Commit 6114067e authored by Boris BREZILLON's avatar Boris BREZILLON Committed by Nicolas Ferre
Browse files

clk: at91: add PMC peripheral clocks 



This patch adds new at91 peripheral clock implementation using common clk
framework.

Almost all peripherals provided by at91 SoCs need a clock to work properly.
This clock is enabled/disabled using PCER/PCDR resgisters.

Each peripheral is given an id (see atmel's datasheets) which is used to
define and reference peripheral clocks.

Some new SoCs (at91sam9x5 and sama5d3) provide a new register (PCR) where you
can configure the peripheral clock as a division of the master clock.
This will help reducing the peripherals power comsumption.

Signed-off-by: default avatarBoris BREZILLON <b.brezillon@overkiz.com>
Acked-by: default avatarMike Turquette <mturquette@linaro.org>
Signed-off-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
parent 5fba62ea

drivers/clk/at91/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -4,4 +4,4 @@ 


obj-y += pmc.o

obj-y += clk-main.o clk-pll.o clk-plldiv.o clk-master.o

obj-y += clk-system.o
 
obj-y += clk-system.o clk-peripheral.o

drivers/clk/at91/clk-peripheral.c

0 → 100644
+410 −0
Original line number Diff line number Diff line 
/*

 *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>

 *

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

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 */



#include <linux/clk-provider.h>

#include <linux/clkdev.h>

#include <linux/clk/at91_pmc.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/io.h>



#include "pmc.h"



#define PERIPHERAL_MAX		64



#define PERIPHERAL_AT91RM9200	0

#define PERIPHERAL_AT91SAM9X5	1



#define PERIPHERAL_ID_MIN	2

#define PERIPHERAL_ID_MAX	31

#define PERIPHERAL_MASK(id)	(1 << ((id) & PERIPHERAL_ID_MAX))



#define PERIPHERAL_RSHIFT_MASK	0x3

#define PERIPHERAL_RSHIFT(val)	(((val) >> 16) & PERIPHERAL_RSHIFT_MASK)



#define PERIPHERAL_MAX_SHIFT	4



struct clk_peripheral {

	struct clk_hw hw;

	struct at91_pmc *pmc;

	u32 id;

};



#define to_clk_peripheral(hw) container_of(hw, struct clk_peripheral, hw)



struct clk_sam9x5_peripheral {

	struct clk_hw hw;

	struct at91_pmc *pmc;

	struct clk_range range;

	u32 id;

	u32 div;

	bool auto_div;

};



#define to_clk_sam9x5_peripheral(hw) \

	container_of(hw, struct clk_sam9x5_peripheral, hw)



static int clk_peripheral_enable(struct clk_hw *hw)

{

	struct clk_peripheral *periph = to_clk_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;

	int offset = AT91_PMC_PCER;

	u32 id = periph->id;



	if (id < PERIPHERAL_ID_MIN)

		return 0;

	if (id > PERIPHERAL_ID_MAX)

		offset = AT91_PMC_PCER1;

	pmc_write(pmc, offset, PERIPHERAL_MASK(id));

	return 0;

}



static void clk_peripheral_disable(struct clk_hw *hw)

{

	struct clk_peripheral *periph = to_clk_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;

	int offset = AT91_PMC_PCDR;

	u32 id = periph->id;



	if (id < PERIPHERAL_ID_MIN)

		return;

	if (id > PERIPHERAL_ID_MAX)

		offset = AT91_PMC_PCDR1;

	pmc_write(pmc, offset, PERIPHERAL_MASK(id));

}



static int clk_peripheral_is_enabled(struct clk_hw *hw)

{

	struct clk_peripheral *periph = to_clk_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;

	int offset = AT91_PMC_PCSR;

	u32 id = periph->id;



	if (id < PERIPHERAL_ID_MIN)

		return 1;

	if (id > PERIPHERAL_ID_MAX)

		offset = AT91_PMC_PCSR1;

	return !!(pmc_read(pmc, offset) & PERIPHERAL_MASK(id));

}



static const struct clk_ops peripheral_ops = {

	.enable = clk_peripheral_enable,

	.disable = clk_peripheral_disable,

	.is_enabled = clk_peripheral_is_enabled,

};



static struct clk * __init

at91_clk_register_peripheral(struct at91_pmc *pmc, const char *name,

			     const char *parent_name, u32 id)

{

	struct clk_peripheral *periph;

	struct clk *clk = NULL;

	struct clk_init_data init;



	if (!pmc || !name || !parent_name || id > PERIPHERAL_ID_MAX)

		return ERR_PTR(-EINVAL);



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

	if (!periph)

		return ERR_PTR(-ENOMEM);



	init.name = name;

	init.ops = &peripheral_ops;

	init.parent_names = (parent_name ? &parent_name : NULL);

	init.num_parents = (parent_name ? 1 : 0);

	init.flags = 0;



	periph->id = id;

	periph->hw.init = &init;

	periph->pmc = pmc;



	clk = clk_register(NULL, &periph->hw);

	if (IS_ERR(clk))

		kfree(periph);



	return clk;

}



static void clk_sam9x5_peripheral_autodiv(struct clk_sam9x5_peripheral *periph)

{

	struct clk *parent;

	unsigned long parent_rate;

	int shift = 0;



	if (!periph->auto_div)

		return;



	if (periph->range.max) {

		parent = clk_get_parent_by_index(periph->hw.clk, 0);

		parent_rate = __clk_get_rate(parent);

		if (!parent_rate)

			return;



		for (; shift < PERIPHERAL_MAX_SHIFT; shift++) {

			if (parent_rate >> shift <= periph->range.max)

				break;

		}

	}



	periph->auto_div = false;

	periph->div = shift;

}



static int clk_sam9x5_peripheral_enable(struct clk_hw *hw)

{

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;



	if (periph->id < PERIPHERAL_ID_MIN)

		return 0;



	pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID) |

				     AT91_PMC_PCR_CMD |

				     AT91_PMC_PCR_DIV(periph->div) |

				     AT91_PMC_PCR_EN);

	return 0;

}



static void clk_sam9x5_peripheral_disable(struct clk_hw *hw)

{

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;



	if (periph->id < PERIPHERAL_ID_MIN)

		return;



	pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID) |

				     AT91_PMC_PCR_CMD);

}



static int clk_sam9x5_peripheral_is_enabled(struct clk_hw *hw)

{

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;

	int ret;



	if (periph->id < PERIPHERAL_ID_MIN)

		return 1;



	pmc_lock(pmc);

	pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID));

	ret = !!(pmc_read(pmc, AT91_PMC_PCR) & AT91_PMC_PCR_EN);

	pmc_unlock(pmc);



	return ret;

}



static unsigned long

clk_sam9x5_peripheral_recalc_rate(struct clk_hw *hw,

				  unsigned long parent_rate)

{

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);

	struct at91_pmc *pmc = periph->pmc;

	u32 tmp;



	if (periph->id < PERIPHERAL_ID_MIN)

		return parent_rate;



	pmc_lock(pmc);

	pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID));

	tmp = pmc_read(pmc, AT91_PMC_PCR);

	pmc_unlock(pmc);



	if (tmp & AT91_PMC_PCR_EN) {

		periph->div = PERIPHERAL_RSHIFT(tmp);

		periph->auto_div = false;

	} else {

		clk_sam9x5_peripheral_autodiv(periph);

	}



	return parent_rate >> periph->div;

}



static long clk_sam9x5_peripheral_round_rate(struct clk_hw *hw,

					     unsigned long rate,

					     unsigned long *parent_rate)

{

	int shift = 0;

	unsigned long best_rate;

	unsigned long best_diff;

	unsigned long cur_rate = *parent_rate;

	unsigned long cur_diff;

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);



	if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max)

		return *parent_rate;



	if (periph->range.max) {

		for (; shift < PERIPHERAL_MAX_SHIFT; shift++) {

			cur_rate = *parent_rate >> shift;

			if (cur_rate <= periph->range.max)

				break;

		}

	}



	if (rate >= cur_rate)

		return cur_rate;



	best_diff = cur_rate - rate;

	best_rate = cur_rate;

	for (; shift < PERIPHERAL_MAX_SHIFT; shift++) {

		cur_rate = *parent_rate >> shift;

		if (cur_rate < rate)

			cur_diff = rate - cur_rate;

		else

			cur_diff = cur_rate - rate;



		if (cur_diff < best_diff) {

			best_diff = cur_diff;

			best_rate = cur_rate;

		}



		if (!best_diff || cur_rate < rate)

			break;

	}



	return best_rate;

}



static int clk_sam9x5_peripheral_set_rate(struct clk_hw *hw,

					  unsigned long rate,

					  unsigned long parent_rate)

{

	int shift;

	struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);

	if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max) {

		if (parent_rate == rate)

			return 0;

		else

			return -EINVAL;

	}



	if (periph->range.max && rate > periph->range.max)

		return -EINVAL;



	for (shift = 0; shift < PERIPHERAL_MAX_SHIFT; shift++) {

		if (parent_rate >> shift == rate) {

			periph->auto_div = false;

			periph->div = shift;

			return 0;

		}

	}



	return -EINVAL;

}



static const struct clk_ops sam9x5_peripheral_ops = {

	.enable = clk_sam9x5_peripheral_enable,

	.disable = clk_sam9x5_peripheral_disable,

	.is_enabled = clk_sam9x5_peripheral_is_enabled,

	.recalc_rate = clk_sam9x5_peripheral_recalc_rate,

	.round_rate = clk_sam9x5_peripheral_round_rate,

	.set_rate = clk_sam9x5_peripheral_set_rate,

};



static struct clk * __init

at91_clk_register_sam9x5_peripheral(struct at91_pmc *pmc, const char *name,

				    const char *parent_name, u32 id,

				    const struct clk_range *range)

{

	struct clk_sam9x5_peripheral *periph;

	struct clk *clk = NULL;

	struct clk_init_data init;



	if (!pmc || !name || !parent_name)

		return ERR_PTR(-EINVAL);



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

	if (!periph)

		return ERR_PTR(-ENOMEM);



	init.name = name;

	init.ops = &sam9x5_peripheral_ops;

	init.parent_names = (parent_name ? &parent_name : NULL);

	init.num_parents = (parent_name ? 1 : 0);

	init.flags = 0;



	periph->id = id;

	periph->hw.init = &init;

	periph->div = 0;

	periph->pmc = pmc;

	periph->auto_div = true;

	periph->range = *range;



	clk = clk_register(NULL, &periph->hw);

	if (IS_ERR(clk))

		kfree(periph);

	else

		clk_sam9x5_peripheral_autodiv(periph);



	return clk;

}



static void __init

of_at91_clk_periph_setup(struct device_node *np, struct at91_pmc *pmc, u8 type)

{

	int num;

	u32 id;

	struct clk *clk;

	const char *parent_name;

	const char *name;

	struct device_node *periphclknp;



	parent_name = of_clk_get_parent_name(np, 0);

	if (!parent_name)

		return;



	num = of_get_child_count(np);

	if (!num || num > PERIPHERAL_MAX)

		return;



	for_each_child_of_node(np, periphclknp) {

		if (of_property_read_u32(periphclknp, "reg", &id))

			continue;



		if (id >= PERIPHERAL_MAX)

			continue;



		if (of_property_read_string(np, "clock-output-names", &name))

			name = periphclknp->name;



		if (type == PERIPHERAL_AT91RM9200) {

			clk = at91_clk_register_peripheral(pmc, name,

							   parent_name, id);

		} else {

			struct clk_range range = CLK_RANGE(0, 0);



			of_at91_get_clk_range(periphclknp,

					      "atmel,clk-output-range",

					      &range);



			clk = at91_clk_register_sam9x5_peripheral(pmc, name,

								  parent_name,

								  id, &range);

		}



		if (IS_ERR(clk))

			continue;



		of_clk_add_provider(periphclknp, of_clk_src_simple_get, clk);

	}

}



void __init of_at91rm9200_clk_periph_setup(struct device_node *np,

					   struct at91_pmc *pmc)

{

	of_at91_clk_periph_setup(np, pmc, PERIPHERAL_AT91RM9200);

}



void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,

					   struct at91_pmc *pmc)

{

	of_at91_clk_periph_setup(np, pmc, PERIPHERAL_AT91SAM9X5);

}

drivers/clk/at91/pmc.c

+9 −0
Original line number Diff line number Diff line
@@ -269,6 +269,15 @@ static const struct of_device_id pmc_clk_ids[] __initdata = { 
		.compatible = "atmel,at91rm9200-clk-system",

		.data = of_at91rm9200_clk_sys_setup,

	},

	/* Peripheral clocks */

	{

		.compatible = "atmel,at91rm9200-clk-peripheral",

		.data = of_at91rm9200_clk_periph_setup,

	},

	{

		.compatible = "atmel,at91sam9x5-clk-peripheral",

		.data = of_at91sam9x5_clk_periph_setup,

	},

	{ /*sentinel*/ }

};

drivers/clk/at91/pmc.h

+5 −0
Original line number Diff line number Diff line
@@ -80,4 +80,9 @@ extern void __init of_at91sam9x5_clk_master_setup(struct device_node *np, 
extern void __init of_at91rm9200_clk_sys_setup(struct device_node *np,

					       struct at91_pmc *pmc);



extern void __init of_at91rm9200_clk_periph_setup(struct device_node *np,

						  struct at91_pmc *pmc);

extern void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,

						  struct at91_pmc *pmc);



#endif /* __PMC_H_ */

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