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Commit 1e832e51 authored by Tomasz Figa's avatar Tomasz Figa
Browse files

clk: samsung: Add driver to control CLKOUT line on Exynos SoCs 



This patch introduces a driver that handles configuration of CLKOUT pin
of Exynos SoCs that can be used to output certain clocks from inside of
the SoC to a dedicated output pin.

Signed-off-by: default avatarTomasz Figa <t.figa@samsung.com>
parent 01f7ec26

Documentation/devicetree/bindings/arm/samsung/pmu.txt

+30 −0
Original line number Diff line number Diff line
@@ -12,8 +12,38 @@ Properties: 


 - reg : offset and length of the register set.



 - #clock-cells : must be <1>, since PMU requires once cell as clock specifier.

		The single specifier cell is used as index to list of clocks

		provided by PMU, which is currently:

			0 : SoC clock output (CLKOUT pin)



 - clock-names : list of clock names for particular CLKOUT mux inputs in

		following format:

			"clkoutN", where N is a decimal number corresponding to

			CLKOUT mux control bits value for given input, e.g.

				"clkout0", "clkout7", "clkout15".



 - clocks : list of phandles and specifiers to all input clocks listed in

		clock-names property.



Example :

pmu_system_controller: system-controller@10040000 {

	compatible = "samsung,exynos5250-pmu", "syscon";

	reg = <0x10040000 0x5000>;

	#clock-cells = <1>;

	clock-names = "clkout0", "clkout1", "clkout2", "clkout3",

			"clkout4", "clkout8", "clkout9";

	clocks = <&clock CLK_OUT_DMC>, <&clock CLK_OUT_TOP>,

		<&clock CLK_OUT_LEFTBUS>, <&clock CLK_OUT_RIGHTBUS>,

		<&clock CLK_OUT_CPU>, <&clock CLK_XXTI>,

		<&clock CLK_XUSBXTI>;

};



Example of clock consumer :



usb3503: usb3503@08 {

	/* ... */

	clock-names = "refclk";

	clocks = <&pmu_system_controller 0>;

	/* ... */

};

drivers/clk/samsung/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ obj-$(CONFIG_SOC_EXYNOS5410) += clk-exynos5410.o 
obj-$(CONFIG_SOC_EXYNOS5420)	+= clk-exynos5420.o

obj-$(CONFIG_SOC_EXYNOS5440)	+= clk-exynos5440.o

obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-audss.o

obj-$(CONFIG_ARCH_EXYNOS)	+= clk-exynos-clkout.o

obj-$(CONFIG_S3C2410_COMMON_CLK)+= clk-s3c2410.o

obj-$(CONFIG_S3C2410_COMMON_DCLK)+= clk-s3c2410-dclk.o

obj-$(CONFIG_S3C2412_COMMON_CLK)+= clk-s3c2412.o

drivers/clk/samsung/clk-exynos-clkout.c

0 → 100644
+153 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2014 Samsung Electronics Co., Ltd.

 * Author: Tomasz Figa <t.figa@samsung.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * Clock driver for Exynos clock output

 */



#include <linux/clk.h>

#include <linux/clkdev.h>

#include <linux/clk-provider.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/syscore_ops.h>



#define EXYNOS_CLKOUT_NR_CLKS		1

#define EXYNOS_CLKOUT_PARENTS		32



#define EXYNOS_PMU_DEBUG_REG		0xa00

#define EXYNOS_CLKOUT_DISABLE_SHIFT	0

#define EXYNOS_CLKOUT_MUX_SHIFT		8

#define EXYNOS4_CLKOUT_MUX_MASK		0xf

#define EXYNOS5_CLKOUT_MUX_MASK		0x1f



struct exynos_clkout {

	struct clk_gate gate;

	struct clk_mux mux;

	spinlock_t slock;

	struct clk_onecell_data data;

	struct clk *clk_table[EXYNOS_CLKOUT_NR_CLKS];

	void __iomem *reg;

	u32 pmu_debug_save;

};



static struct exynos_clkout *clkout;



static int exynos_clkout_suspend(void)

{

	clkout->pmu_debug_save = readl(clkout->reg + EXYNOS_PMU_DEBUG_REG);



	return 0;

}



static void exynos_clkout_resume(void)

{

	writel(clkout->pmu_debug_save, clkout->reg + EXYNOS_PMU_DEBUG_REG);

}



static struct syscore_ops exynos_clkout_syscore_ops = {

	.suspend = exynos_clkout_suspend,

	.resume = exynos_clkout_resume,

};



static void __init exynos_clkout_init(struct device_node *node, u32 mux_mask)

{

	const char *parent_names[EXYNOS_CLKOUT_PARENTS];

	struct clk *parents[EXYNOS_CLKOUT_PARENTS];

	int parent_count;

	int ret;

	int i;



	clkout = kzalloc(sizeof(*clkout), GFP_KERNEL);

	if (!clkout)

		return;



	spin_lock_init(&clkout->slock);



	parent_count = 0;

	for (i = 0; i < EXYNOS_CLKOUT_PARENTS; ++i) {

		char name[] = "clkoutXX";



		snprintf(name, sizeof(name), "clkout%d", i);

		parents[i] = of_clk_get_by_name(node, name);

		if (IS_ERR(parents[i])) {

			parent_names[i] = "none";

			continue;

		}



		parent_names[i] = __clk_get_name(parents[i]);

		parent_count = i + 1;

	}



	if (!parent_count)

		goto free_clkout;



	clkout->reg = of_iomap(node, 0);

	if (!clkout->reg)

		goto clks_put;



	clkout->gate.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;

	clkout->gate.bit_idx = EXYNOS_CLKOUT_DISABLE_SHIFT;

	clkout->gate.flags = CLK_GATE_SET_TO_DISABLE;

	clkout->gate.lock = &clkout->slock;



	clkout->mux.reg = clkout->reg + EXYNOS_PMU_DEBUG_REG;

	clkout->mux.mask = mux_mask;

	clkout->mux.shift = EXYNOS_CLKOUT_MUX_SHIFT;

	clkout->mux.lock = &clkout->slock;



	clkout->clk_table[0] = clk_register_composite(NULL, "clkout",

				parent_names, parent_count, &clkout->mux.hw,

				&clk_mux_ops, NULL, NULL, &clkout->gate.hw,

				&clk_gate_ops, CLK_SET_RATE_PARENT

				| CLK_SET_RATE_NO_REPARENT);

	if (IS_ERR(clkout->clk_table[0]))

		goto err_unmap;



	clkout->data.clks = clkout->clk_table;

	clkout->data.clk_num = EXYNOS_CLKOUT_NR_CLKS;

	ret = of_clk_add_provider(node, of_clk_src_onecell_get, &clkout->data);

	if (ret)

		goto err_clk_unreg;



	register_syscore_ops(&exynos_clkout_syscore_ops);



	return;



err_clk_unreg:

	clk_unregister(clkout->clk_table[0]);

err_unmap:

	iounmap(clkout->reg);

clks_put:

	for (i = 0; i < EXYNOS_CLKOUT_PARENTS; ++i)

		if (!IS_ERR(parents[i]))

			clk_put(parents[i]);

free_clkout:

	kfree(clkout);



	pr_err("%s: failed to register clkout clock\n", __func__);

}



static void __init exynos4_clkout_init(struct device_node *node)

{

	exynos_clkout_init(node, EXYNOS4_CLKOUT_MUX_MASK);

}

CLK_OF_DECLARE(exynos4210_clkout, "samsung,exynos4210-pmu",

		exynos4_clkout_init);

CLK_OF_DECLARE(exynos4212_clkout, "samsung,exynos4212-pmu",

		exynos4_clkout_init);

CLK_OF_DECLARE(exynos4412_clkout, "samsung,exynos4412-pmu",

		exynos4_clkout_init);



static void __init exynos5_clkout_init(struct device_node *node)

{

	exynos_clkout_init(node, EXYNOS5_CLKOUT_MUX_MASK);

}

CLK_OF_DECLARE(exynos5250_clkout, "samsung,exynos5250-pmu",

		exynos5_clkout_init);

CLK_OF_DECLARE(exynos5420_clkout, "samsung,exynos5420-pmu",

		exynos5_clkout_init);