a4b5) · Commits · 戴 / test

drivers/clk/at91/clk-slow.c

+27 −0

Original line number	Diff line number	Diff line
		@@ -70,6 +70,7 @@ struct clk_sam9x5_slow {

		#define to_clk_sam9x5_slow(hw) container_of(hw, struct clk_sam9x5_slow, hw)

		static struct clk *slow_clk;

		static int clk_slow_osc_prepare(struct clk_hw *hw)
		{
		@@ -357,6 +358,8 @@ at91_clk_register_sam9x5_slow(void __iomem *sckcr,
		clk = clk_register(NULL, &slowck->hw);
		if (IS_ERR(clk))
		kfree(slowck);
		else
		slow_clk = clk;

		return clk;
		}
		@@ -433,6 +436,8 @@ at91_clk_register_sam9260_slow(struct at91_pmc *pmc,
		clk = clk_register(NULL, &slowck->hw);
		if (IS_ERR(clk))
		kfree(slowck);
		else
		slow_clk = clk;

		return clk;
		}
		@@ -465,3 +470,25 @@ void __init of_at91sam9260_clk_slow_setup(struct device_node *np,

		of_clk_add_provider(np, of_clk_src_simple_get, clk);
		}

		/*
		* FIXME: All slow clk users are not properly claiming it (get + prepare +
		* enable) before using it.
		* If all users properly claiming this clock decide that they don't need it
		* anymore (or are removed), it is disabled while faulty users are still
		* requiring it, and the system hangs.
		* Prevent this clock from being disabled until all users are properly
		* requesting it.
		* Once this is done we should remove this function and the slow_clk variable.
		*/
		static int __init of_at91_clk_slow_retain(void)
		{
		if (!slow_clk)
		return 0;

		__clk_get(slow_clk);
		clk_prepare_enable(slow_clk);

		return 0;
		}
		arch_initcall(of_at91_clk_slow_retain);