Commit 1f22f8bb authored by Boris BREZILLON's avatar Boris BREZILLON Committed by Nicolas Ferre
Browse files

clk: at91: add PMC programmable clocks 



This patch adds new at91 programmable clocks implementation using common clk
framework.
A programmable clock is a clock which can be exported on a given pin to clock
external devices.
Each programmable clock is given an id (from 0 to 8).
The number of available programmable clocks depends on the SoC you're using.
Programmable clock driver only implements the clock setting (clock rate and
parent setting). It must be chained to a system clock in order to
enable/disable the generated clock.
The PCKX pins used to output the clock signals must be assigned to the
appropriate peripheral (see atmel's datasheets).

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 6114067e

drivers/clk/at91/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -5,3 +5,5 @@ 
obj-y += pmc.o

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

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



obj-$(CONFIG_AT91_PROGRAMMABLE_CLOCKS)	+= clk-programmable.o

drivers/clk/at91/clk-programmable.c

0 → 100644
+366 −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/of_irq.h>

#include <linux/io.h>

#include <linux/wait.h>

#include <linux/sched.h>

#include <linux/interrupt.h>

#include <linux/irq.h>



#include "pmc.h"



#define PROG_SOURCE_MAX		5

#define PROG_ID_MAX		7



#define PROG_STATUS_MASK(id)	(1 << ((id) + 8))

#define PROG_PRES_MASK		0x7

#define PROG_MAX_RM9200_CSS	3



struct clk_programmable_layout {

	u8 pres_shift;

	u8 css_mask;

	u8 have_slck_mck;

};



struct clk_programmable {

	struct clk_hw hw;

	struct at91_pmc *pmc;

	unsigned int irq;

	wait_queue_head_t wait;

	u8 id;

	u8 css;

	u8 pres;

	u8 slckmck;

	const struct clk_programmable_layout *layout;

};



#define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)





static irqreturn_t clk_programmable_irq_handler(int irq, void *dev_id)

{

	struct clk_programmable *prog = (struct clk_programmable *)dev_id;



	wake_up(&prog->wait);



	return IRQ_HANDLED;

}



static int clk_programmable_prepare(struct clk_hw *hw)

{

	u32 tmp;

	struct clk_programmable *prog = to_clk_programmable(hw);

	struct at91_pmc *pmc = prog->pmc;

	const struct clk_programmable_layout *layout = prog->layout;

	u8 id = prog->id;

	u32 mask = PROG_STATUS_MASK(id);



	tmp = prog->css | (prog->pres << layout->pres_shift);

	if (layout->have_slck_mck && prog->slckmck)

		tmp |= AT91_PMC_CSSMCK_MCK;



	pmc_write(pmc, AT91_PMC_PCKR(id), tmp);



	while (!(pmc_read(pmc, AT91_PMC_SR) & mask))

		wait_event(prog->wait, pmc_read(pmc, AT91_PMC_SR) & mask);



	return 0;

}



static int clk_programmable_is_ready(struct clk_hw *hw)

{

	struct clk_programmable *prog = to_clk_programmable(hw);

	struct at91_pmc *pmc = prog->pmc;



	return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_PCKR(prog->id));

}



static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,

						  unsigned long parent_rate)

{

	u32 tmp;

	struct clk_programmable *prog = to_clk_programmable(hw);

	struct at91_pmc *pmc = prog->pmc;

	const struct clk_programmable_layout *layout = prog->layout;



	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));

	prog->pres = (tmp >> layout->pres_shift) & PROG_PRES_MASK;



	return parent_rate >> prog->pres;

}



static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,

					unsigned long *parent_rate)

{

	unsigned long best_rate = *parent_rate;

	unsigned long best_diff;

	unsigned long new_diff;

	unsigned long cur_rate;

	int shift = shift;



	if (rate > *parent_rate)

		return *parent_rate;

	else

		best_diff = *parent_rate - rate;



	if (!best_diff)

		return best_rate;



	for (shift = 1; shift < PROG_PRES_MASK; shift++) {

		cur_rate = *parent_rate >> shift;



		if (cur_rate > rate)

			new_diff = cur_rate - rate;

		else

			new_diff = rate - cur_rate;



		if (!new_diff)

			return cur_rate;



		if (new_diff < best_diff) {

			best_diff = new_diff;

			best_rate = cur_rate;

		}



		if (rate > cur_rate)

			break;

	}



	return best_rate;

}



static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)

{

	struct clk_programmable *prog = to_clk_programmable(hw);

	const struct clk_programmable_layout *layout = prog->layout;

	if (index > layout->css_mask) {

		if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {

			prog->css = 0;

			prog->slckmck = 1;

			return 0;

		} else {

			return -EINVAL;

		}

	}



	prog->css = index;

	return 0;

}



static u8 clk_programmable_get_parent(struct clk_hw *hw)

{

	u32 tmp;

	u8 ret;

	struct clk_programmable *prog = to_clk_programmable(hw);

	struct at91_pmc *pmc = prog->pmc;

	const struct clk_programmable_layout *layout = prog->layout;



	tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));

	prog->css = tmp & layout->css_mask;

	ret = prog->css;

	if (layout->have_slck_mck) {

		prog->slckmck = !!(tmp & AT91_PMC_CSSMCK_MCK);

		if (prog->slckmck && !ret)

			ret = PROG_MAX_RM9200_CSS + 1;

	}



	return ret;

}



static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,

				     unsigned long parent_rate)

{

	struct clk_programmable *prog = to_clk_programmable(hw);

	unsigned long best_rate = parent_rate;

	unsigned long best_diff;

	unsigned long new_diff;

	unsigned long cur_rate;

	int shift = 0;



	if (rate > parent_rate)

		return parent_rate;

	else

		best_diff = parent_rate - rate;



	if (!best_diff) {

		prog->pres = shift;

		return 0;

	}



	for (shift = 1; shift < PROG_PRES_MASK; shift++) {

		cur_rate = parent_rate >> shift;



		if (cur_rate > rate)

			new_diff = cur_rate - rate;

		else

			new_diff = rate - cur_rate;



		if (!new_diff)

			break;



		if (new_diff < best_diff) {

			best_diff = new_diff;

			best_rate = cur_rate;

		}



		if (rate > cur_rate)

			break;

	}



	prog->pres = shift;

	return 0;

}



static const struct clk_ops programmable_ops = {

	.prepare = clk_programmable_prepare,

	.is_prepared = clk_programmable_is_ready,

	.recalc_rate = clk_programmable_recalc_rate,

	.round_rate = clk_programmable_round_rate,

	.get_parent = clk_programmable_get_parent,

	.set_parent = clk_programmable_set_parent,

	.set_rate = clk_programmable_set_rate,

};



static struct clk * __init

at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,

			       const char *name, const char **parent_names,

			       u8 num_parents, u8 id,

			       const struct clk_programmable_layout *layout)

{

	int ret;

	struct clk_programmable *prog;

	struct clk *clk = NULL;

	struct clk_init_data init;

	char irq_name[11];



	if (id > PROG_ID_MAX)

		return ERR_PTR(-EINVAL);



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

	if (!prog)

		return ERR_PTR(-ENOMEM);



	init.name = name;

	init.ops = &programmable_ops;

	init.parent_names = parent_names;

	init.num_parents = num_parents;

	init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;



	prog->id = id;

	prog->layout = layout;

	prog->hw.init = &init;

	prog->pmc = pmc;

	prog->irq = irq;

	init_waitqueue_head(&prog->wait);

	irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);

	snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);

	ret = request_irq(prog->irq, clk_programmable_irq_handler,

			  IRQF_TRIGGER_HIGH, irq_name, prog);

	if (ret)

		return ERR_PTR(ret);



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

	if (IS_ERR(clk))

		kfree(prog);



	return clk;

}



static const struct clk_programmable_layout at91rm9200_programmable_layout = {

	.pres_shift = 2,

	.css_mask = 0x3,

	.have_slck_mck = 0,

};



static const struct clk_programmable_layout at91sam9g45_programmable_layout = {

	.pres_shift = 2,

	.css_mask = 0x3,

	.have_slck_mck = 1,

};



static const struct clk_programmable_layout at91sam9x5_programmable_layout = {

	.pres_shift = 4,

	.css_mask = 0x7,

	.have_slck_mck = 0,

};



static void __init

of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,

		       const struct clk_programmable_layout *layout)

{

	int num;

	u32 id;

	int i;

	unsigned int irq;

	struct clk *clk;

	int num_parents;

	const char *parent_names[PROG_SOURCE_MAX];

	const char *name;

	struct device_node *progclknp;



	num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");

	if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)

		return;



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

		parent_names[i] = of_clk_get_parent_name(np, i);

		if (!parent_names[i])

			return;

	}



	num = of_get_child_count(np);

	if (!num || num > (PROG_ID_MAX + 1))

		return;



	for_each_child_of_node(np, progclknp) {

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

			continue;



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

			name = progclknp->name;



		irq = irq_of_parse_and_map(progclknp, 0);

		if (!irq)

			continue;



		clk = at91_clk_register_programmable(pmc, irq, name,

						     parent_names, num_parents,

						     id, layout);

		if (IS_ERR(clk))

			continue;



		of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);

	}

}





void __init of_at91rm9200_clk_prog_setup(struct device_node *np,

					 struct at91_pmc *pmc)

{

	of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);

}



void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,

					  struct at91_pmc *pmc)

{

	of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);

}



void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,

					 struct at91_pmc *pmc)

{

	of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);

}

drivers/clk/at91/pmc.c

+15 −0
Original line number Diff line number Diff line
@@ -278,6 +278,21 @@ static const struct of_device_id pmc_clk_ids[] __initdata = { 
		.compatible = "atmel,at91sam9x5-clk-peripheral",

		.data = of_at91sam9x5_clk_periph_setup,

	},

	/* Programmable clocks */

#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)

	{

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

		.data = of_at91rm9200_clk_prog_setup,

	},

	{

		.compatible = "atmel,at91sam9g45-clk-programmable",

		.data = of_at91sam9g45_clk_prog_setup,

	},

	{

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

		.data = of_at91sam9x5_clk_prog_setup,

	},

#endif

	{ /*sentinel*/ }

};

drivers/clk/at91/pmc.h

+9 −0
Original line number Diff line number Diff line
@@ -85,4 +85,13 @@ extern void __init of_at91rm9200_clk_periph_setup(struct device_node *np, 
extern void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,

						  struct at91_pmc *pmc);



#if defined(CONFIG_AT91_PROGRAMMABLE_CLOCKS)

extern void __init of_at91rm9200_clk_prog_setup(struct device_node *np,

						struct at91_pmc *pmc);

extern void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,

						 struct at91_pmc *pmc);

extern void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,

						struct at91_pmc *pmc);

#endif



#endif /* __PMC_H_ */

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