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Commit b1a07b47 authored by Tero Kristo's avatar Tero Kristo Committed by Mike Turquette
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CLK: TI: add autoidle support 



TI clk driver now routes some of the basic clocks through own
registration routine to allow autoidle support. This routine just
checks a couple of device node properties and adds autoidle support
if required, and just passes the registration forward to basic clocks.

Signed-off-by: default avatarTero Kristo <t-kristo@ti.com>
Acked-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarMike Turquette <mturquette@linaro.org>
parent f38b0dd6

Documentation/devicetree/bindings/clock/ti/autoidle.txt

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+39 −0
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Binding for Texas Instruments autoidle clock.



Binding status: Unstable - ABI compatibility may be broken in the future



This binding uses the common clock binding[1]. It assumes a register mapped

clock which can be put to idle automatically by hardware based on the usage

and a configuration bit setting. Autoidle clock is never an individual

clock, it is always a derivative of some basic clock like a gate, divider,

or fixed-factor.



[1] Documentation/devicetree/bindings/clock/clock-bindings.txt



Required properties:

- reg : offset for the register controlling the autoidle

- ti,autoidle-shift : bit shift of the autoidle enable bit

- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0



Examples:

	dpll_core_m4_ck: dpll_core_m4_ck {

		#clock-cells = <0>;

		compatible = "ti,divider-clock";

		clocks = <&dpll_core_x2_ck>;

		ti,max-div = <31>;

		ti,autoidle-shift = <8>;

		reg = <0x2d38>;

		ti,index-starts-at-one;

		ti,invert-autoidle-bit;

	};



	dpll_usb_clkdcoldo_ck: dpll_usb_clkdcoldo_ck {

		#clock-cells = <0>;

		compatible = "ti,fixed-factor-clock";

		clocks = <&dpll_usb_ck>;

		ti,clock-div = <1>;

		ti,autoidle-shift = <8>;

		reg = <0x01b4>;

		ti,clock-mult = <1>;

		ti,invert-autoidle-bit;

	};

arch/arm/mach-omap2/clock.c

+6 −0
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@@ -520,6 +520,9 @@ int omap2_clk_enable_autoidle_all(void) 
	list_for_each_entry(c, &clk_hw_omap_clocks, node)

		if (c->ops && c->ops->allow_idle)

			c->ops->allow_idle(c);



	of_ti_clk_allow_autoidle_all();



	return 0;

}
@@ -539,6 +542,9 @@ int omap2_clk_disable_autoidle_all(void) 
	list_for_each_entry(c, &clk_hw_omap_clocks, node)

		if (c->ops && c->ops->deny_idle)

			c->ops->deny_idle(c);



	of_ti_clk_deny_autoidle_all();



	return 0;

}

drivers/clk/ti/Makefile

+1 −1
Original line number Diff line number Diff line 
ifneq ($(CONFIG_OF),)

obj-y					+= clk.o

obj-y					+= clk.o autoidle.o

clk-common				= dpll.o

endif

drivers/clk/ti/autoidle.c

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/*

 * TI clock autoidle support

 *

 * Copyright (C) 2013 Texas Instruments, Inc.

 *

 * Tero Kristo <t-kristo@ti.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.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/clk-provider.h>

#include <linux/slab.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/clk/ti.h>



struct clk_ti_autoidle {

	void __iomem		*reg;

	u8			shift;

	u8			flags;

	const char		*name;

	struct list_head	node;

};



#define AUTOIDLE_LOW		0x1



static LIST_HEAD(autoidle_clks);



static void ti_allow_autoidle(struct clk_ti_autoidle *clk)

{

	u32 val;



	val = ti_clk_ll_ops->clk_readl(clk->reg);



	if (clk->flags & AUTOIDLE_LOW)

		val &= ~(1 << clk->shift);

	else

		val |= (1 << clk->shift);



	ti_clk_ll_ops->clk_writel(val, clk->reg);

}



static void ti_deny_autoidle(struct clk_ti_autoidle *clk)

{

	u32 val;



	val = ti_clk_ll_ops->clk_readl(clk->reg);



	if (clk->flags & AUTOIDLE_LOW)

		val |= (1 << clk->shift);

	else

		val &= ~(1 << clk->shift);



	ti_clk_ll_ops->clk_writel(val, clk->reg);

}



/**

 * of_ti_clk_allow_autoidle_all - enable autoidle for all clocks

 *

 * Enables hardware autoidle for all registered DT clocks, which have

 * the feature.

 */

void of_ti_clk_allow_autoidle_all(void)

{

	struct clk_ti_autoidle *c;



	list_for_each_entry(c, &autoidle_clks, node)

		ti_allow_autoidle(c);

}



/**

 * of_ti_clk_deny_autoidle_all - disable autoidle for all clocks

 *

 * Disables hardware autoidle for all registered DT clocks, which have

 * the feature.

 */

void of_ti_clk_deny_autoidle_all(void)

{

	struct clk_ti_autoidle *c;



	list_for_each_entry(c, &autoidle_clks, node)

		ti_deny_autoidle(c);

}



/**

 * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock

 * @node: pointer to the clock device node

 *

 * Checks if a clock has hardware autoidle support or not (check

 * for presence of 'ti,autoidle-shift' property in the device tree

 * node) and sets up the hardware autoidle feature for the clock

 * if available. If autoidle is available, the clock is also added

 * to the autoidle list for later processing. Returns 0 on success,

 * negative error value on failure.

 */

int __init of_ti_clk_autoidle_setup(struct device_node *node)

{

	u32 shift;

	struct clk_ti_autoidle *clk;



	/* Check if this clock has autoidle support or not */

	if (of_property_read_u32(node, "ti,autoidle-shift", &shift))

		return 0;



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



	if (!clk)

		return -ENOMEM;



	clk->shift = shift;

	clk->name = node->name;

	clk->reg = ti_clk_get_reg_addr(node, 0);



	if (!clk->reg) {

		kfree(clk);

		return -EINVAL;

	}



	if (of_property_read_bool(node, "ti,invert-autoidle-bit"))

		clk->flags |= AUTOIDLE_LOW;



	list_add(&clk->node, &autoidle_clks);



	return 0;

}

include/linux/clk/ti.h

+9 −0
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@@ -242,6 +242,15 @@ void ti_dt_clocks_register(struct ti_dt_clk *oclks); 
void ti_dt_clk_init_provider(struct device_node *np, int index);

int ti_clk_retry_init(struct device_node *node, struct clk_hw *hw,

		      ti_of_clk_init_cb_t func);

int of_ti_clk_autoidle_setup(struct device_node *node);



#ifdef CONFIG_OF

void of_ti_clk_allow_autoidle_all(void);

void of_ti_clk_deny_autoidle_all(void);

#else

static inline void of_ti_clk_allow_autoidle_all(void) { }

static inline void of_ti_clk_deny_autoidle_all(void) { }

#endif



extern const struct clk_hw_omap_ops clkhwops_omap3_dpll;

extern const struct clk_hw_omap_ops clkhwops_omap4_dpllmx;