Commit 514fddba authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Thierry Reding
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clk: tegra20: Turn EMC clock gate into divider 



Kernel should never gate the EMC clock as it causes immediate lockup, so
removing clk-gate functionality doesn't affect anything. Turning EMC clk
gate into divider allows to implement glitch-less EMC scaling, avoiding
reparenting to a backup clock.

Signed-off-by: default avatarDmitry Osipenko <digetx@gmail.com>
Acked-by: default avatarPeter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: default avatarStephen Boyd <sboyd@kernel.org>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent 65102238

drivers/clk/tegra/clk-tegra20.c

+26 −10
Original line number Diff line number Diff line
@@ -578,7 +578,6 @@ static struct tegra_clk tegra20_clks[tegra_clk_max] __initdata = { 
	[tegra_clk_afi] = { .dt_id = TEGRA20_CLK_AFI, .present = true },

	[tegra_clk_fuse] = { .dt_id = TEGRA20_CLK_FUSE, .present = true },

	[tegra_clk_kfuse] = { .dt_id = TEGRA20_CLK_KFUSE, .present = true },

	[tegra_clk_emc] = { .dt_id = TEGRA20_CLK_EMC, .present = true },

};



static unsigned long tegra20_clk_measure_input_freq(void)
@@ -799,6 +798,31 @@ static struct tegra_periph_init_data tegra_periph_nodiv_clk_list[] = { 
	TEGRA_INIT_DATA_NODIV("disp2",	mux_pllpdc_clkm, CLK_SOURCE_DISP2, 30, 2, 26,  0, TEGRA20_CLK_DISP2),

};



static void __init tegra20_emc_clk_init(void)

{

	struct clk *clk;



	clk = clk_register_mux(NULL, "emc_mux", mux_pllmcp_clkm,

			       ARRAY_SIZE(mux_pllmcp_clkm),

			       CLK_SET_RATE_NO_REPARENT,

			       clk_base + CLK_SOURCE_EMC,

			       30, 2, 0, &emc_lock);



	clk = tegra_clk_register_mc("mc", "emc_mux", clk_base + CLK_SOURCE_EMC,

				    &emc_lock);

	clks[TEGRA20_CLK_MC] = clk;



	/*

	 * Note that 'emc_mux' source and 'emc' rate shouldn't be changed at

	 * the same time due to a HW bug, this won't happen because we're

	 * defining 'emc_mux' and 'emc' as distinct clocks.

	 */

	clk = tegra_clk_register_divider("emc", "emc_mux",

				clk_base + CLK_SOURCE_EMC, CLK_IS_CRITICAL,

				TEGRA_DIVIDER_INT, 0, 8, 1, &emc_lock);

	clks[TEGRA20_CLK_EMC] = clk;

}



static void __init tegra20_periph_clk_init(void)

{

	struct tegra_periph_init_data *data;
@@ -812,15 +836,7 @@ static void __init tegra20_periph_clk_init(void) 
	clks[TEGRA20_CLK_AC97] = clk;



	/* emc */

	clk = clk_register_mux(NULL, "emc_mux", mux_pllmcp_clkm,

			       ARRAY_SIZE(mux_pllmcp_clkm),

			       CLK_SET_RATE_NO_REPARENT,

			       clk_base + CLK_SOURCE_EMC,

			       30, 2, 0, &emc_lock);



	clk = tegra_clk_register_mc("mc", "emc_mux", clk_base + CLK_SOURCE_EMC,

				    &emc_lock);

	clks[TEGRA20_CLK_MC] = clk;

	tegra20_emc_clk_init();



	/* dsi */

	clk = tegra_clk_register_periph_gate("dsi", "pll_d", 0, clk_base, 0,

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