Commit 2004b7b1 authored by Elaine Zhang's avatar Elaine Zhang Committed by Heiko Stuebner
Browse files

clk: rockchip: allow additional mux options for cpu-clock frequency changes 



In order to improve the main frequency of CPU, the clock path of CPU is
simplified as follows:
                         |--\
                         |   \            |--\
 --apll--|\              |    \           |   \
         | |--apll_core--|     \          |    \
 --24M---|/              |mux1 |--[gate]--|mux2|---clk_core
                         |     /          |    /
 --gpll--|\              |    /    |------|   /
         | |--gpll_core--|   /     |      |--/
 --24M---|/              |--/      |
                                   |
 -------apll_directly--------------|

When the CPU requests high frequency, we want to use MUX2 select the
"apll_directly".
At low frequencies use MUX1 to select “apll_core" and then MUX2 to
select "apll_core_gate".

However, in this way, the CPU frequency conversion needs to be
in the following order:
1. MUX2 select to "apll_core_gate", MUX1 select "gpll_core"
2. Apll sets slow_mode, sets APLL parameters, locks APLL, and then APLL
sets normal_mode
3. MUX1 select "apll_core", MUX2 select "apll_directly"

So add pre_mux and post_mux options to cover this special requirements.

Signed-off-by: default avatarElaine Zhang <zhangqing@rock-chips.com>
[rebase]
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20221018151407.63395-7-sebastian.reichel@collabora.com


Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
parent 8f659449

drivers/clk/rockchip/clk-cpu.c

+41 −0
Original line number Diff line number Diff line
@@ -113,6 +113,42 @@ static void rockchip_cpuclk_set_dividers(struct rockchip_cpuclk *cpuclk, 
	}

}



static void rockchip_cpuclk_set_pre_muxs(struct rockchip_cpuclk *cpuclk,

					 const struct rockchip_cpuclk_rate_table *rate)

{

	int i;



	/* alternate parent is active now. set the pre_muxs */

	for (i = 0; i < ARRAY_SIZE(rate->pre_muxs); i++) {

		const struct rockchip_cpuclk_clksel *clksel = &rate->pre_muxs[i];



		if (!clksel->reg)

			break;



		pr_debug("%s: setting reg 0x%x to 0x%x\n",

			 __func__, clksel->reg, clksel->val);

		writel(clksel->val, cpuclk->reg_base + clksel->reg);

	}

}



static void rockchip_cpuclk_set_post_muxs(struct rockchip_cpuclk *cpuclk,

					  const struct rockchip_cpuclk_rate_table *rate)

{

	int i;



	/* alternate parent is active now. set the muxs */

	for (i = 0; i < ARRAY_SIZE(rate->post_muxs); i++) {

		const struct rockchip_cpuclk_clksel *clksel = &rate->post_muxs[i];



		if (!clksel->reg)

			break;



		pr_debug("%s: setting reg 0x%x to 0x%x\n",

			 __func__, clksel->reg, clksel->val);

		writel(clksel->val, cpuclk->reg_base + clksel->reg);

	}

}



static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk,

					   struct clk_notifier_data *ndata)

{
@@ -165,6 +201,9 @@ static int rockchip_cpuclk_pre_rate_change(struct rockchip_cpuclk *cpuclk, 
			       cpuclk->reg_base + reg_data->core_reg[i]);

		}

	}



	rockchip_cpuclk_set_pre_muxs(cpuclk, rate);



	/* select alternate parent */

	if (reg_data->mux_core_reg)

		writel(HIWORD_UPDATE(reg_data->mux_core_alt,
@@ -219,6 +258,8 @@ static int rockchip_cpuclk_post_rate_change(struct rockchip_cpuclk *cpuclk, 
				     reg_data->mux_core_shift),

		       cpuclk->reg_base + reg_data->core_reg[0]);



	rockchip_cpuclk_set_post_muxs(cpuclk, rate);



	/* remove dividers */

	for (i = 0; i < reg_data->num_cores; i++) {

		writel(HIWORD_UPDATE(0, reg_data->div_core_mask[i],

drivers/clk/rockchip/clk.h

+2 −0
Original line number Diff line number Diff line
@@ -399,6 +399,8 @@ struct rockchip_cpuclk_clksel { 
struct rockchip_cpuclk_rate_table {

	unsigned long prate;

	struct rockchip_cpuclk_clksel divs[ROCKCHIP_CPUCLK_NUM_DIVIDERS];

	struct rockchip_cpuclk_clksel pre_muxs[ROCKCHIP_CPUCLK_NUM_DIVIDERS];

	struct rockchip_cpuclk_clksel post_muxs[ROCKCHIP_CPUCLK_NUM_DIVIDERS];

};



/**